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Implementation of a control system for a scaled series hybrid electric

1. Implementation of a control system for a scaled serles hybrid electric vehicle Master of Science Thesis MAGNUS RONNBERG Department of Signals and Systems Division of Automatic Control Automation and Mechatronics CHALMERS UNIVERSITY OF TECHNOLOGY Goteborg Sweden 2007 Report No EX090 2007 Implementation of a Control System for a Scaled Series Hybrid Electric Vehicle Magnus R nnberg Master Thesis student Department of Machine and Vehicle Systems Chalmers University of Technology Gothenburg Sweden September 2004 Abstract In the Mechatronics division of the department of Machine and Vehicle Systems at Chalmers University of Technology research related to hybrid electric vehicles HEVs is performed This master thesis is part of a project which is proposed to develop a HEV prototype and it is to be done in the form of a 1 5 scale model car SMC The specific task of this thesis is to design and construct a control system for the SMC including the necessary means to control the energy management of the powertrain Several modules for the SMC were determined and acquired outside the boundaries of this thesis namely digital signal processor DSP electric motor DC converter buffer and primary power unit PPU The different modules had to be integrated and put under software control of the DSP The SMC
2. RI EE EEEE KEKEE KEEKEEKE EERE ER ED EE By loading COMPARE register 1 PWM signal to steer servo and COMPARE register 2 PWM signal to brake servo 2 separate PWM signals generated to control the servos E KEELE CMPR1 50Hz od gt steer 548 steer scaling 1882 set PWM1 if od brake mode 0 set PWM3 if mechanical brake is requested i CMPR2 per 50Hz od brake signal 375 brake scaling 1380 Appendix XIX Power Supply header file Power Supply PS Handles sensors and actuators for Power Supply Functional partitioning is made at differential Calculates buffer current Calculates buffer voltage Calculates motor current Calculates motor voltage Calculates motor rotational speed Generates motor control signals direction and brake or speed Generates DC converter control signals E X X X X X X X X X Authors Magnus Leo x Structures PS Converted sensor signals description values rot_speed Motor rotational speed rps X buff_I buffer current A mot I motor current A buff_V buffer voltage V mot_V motor voltage V
3. A A R 16 External e GUllS deren dd opi a A D RUD DEDE LU 16 9 Za GurrenbSeriSols woe deate dada d cut Rap 17 722 eo sut pud 18 Su d OP amplitiGr eate ads dote ea 18 3 7 4 Voltage regulator for 5 Volt circuitry a 18 3 7 5 and motor voltage sensor circuit sse 18 3 7 6 Buffer voltage Sesso tet eus ete 19 3 7 1 Optic rotational SONS Olei tee wed bo a Re b EM n 21 3 8 Connecting the System 21 3 8 1 Wiring and shielding ete tenute te tec t 22 4 Control System Software U U 24 4 1 DSP f n tionality 5 u tect 24 4 1 1 Quadrature Encoded Pulse Circuit 24 4 1 2 Analogue to Digital Converter ADC r 24 4 1 3 Digital to Analogue Converter 24 4 1 4 Pulse Width Modulated PWM signals 24 25 4 2 The Functional structure of the 25 4 2 1 Driver Interface 26 4 2
4. extern void em_fcn EM DIP PS ps ch RG olore em fcn PROG EA EE EEE f em gt speed dip gt speed em gt brake dip gt brake Appendix XIX Operative Decisions header file RRR Sa Operative Decisions OD Finalization of orders from Vehicle Motion Control VMC and Energy Management EM Handles conflicts between VMC and EM Authors Leo Magnus OE A PEE TD a SS TRES Structures Variables used for orders name description values forward_mode motor forward or reverse lor 0 brake_mode regenerative brake or not lor 0 Saw Sa S siwa chen ee Ka AS qasaqa a Routines Functions od_fcn Finalization of orders to Chassis and Power Supply Declare variable structure typedef struct double steer double speed double brake_mode double forward mode double brake signal functions AKEKE EEL ER EEE EAE EB EE
5. TEE ne a ee a UP uuu Routines Functions T Calculates corresponding physical values from the generic values from DIF however at this point it is only done for longitudinal gt speed II Declare variable structure REE AEE KERKEE KEEKEKE typedef struct dip double speed double steer double brake DIP EEE REE KERKEE functions extern void dip_fcn DIP dip DIF Appendix XIX Driver Interpreter source file SSS ED A EKKE ERIE AE Driver Interpreter DIP m Interpret the signals from Driver Interface to physical motion SERRE EE A eR RnR include main h extern void dip_fcn DIP dip DIF dif EEA RE RTT Variable declaration EKKA const Cspeed_max 6 PC uk dip fcn dip gt speed dif gt longitudinal Cspeed_max dip gt steer dif gt lateral dip gt brake dif gt brake Appendix XIX Vehicle Motion Control header file RIE ER RE ARIE
6. include main h main t LEE Variable declaration DETR FP AE OR A PER RS ACA EKEK RGA KEKEE KEE EE RE A RE COE EERE BUS bus 0 0 0 0 0 ER ERG EE EO hn OR Rone eo eae Core program KEk system init system initiazation called for 5 dif_fcn amp bus dif dif function called dip_fcn amp bus dip amp bus dif dip function called vmc_fcn amp bus vmc amp bus dip amp bus ch function called em_fcn amp bus em amp bus dip amp bus ps amp bus ch em function called od_fcn amp bus od amp bus vmc amp bus em amp bus ps od function called ch_fcn amp bus ch amp bus od ch function called ps_fcn amp bus ps amp bus od ps function called Appendix XIX System Initiation header file EE Initiation init System initiation and configuration Authors Magnus Leo x is Steer servo control signal PWM1 pin 3 1 m Brake servo control signal PWM3 pin 5 P1 channel 4 IOPB7 pin 16 P1 RC receiver channel 2 5 pin 13 P1 RC receiver
7. sR hd SR he ct Cu OL T RE Routines Functions Uses pulses from pin 9 and pin 10 on the motor to calculate the rotational speed Interprets signals from buffer current sensor and motor current sensor and calculates currents and directions Interprets signals from buffer voltage sensor and motor voltage sensor and calculates corresponding voltages Generates control signals for motor with DAC1 IOPA0 and IOPA2 m Generates control signal to DC converter with DAC2 not used in this version 5 DAC1 25 P2 out port for motor control signal motor pin 4 DAC2 26 P2 out port for DC converter control signal QEP3 24 in port for pulse from motor pin 9 QEP4 20 P4 in port for 90 degrees phase shifted pulse from motor pin 10 m ADCINO pin 23 P2 in port for Buffer Current Sensor ADCIN1 pin 24 P2 in port for Motor Current Sensor IOPAO pin 27 P1 control brake drive mode of motor T IOPA2 pin 16 P4 control forward backward direction of motor SRR EEE EA ER EERIE EAE AE ROR EK RE Addresses GR A A AR ESE define TACNT volatile unsigned int 0x7505 GP timer 4 counter reg define PADATDIR volatile unsigned int 0x7098 port A data amp dir reg define MAX CONV volatile unsigned int 0x70A2
8. BuffV 0 0 5 14 SensV 3 28 3 28 3 28 3 27 3 24 3 19 3 13 3 06 2 98 2 9 2 8 2 71 2 61 2 51 2 4 2 3 2 19 2 08 1 96 1 86 1 75 1 64 1 55 L 48 1 44 2 4 1 306 1 94 1 31 1 Plot sampled data plot BuffV SensV hold on break Ss ones size SensV 1 1 SensV SensV 2 SensV 3 A inv Ss Ss Ss BuffV BV SS A plot BV SensV g grid on hold off The Matlab program gives a matrix A which is used to calculate the buffer voltage in the prototype software A a1 a2 a3 a4 Buffer Voltage a1 a2 bsV a3 bsV a4 bsVy The variable bsV is the measured buffer sensor voltage Sensor Voltage 4 8 10 12 14 Buffer Voltage Graph is showing the relationship between buffer voltage and sensor voltage which is read by the DSP as a solid line The dotted line is the calculated buffer voltage derived by the DSP Appendix XI optic rotational sensor circuit The optic sensors is mounted on the back side of the circuit with the emitter ports E and the sensor ports S placed as shown on the figure O1 QEP1 pin 21 P1 DSP 02 712 External circuit board QEP2 pin 22 P1 DSP OA L1 External circuit board 1 1 kohm R2 68 ohm List of components for optic rotational sensor circuit Etch mask for optic rotational circuit Uy Appendix XII PPU and 12 Volt battery connections Motor pin 2
9. kiki ag th Vehicle Motion Control VMC Desired motion from Driver Interpreter is applied 2s on Wheel Unit actuators Authors Magnus Leo W 2 PES Sh NUN Structures Variables generated by K name description values Lime wi A DE TI IE ote ee Rd ee on eee E MUTET ER oe Routines Functions vmc fcn Declare variable structure nf typedef struct double steer VMC EEE functions EE SER f extern void vmc_fcn Appendix XIX Vehicle Motion Control source file FE PEE EEE TES OE PG Vehicle Motion Control VMC m Desired motion from Driver Interpreter is applied on Wheel Unit actuators u ER q RE include main h extern void vmc_fcn VMC vmc DIP dip CH ch E
10. 0 95 DAC2_target 1241 initial_SoC 0 0869 1 28 mot_V 28 0 95 DAC2 DAC2_var load DAC2 with the value that when transferred DAC_XFER 1 gives an output voltage from the DC unit which is approximately the same as the buffer voltage WAIT_image 0x03 OUTMAC _TI_LED WAIT_image indicates that buffer switch now can be turned ON bs_OFF PBDATDIR amp 0x0004 mask everything but bit 3 buffer switch status while bs_OFF bs OFF PBDATDIR 4 0 0004 mask everything but bit 3 buffer switch status WAIT_image 0x01 OUTMAC _TI_LED WAIT_image indicates buffer switch is turned ON ERE AEE REEERE EI EE RA RE In order to charge the buffer to the initial SoC the DAC2 value should increase gradually When DAC2 has reached a value in the vicinity of the DAC2_target value the program will exit the WHILE loop and the remaining LED will be turned off and that indicates that the car is ready to run SE RR if DAC2_var lt DAC2_ target else while DAC2_var lt 0 98 DAC2_target t DAC2_var DAC2_var 2 DAC2 DAC2_var DAC_XFER 1 while in_q in_q in_q 6000 while DAC2_var gt 1 02 DAC2_target t DAC2_var DAC2_var 2 DAC2 DAC2_var DAC XFER 1
11. compare reg 2 define 2 volatile unsigned int 0x7408 GP timer 2 control reg Constant Definitions FEKRR AAA AAA AK AEK KAR AAR f define 50 2 25000 20ms timer1 period with 1 32 timer prescaler and 40MHz CPUCLK variable structure typedef struct ch double fw_rot_speed REECE EREK functions S Sa A EE extern void ch_fcn CH ch OD od Appendix XIX Chassis source file OR ER AE EIR EI es RA ICE Sat inka RN RCN geen eaten ae AR Nag Chassis Ch Generates PWM signals to control brake and steer servos calculates right front wheel rotational speed Applies scale factors to increase or decrease brake and steer servo movements PPR ROR 2 2 RI A A AE ORO RO OR AE OR ER A A ERR EE ERE include main h Joy koko EEE ERE ERLE EE EERE CH PER RR ORI RR EGO OE ROR EAR A EO RE kR AEE A extern void ch_fcn CH ch OD od Variable declaration RIERA RE EEE static double steer_scaling 1 5 static double brake_scaling 1 5 double alfa_pulse 1000 fw_rot_speed T2CNT alfa_pulse 0 015625 0 02 64 flanks per turn T2CNT alfa_pulse re load QEP counter
12. DCout 1 0 1 0 42 0 84 1 68 2 74 3 48 4 64 5 38 6 65 7 38 8 54 9 28 10 03 10 03 PPU 28 Volt cntl sgnl 2 0 95 0 96 1 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 81 1 84 1 9 2 DCout 2 0 12 0 49 0 98 1 96 3 19 4 05 5 4 6 26 7 74 8 6 9 95 10 03 10 33 10 82 12 2 plot sampled data plot cntl sgnl 2 DCout 2 cntl sgnl 1 DCout 1 hold on grid on The relationship between DC converter control signal and DC out port voltage is shown in the Matlab plot below The dashed line is with a PPU voltage motor voltage of 28 Volt and the solid line shows the relationship at 24 Volt l L 0 i i 0 8 1 1 2 1 4 1 6 1 8 2 control signal Volt The algorithm for calculating the DC converter control signal has two variables PPU voltage measured and DC out port voltage desired ControlSignal DCout 0 0869 1 28 volt 28 0 95 Appendix V buffer box connections m Buffer switch 1 External circuit box G4 External circuit board DC converter switch 2 External circuit box lll lel ADCIN6 pin 9 P2 DSP DAC2 pin 26 P2 DSP K8 External circuit board K6 External circuit board List of components for buffer box L 1000 uH 1 kohm Appendix VI external circuit board e N U Appendix VII external circuit board List of components for external circuit board R1 8 R2 4 3 ko
13. They can be seen as the interface between the digital realm of the software and the actions and status of the SMC Vehicle Motion Control Driver Energy Interpreter Management Functional level 1 Operative Decision Functional level 2 Functional level 3 Fig 25 The program structure has three functional levels with level 1 being the highest Functional level 2 interprets sensor signals through the ADC QEP and digital in ports of the DSP It translates the incoming signals to generic values representing the status of the SMC e g buffer current velocity and makes them available for processing in level 1 Functional level 2 is also responsible for the generation of control signals to the actuators according to decisions taken by functional level 1 The highest functional level level 1 collects data from the various subprograms and orders performed by level 2 and 3 have their origin in level 1 The SMC software presented in this thesis is simplified in functional level 1 though it is designed to be equipped and tested with energy management strategies developed at the Chalmers Mechatronics Department 4 2 1 Driver Interface Driver Interface is responsible for reading the PWM signals from the RC receiver and making the extracted information available for other parts of the program Since it is the pulse peak widths that hold the information about lever positions on the RC transmitter itis a matter of
14. a2 bsV a3 bsV 2 a4 bsV Fig 19 The algorithm calculates the buffer voltage with the buffer sensor voltage bsV as an input variable The constants a1 a2 a3 and a4 are derived from Matlab in order to approximate the non linear relationship between buffer voltage and sensor voltage The positive collector pin of the optic connector is connected via a resistor to a voltage regulator which supplies a reference voltage of 3 3 Volts see Fig 20 The buffer voltage sensor is placed in the buffer box see Fig 21 and the DC converter is used as power source for the 3 3 Volt regulator 2 4 kohm Oc Buffer Buffer B6 PPU Oc optic connector Vr 3 3 volt regulator Fig 20 The 3 3 volt regulator Vr gets power from port B6 on the DC converter The buffer voltage is transferred to the ADC sensor signal voltage while the two sides are kept electronically separated Fig 21 The buffer box with the buffer voltage sensor circuit circled in the bottom To the left is the buffer and above the buffer voltage sensor circuit is the DC converter 3 7 7 Optic rotational sensor The prototype is equipped with an optic rotational sensor circuit see Appendix XI mounted al the right front wheel see Fig 22 The mechanical brake disc is used as an encoder disc due to the suitable design with pre drilled cooling holes There are 16 holes at the outer rim of the disc that are used by the rotational sensor to produce a pair of
