Khepera®
Contents
1. Figure 9 Typical measurement of the ambient light versus the distance of a light source of 1 Watt As it can be seen the measured value decreases when the intensity of the light increases The standard value in the dark is around 450 The measurement of the ambient light versus the angle between the forward direc tion of the robot and the direction of the light has the shape illustrated in figure 10 500 4 Dark 450 7 400 F 350 7 E 300 sensor left 85 E 250 sensor left 45 g 200 7 sensor left 10 2 150 7 sensor right 10 100 gt sensor right 45 50 a sensor right 85 Ota tat fat fata ot tell tt at a tt 180 150 120 90 60 30 0 30 60 90 120 150 180 210 240 angle Figure 10 Typical measurement of the ambient light with a light source moving around the robot The angle on the X axis is measured between the forward direction of the robot and the direction of the light All these measurements depend very strongly from various factors like the distance of the light source the colour the intensity the vertical position etc These two figures show only the global shape of the sensor s response 3 1 6 2 Reflected light measurements The measurement of the proximity of obstacles by reflected light depends on two major factors the reflexivity of the obstacle colour kind of surface and the ambient light Figure 9 shows some measurements giving an idea of the re2. To control the speed of the wheels from another VI the Motors VI can be used as sub VI This use is demonstrated with the KheBraitenberg3c VI The help window figure 31 displays positions and semantics associated to the icon 30 Stop creer Speed motor right BE Speed motor left Serial port Motors Figure 31 Semantic of the Motors connector 7 6 1 Sensors Select the Sensors panel and open the diagram using the option Show diagram of the menu Windows Your screen now displays the following schema Sensors Diagram 5 Umea E aE Figure 32 Diagram corresponding to the Sensors panel On the contrary to the Motors panel which sends values this panel receives val ues from the serial link Eight values are extracted in four steps from the string These values are put into the variables type Unsigned 16 bits corresponding to the panel gauges They are also put into a vector so to be displayed by Sensors_displ These 8 values are transmitted to others modules through the icon used as a con 31 nector This use is demonstrated with the experiment on Braitenberg s vehicle The help window figure 33 displays positions and semantics associated to the icon Serial port J Sensors cid i Figure 33 Semantic of the Sensors connector 7 6 2 Example of Braitenberg s vehicle Select the Braitenberg panel and open the diagram using
3. 42 Appendix D RS232 configuration 00 45 Appendix E Running modes 0 000 48 1 INTRODUCTION O Khepera has originally been designed as a research and teaching tool in the frame work of a Swiss Research Priority Program It allows confrontation to the real world of algorithms developed in simulation for trajectory execution obstacle avoidance pre processing of sensory information hypothesis on behaviours processing To be able to program the robot easily LabVIEW is proposed as a development environment It is a graphical programming software basically dedicated to instrumentation which allows quick development of input output interfaces a necessity when dealing with the real world by definition unpredictable and noisy Please note that LabVIEW is just a sug gestion and is absolutely not needed to use the robot Any other environment able to deal with the serial port of your computer can be use instead of LabVIEW The communica tion protocol implemented on Khepera and used by LabVIEW is presented in chapter 6 and described in detail in appendix A 1 1 How to Use this Manual This manual is organised into six chapters and one appendix To learn how to make the best use of your Khepera robot you are urged to read all of chapters 1 through 5 Chapter 6 presents the serial communication protocol that makes a remote control from a workstation possible You need to read the chapter 7 if you us
4. Top view Figure 20 Settings of the jumpers for the 9600 baud communication mode e Set the connection configuration presented in section 5 2 e Start on your host computer a terminal emulator for instance Hyper Termi nal on PCs Microphone on MACs tip on UNIX or minicom on linux see RS232 configuration on page 45 with the serial line set to 9600 Baud 8 bit data 1 start bit 2 stop bit no parity We start testing some protocol commands e Type the capital letter B followed by a carriage return or a line feed e The robot must respond with b followed by an indication of the version of software running on the robot and terminated by a line feed e Type the capital letter N followed by a carriage return or a line feed e The robot must respond with n followed by 8 numbers separated by a comma and terminated by a line feed These numbers are the values of the robot proximity sensors presented in section 3 1 6 e Retry the same command N putting some obstacles in front of the robot The response must change e Type the protocol command D 5 5 followed by a carriage return or a line feed e The robot must start turning on place and respond with d and a line feed e To stop the robot type the protocol command D 0 0 followed by a carriage return or a line feed e Type the protocol command H followed by a carriage return or a line feed e The robot must respond with h followed by 2 numbers separated by a comma and terminated