15. bit 12 0 enables CAP3 bit 11 reserved bit 10 1 selects timer 2 for CAP3 bit 9 ignored bit 8 0 no action on CAP3 bit 7 6 ignored bit 5 4 ignored bit 3 2 00 no detection on CAP3 bit 1 0 reserved define CAPCONB set 0x6400 0110 0100 0000 0000 bit 15 0 clears all registers of CAP4 6 bit 14 13 11 enables QEP Bits 4 7 amp 9 are ignored bit 12 0 enable CAP6 bit 11 reserved bit 10 1 selects timer 3 for CAP6 bit 9 ignored bit 8 0 no action on CAP6 bit 7 6 ignored bit 5 4 ignored bit 3 2 00 no detection on CAP6 bit 1 0 reserved define ADCTRL1_set 0x2FA0 0010 1111 1010 0000 bit 15 0 reserved bit 14 0 don t reset ADC module software bit 13 12 10 complete current conversion before stopping bit 11 8 1111 32xTclk for acquisition portion of conversion bit 7 1 ADC logic clock prescale 2 1 bit 6 0 sequencer stops after reaching EOS bit 5 1 ADC interrupt request priority low bit 4 0 SEQ1 amp SEQ2 not cascade connected bit 3 0 reserved calibration mode disabled i bit 2 bit 1 bit 0 z define ADCTRL2 set 0100 0010 0000 0010 bit 15 bit 14 bit 13 bit 12 bit 11 10 bit 9 bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 2 bit 1 bit 0 0 reserved full ref voltage to ADC input 0 reserved Vreflo is used as precharge value 0 reserved self test mode disabled 0x4202 0 reserved 1 reset sequencer SEQ1 0 no effect SEQ1 0 reserved status SEQ1 00 interrupt disabled SEQ1
16. 28 Excerpt from Operative Decision showing how the forward mode variable is set Traction mode or regenerative brake mode is controlled by the normalized brake variable derived from Driver Interface see chapter 4 2 1 The program checks the brake variable and if it exceeds the threshold value the brake mode bit is set to 1 see Fig 29 This will affect the operational mode of the motor as the motor pin configuration is set in Power Supply see chapter 4 2 7 according to the values of forward mode and brake mode if em brake gt 0 02 check if requested brake signal exceeds threshold value od brake mod gt put motor in regenerative brake mod else od gt brake_mod put motor in traction mode Fig 29 Excerpt from Operative Decision showing how the brake mode variable is set 4 2 6 Chassis Chassis generates control signals to the brake servo and the steer servo This is done by loading the compare registers see chapter 4 1 4 of the PWM channels with the values derived from the equations shown in Fig 30 However the compare register for the PWM signal to the brake servo will not be updated if the brake mode variable see chapter 4 2 5 is set to 1 In that case the operator requests regenerative braking and the mechanical brake is disengaged 1 per 50Hz od gt steer 548 steer scaling 1882 set if od brake mode 0 set PWM3 if mechanical brake is requested CMPR2
17. 4 1 4 Pulse Width Modulated PWM signals A pulse width modulated PWM signal is a sequence of pulses with changing pulse widths The pulses are spread over a number of fixed length periods so that there is one pulse in each period The fixed period is called the PWM carrier period and its inverse is called the PWM carrier frequency The widths of the PWM pulses are determined or modulated from pulse to pulse according to another sequence of desired values the modulating signal To generate a PWM signal an appropriate timer is needed to repeat a counting period that is the same as the PWM period A compare register is used to hold the modulating values and the value of the compare register is constantly compared with the value of the timer counter see Fig 24 When the values match a transition from low 0 Volt to high 3 3 Volt happens on the associated output When the end of a timer period is reached another transition from high to low happens on the associated output In this way an output pulse is generated where the ON duration is proportional to the value in the compare register This process is automatically repeated and generates a PWM signal at the associated output see 13 Signal Signal Signal level level level High High High Counter Counter Counter Low Low Low 5 10 5 10 15 30 Fig 24 The figure shows how PWM signal is created with a PERIOD value of 10 and COMPARE value of 5 The signal level remai
18. Ampere The sensor generates a signal voltage between 0 25 4 75 Volts that is proportional to the current However the analogue to digital converter ADC of the DSP can only interpret signals between 0 3 3 Volts see chapter 4 1 2 and the sensor signals need to be downscaled before the DSP can interpret them The downscaling is achieved by connecting a pair of resistors in series from the signal port of the current sensor to ground potential The proportion of the resistors was chosen so the voltage at the probe point between the resistors came within the limits of the ADC while keeping the full measurable range of the current sensors The drawback of this solution is a lower resolution of the sensor signal but an advantage of connecting resistors between the signal port and ground potential is that it increases the sensor signal current which in turn makes it more resilient to outside interference see 10 Since current ripple is produced by the armature phase current commutation in the BLDC motor see 2 the motor current sensor will give the same ripples in the sensor signal It is a high frequency ripple generated by the motor inductance components in stator windings and back EMF see 2 and the noisy sensor signal leads to poor precision of the signal interpretation in the DSP By connecting a capacitor in parallel with a resistor the sensor signal is low pass filtered see Appendix VI and VII 3 7 2 Optic connectors Two optic con
19. F3 Buffer box PPU switch 1 External circuit box G6 External circuit board G5 External circuit board Appendix XIII external circuit box connections 450 14 LYdOl Jamod 450 Jamod 458 JaMOd J9Al228J 9H Jamod 2 WYO 6 q WYO 14 10 351 ee N ic 5 2 2 2 Buffer switch Motor switch RC receiver switch DC converter switch PPU switch 9 10 0W J J ng Z4 MOAcCL MOACIL 14 Appendix XIV motor connections M1 QEP and motor voltage sensor G1 External circuit board PPU M4 QEP and motor voltage sensor K11 External circuit board K2 External circuit board K4 External circuit board M2 QEP and motor voltage sensor M3 QEP and motor voltage sensor Appendix XV external circuit board ports and connections G1 Motor pin 1 G2 Motor switch 2 External circuit box G3 Buffer switch 2 External circuit box G4 22 Buffer box G5 12 Volt battery G6 12 Volt battery H1 5 Volt switch 2 External circuit box H2 5 Volt switch 1 External circuit box H3 5 Volt switch 3 External circuit box 11 DSP switch 1 External circuit box 12 DSP power DSP J
20. Max conversion channels reg define volatile unsigned int 0x70A3 Ch select seq control reg 1 define ADCTRL2 volatile unsigned int 0 70 1 ADC control reg 2 define RESULTO volatile unsigned int 0x70A8 Conv result buffer reg 0 define RESULT1 volatile unsigned int 0x70A9 Conv result buffer reg 1 define RESULT2 volatile unsigned int 0x70AA Conv result buffer reg 2 define RESULT3 volatile unsigned int 0x70AB Conv result buffer reg 3 RTE ERE I O space mapped registers PER REE ARIE oot kok ARR define DAC1 port0000 DAC1 register ioport unsigned int port0000 i define DAC2 port0001 DAC2 register ioport unsigned int port0001 define XFER port0004 DAC Transfer register ioport unsigned int port0004 variable structure EERE EERE EEA EE EEE EE EEE ERE EE EE EE typedef struct ps double rot_speed PS functions TOE RRR ORIG RRM A A PRR RR RAE RRR RR extern void ps_fcn Appendix XIX Power Supply source file KEE KEEKEEKE Power Supply PS Handles sensors and actuators for Power Supply Functional partitioning is made at differential Uses QEP pulses out from motor pins 9 and 10 to calculate motor rotational speed Interprets signals from buffer current sensor an
21. PPU has a voltage of 28 volts and the solid line when it is 24 volts The same control signal will result in different out port voltages depending on the PPU voltage Control Signal DCout 0 0869 1 28 PPU_volt 28 0 95 Fig 12 To get the desired out port voltage from the DC converter the control signal is calculated with an algorithm which uses the measured PPU voltage and the desired out port voltage as input variables Depending on the relationship between buffer voltage and DC converter out port voltage the energy will be shifted either in or out of the buffer see Fig 13 The in port of the DC converter is connected to the PPU and motor which allows the buffer to be charged by energy from the PPU but also from the motor when it is in regenerative brake mode A B volt Power l volt Power iow flow Buffer I Out port Buffer Out port Buffer Outport Fig 13 In case A when the buffer voltage is higher than the out port voltage of the DC converter the buffer will discharge In case B when the out port voltage is higher than the buffer voltage the buffer will be charged In case C when voltages are even there will be no power flow between the buffer and the DC converter 3 5 Mechanical Brake Servo The prototype is equipped with a small analogue Hitec HS 322HD servo see Appendix as an actuator for mechanical braking The servo is connected to both frontal disc brakes and
22. RC a green LED on RC receiver indicates power is ON IMPORTANT Buffer switch is to remain OFF Otherwise there is a risk of burning circuits on SMC as the buffer discharges without the DC converter to control it 5 Start Code Composer open project file compile build and download code to DSP 6 Run code 7 Four red LEDs on the DSP will display the status of the System Initiation routine 4 LEDs ON DC converter start up routine has commenced 2 LEDs ON Buffer switch on external circuit box can now be turned ON The program has now measured the buffer voltage and adjusted the control signal to the DC converter accordingly see chapter 4 3 1 1 LED ON The buffer switch has been turned ON and the buffer is charging or discharging in order to reach the predefined voltage All LEDs are OFF The buffer has reached the desired voltage and System Initiation is finished 8 The SMC can now be controlled by the RC transmitter 9 When the J tag is connected to the DSP the program execution can be stopped at any time through Code Composer 10 Before another test run turn OFF buffer switch on external circuit box 11 Compile build and download code to the DSP 12 Resume procedure at step 6 When last test run has been made 13 Stop program execution and exit Code Composer 14 Turn OFF RC transmitter and all switches on external circuit box no particular order 15 Before leaving the SMC for the night disconnect the positiv
23. a predefined voltage 5 Control System Summary The work consisted of developing a control system that could monitor and control the energy management power flow of the SMC as well as basic motion control of the vehicle The use of sensors actuators and interfacing external circuits offers the DSP the necessary means to control following aspects of the prototype Steering The DSP interprets corresponding RC receiver signal channel 4 and generates control signal to the steer servo The responsible sub programs are Driver Interface and Chassis Mechanical brake The DSP interprets corresponding RC receiver signal channel 2 and generates control signal to the brake servo The responsible sub programs are Driver Interface Operative Decisions and Chassis Regenerative brake The DSP interprets corresponding RC receiver signal channel 2 and generates control signals to the motor which puts it in regenerative brake mode The responsible sub programs are Driver Interface Operative Decisions and Power Supply Buffer power flow The DSP generates analogue control signal to the DC converter which affects the power flow to from the buffer In present version the only responsible sub program is System Initiation Motor direction The DSP interprets corresponding RC receiver signal channel 3 and monitors the rotational speed of the motor If there is no conflict the DSP generates control signal to the motor which alters the rotational di
24. affects the power flow between the two modules as the voltages strive to reach the same potential The DC converter is originally designed to be used as a driver circuit for a DC motor and the full bridge configuration of the unit results in different ground potentials for the buffer and the PPU and motor see Fig 10 see 8 An analogue control signal to the DC converter controls the switching characteristics of the circuit which affects the voltage over the out port of the unit The DC converter is designed to be used with an inductive load see 7 and since the buffer is a capacitive load an inductor was placed between the positive out port of the DC converter and the positive pole of the buffer see Appendix V Fig 10 The DC converter has a full bridge configuration resulting in separate ground potentials for buffer and PPU motor The switching characteristic of S1 S2 S3 and S4 is controlled by an analogue control signal to the DC converter The out port voltage of the DC converter depends on two variables PPU voltage and the analogue control signal see Fig 11 To produce the desired out port voltage a proper control signal is calculated with an algorithm see Fig 12 The Matlab file used to derive the algorithm can be found in Appendix IV 0 8 1 12 14 15 18 2 control signal Volt Fig 11 The out port voltage depends on two variables PPU voltage and control signal voltage The dotted line shows the relationship when
25. brake_signal 4000 do digital to analogue conversion DAC_XFER 1 transfer write to DAC1 PADATDIR PADATDIR amp OxFFFE write low on IOPAO brake mode else set motor speed control signal with DAC 1 if od gt forward_mode motor drives car forward DAC1 od gt speed 4000 Cspeed_max do digital to analogue conversion DAC_XFER 1 transfer write to DAC1 PADATDIR PADATDIR amp OxFFFB 0x0001 write high on IOPAO speed mode and low on IOPA2 forward else motor drives car backward od gt speed 8000 Cspeed max do digital to analogue conversion DAC_XFER 1 transfer write to DAC1 PADATDIR PADATDIR 0x0005 write high on IOPAO speed mode and high IOPA2 backward Appendix XX operational procedure e Check the condition of PPU range 20 28 Volt and 12 Volt battery range 11 14 Volt Connect the positive wires to PPU and 12 Volt battery if conditions are OK e Check frequencies of RC system crystals Make sure they are the same 1 Connect PC to DSP on SMC parallel cable and J tag emulator 2 Turn ON the RC transmitter 3 Make sure all switches on external circuit box are OFF 4 Turn ON following switches in order PPU Motor a green LED on motor indicates power is ON DC converter a red LED on DC converter indicates power is ON 5 Volt DSP a green LED on DSP indicates power is ON
26. channel 3 IOPB1 pin 7 P1 RC receiver channel 1 IOPB4 12 4 Optic rotational sensor 1 QEP1 pin 21 P1 Optic rotational sensor 2 QEP2 pin 22 P1 Motor pulse 1 QEP3 pin 24 P1 Motor pulse 2 QEP4 pin 20 P4 Motor brake mode signal IOPA0 pin 27 P1 z Motor direction signal IOPA2 pinz 16 P4 Buffer current sensor signal _ ADCINO pin 23 P2 Motor current sensor signal pin 24 P2 Buffer voltage sensor signal ADCIN6 pin 9 P2 Motor voltage sensor signal ADCIN5 pin 8 P2 Motor control signal DAC1 pin 25 P2 DC DC software switch IOPB6 pinz 15 P1 DC DC control signal DAC2 pin 26 P2 Buffer switch status IOPB2 pin 7 P1 x Initiation Routine and Function Configuration System Control enable peripheral modules Clock frequency 40 MHz Wait state setup for external memory interface Disable watchdog Setup shared I O pins GP timer configuration 1 2 3 4 PWM configuration PWM1 amp PWM3 Capture Unit and QEP configuration QEP1 QEP2 QEP3 QEP4 ADC configuration enable software trigger X X X X X X EER RG IE EAA RO A RE ERE f EER IE I DA A EOE Hardware defined addresses for 53201 2407 AR EO A EE f JAA EM System Control and Status re
27. circuit QMoVoSe and Motor Voltage Sensor circuit X 7 External circuit box BufVoSe Buffer Voltage Sensor circuit DSP DSP X DSP BufVoSe port amp pin control ground control ground P1 pin 12 ground P1 pin 13 P1 pin 7 ground P1 pin 16 P1 pin 21 ground P1 pin 22 ground P1 pin 24 ground P4 pin 20 ground P2 pin 8 K1 P1 pin 28 K5 K3 P2 pin 23 P2 pin 24 K9 P2 pin 9 E3 Appendix XIX Main header file EE EEE EEE SSS EA RAGE Be RRR RAE Neg natn tate Main file 2 Core program for 1 5 SMC Authors Leo Magnus Jonas Wu CT REN 44 o Sus PRD uuu APS SR u A CIS PEE TN Structures X BUS Nested structures DIF DIP VMC OD Ch hn nek ne eR eRe Link all header files to main h include init h include dif h include dip h include vmc h include od h include ch h include em h include ps h typedef struct bus DIF dif DIP dip VMC vmc OD od CH ch EM em PS ps BUS Appendix XIX Main source file KERE EEE ED AEG EAE k a Main file m Core program for 1 5 SMC
28. described in the master thesis of Dennys Gomes see 3 while the focus of this report is placed on the SMC control system Most of the electronics of the prototype are part of the control system but there are a couple of passive components namely PPU and buffer that don t participate in the dynamic control of the prototype However both PPU and buffer are interfaced to the control system by the use of sensors Emulator Emulator connection to DSP Parallel cable to PC Fig 1 The communication between PC and DSP is done via a parallel cable and an emulator connected to the DSP The prototype PPU consists of two 12 Volt lead acid batteries connected in series see Fig 2 resulting in a 24 Volt power source The PPU is directly connected to the electric motor and also connected to the buffer via a DC converter The buffer consists of eight super capacitors 2 5 V 50 F in a 2 in parallel and 4 in series configuration This particular powertrain configuration with PPU and buffer via DC converter directly connected to the motor makes the prototype a series HEV The programming is done with a PC and the operator downloads the code to the DSP via a parallel cable and an emulator see Fig 1 When the program runs the operator controls the actions of the SMC with a 4 channel RC transmitter see Appendix XX for operational procedure The FM signal from the transmitter is received and translated into four PWM signals by RC recei
29. during all parts of the project The reason for this is that the experience derived from designing the SMC and the knowledge gained by testing it ought to be transferable to a full scale model The process of designing a SMC has been divided amongst the members in the project group and this thesis is focused on the development and construction of the control system The control system is incorporating ideas regarding control architecture developed within the Mechatronics group It is designed and equipped with sensors and actuators to monitor and control the powerflow within the powertrain motor PPU and buffer as well as the physical behavior of the SMC A digital signal processor DSP controls the SMC according to a downloaded program and the requested actions from the real time operator The control system offers the necessary means to test different energy management strategies that has been developed within the Mechatronics group One guiding principle during the design and construction of the control system has been advanced simplicity By avoiding complex solutions to individual problems the integration of the various solutions and components is facilitated since there is less risk of conflicts The advanced functionality of the prototype is gained by combining the simple solutions 1 1 Thesis Objectives The objective of this thesis is to design develop and implement a computerized control system for a scaled HEV prototype The contr
30. f extern void od_fcn Appendix XIX Operative Decisions source file KEEKEEKE IG RI REE AE Decisions OD Finalization of orders from Vehicle Motion Control VMC and Energy Management EM Handles conflicts between VMC and EM X PRR RS 2 RI I kt IR ORR EOE f include main h OD RA KAA HEA extern void od_fcn OD od VMC vmc EM em PS ps od gt steer vmc gt steer od gt speed em gt speed od gt brake_signal em gt brake AIEEE A A EK EEEE KEEKEKE KE EEEE ER OG OER EE Regenerative brake request from driver enables regenerative braking mode RA EE REE REE if em gt brake gt 0 02 od gt brake_mode 1 regenerative brake request else od gt brake_mode 0 REEL EERE EEE A EERE OR BREE RO RE KEKEE GOR If car is standing still AND reverse motion is requested motor rotation direction is altered and kept until car is standing still again AND forward motion is requested once more ORG if ps rot speed 0 amp amp od gt speed gt 0 motor is put in forward di
31. is equipped with a brush less DC motor which can regenerate kinetic energy The regenerated energy is stored both in the PPU batteries and in the buffer which consists of super capacitors Through the use of a DC converter connected to the buffer the energy level of the buffer can be regulated Two analogue servos control the front mechanical disc brakes and the steering The actuators of the SMC are controlled by a TMS320LF2407A DSP from Texas Instruments which is integrated in the control system The control system of the SMC incorporates ideas regarding generic control architecture developed within the Mechatronics division at Chalmers An operator controls the prototype with a 4 channel RC transmitter and the requested actions are interpreted and processed by the DSP according to a downloaded program The DSP receives and interprets sensor signals regarding power flow within the powertrain as well as motor rotational speed rotational speed on the right front wheel and lever positions on the RC transmitter The modular computerized SMC control system offers a highly functional and yet low budget HEV for educational purposes and future developments Abbreviations ADC Analogue to Digital Converter BLDC Brush Less Direct Current CPU Central Processor Unit DAC Digital to Analogue Converter DC Direct Current DSP Digital Signal Processor EMI Electro Magnetic Interference EMS Energy Management Strategy FM Frequ
32. low ch2 PBDATDIR amp 0x0020 neg_flank2 T3CNT stores time stamp for negative flank ELE AGE PE EERE ER EEE EEE EE EE reading information on channel 3 ch3 PBDATDIR amp 0 0040 while ch3 0 waits for ch 3 signal from receiver to go high ch3 PBDATDIR amp 0x0040 pos_flank3 T3CNT stores time stamp for positive flank while ch3 0x0040 waits for ch 3 signal from receiver to go low ch3 PBDATDIR amp 0x0040 neg_flank3 T3CNT stores time stamp for negative flank G AE ER u A RG EP REE reading information on channel 4 REE ch4 PBDATDIR 4 0x0080 while ch4 0 waits for ch 4 signal from receiver to go high ch4 PBDATDIR amp 0x0080 pos_flank4 T3CNT stores time stamp for positive flank while ch4 0x0080 waits for ch 4 signal from receiver to go low ch4 PBDATDIR amp 0x0080 neg_flank4 T3CNT stores time stamp for negative flank PEPPER MORE AE RR IE I A A ROR A AEC HK OER RAE EE ER EEE AEE EKEK EE AEE EE EEE KEKEE Use time stamps to calculate peak widths of RC channels 2 3 4 Translate peak widths t
33. measuring the elapsed time between the positive flank and the negative flank of the PWM signals This is done by connecting a digital in port on the DSP to each of the four channels of the receiver In order to start the detection of the information bearing channels 2 3 and 4 see chapter 3 2 in an appropriate sequence the first channel is used as a trigger signal The program will not measure the elapsed time between the positive and negative flanks of channel 1 Instead the program waits for the signal to go high and when it occurs a counter is set to 0 and starts counting while the program waits for the next incoming pulse see Fig 26 trigg PBDATDIR amp 0x0010 mask everything but bit 4 ch 1 signal info while trigg 0 waits for ch 1 signal from receiver to go high trigg PBDATDIR amp 0 0010 T3CNT E reset GP timer 3 Fig 26 Excerpt from Driver Interface showing the while loop for detection of the positive flank of channel 1 PWM pulse and the reset of the GP timer after that occurs Then the program is ready to enter another while loop as it waits for the positive flank of the channel 2 PWM pulse When the PWM signal from information bearing channel 2 brake goes high the program detects it and stores the value of the counter as the time stamp for the positive flank see Fig 27 When the same signal then goes low again the counter value is stored as the time stamp for the negative flank The differe
34. per 50Hz od brake signal 375 brake scaling 1380 Fig 30 Excerpt from Chassis showing how the PWM compare registers are loaded The two scaling constants both are set to 1 35 are used to increase the movement of the servos Chassis also calculates the rotational speed of the right front wheel uses two QEP channels to receive and interpret the QEP signals from the optic rotational sensors mounted on the brake disc of the wheel see chapter 3 7 7 4 2 7 Power Supply Power Supply or PS is handling sensor readings regarding motor and buffer and the generation of control signals to motor and DC converter The first part of the program uses the ADC unit of the DSP to translate sensor signals and making them available for processing in the code Power Supply monitors motor current and voltage as well as buffer current and voltage The rotational speed of the motor is calculated by using two QEP channels connected to the QEP and motor voltage sensor circuit see chapter 3 7 5 and it is updated with a frequency of 5 Hz The reason for using 5 Hz as the update frequency is the low resolution of the QEP signals from the motor which only gives 2 pulses per revolution of the motor axis When all sensor readings have been performed the program generates control signals to the motor depending on the decisions that were taken in Operative Decisions see chapter 4 2 5 The operational mode of the motor is controlled by a pair
35. phase shifted QEP signals These signals are received and interpreted by two QEP channels on the DSP to calculate the speed and direction forward backward of the vehicle Fig 22 The optic rotational sensor circuit mounted at the brake disc of the right front wheel of the prototype 3 8 Connecting the System The DSP board is connected to the system through a 37 wire flat cable going from the expansion connectors on the DSP board to 37 pin data port on the inside of the DSP box The wires are connected to the expansion connectors according to Appendix XVII Another 37 wire flat cable is connected to the data port on the outside of the DSP box carrying signals between the DSP and peripheral modules see Appendix XVIII Table 1 shows the different modules of the control system with references to corresponding wiring diagram in the Appendix Module Appendix DSP I XVII XVIII PPU and 12 Volt battery XII External circuit box XIII XV Buffer box V Motor XIV QEP and motor voltage sensor circuit VIII RC receiver brake servo steer servo XVI Optic rotational sensor circuit XI Buffer voltage sensor circuit IX Table 1 Control system modules and the corresponding wiring diagrams in the Appendix When the control system is connected every module except the buffer shares the same ground potential see chapter 3 4 This common ground is used as a reference value for the DSP when it interprets sen