5. by a line feed These numbers are the values of the position counters of each wheel e Type the protocol command G 0 0 followed by a carriage return or a line feed 20 e This command set the position counters to the 2 values given as parame ters The answer is composed by a g and a line feed e Retry the protocol command H to verify that the G command has been exe cuted e Type the protocol command C 1000 1000 followed by a carriage return or a line feed e The robot respond with c and goes forward 80 mm e Retry the protocol command H to verify the final position e Try other commands following the description given in Appendix A We continue testing some tools e Type the command help followed by a carriage return or a line feed The robot must respond with the list of all tools available e Type the command help serial followed by a carriage return or a line feed e The robot must respond with the description of the serial tool e Type the command help D followed by a carriage return or a line feed e The robot must respond with the description of the D protocol command e Type the command list followed by a carriage return or a line feed The robot must respond with the list of all software modules present in the ROM In addition to the tools characterised by a TOXX ID and the protocol commands characterised by a PRXX ID you can find on the list functions characterise
6. dis tances in a short delay The robot is normally charged when delivered e Verify that the three jumpers are not connected setting for the running mode 0 see Jumpers reset button and settings on page 5 Top view Figure 16 Settings of the jumpers for the Braitenberg vehicle test e Switch the robot battery switch ON and put the robot on the surface The robot must start to go forward while avoiding obstacles The obstacles must be bright to better reflect the light of the proximity sensors If the robot does not operate properly check the three points mentioned above recharge the robot and retry If the robot does not correctly avoid the obstacles please contact your Khepera dealer 5 CONNECTIONS O There are two standard configurations a first one used to charge the robot and a second one that allows the communication between the robot and the host computer 5 1 Charging configuration Warning It is necessary to discharge the batteries before recharging Avoid to start a recharging process on charged batteries This can cause damages To charge the battery of the robot the following connections have to be made e Between the robot and the interface charger module with the charging cable 4 pins e Warning the robot battery switch must be on the OFF position 14 Figure 17 Connections to recharge the robot s batteries e Between the interface charger module and the power supply with the jac
7. sensor value is displayed as a gauge The gauges are placed on the panel like the corresponding sensors on the robot The exact value received is written underneath Values are between 0 and 1023 Start the acquisition as before by clicking on the double arrow to stop the execution click on the stop icon that will appear Now you are free to test the response of the sensors In particular some materials reflect better than others the infra red light emitted by the sensors You are also able to state difference in the individual response of the proximity sensors The graph on the left of the panel shows the values for each sensor against time 7 5 Braitenberg s vehicle At this stage you have a good understanding of motors and sensors functionality In this section we will combine these two modules as sub VIs of a main sensory motor loop VI Let s open both panels Motors and Sensors but do not start them This way you will be able to watch at the same time data issued from the sensors and those send to the motors Open the instrument called KheBraitenberg3c You should see on your screen the panel illustrated in figure 29 28 KheBraitenbergic apt Application Font Fils 90 degree 45 degree Front E a Sram 2 z0 20 z0 Moem Eaudrate eo o l Oo l mm I I hd D m lid I I a D m li eT il Figure 29 Braitenberg s vehicle panel 3 sliders defining the link weights
8. the batteries are disconnected and the robot can be powered by the S serial line connector 3 1 3 Jumpers reset button and settings OO Top view Mode 0 IO Mode 4 E Mode 1 OKO Mode 5 Mode 2 A Mode 6 sy Mode CD Wiode ORROQOCO So OO 0 0 0 OO gt C Mode 3 Ce Mode 7 Figure 4 Position and setting of the jumpers The ROM installed on your robot has an important library of software modules for the real time control of the Khepera robot Part of these modules building the BIOS ensure the basic functionnalities of the Khepera robot like motor control sensors scan ning etc Another part of these modules ensure the interface with the user through the serial line Depending on your use of the robot remote control downloading test demo etc you can select a specific module by setting the correspondent running mode The 3 jumpers see Overview on page 4 allow the selection of the most important running modes in several configurations You have the choice between the following jumper con figurations see figure 4 for the corresponding jumper positions 0 Demonstration mode Braitenberg vehicle algorithm number 3 accord ing to the Vehicle book Braitenberg84 for obstacle avoidance 1 Mode for the control of the robot by the serial communication protocol see The serial communication protocol on page 18 using a serial link with a communicati