36. sensor signal 1 is the leading sequence The QEP signals from motor pins 9 and 10 have a peak voltage of approximately 12 Volts Since the QEP circuit on the DSP tolerates a 5 Volt input maximum see 12 the signals need to be downscaled This is done by connecting a pair of resistors in series between the QEP ports on the motor and ground potential see Appendix VIII As the motor is directly connected to the PPU motor voltage and PPU voltage are the same In order to measure the motor voltage a pair of resistors is connected in series between motor pins 1 and 3 The resistors are dimensioned to produce a sensor signal within the range of the ADC which is proportional to the measured voltage The sizes of the resistors are also chosen to minimize the current while keeping the current large enough for steady readings see 10 The motor has the same ground potential as the DSP see chapter 3 8 and therefore an ADC channel on the DSP can be directly connected to measure the voltage at the probe point between the two resistors 3 7 6 Buffer voltage sensor The buffer does not share the same ground potential as the DSP see chapter 3 4 and 3 8 and therefore the buffer voltage sensor calls for a solution where the two different ground potentials are kept separated The voltage sensor has to measure the buffer and send a corresponding sensor signal to the DSP with the DSP ground potential as a reference value in order for the DSP
37. system Conclusions and discussions regarding the control system are presented in chapter 6 In chapter 7 some suggestions are presented about future work on the SMC Circuit diagrams prototype software and additional information can be found in the Appendix 1 5 Acknowledgments The knowledge and experience of Hans Sandholt Assistant Professor at the Mechatronics Division regarding DSP applications has been a valuable resource in the design and development of the SMC control system When difficult challenges arose in the field of electronics the wisdom of Jan M ller Research Engineer at the Department of Machine and Vehicle Systems seemed endless His advice has been inspiring as well as the seed for many good solutions The senior members of the project group Jonas Hellgren and Leo Laine have contributed with support during all phases of this thesis and their ideas have had much influence on the design and construction of the prototype Master thesis student Aizezi Abuding joined the project group in the latter part of the work of this master thesis His arrival was much appreciated as he had the patience and ability to probe the control system which proved to be valuable during the writing of this thesis report 2 The Complete Vehicle Control System 2 1 Overview The prototype is built on a modified chassis of a 1 5 scaled remote controlled vehicle or RC vehicle The mechanical design and physical features of the prototype is
38. the action of it is controlled by a 50 Hz PWM signal with an amplitude between 3 5 Volts see 6 3 6 Steer Servo The steering is performed by an analogue Hitec HS 805BB mega quarter scale servo see Appendix 11 which offers enough torque to turn the front wheels of the prototype even at low or no speed This servo is also controlled by a 50 Hz PWM signal with an amplitude between 3 5 Volts see 9 3 7 External Circuits The integration of the control system modules and to put them under the software control of the DSP requires additional circuits It was also necessary to add various sensors in order to make the status of the system available for the DSP to read and interpret All external circuits except the QEP and motor voltage sensor see chapter 3 7 5 and the buffer voltage sensor see chapter 3 7 6 are placed in the external circuit box see Fig 14 Voltage regulator OP amplifier chapter 3 7 4 chapter 3 7 3 Current sensors Optic connectors chapter 3 7 1 chapter 3 7 2 Fig 14 The external circuit box holds most of the external circuits of the prototype More information about the specific components is available in corresponding chapters 3 7 1 Current sensors The prototype is equipped with two current sensors One is measuring the current going in out from the buffer and the other is measuring the current going in out from the motor Both sensors are configured for a measurable range from 6 Ampere to 6
39. to be able to interpret it correctly see chapter 4 1 This was achieved by using an optic connector where the diode side is connected to the buffer and the collector side is connected to the DSP see Appendix IX The communication between the two sides is done through light emitted by the diode and received by the photo sensitive collector side Depending on the diode current which is proportional to the buffer voltage the intensity of the emitted light will vary accordingly The light intensity will result in certain conductivity on the photo sensitive collector side and when the current is affected by the conductivity so is the voltage over the collector pins This voltage is then measured by an ADC channel on the DSP but since the measured sensor voltage doesn t have a linear relationship with the buffer voltage see Fig 18 an algorithm was developed in Matlab for calculating the buffer voltage see Fig 19 The Matlab file used for the buffer voltage sensor algorithm can be found in Appendix X sassa ka a ee gt E S a S gt s S osa sn E S e sal Sensor voltage 4 4 lt 2 4 6 8 10 12 14 Buffer Voltage Fig 18 The solid line shows the actual relationship between buffer voltage and sensor voltage The dotted line shows the DSP calculated buffer voltage derived from the algorithm with the measured sensor voltage as an input variable Buffer Voltage a1
40. while in q in_q in_q 6000 DAC2 DAC2 target DAC_XFER 1 WAIT_image 0x00 OUTMAC _TI_LED WAIT_image ADCTRL2 ADCTRL2 0x4000 charge buffer quick loop while buffer is charging reload que variable discharge buffer quick loop while buffer is discharging reload que variable charge buffer to initial SoC transfer write to DAC2 turn off all 4 LEDs reset sequencer SEQ1 Appendix XIX Driver Interface header file RESET EEE eee Bokeh nas Renan Driver Interface Extracts information from RC receiver 4 PWM signals 50 Hz regarding requested actions by driver Authors Magnus Leo W an s a EE G ET den tua PN NS PC Structures DIF Converted sensor signals name description values longitudinal desired long motion 0 3 1 lateral desired lat motion 1 1 brake reg brake or mech brake 1 1 MANLIO QM CURE E TNR M NO IE EE T URS Mela eC Ra aaa Routines Functions DIF uses 4 digital in ports connected to the PWM signals from RC receiver to read T and inte
41. 000 0111 0000 bit 15 14 bit 13 bit 12 11 bit 10 8 bit 7 bit 6 bit 5 4 bit 3 2 bit 1 bit 0 T3CON_set 10 no stop on emulator suspend 0 reserved 11 directional up down count mode 000 prescaler doesn t work in QEP counting 0 reserved in 1 1 TENABLE 1 enable timer 11 QEP circuit is clock source 00 00 reload compare reg on underflow 0 0 disable timer compare 0 use own period register 0x9540 1001 0101 0100 0000 bit 15 14 bit 13 bit 12 11 bit 10 8 bit 7 bit 6 bit 5 4 bit 3 2 bit 1 bit 0 define T4CON_set 10 no stop on emulator suspend 0 reserved 10 continuous up count mode 101 x 32 prescaler 0 reserved 1 TENABLE 1 enable timer 00 00 CPUCLK is clock source 00 00 reload compare reg on underflow 0 0 disable timer compare 0 reserved 0x9870 1001 1000 0111 0000 bit 15 14 10 no stop on emulator suspend bit 13 0 reserved bit 12 11 11 directional up down count mode bit 10 8 000 prescaler doesn t work in QEP counting bit 7 0 reserved in 1 bit 6 1 TENABLE 1 enable timer bit 5 4 11 QEP circuit is clock source bit 3 2 00 00 reload compare reg on underflow bit 1 0 0 disable timer compare bit 0 0 use own period register define CAPCONA set 0x6400 0110 0100 0000 0000 bit 15 0 clears all registers of CAP1 3 bit 14 13 11 enables QEP Bits 4 7 amp 9 are ignored
42. 1 RC receiver 1 External circuit box J2 RC receiver power RC receiver IOPAO pin 27 P1 DSP K2 Motor pin 6 IOPA2 pin 16 P4 DSP K4 Motor pin 7 K5 IOPB6 pin 15 P1 DSP K6 A15 Buffer box K7 K8 A6 Buffer box K9 pin 25 P2 DSP K10 K11 Motor pin 4 K12 K13 ADCIN1 pin 24 P2 DSP K14 ADCINO pin 23 P2 DSP L1 O4 Optic rotational sensor circuit L2 O2 Optic rotational sensor circuit L3 L4 L5 L6 L7 L8 L9 Buffer switch 5 External circuit box L10 Buffer switch 6 External circuit box PWM1 pin 3 P1 DSP IOPB7 pin 16 P1 DSP PWM3 pin 5 P1 DSP IOPB5 pin 13 P1 DSP DSP ground IOPB1 pin 7 P1 DSP DSP ground IOPB4 pin 12 P1 DSP Steer servo control ground 5V control Appendix XVI RC receiver and servo connections Brake servo ground EY 9 cc RC receiver power J2 External circuit board RC receiver power RC receiver switch 2 External circuit box signal Steer servo control signal Brake servo control signal RC receiver channel 1 RC receiver channel 2 RC receiver channel 3 RC receiver channel 4 Optic rotational sensor 1 Optic rotational sensor 2 Motor pulse 1 Motor pulse 2 Motor voltage sensor signal Motor brake mode signal Buffer switch signal DC converter soft switch Motor direction
43. 1 clear interrupt flag SEQ1 SEQ cannot be started by EVA trigger external trigger disabled no action SEQ2 no effect SEQ2 reserved status SEQ2 00 interrupt disabled SEQ2 1 clear interrupt flag SEQ2 0 SEQ cannot be started by EVB trigger Appendix XIX System Initiation source file RD ERE Initiation Routine Function Configuration System Control enable peripheral modules Clock frequency 40 MHz Wait state setup for external memory interface Disable watchdog Setup shared I O pins GP timer configuration 1 2 3 4 PWM configuration PWM1 amp PWM3 QEP configuration QEP1 QEP2 QEP3 QEP4 ADC configuration enable software trigger X X X X X A ROE RE RE RE include main h extern void system init Variable declaration Q AE ERIE EE int in q 10000 que constant gives 8 ms wait time unsigned int WAIT image int bs OFF DAC2 var 0 DAC2 target 0 double dig val bs Volt buff Volt mot Volt Configurations POR EE RA OK EIR RE I A AER IO ROR RE REE RE Jr SCSR1 SCSR1 set SCSR2 SCSR2 0x000B amp 0x000F bit 15 6 0 5 reserved bit 5 0 d
44. 2 Driver Interpreter uio a uei cU ERR 27 4 2 3 Vehicle Motion Controll sssrini eiiean eun eaaa eare 27 4 2 4 Energy Managementi U dese pate spia 27 4 2 5 Operative Decision eer or o E tibiae Maal 28 d 2 5 uot ots tr EROR SD uyu DK c deat aq RR 28 4 2 7 Power ERR 29 4 3 Program execution dad eS le ee cd i na 30 T SystermimtialioE ss u Ua eae hee 30 5 Control System Summary J 32 6 Discussion and 5 33 7 Suggestions for Future Work 34 8 Refer rc68S Susu SE qa 35 1 Introduction In a world of limited resources and many petroleum users and emission sources the policy question is whether the best use of resources is to build hybrid electric vehicles HEVs to improve the fuel economy and environmental emissions of other mobile sources or to devote the resources to other environmental projects see 1 In the Mechatronics group of the Department of machine and vehicle systems at Chalmers University of Technology research related to HEVs is performed Currently computer base
45. 40 DC controller User Manual ZAPI 8 J N Ross The Essence of Power Electronics Prentice Hall Cornwall Great Britain 1997 ISBN 0 13 525643 7 9 HS 805BB User Manual Hitec 10 Compendium for 1 day course in Environmental Technique and Handling of Interference Chalmers University of Technology Karlskrona Sweden May 1990 11 SPRS145i User Manual for TMS320LF2407A Evaluation Module Texas Instruments 12 EVM2407d User Manual for TMS320LF2407A Evaluation Module Texas Instruments 13 SPRU357b User Manual for TMS320LF2407A Evaluation Module Texas Instruments 14 L Laine and J Andreasson Generic Control Architecture Applied to a Hybrid Electric Sports Utility Vehicle 20 International Electric Vehicle Symposium Long Beach USA November 2003 Appendix DSP evaluation module Expansion Expansion connector connector P1 P3 Reset button gt 633 m m LEDs J tag emulator DSP power in connector DSP ground 70 Eaz Pwo Ay Pty C TA Fel 7 000 2 P4 Expansion Expansion connector connector Module DSP Evaluation module Motor Steer servo Brake servo RC receiver RC transmitter DC converter Appendix Model TMS320LF2407A TMS320LF2407A EVM BLDC3 57ZWX03 HS 805BB HS 322HD HFS 04MG Laser 4 FM 4Q DC controller Manufacturer Texas Instruments Spectrum Dig
46. AX_CONV 0x0001 total of 2 conversions ADCTRL2 ADCTRL2 0x2000 software trigger for ADC set bit 13 while in_q quick loop while ADC conversion is finishing in_q in_q 10000 reload que variable dig_val RESULT1 ADC value from channel 5 motor voltage mot_Volt dig_val 2142 calculate motor voltage ROLES RE REG haben tok No an EREKE Here the program calculates the buffer voltage from the buffer voltage sensor reading PER RE A A A A dig_val RESULTO ADC value from channel 6 buffer sensor voltage bs_Volt dig_val 19776 calculate buffer sensor voltage buff_Volt 49 33 47 81 bs_Volt 19 42 bs_Volt bs_Volt 2 85 bs_Volt bs_Volt bs_Volt J RAEI A ARIE ROOK PG I TA OER KEEKEKE DAC2_var is the digital value corresponding to an output control signal voltage from the DSP to the DC unit which will give a DC unit output voltage adjusted to the present voltage of the buffer DAC2_target is the digital value corresponding to an output control signal voltage from the DSP to the DC unit which will charge the buffer to the desired initial State of Charge FERRIS RE EIS EEE EEEE AE ROGGE RE RIE RG RE A AERC ee DAC2_var 1241 buff_Volt 0 0869 1 28 mot_V 28
47. EE EI RIS Re vmc fcn vmc gt steer dip gt steer Appendix XIX Energy Management header file Energy Management The desired vehicle motion is performed energy efficient way Authors Magnus Jonas Leo Wiese aasma Soak a ot as ee te TIBIA te oe see re ee ot ee he her UE ES Structures EM Generated variables from EM description values a TECH SONO E NONE REL NN Suyu qap c FO SERERE NDA S Routines Functions EEE KKE RE EKEK EERE EEEE E Declare variable structure typedef struct double speed double brake functions REE okk KEEKEKE extern void em_fcn Appendix XIX Energy Management source file EKE KER KEE a Energy Management m The desired vehicle motion is performed in a energy efficient way ERLE EAL EER RN nee ae HORSE IOEIOECIOGOIOR include main h
48. EP4 T4PR OxFFFF maximum period register DBTCONA 0 0000 set dead band of PWM signals to 0 ACTRA ACTRA set PWM1 amp PWM3 pins set active high COMCONA set configure COMCON register T1CON set configure T1CON register T2CON T2CON_set configure T2CON register T4CON T4CON set configure register CAPCONA CAPCONA set configure QEP1 QEP2 in EVA CAPCONB CAPCONB set configure QEP3 and QEP4 in EVB Setup up ADC unit and prepare for software triggers ADCTRL1 ADCTRLI set configure ADC control register 1 ADCTRL2 ADCTRL2 set configure ADC control register 2 KEEKEKE Start DC DC controller PERE EE EEE WAIT_image 0x0F OUTMAC _TI_LED WAIT_image turn on all 4 LEDs PBDATDIR PBDATDIR amp OxFFBF write low on IOPB6 to turn off DC DC unit DAC2 0 write low on DAC2 to enable startup DAC XFER 1 transfer write to DAC2 while in q quick loop to make sure DAC2 gets low in_q in_q 10000 reload que variable PBDATDIR PBDATDIR 0x0040 write high on IOPB6 to turn on DC DC unit while in_q quick loop to make sure electronic switch on DC converter turns ON in_q in_q 10000 reload que variable CHSELSEQ1 0x0058 conversions on channel 5 and 8 M