9. the option Show diagram of the menu Windows Your screen now displays the following schema Braitenberg3c Kh Diagram Figure 34 Braitenberg s vehicle diagram of Braitenberg s vehicle panel 32 This schema may appear complex at first glance But as we will see it takes back elements already studied It can be decomposed into two parts serial link initialisation and avoiding behaviour LabVIEW is a data flow controlled language so the execution order of non dependent control structures is not fixed Serial link initialisation and avoid ance behaviour are independent but initialisation must occur first The sequential struc ture allows the definition of an execution order so initialisation is the first element of the sequence The second element contains the while loop where the avoidance behaviour is executed until the boolean variable Stop becomes True note the presence of a logical inversion This boolean variable is also transmitted to the Motors VI through its icon Its action will be to stop both motors In the same way the two speeds computed here are sent to the Motors VI to be sent through the serial link to Khepera Sensors values are received from the Sensors icon They are normalised 1000 and multiplied by the corresponding sensibility value type real Single Front corre sponds to the two central sensors numbers 2 and 3 45 degree corresponds to the two oblique sensors numbe
10. Each of these three sliders defines the sensibility of the motors reaction to the obstacles of a given group of sensors e Front corresponds to the two central front sensors 2 and 3 e 45 degrees corresponds to the two lateral front sensors 1 and 4 e 90 degrees corresponds to the two sensors on the side of the robot 0 and 5 Set carefully the serial port and the baudrate according to the settings of your Khepera robot Start the application by clicking on the arrow It is not necessary to click on the double arrow in the present case The sensibility can be modified by moving the cursors or writing directly the desired values Khepera now moves avoiding bumping into obstacles In a parallel way you can observe the motor commands and the sensor readings from the Motors and Sensors panels Test different sensibilities on its behaviour This control structure is inspired from the work of V Braitenberg Braitenberg84 Note that this VI uses Motors and Sensors as sub VIs One of the advantages of LabVIEW is to allow a context free use of the building modules This fact is particu larly interesting for creating programs in a structured way and for debugging The button inside the panel labelled stop stops the robot and the execution of the VI It is a much better way than using the stop icon above rubber because the stop button stops the robot before stopping the VI 29 7 6 Advan
11. NG MODES O i OXO OXO Top view Mode 0 Mode 4 OXO C C C Mode 1 OKO Mode 5 OXO gt OXO OXO Mode 2 Mode 6 OXO Ca C C CJ Mode 3 C Mode 7 OXO gt Running modes see Jumpers reset button and settings on page 5 0 Demonstration mode execution of a Braitenberg vehicle algorithm number 3 according to the Vehicle book Braitenberg84 for obstacle avoidance Mode for the control of the robot by the serial communication protocol using a serial link with a communication speed of 9600 Baud Mode for the control of the robot by the serial communication protocol using a serial link with a communication speed of 19200 Baud Mode for the control of the robot by the serial communication protocol using a serial link with a communication speed of 38400 Baud User application mode start an application stored into the EPROM if any Downloading mode in this mode the robot waits for a program to be transferred S format 9600 Baud Downloading mode in this mode the robot waits for a program to be transferred S format 38400 Baud Test of the functionality of the robot The result of successive tests is given on the serial link 9600 Baud The serial link set up is always 8 bit 1 start bit 2 stop bit no parity Only the baud rate changes The set up of the jumpers can be changed at any time If the robot is running it is necessary to reset it to make t
12. SCII codes A command goes from the host computer to the robot it is constituted by a capital letter followed if necessary by numerical or literal parameters separated by a comma and terminated by a line feed The response goes from the robot to the host computer it is constituted by the same letter of the command but in lower case followed if necessary by numerical or literal parameters separated by a comma and terminated by a line feed To better understand this protocol we propose a very simple test as following e Set the jumpers of the robot for running mode number See figure 20 e Set the connection configuration presented in section 5 2 e Start a terminal emulator on your host computer with the serial line set to 9600 Baud 8 bit data 1 start bit 2 stop bits no parity e Type the capital letter B followed by a carriage return or a line feed The robot must respond with b followed by an indication of the version of software running on the robot and terminated by a line feed e Type the capital letter N followed by a carriage return or a line feed e The robot must respond with n followed by 8 numbers separated by a comma and terminated by a line feed These numbers are the values of the proximity sensors presents on the robots e Retry the same command N putting some obstacles on the front of the robot The response must change e Try other commands 34 List of Available Commands II indicates CR carriage re