49. OPA6 1 PWM1 bit 5 0 0 IOPA5 1 bit 4 1 0 IOPA4 1 2 2 bit 3 1 0 IOPA3 1 CAP1 QEP1 bit 2 0 0 2 1 XINT1 bit 1 0 0 1 1 SCIRXD bit 0 0 0 1 SCITXD MCRB_set 11111110 0000 0000 bit 15 1 0 reserved 1 TMS2 always write as 1 bit 14 1 Ozreserved 1 TMS always write as 1 bit 13 1 Ozreserved 1 TDO always write as 1 bit 12 1 Ozreserved 1 TDI always write as 1 bit 11 1 Ozreserved 1 TCK always write as 1 bit 10 1 Ozreserved 1 EMU1 always write as 1 bit 9 1 Ozreserved 1 always write as 1 define define define define bit 8 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 set bit 15 bit 14 bit 13 bit 12 11 bit 10 9 bit 8 7 bit 6 bit 5 4 bit 3 2 bit 1 0 GPTCONB_ set bit 15 bit 14 bit 13 bit 12 11 bit 10 9 bit 8 7 bit 6 bit 5 4 bit 3 2 bit 1 0 ACTRA_set bit 15 bit 14 12 bit 11 10 bit 9 8 bit 7 6 bit 5 4 bit 3 2 bit 1 0 COMCONA_ set O IOPDO 1 XINT2 ADCSOC O IOPC7 1 CANRX O IOPC6 1 CANTX O IOPC5 1 SPISTE O IOPC4 1 SPICLK O IOPC3 1 SPISOMI O IOPC2 1 SPISIMO O IOPC1 1 BIO 0 1 W R 0 0000 0 reserved 0 T2STAT read only 0 15 read only 00 reserved 00 T2TOADC 00 no timer2 event starts ADC 00 00 ti
50. and also rotational direction forward reverse Both pins can be put in two different states Open or connected to ground which will determine the operational mode see Fig 8 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 6 7 i 7 7 8 8 8 8 9 9 9 9 10 10 10 10 Fig 8 The operating mode of the motor is controlled by pin 6 and pin 7 In configuration A pin 6 is connected to ground and pin 7 is open resulting in motor propelling vehicle forward In configuration B both pins are connected to ground resulting in motor propelling car backwards In configuration C both pins are open resulting in regenerative braking when car is moving forward In configuration D pin 6 is open and pin 7 is connected to ground resulting in regenerative braking when car is moving backward The motor also requires an analogue control signal between 0 5 Volts to motor pin 4 as a reference value for either speed or regenerative brake current 3 4 DC converter The DC converter manufactured by ZAPI see Appendix 11 is arranged in the powertrain of the SMC according to Fig 9 It is a bi directional unit responsible for shifting energy between the buffer on one side out port and the PPU and the motor on the other side in port Fig 9 The powertrain configuration of the SMC The PPU voltage Uppu determines the voltage over the motor and the DC converter in port The relationship between buffer voltage Ub and DC converter out port voltage Udc
51. as been performed The sub programs only have access to the variable structures determined in the main file 4 3 1 System Initiation The first step in execution of the program is the System Initiation where DSP functions are configured and prepared for use It includes settings for clock frequency timers ADC units event managers and other peripherals of the DSP evaluation module The last part of the initiation routine handles the start up of the DC converter and the initial charging of the buffer The DC converter needs to receive certain control signals in a specific order in order to function As out going signals from the DSP retain the values they had at the end of the prior execution of the program unless a soft or hardware reset is performed the software switch of the DC converter is first used to turn off the unit and then the control signals are set to their proper initial values see Fig 33 PBDATDIR PBDATDIR amp OxFFBF write low on IOPB6 to turn off DC DC unit DAC2 0 write low on DAC2 to enable startup DAC_XFER 1 transfer write to DAC2 while in_q quick loop to make sure DAC2 gets low in q in q 10000 reload queue variable PBDATDIR PBDATDIR 0x0040 write high on IOPB6 to turn on DC unit Fig 33 Excerpt from the system initiation program showing how the software switch of the DC converter is first used to turn off the DC unit as the DAC2 control signal is adjusted After t
52. d modeling and simulation of such vehicles has been used for evaluation However it is desirable to get more practical insight and experience by building a real prototype of a hybrid electric vehicle The step from computer based modeling and simulation to a full scale prototype is a gigantic leap which is bound to include many unforeseen problems Since money is an issue in science research as well in the rest of society the costs of a full scale HEV prototype appears as daunting Therefore as a part of the HEV research at Chalmers this project is proposed to develop a prototype in a 1 5 scale of a full scale series HEV The prior theories that the SMC incorporates mainly comes from three fields of the HEV research at Chalmers powertrain design energy management and control system architecture These theories have influenced the design of the SMC on various levels and of various degrees Powertrain design e The sizing of hardware components such as motor DC converter buffer and PPU batteries Energy management e Sensors and actuators to offer the necessary means for the DSP to control the power flow Control system architecture e Software structure and communication within the control system The scaled model car SMC should be constructed to represent a real vehicle in as many aspects as possible Basically it should feature the same functionality controllability and behavior as a full scale model and this has been considered
53. d motor current sensor and calculates current and direction Interprets signals from buffer voltage sensor and motor voltage sensor and calculates corresponding voltages Generates control signals for motor with DAC1 IOPA0 and IOPA2 Generates control signal to DC converter with DAC2 not used in this version X X X X REE ER ROR include main h REE EEE EEE Speed check variable declaration REET unsigned int speed_check 0 extern void ps_fcn PS ps OD od k kk Variable declaration A ROK double buff I mot I bs V buff V mot V double dig value unsigned int ps q 500 float time const Cspeed max 6 CHSELSEQ1 0x5810 conversions on channel 0 1 8 and 5 MAX CONV 0x0003 total of 4 conversions ADCTRL2 ADCTRL2 0x2000 software trigger for ADC set bit 13 while ps_q quick loop while ADC conversion is finishing Pps_q ps_q 500 dig_value RESULT3 ADC value from channel 5 motor voltage mot_V dig_value 2216 calculate motor voltage dig_value RESULT2 ADC value from channel 6 buffer voltage sensor bs_V dig_value 19776 calculate buffer sensor voltage buff V 49 3318 47 8193 bs V 19 4343 bs V bs V 2 8473 bs V bs V bs V di
54. e wires to PPU and 12 Volt battery since sneak currents can discharge the batteries Charging e PPU is charged with a maximum current of 0 92 Ampere at 29 8 Volts When charge current drops below 0 1 Ampere the battery is ready for use 12 Volt battery is charged with a maximum current of 0 92 Ampere at 14 9 Volts When charge current drops below 0 1 Ampere the battery is ready for use e RC transmitter is charged using an adapter Do not charge for more than 24 hours
55. ency Modulated GP General Purpose HEV Hybrid Electric Vehicle IO In Out LED Light Emitting Diode OP Operation PC Personal Computer PPU Primary Power Unit Pulse Width Modulated Quadrature Encoded Pulse RC Radio Control SMC Scale Model Car 1 Introduction 5 1 1 6 Der 6 1 39 Ms OP VEC HO UNIS u uu aha aha aie ai ich ane 6 1 4 Thesis Outline ice cans aere iae eee 7 1 5 Acknowledgments rioei te u A M U QS S lee C 7 2 The Complete Vehicle Control System 8 pM 8 3 Control System Hardware J J J 11 3 1 Digital Signal Processor 12 3 2 Radio Control RC s caeteri deett et 13 Eleetrier a 13 Ju DG COMVGN Cl used 14 3 5 Mechanical Brake 16
56. erator can control the actions of the car The RC system transmitter and receiver handles the communication from driver to car and signals from the RC receiver are interpreted by the DSP A brushless DC motor see chapter 3 3 is used to propel the car and it is also responsible for regenerating kinetic energy to electric energy The DSP generates control signals for the motor and it receives sensor signals regarding voltage current rotational speed and rotational direction The DC converter see chapter 3 4 is the actuator for power management on the prototype where it shifts power between on one side the buffer and on the other side PPU and motor The actions of the DC converter are controlled by the DSP which also monitors relevant sensor signals such as buffer current and buffer voltage The two servos mechanical brake see chapter 3 5 and steer see chapter 3 6 receive control signals from the DSP The brake servo is connected to both front wheel disc brakes and offers a non regenerative braking mode while the steer servo controls the steering angle of the front wheels The external circuits see chapter 3 7 are components that have been integrated in the system in order to handle various tasks e g signal amplification sensor readings and voltage regulation 3 1 Digital Signal Processor DSP The CPU core of the prototype consists of a TMS320LF2407A processor from Texas Instruments and it is mounted on an evaluation
57. etermine if the performance of the control system is adequate in this aspect Are there any drawbacks or limits of the control system The maximum program frequency is 50 Hz see chapter 4 3 which could prove to be insufficient for the software to properly detect fast transitions and spikes on sensor signals The possibilities What can the SMC be used for The cost of the SMC and the accessibility of the control system should make it appealing for educational purposes The fundamental design of the control system is simple enough to be understood by master students with basic knowledge of electronics and programming Yet it offers plenty of possibilities for further development and advanced functionality The present version of the SMC is the first step towards a low budget test platform useable for research in the field of HEV However for research purposes the performance of the SMC would have to be enhanced in some aspects 7 Suggestions for Future Work This chapter presents suggestions for future developments of the SMC The suggestions are not ranked in order of importance but modifications that improve the stability and reliability of the system could be considered of higher priority since every pyramid relies on a solid base e When the buffer is being charged or discharged in the System Initiation routine see chapter 4 3 1 there is no feedback to the DSP regarding the buffer current In order to make the procedure safe
58. g value RESULT1 ADC value from channel 1 motor current I dig value 19556 1 87 4 2307 calculate motor current dig_value RESULTO ADC value from channel 0 buffer current buff_I dig_value 19718 1 86 4 2716 calculate buffer current ADCTRL2 ADCTRL2 0x4000 reset sequencer SEQ1 EEE IE EET CRE RRO A RRR OR A RE AR olor do eie Kore RPO k ERO Motor rotational speed EEE REAL ERR if speed_check 10 update with a frequency of 5 Hz time speed_check 0 02 elapsed time in seconds ps gt rot_speed T4CNT 1000 0 125 time 8 flanks per turn T4CNT 1000 set QEP counter speed_check 0 reset speed_check variable speed_check increase speed_check variable Jr AIRE RE BR RIE AEE ROR A ROR KE KKE A E KE OR OK ACT HA OK j EER REEL EE EAT DC converter control set DAC2 to control DC converter The analogue signal voltage should be between 0 95 and 2 00 V which gives DC converter output voltage between 0 1 and 10 V Motor control ARIS I ROK ARE ZI A IE IR if od gt brake_mode set motor brake control signal with DAC 1 DAC1 od gt
59. ge of control Therefore the DAC signal is connected to an OP amplifier which gives a 1 7 amplification of the signal voltage see Appendix VI and VII 3 7 4 Voltage regulator for 5 Volt circuitry The 5 Volt switch regulator supplies all parts of the control system except motor DC converter and OP amplifier with power The regulator is mounted on the external circuit board and it uses a 12 Volt lead acid battery as power source and regulates it down to 5 Volts see Appendix VI and VII 3 7 5 QEP and motor voltage sensor circuit Quadrature encoded pulses QEP are two sequences of pulses with a variable frequency and a fixed phase shift When generated by an optical encoder on a motor shaft the direction of rotation of the motor can be determined by detecting which of the two sequences is the leading sequence see Fig 16 and 17 The angular position and speed can be determined by the pulse count and pulse frequency see 13 85 Signal level sensor signal 2 High NS Fig 16 Transition of the signal level occurs when the optic sensor detects the transitions of dark transparent fields of the rotating optical encoder disc The distance between the optic sensors determines the phase shift between the pulse sequences With a counter clockwise rotation sensor signal 2 is the leading sequence ee Signal level sensor signal 2 High s Fig 17 With clockwise rotation of the optic encoder disc
60. gisters PERRE EEKE define SCSR1 volatile unsigned int 0x7018 System control amp status reg 1 define SCSR2 volatile unsigned int 0x7019 System control amp status reg 2 define WDCR volatile unsigned int 0x7029 WD timer control reg EEE EEE Digital I O registers EEE unsigned int 0x7090 control reg define volatile unsigned int 0x7092 mux control reg B define MCRC volatile unsigned int 0x7094 mux control reg C define PADATDIR volatile unsigned int 0x7098 port A data amp dir reg define PBDATDIR volatile unsigned int 0x709A I O port B data amp dir reg Event Manager A EVA registers define GPTCONA volatile unsigned int 0x7400 GP timer control reg A define volatile unsigned int 0x7401 GP timer 1 counter reg define volatile unsigned int 0x7403 GP timer 1 period reg define 1 volatile unsigned int 0x7404 GP timer 1 control reg define 2 volatile unsigned int 0x7405 GP timer 2 counter reg define T2PR volatile unsigned int 0x7407 GP timer 2 period reg define T2CON volatile unsigned int 0x7408 GP timer 2 control reg define CAPCONA volatile unsigned int 0x7420 Capture control reg A define COMCONA vola
61. gn and development of the control system The initial tests of the DSP and the possibilities it offered consumed a lot of time in the beginning However this had to be done thoroughly since implementing a control system without proper knowledge of the DSP functionality would have been like laying a puzzle blindfolded Were there any major modifications of the control system during the process There were several minor changes which resulted in major improvements of the control system Particularly the DSP readings of the motor current sensor signal was an enduring problem as the readings fluctuated wildly due to the phase current commutation of the motor see chapter 3 7 1 When the reason was identified the solution only called for a capacitor as a low pass filter for the sensor signal The result How well does the control system of the SMC work considering the stated objectives The basic motion control of the SMC velocity and steering is fully controllable With the RC transmitter the operator can directly control the mechanical brake regenerative brake steering vehicle speed and direction forward reverse Considering the energy management of the prototype the DSP has access to the necessary sensor information and it can also control the actuators of the powertrain motor and DC converter In this regard the stated objectives have been fulfilled However since no energy management strategy has been tested yet it is too soon to d
62. he loop the DC unit is turned on again The analogue control signal to the DC converter DAC2 is set to 0 and then the program spins in a short loop in order to give the outgoing signal enough time to get low the DAC circuits are equipped with capacitors which limits the speed of transition between high and low signal voltages This is done since the DC converter will not function unless the DAC2 signal voltage is below a threshold value of 0 95 V When the program exits the short loop the DC unit is ready to be turned on which is done by toggling the software switch When DC converter has been turned on the program will read the motor voltage PPU voltage when motor switch is turned on and buffer voltage in order to calculate a proper value for the DAC2 It is important that the DAC2 or control signal to the DC converter is adjusted to a level where the DC unit out port voltage is close to the buffer voltage before the buffer switch is turned on If the voltage difference is too great it may result in a charge or discharge current that exceeds the tolerated limits of wires and circuits of the buffer When DAC2 has been adjusted to an appropriate level two LEDs will be turned off to indicate that the manual buffer switch can be turned on When the manual buffer switch is turned on the DSP receives a signal from the switch see Appendix XV and the buffer charging commences The DAC2 will now increase gradually until the buffer is charged to
63. hm R3 1 R4 15 kohm R5 20 kohm C1 47 uF C2 1000 100 100 uH Sd 1N5822 Cs LTS6 NP current sensor Oc PC817 optic connector Sr LM2576 5 0 switch regulator Op CA3140 E operation amplifier Etch mask for external circuit board Appendix VIII QEP and motor voltage sensor circuit Motor pin 3 M4 N5 QEP4 pin 20 P4 DSP Motor pin 10 M3 N4 DSP ground Motor pinf9 M2 N3 pin 24 P1 DSP N2 DSP d Motor pin 1 M1 ger ON1 ADCIN5 pin 8 P2 DSP List of components for QEP and motor voltage sensor circuit R1216kohm R2 8 2 kohm 16 kohm R4 2 kohm Etch mask for QEP and motor voltage sensor circuit am ap gt Appendix IX buffer voltage sensor circuit R1 Oc Buffer lt Buffer C3 Vr R2 B6 DC converter C2 PPU CI List of components for buffer voltage sensor R1 2 4 kohm R2 200 ohm C1 0 1 uF C2 2 2 uF Oc PC817 optic connector Vr LE33ABZ voltage regulator ADCIN6 pin 9 P2 DSP TUN Etch mask for buffer voltage sensor 15 01 1 DC converter D2 A6 DC converter rri rm DAC2 pin 26 P2 DSP K8 External circuit board D3 A15 DC converter K6 External circuit board Appendix X buffer voltage sensor algorithm
64. ital Ostergrens Motor Hitec Hitec Hitec Hitec ZAPI Appendix III connector pin functions for BLDC electric motor Pin Type Description 1 Power high 24 Volt DC power input Pin 2 Power ground 0 Volt power ground Pin 3 Signal ground Signal ground for all control signals Internally connected to power ground Pin 4 Control signal Analogue control signal 0 5 Volt for speed and current control during regenerative braking Pin 5 Potentiometer 5 7 Volt via 1 kohm if used with 5k potentiometer supply 0 5 Volt from pot to control pin 4 Pin 6 Regenerative brake When open the motor is braking Braking current controlled via pin 4 0 5 Volt where 5 Volt gives shorted motor without current limit To enable speed control of motor pull to pin 3 signal ground Pin 7 Direction When pulled to pin 3 signal ground this input changes motor rotation direction Operate with no rotation in motor since if used when motor is rotating at high speed it will result in high current in motor winding Pin 8 Enable When connected to 5 24 Volt DC this input enables all control functions Pin 9 QEP output pulse 2 pulses per motor revolution Pin 10 QEP output pulse 2 pulses per motor revolution 60 degrees phase shifted from pin 9 pulse Appendix IV DC converter control signal algorithm PPU 24 Volt cntl sgnl 1 0 95 0 96 T 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 1 97 2
65. les brake mode and forward mode The rotational direction of the motor is controlled by the variable forward_mode as long as the motor is in traction mode Power Supply also generates the control signal DAC2 to the DC converter in order to shift energy in or out from the buffer see chapter 3 4 However this is not implemented in the present version of the SMC software 4 3 Program execution The core program consists of a main file which calls the different sub programs in a never ending loop and the main file also determines which variable structures each sub program has access to see Fig 32 The duration of a single loop is 20 milliseconds and this time is determined in Driver Interface see chapter 4 2 1 as the program holds until it detects the 50 Hz PWM pulse train from the RC receiver main system_init system initiation called for dif fcn amp bus dif dif function called dip fcn amp bus dip amp bus dif dip function called vmc fcn amp bus vmc amp bus dip amp bus ch vmc function called em fcn amp bus em amp bus dip amp bus ps amp bus ch em function called od fcn amp bus od amp bus vmc amp bus em amp bus ps od function called ch fecn amp bus ch amp bus od ch function called ps fcn amp bus ps amp bus od ps function called Fig 32 The main file of the SMC software consists of a never ending loop after system initiation h
66. lse Circuit QEP The DSP has two QEP circuits with two channels each and each circuit is connected to a separate general purpose GP timer which counts every incoming flank positive and negative on the corresponding channels Depending on which sequence is leading the counter either counts up or down see 13 One QEP circuit is used to determine the rotational speed of the motor see chapter 3 7 5 and the other for the rotational speed of the right front wheel see chapter 3 7 7 4 1 2 Analogue to Digital Converter ADC The DSP has 16 ADC channels which convert analogue signal voltages to digital values They are used for interpreting sensor signals such as current and voltage sensors The limits of the possible conversions are set to a minimum of 0 Volts and a maximum of 3 3 Volts The ADC works with a resolution of 10 bits which corresponds to an analogue resolution of approximately 3 2 mV 4 1 3 Digital to Analogue Converter DAC The DAC circuit mounted on the DSP board is a four channel 12 bit double buffered DAC This means that data is written to holding registers before it is transferred to the actual converters In this manner all four channels can be loaded separately and then converted at the same time The minimum output voltage is O Volts and the maximum voltage is 3 3 volts Two DAC channels are used in the software One sends an analogue control signal to the motor and the other sends it to the DC converter
67. m is done by electrical signals analogue and digital Steer Brake servo servo Motor DC converter External and buffer circuits Fig 5 The control system modules and the communication within the control system The arrows show the paths of the control signals out from DSP and sensor signals in to DSP The DSP is the central unit of the control system hardware but it also operates according to the downloaded prototype software The defining borderline between these separate sub systems can be seen in Fig 6 where Functional level 3 is part of the hardware and Functional level 2 is where the software begins Fig 6 will be further explained in chapter 4 2 Driver Enerqy Interpreter Manaqement Vehicle Motion Control Functional level 1 Operative Decision Functional level 2 Functional level 3 Fig 6 The borderline between control system hardware and software is between functional level 2 and 3 The DSP see chapter 3 1 receives reference signals from RC receiver and sensor signals from the external circuits The sensors give information to the DSP regarding e Buffer voltage and current e Motor voltage current and rotational speed e Front wheel rotational speed The DSP then processes the sensor information and generates control signals to the actuators on the car motor DC converter and servos The prototype is equipped with a RC system see chapter 3 2 through which the op
68. mer1 event starts ADC 0 TCOMPOE 0 Hi z all timer compare outputs 00 reserved 00 T2PIN 00 forced low 00 T1PIN 00 forced low 0x0000 0 reserved 0 T4STAT read only 0 T3STAT read only 00 reserved 00 T4TOADC 00 no timer2 event starts ADC 00 T3TOADC 00 no timer1 event starts ADC 0 TCOMPOE 0 Hi z all timer compare outputs 00 reserved 00 T4PIN 00 forced low 00 T3PIN 00 forced low 0x0022 0 space vector dir is CCW don t care 000 basic space vector is 000 dont care 00 PWM6 IOPB3 pin forced low 00 PWM5 IOPB2 pin forced low 00 PWM4 IOPB1 pin forced low 10 PWM3 IOPBO pin active high 00 PWM2 IOPA7 pin forced low 10 PWM1 IOPA6 pin active high 0x8200 bit 15 bit 14 13 bit 12 bit 11 10 bit 9 bit 8 0 define T1CON_set 1 1 enable compare operation 00 00 reload CMPRx regs on timer 1 underflow 0 0 space vector disabled 00 00 reload ACTR on timer 1 underflow 1 1 enable PWM pins 0 5 reserved 0x9540 1001 0101 0100 0000 bit 15 14 bit 13 bit 12 11 bit 10 8 bit 7 bit 6 bit 5 4 bit 3 2 bit 1 bit 0 z define T2CON set 10 no stop on emulator suspend 0 reserved 10 continuous up count mode 101 x 32 prescaler 0 reserved in 1 TENABLE 1 enable timer 00 00 CPUCLK is clock source 00 00 reload compare reg on underflow 0 0 disable timer compare 0 reserved in 0x9870 1001 1
69. module from Spectrum Digital see Appendix l The DSP receives and sends signals through four expansion connectors The DSP is interfaced with a PC via the parallel port and a J tag emulator The emulator is a hardware development system that emulates device operation and it gives access to internal and external memory when CPU is running see 4 This is an efficient way to monitor variables and registers on the PC in real time operation of the DSP program Software for the DSP is written in C which is supported by the development environment Code Composer from Texas Instruments see 5 Code Composer features compiler assembler and linker for C language 3 2 Radio Control RC system The RC system consists of a Hitec Laser 4 FM transmitter and a HFS 04MG receiver also from Hitec see Appendix 11 The RC system has four available channels where each channel can be individually adjusted by the levers of the RC transmitter The RC receiver translates the FM signal from the transmitter into four separate 50 Hz PWM signals The pulse peak width of each PWM signal holds information about the position of corresponding lever on the transmitter The receiver creates pulses for the four channels and sends them out in subsequent order channel 1 2 3 4 where each pulse is between 0 9 and 2 1 milliseconds long see 6 depending on the lever positions and have a peak voltage of 3 6 Volts The RC transmitter is a handheld device with two lever
70. n order to avoid loss of control of the vehicle This is to be implemented in later versions of the SMC 4 2 4 Energy Management Energy Management is intended to control and regulate the power flow within the powertrain PPU motor and buffer of the prototype However this is not implemented in the present version of the SMC software 4 2 5 Operative Decision Operative Decision is responsible for deciding how the motor pins should be configured depending on the normalized values from DIF There are two decisions being taken in Operative Decision and they affect the motor rotational direction and whether the motor should be put in traction mode or regenerative brake mode see chapter 3 3 The decision regarding rotational direction considers two variables the normalized value for channel 3 ongitudinal and the motor rotational speed The rotational speed is of importance since changing the rotational direction of the motor while it is still turning could damage the stator windings see Appendix 111 Therefore the motor rotational speed is checked to be zero before a decision to change the direction can be made The decision regarding motor rotational direction is communicated through the forward_mode variable see Fig 28 if ps rot speed 0 amp amp od gt speed gt 0 check motor speed and requested speed od gt forward_mode put motor in forward mode else od gt forward_mode E put motor in reverse mode Fig
71. nce between the two time stamps is then used to calculate the corresponding lever position on the transmitter and it is translated into a normalized value 1 1 This procedure is then repeated for channel normalized value 0 2 1 and channel 4 normalized value 1 1 ch2 PBDATDIR amp 0x0020 mask everything but bit 5 ch 2 signal info while ch2 0 waits for ch 2 signal from receiver to go high ch2 PBDATDIR amp 0x0020 pos flank2 T3CNT stores time stamp for positive flank while ch2 0x0020 waits for ch 2 signal from receiver to go low ch2 PBDATDIR amp 0x0020 neg flank2 T3CNT stores time stamp for negative flank Fig 27 Excerpt from Driver Interface showing the detection of the positive and negative flanks of channel 2 PWM pulse and the storing of the time stamps according to the GP timer 4 2 2 Driver Interpreter Driver Interpreter interprets the normalized values from Driver Interface regarding requested actions by the operator In the present version of the software only the normalized value for channel 3 longitudinal is interpreted to a corresponding requested speed in meters per second 4 2 3 Vehicle Motion Control Vehicle Motion Control is intended to control and regulate the physical behavior of the vehicle after interpreting the status of the system VMC can then suggest appropriate measures to be taken e g in case of spinning wheels when accelerating i
72. nectors are used to switch between the different operational modes of the motor see Appendix VI and VII By connecting a digital out port of the DSP to the diode side of the optic connector through a 1 kohm resistor and then have ground potential and motor pin connected to the collector ports the DSP signal can either connect or disconnect the collector ports see Fig 15 The chosen IO ports can source a current of 8 mA see 11 which is sufficient for good switching capabilities The same solution is used to perform the software switch of the DC converter see chapter 4 3 1 which also offers the means to shut down the DC converter in case of operational failure e g if current through the buffer exceeds a tolerated limit however this is not yet implemented R Motor pin R Motor pin Fig 15 If the digital out port of the DSP writes low it results in a broken connection between the motor pin and ground potential When the digital out port writes high current flows through the diode which emits light that is received by the photosensitive collector side This results in the two collector ports being connected 3 7 3 OP amplifier The motor expects an analogue control signal voltage between 0 5 Volts to motor pin 4 as a reference value see chapter 3 3 However since the maximum output from the digital to analogue converter DAC on the DSP is 3 3 Volts see chapter 4 1 3 the signal needs to be amplified in order to get the full ran
73. ns low until the value of the counter matches the COMPARE value and then a transition occurs to high signal level The signal level will now stay high until the counter reaches the PERIOD value and the signal goes low again This is automatically repeated and results in a PWM signal Two PWM channels are used by the software to control the brake servo see chapter 3 5 and the steer servo see chapter 3 6 4 1 5 Digital IO ports The DSP has up to 40 multi purpose digital IO ports depending on the setup and configuration of the system see 11 Each IO port can be used as either an in or out port and they are controlled by 5 registers with 8 IO ports assigned to each register The register controls individual data direction for the IO ports and the current value written to them The software uses two digital out ports to control the modes of the motor see chapter 4 2 7 and one out port for the software switch of the DC converter see chapter 4 3 1 One digital in port is used to determine the position of the manual buffer switch see chapter 4 3 1 and Appendix XV 4 2 The Functional structure of the code The SMC software see Appendix XIX is developed according to generic control architecture principles see 14 with specific functions of the program allocated in three different functional levels see Fig 25 The third level or the lowest consists of sensors e g current sensors and actuators e g motor steer servo on the SMC
74. ntrol of the DSP following ideas regarding control architecture developed by project group member Leo Laine PhD student at the Department of Machine and Vehicle Systems Project group member and Master thesis student Dennys Gomez is responsible for the mechanical design of the prototype and the construction of the buffer It is presented in his thesis report Design and Development of a Hybrid Electric Scale Model Car see 8 The contribution of this thesis is a computerized control system for the SMC It features integrated sensors and actuators that the DSP can use to monitor and control the power flow in the powertrain of the SMC as well as the physical behavior of the vehicle The control system hardware and software is designed in a modular fashion which facilitates modifications and further developments 1 4 Thesis Outline Chapter 1 gives an introduction to the problem with objectives and limitations of the thesis Chapter 2 presents the complete vehicle control system and briefly describes the different parts and their functions In chapter 3 the hardware of the control system is presented more thoroughly It is also described how the hardware components are connected monitored and controlled Chapter 4 presents basic functions of the DSP for interfacing hardware with software The functional structure of the program and the various sub programs are also described Chapter 5 gives a summary of the sensors and actuators of the control
75. o NOT clear the WD OVERRIDE bit bit 4 0 XMIF_HI Z mode 1 Hi bit 3 1 disable the boot ROM enable the FLASH bit 2 no change MP MC bit reflects state of MP MC pin bit 1 0 11 11 SARAM mapped to prog and data WDCR WDCR_set Disable the watchdog timer WSGR WSGR_set Setup external memory interface for LF2407A EVM AEE EAL Setup shared I O pins EEE RRR ie TER dee Ronen MCRA MCRA_set group A pins MCRB MCRB_set group B pins PADATDIR PADATDIR set set IOPAO and IOPA2 as out ports PBDATDIR PBDATDIR set set IOPB6 and IOPB7 as out ports and IOPB2 as in port Setup GP timers and PWM configuration A AE T1CON 0 0000 disable timer 1 EVA T2CON 0x0000 disable timer 2 EVA T3CON 0x0000 disable timer 3 EVB T4CON 0x0000 disable timer 4 EVB GPTCONA GPTCONA set configure GPTCONA GPTCONB GPTCONB set configure GPTCONB T1CNT 0 GP timer 1 works to produce PWM1 and PWM3 on COMPARE T1PR _50 2 with x 32 prescaler the counter is full after 20 ms T2CNT 0 GP timer 2 is QEP counter for QEP1 amp QEP2 T2PR 0x1000 maximum period register T3CNT 0 GP timer 3 provides time base to interpret RC receiver signals T3PR OxFFFF maximum period register T4CNT 1000 GP timer 4 is QEP counter for QEP3 amp Q
76. o generic values responding to lever position of corresponding RC transmitter channel RR A AR br count neg flank2 pos flank2 if br count lt 2433 amp amp br count gt 1431 is brake signal valid dif gt brake 1931 count 500 translate to normalized value 1 1 lat_count neg_flank4 pos_flank4 if lat_count lt 2605 amp amp lat_count gt 1098 is lateral signal valid dif gt lateral lat_count 1882 548 translate to normalized value 1 1 long_count neg_flank3 pos_flank3 if long_count lt 2610 amp amp long_count gt 1050 is longitudinal signal valid dif gt longitudinal long count 1370 960 translate to normalized value 0 3 1 Appendix XIX Driver Interpreter header file aS SSS Driver Interpreter DIP Interpret the signals from Driver Interface to physical motion Authors Magnus Leo dS OOP NAE NN a A a tS at ee Structures DIP Variables used to describe the desired motion description values speed desired speed m s brake desired brake action 0 1 Z
77. odule clock bit 5 1 1 enable SPI module clock bit 4 0 1 disable CAN module clock bit 3 1 1 enable EVB module clock bit 2 1 1 enable EVA module clock bit 1 0 reserved bit 0 1 clear the ILLADR bit ai z define WDCR set OxOOE8 0000 0000 1110 1000 bits 15 8 0 s reserved bit 7 1 clear WD flag bit 6 1 disable the dog bit 5 3 101 must be written as 101 bit 2 0 000 WDCLK divider 1 define WSGR_ set 0x0040 10000 0000 0100 0000 bit 15 11 0 5 reserved bit 10 9 00 bus visibility off bit 8 6 001 1 wait state for I O space define define define define bit 5 3 000 0 wait state for data space bit 2 0 000 0 wait state for program space PADATDIR_set 0x0500 J 0000 0101 0000 0000 bit 15 8 0 pin set as an input 1 pin set as an output bit 7 0 if pin is input 0 reads as low 1 reads as high if pin is output 0 writes low 1 writes high PBDATDIR_set 0xC000 1100 0000 0000 0000 bit 15 8 0 set as an input 1 pin set as an output bit 7 0 if pin is input 0 reads as low 1 reads as high if pin is output 0 writes low 1 writes high MCRA set 0x0158 0000 0001 0101 1000 bit 15 0 0 10 87 1 TCLKINA bit 14 0 O IOPB6 1 TDIRA bit 13 0 0 5 12 T2PWM T2CMP bit 12 0 0 4 12 TIPWM T1CMP bit 11 0 0 12 PWM6 bit 10 0 0 2 12 PWM5 bit 9 0 O IOPB1 1 PWM4 bit 8 1 1 PWM3 bit 7 0 O IOPA7 1 PWM2 bit 6 1 0 I
78. of digital out ports which in turn are controlled by the forward_mode and brake_mode variables see Fig 31 If brake_mode is set to 0 the motor will be put in traction mode the DAC1 control signal to motor pin 4 see chapter 3 3 corresponds to RC channel 3 longitudinal When brake_mode is set to 1 the motor will be put in regenerative brake mode and DAC1 will be set according to channel 2 brake In terms of conventional vehicles this functionality is similar to the gas and brake pedal where one foot controls them both if od gt brake_mode regenerative brake mode is requested DAC1 od gt brake_signal 4000 perform DAC DAC_XFER 1 transfer write to PADATDIR PADATDIR amp OXFFFE write low on IOPAO reg brake mode traction mode is requested if od gt forward_mode forward mode is requested DAC1 od gt speed 4000 Cspeed_max perform DAC DAC_XFER 1 transfer write to 1 PADATDIR PADATDIR 68 OxFFFB 0x0001 high on IOPAO traction mode low on IOPA2 forward mode else reverse mode is requested DAC1 od gt speed 8000 Cspeed_max perform DAC DAC_XFER 1 transfer write to DAC1 PADATDIR PADATDIR 0x0005 write high on speed mode and high on IOPA2 reverse mode Fig 31 Excerpt from Power Supply showing how the motor pin configuration is controlled and altered according to the variab
79. ol system should be able to monitor and control the power flow of the SMC as well as basic motion control of the vehicle velocity and steering The work includes the design and construction of hardware and software necessary to perform these actions In order to do this the status of the prototype should be available through sensor signals for the DSP to read and interpret and the DSP will also generate control signals for the actuators of the prototype 1 2 Limitations Following limitations have been made e DSP electric motor DC converter buffer and primary power unit PPU were determined and acquired outside the boundaries of this thesis e This thesis does not include the design of any regulatory systems for the prototype and neither does it include the mechanical aspects of the prototype e The prototype software is not optimized considering factors like DSP memory or run time efficiency e Equations and calculations used to size electric components in prototype circuits are not presented 1 3 Contributions The work of project group leader Jonas Hellgren PhD student at the Department of Machine and Vehicle Systems regarding energy management strategies has been a contributing factor in the design of the powertrain His work has also influenced the design of the control system since it is crucial that the power flow within the system can be monitored and controlled The control system is structured and put under software co
80. r and more efficient the DSP can monitor the buffer current sensor and adjust the control signal to the DC converter so the current is regulated This will protect components in the buffer box that otherwise might be damaged by high currents and it is a step towards finding an optimal buffer charging routine e An additional 5 Volt switch regulator could be advisable to install since if the maximum current supply limit of a single regulator about 3 Ampere is exceeded and the power drops there is an imminent risk of DSP system breakdown The servos are the prime consumers of power among the 5 Volt components and when they are operating at their maximum ability simultaneously they can sink currents up to 3 Ampere together e During regenerative braking the energy from the motor is divided between the PPU and the buffer However since the PPU is intended to be replaced by a fuelcell in later versions of the SMC it will not be able to be charged during regenerative braking In order to simulate the fuelcell in this aspect the PPU batteries can be equipped with a diode at the positive pole By doing this the batteries will not be charged during regenerative braking and all the regenerated power will be diverted to the buffer e Since a fuelcell has an upper limit regarding the power it can provide the PPU batteries could be fitted with a current limiter in order to make them simulate a fuelcell more closely Otherwise due to the low inner resis
81. rection The responsible sub programs are Driver Interface Operative Decisions and Power Supply Motor rotational speed The DSP interprets corresponding RC receiver signal channel 3 and generates an analogue control signal to the motor The responsible sub programs are Driver Interface Driver Interpreter and Power Supply The DSP updates all sensor readings with a frequency of 50 Hz except the motor rotational speed readings which are updated at 5 Hz see chapter 4 2 7 Following sensor feedback is available to the DSP Motor voltage performed in System Initiation and Power Supply Motor current performed in Power Supply e Motor power flow voltage and current can be used to calculate the power flow in out from the motor according to P U Buffer voltage performed in System Initiation and Power Supply Buffer current performed in Power Supply e Buffer power flow voltage and current can be used to calculate the power flow in out from the buffer according to P U I Motor rotational speed performed in Power Supply Right front wheel rotational speed performed in Chassis Lever positions on RC transmitter performed in Driver Interface 6 Discussion and Conclusions There are a number of questions to consider when evaluating the control system of the SMC and they have been divided in three groups the development process the result and the possibilities The development process What was most demanding during the desi
82. rection mode i od forward mode 1 else od gt forward_mode 0 motor is put in reverse direction mode Appendix XIX Chassis header file ROE ER ICE Chassis Ch Generates 50 Hz PWM signals to control brake and steer servos Calculates rotational speed of right front wheel Authors Magnus Leo Wu ceu a E ERI B TURON EUR CU Ee Ac Ctt tele ZO AS Structures CH Converted sensor signals K name description values fw_rot_speed Front wheel rotational speed rps sh ts ce i d eee ORDER ee ee ee es x Routines Functions Generates PWM signals to control brake and steer servos Calculates rotational speed of right front wheel DSP interprets QEP signals from optic rotational sensors PWM1 pin 3 P1 steer servo channel 4 PWM3 pin 5 1 brake servo channel 2 QEP1 pin 21 P1 optic rotational sensor 1 QEP2 pin 22 P2 optic rotational sensor 2 EEA EEEE EEKE KEE EREK KEKERE ERE RIG RA ROLE RA EE RRL RE EA AE EEE EAE OE Addresses KEEKEEKE define CMPR1 volatile unsigned int 0x7417 compare reg 1 define CMPR2 volatile unsigned int 0x7418
83. rpret the signals When the signal goes high on an in port the current value of GP timer 3 is stored as time stamp for the positive flank of the PWM signal The time stamp for the negative flank is stored in the same way when the signal goes low m The difference of the positive and negative flanks gives the pulse width which corresponds to the lever position on the RC transmitter Captured peak widths are translated to generic values IOPB4 pin 12 P1 RC receiver channel 1 trigger signal m IOPB5 pin 13 P1 RC receiver channel 2 brake IOPB6 pin 15 P1 RC receiver channel 3 longitudinal 2 IOPB7 pin 16 P1 RC receiver channel 4 steering RE OR ERA A ERE ERE EE EEE Addresses AER REA define PBDATDIR volatile unsigned int 0x709A port B data amp dir reg define T3CNT volatile unsigned int 0x7501 GP timer 3 counter reg variable structure typedef struct dif double longitudinal double lateral double brake DIF EEA Declare functions extern void dif_fcn DIF dif Appendix XIX Driver Interface source file a Driver Interface DIF Extracts information from PWM signals from RC recei
84. s for controlling the four channels Both levers can be adjusted in a two dimensional fashion X Y and each channel has a calibration dial for tuning Channel designation is shown in Fig 7 2 Brake signal Mechanical brake Regenerative brake 3 Speed signal Forward Reverse 3 4 Steer signal 1 Trigger signal right for DSP software left si c 1 Fig 7 RC transmitter and channel designation The type of braking mechanical or regenerative is here determined by the lever position but in future versions of the SMC it is intended to be done by the software Channel 1 2 and 4 are equipped with springs which makes the levers to return to neutral middle position when released To put the prototype in reverse the operator needs to put the channel 3 lever in the bottom position and then use the calibration dial for the channel to control the reverse speed 3 3 Electric Motor The motor is a brush less permanent magnet DC motor BLDC from Ostergrens Motor see Appendix with a nominal operational voltage of 24 Volts It is equipped with an internal control circuit which allows motor control to be done through the use of 10 external motor pins see Appendix 111 A key feature of the motor is the regenerative braking where it transforms kinetic energy into electric energy The operational mode of the motor depends on the configuration of motor pins 6 and 7 which controls regenerative brake or traction mode
85. signal Buffer current sensor signal Motor current sensor signal Motor control signal Buffer voltage sensor signal DC converter control signal coupled with ground wire SS Steer Servo BS Brake Servo RC RC receiver Appendix XVII DSP type pin PWM1 pin 3 PWM3 pin 5 IOPB4 pin 12 IOPB5 pin 13 IOPB1 pin 7 IOPB7 pin 16 QEP1 pin 21 QEP2 pin 22 QEP3 pin 24 QEP4 pin 20 ADCIN5 pin 8 IOPA0 pin 27 IOPA1 pin 28 IOPB6 pin 15 IOPA2 pin 16 ADCIN0 pin 23 ADCIN1 pin 24 DAC1 pin 25 ADCIN6 pin 9 DAC2 pin 26 OpRoSe Optic Rotational Sensor circuit QMoVoSe QEP and Motor Voltage Sensor circuit X External circuit box BufVoSe Buffer Voltage Sensor circuit to from BufVoSe Appendix XVIII DSP bus wire from port amp pin 1 DSP P1 pin 3 2 wire 12 3 DSP P1 pin 5 4 wire 8 5 RC ch 1 control 6 RC ch 1 ground 7 RC ch 2 control 8 RC ch 2 ground 9 RC ch 3 control 10 RC ch 3 ground 11 RC ch 4 control 12 RC ch 4 ground 13 OpRoSe O1 14 OpRoSe O4 15 OpRoSe O3 16 OpRoSe O4 17 QMoVoSe N3 18 QMoVoSe N2 19 QMoVoSe N5 20 QMoVoSe N4 21 QMoVoSe N1 22 DSP P1 pin 27 23 X buffer switch 24 DSP P1 pin 15 25 DSP P4 pin 16 26 X K4 27 X K13 28 DSP P2 pin 25 29 BufVoSe E1 30 DSP P2 pin 26 31 32 33 34 35 36 37 DSP Digital Signal Processor board SS Steer Servo BS Brake Servo RC RC receiver OpRoSe Optic Rotational Sensor
86. sor signals and generates control signals see chapter 4 1 3 8 1 Wiring and shielding There are several sources of electro magnetic interference EMI on the SMC EMI can cause corrupted signals within the control system since every wire serves as an antenna by picking up interference from the surrounding The EMI of primal concern comes from flowing currents in wires and components such as Motor RC receiver DC converter Buffer Power wires carrying high currents between modules The best method to avoid interference in general is distance to the source see 10 Therefore the power wires are mainly situated in the rear half of the prototype together with motor DC converter and buffer and the signal wires are kept in the front half However the RC receiver is placed in the front of the SMC and since it is functioning as a power relay station for the servos the power wires to the RC receiver can carry currents up to 3 Ampere see 6 and 9 In order to minimize the emitted EMI the positive and negative power wire are coupled and twisted This results in the electro magnetic fields of the wires annulling each other see 10 Another source of EMI is wires carrying pulse signals QEP and PWM signals to and from the DSP where the alternating signal levels causes fluctuating electromagnetic fields around the wires By coupling these signal wires with ground wires the emitted EMI is reduced see 10 The wires that are mos
87. t sensitive to EMI are the sensor signal wires to the ADC ports on the DSP The sensitivity is due to the analogue nature of these signals where surrounding interference affects the signal voltage which results in poor precision of the DSP readings To protect analogue wires from EMI they are grouped and placed inside metallic mesh covers which are connected to ground potential at both ends see Fig 23 The metallic mesh covers are then insulated with electric tape to avoid involuntary connections and short circuit within the system This method shields the wires from EMI between 10 kHz and 20 GHz see 10 which effectively protects them from the RC transmitter FM signal at 35 MHz see 6 Metallic Signal mesh cover wires Signal wires Ground Ground connection connection Fig 23 The metallic mesh cover is connected to ground potential at both ends and the signal wires are protected inside the cover from a wide spectrum of EMI 4 Control System Software 4 1 DSP functionality For the proper DSP functionality it is necessary that the DSP and the modules it communicates with are sharing the same ground potential This common ground is used as a reference value by the DSP when it interprets sensor signals and generates control signals There are a number of DSP functions that integrates hardware signals to digital control by software and these functions are briefly described in this chapter 4 1 1 Quadrature Encoded Pu
88. tance of the batteries the present PPU can supply almost infinite power e By adding a voltage sensor for the 12 Volt battery supplying the 5 Volt circuits the DSP can monitor the condition of the battery and the program can detect and enter a safe mode if the voltage drops below a certain level e In order to collect data from the SMC after test runs it is necessary to implement a log function that saves information regarding the system e g sensor values and control signals during program execution The data can then be down loaded and analyzed afterwards 8 References 1 L B Lave and H L MacLean An Environmental Economic Evaluation of Hybrid Electric Vehicles Toyota s Prius vs its Conventional Internal Combustion Engine Corolla Transportation Research Part D Transport and environment Vol 7D no 2 Mar 2002 ISSN 1362 9209 2 Tae Sung Kim et Al A New Current Control Algorithm for Torque Ripple Reduction of BLDC Motors Department of electric engineering Hanyang University Seoul South Korea 2001 3 D E B Gomes Design and Development of a Hybrid Electric Scale Model Car Department of Machine and Vehicle Systems Chalmers University of Technology Sweden 2004 4 XDS510PP PLUS User Manual for Parallel J Tag Emulator Spectrum Digital 5 SPRUO24e user manual for TMS320LF2407A Evaluation Module Texas Instruments 6 Laser 4 amp 6 Digital Proportional FM Radio Control System User Manual Hitec 7
89. tile unsigned int 0x7411 Compare control reg A define ACTRA volatile unsigned int 0x7413 Compare action control reg A x define DBTCONA volatile unsigned int 0x7415 Dead band timer control reg A Event Manager B EVB registers RR EE AE define volatile unsigned int 0x7500 GP timer control reg B define T3CNT volatile unsigned int 0x7501 GP timer 3 counter reg define T3PR volatile unsigned int 0x7503 GP timer 3 period reg define T3CON volatile unsigned int 0x7504 GP timer 3 control reg define T4CNT volatile unsigned int 0x7505 GP timer 4 counter reg define volatile unsigned int 0x7507 GP timer 4 period reg define TACON volatile unsigned int 0x7508 GP timer 4 control reg define CAPCONB volatile unsigned int 0x7520 Capture control reg B Analog to Digital Converter ADC registers EEE EA define ADCTRL1 volatile unsigned int 0x70A0 ADC control reg 1 define ADCTRL2 volatile unsigned int 0x70A1 ADC control reg 2 define MAX CONV volatile unsigned int 0x70A2 Max conversion channels reg define CHSELSEQ1 volatile unsigned int 0x70A3 Ch select seq control reg 1 define CHSELSEQ2 volatile unsigned int 0x70A4 Ch select seq control reg 2 define CHSELSEQ3 volatile unsigned int 0x70A5 Ch select seq control reg 3 define CHSELSEQ4
90. ver 4 channels 50 Hz by measuring the individual pulse peak widths Each receiver channel is connected to a digital in port that can detect signal transitions DIF uses rising edge of channel 1 pulse as trigger for peak width detection on channel 2 3 and 4 By using a GP timer the timestamps for positive and negative flanks are stored and used to calculate the peak widths Measured peak widths are translated to generic values and put on the BUS X X X X X X X include main h extern void dif_fcn DIF dif uku EE GR Variable declaration RE RR ROR RAE ER RIE CE A double pos_flank2 neg_flank2 pos_flank3 neg_flank3 pos_flank4 neg_flank4 double lat_count br_count long_count int trigg ch2 ch3 ch4 handling channel 1 trigger signal EE trigg PBDATDIR amp 0 0010 mask everything but bit 4 while trigg 0 waits for ch 1 signal from receiver to go high trigg PBDATDIR amp 0x0010 OEE EEA EE EGE Te te te reading information on channel 2 EE p T3CNT 0 reset GP timer 3 ch2 PBDATDIR amp 0x0020 while ch2 0 waits for ch 2 signal from receiver to go high ch2 PBDATDIR amp 0x0020 pos_flank2 T3CNT stores time stamp for positive flank ore 0x0020 waits for ch 2 signal from receiver to go
91. ver which the DSP then interprets Buffer box DSP box PPU and 12 Volt battery External circuit box Fig 2 Top view of prototype showing buffer box with DC converter DSP box external circuit box PPU and 12 Volt batteries Control of the system is achieved by the integrated DSP see Fig 3 which receives sensor signals processes data and sends out control signals to the actuators on the car The actuators steer servo mechanical brake servo motor and DC converter controls the physical behavior of the SMC as well as the power flow within the powertrain DSP box Motor Fig 3 Left side of prototype showing the DSP box and motor In order to achieve the complete control system additional circuits has been developed and integrated into the system The additional circuits are responsible for interfacing actuators with the DSP as well as monitoring the status of the system in the form of sensors They are mainly placed in the external circuit box see Fig 4 Buffer box External circuit box Fig 4 Right side of prototype showing the external circuit box with switches on top of the box The buffer box is placed in the rear of the car 3 Control System Hardware The vehicle control system consists of seven hardware modules see Fig 5 DSP RC system transmitter and receiver mechanical brake servo steer servo electric motor DC converter and the external circuits The communication within the control syste
92. volatile unsigned int 0x70A6 Ch select seq control reg 4 define AUTO SEQ SR volatile unsigned int 0x70A7 Autosequence status reg define RESULTO volatile unsigned int 0x70A8 Conv result buffer reg 0 define RESULT1 volatile unsigned int 0x70A9 Conv result buffer reg 1 define RESULT2 volatile unsigned int 0x70AA Conv result buffer reg 2 define RESULT3 volatile unsigned int 0x70AB Conv result buffer reg 3 define RESULT4 volatile unsigned int 0 70 Conv result buffer reg 4 define WSGR portFFFF ioport unsigned int portFFFF define DAC2 port0001 ioport unsigned int port0001 define DAC_XFER port0004 ioport unsigned int port0004 define STR X x define _TI_LED 000ch define OUTMAC address data asm LDPK _ STR data asm OUT _ STR data Wait state generator reg C2xx compiler specific keyword 2 register DAC Transfer register STR address initial State of Charge Voltage 20ms GP timer 1 period with a x 32 timer prescaler and 40MHz CPUCLK to produce 50 000 PLL 4 mode gives 30 MHz CPUCLK frequency define initial SoC 7 define per_50Hz 25000 Hz PWM signals define SCSR1_set 0x00AD 0000 0000 1010 1101 bit 15 0 reserved bit 14 0 CLKOUT CPUCLK bit 13 12 00 IDLE1 selected for low power mode bit 11 9 bit 8 0 reserved bit 7 1 1 enable ADC module clock bit 6 0 1 disable SCI m

Implementation of a control system for a scaled series hybrid electric

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