13. _kheoera___ aui USER MANUAL Version 5 02 K Team Lausanne 12 March 1999 Documentation author K Team Ch de Vuasset CP 111 1028 Pr verenges Switzerland email info k team com WWW http www k team com Trademark Acknowledgements IBM PC International Business Machines Corp Macintosh Apple Corp SUN Sparc Station SUN Microsystems Corp LabVIEW National Instruments Corp Khepera K Team NOTICE e The contents of this manual are subject to change without notice e All efforts have been made to ensure the accuracy of the content of this manual How ever should any error be detected please inform K Team e The above notwithstanding K Team can assume no responsibility for any error in this manual TABLE OF CONTENT Introduction 22 4 ose becine sedeeckeeeeerdbarebagnkareee 1 How to Use this Manual 0 00 1 Safety Precautions occecsreisiessieceresniesi ress 2 Rec ling o23 22 nce assancese Ghee test a n ERE Anas 2 Unpacking and Inspection 2 2264262 20s4 s0ee00d 400084 3 The Robot and its Accessories uusuuuuruea nee 4 The Khepera miniature robot 0 000 5 4 VIVEINIOW daas ete seus e ei dates Goede ewes 4 ON OFF battery switch 00 4 Jumpers reset button and settings 5 The S serial line osnsnnanrensnsessnseo 6 Motors and motor control 00 6 Infra red proximity sensors 4 8 Ambient li
14. ced programming Now that we have executed different manipulations using LabVIEW and Khep era it becomes interesting to present how it has been programmed First it is important to be able to manipulate LabVIEW and its rolling menus Select the Motors panel and open the diagram using the option Show diagram of the menu Windows Your screen now displays the following schema Motors Diagram lool FP l z Set Application Font Figure 30 Motors diagram corresponding to the Motors panel Each element of the panel used for displaying or getting data corresponds to an icon So the box I32 under Speed motor right is the getting variable of the correspond ing slider on the front panel of type 32 bits Integer The same is true for the icon TF labelled Stop on the left which is a boolean variable type True False This variable allows to stop the motors by sending to each one a null speed value The triangle repre sents an indirection controlled by the boolean variable Stop If Stop is true then the output value on the right will be 0 if Stop is false then the output value is the Speed variable These values are formatted by the next two icons to a string of ASCII charac ters The character D is placed at the beginning of the string Then successively the two speed values are added and the string is terminated by a carriage return n This string is send to the robot using the serial link
15. coder is placed on the motor axis and gives 24 pulses per revolution of the motor This allows a resolution of 600 pulses per revolution of the wheel that corresponds to 12 pulses per millimetre of path of the robot The Khepera main processor has the direct control on the motor power supply and can read the pulses of the incremental encoder An interrupt routine detects every pulse of the incremental encoder and updates a wheel position counter The motor power supply can be adjusted by the main processor by switching it ON and OFF at a given frequency and during a given time The basic switching frequency is constant and sufficiently high not to let the motor react to the single switching By this way the motor react to the time average of the power supply which can be modified by changing the period the motor is switched ON This means that only the ratio between ON and OFF periods is modified as illustrated in figure 5 This power control method is called pulse width modulation PWM The PWM value is defined as the time the motor is switched ON basic period 50 power i ON period gt power power ON period time time Figure 5 The pulse width modulation PWM power supply mode is based on a ratio between the ON time and the total time The basic switching frequency is constant The PWM values can be set directly or can be managed by a local motor control ler The motor controller can perform the c
16. command D speed_motor_left speed_motor_right Format of the response dq Effect Set the speed of the two motors The unit is the pulse 10 ms that corre sponds to 8 millimetres per second The maximum speed is 127 pulses 10ms that correspond to 1m s E Read speed Format of the command EI Format of the response e speed_motor_left speed_motor_right Effect Read the instantaneous speed of the two motors The unit is the pulse 10 ms that corresponds to 8 millimetres per second F Configure the position PID controller Format of the command F Kp Ki Kd Format of the response fI Effect Set the proportional Kp the integral Ki and the derivative Kd param eters of the position regulator At the reset these parameters are set to standard values Kp to 3000 Ki to 20 Kd to 4000 G Set position to the position counter Format of the command G position_motor_left position_motor_right Format of the response gf Effect Set the 32 bit position counter of the two motors The unit is the pulse that corresponds to 0 08 mm H Read position Format of the command HI Format of the response h position_motor_left position_motor_right 36 Effect Read the 32 bit position counter of the two motors The unit is the pulse that corresponds to 0 08 mm I Read A D input Format of the command I channel_ number Format of the response i analog_value Effect Read the 10 bit value corr
17. d by a FUXX ID and BIOS modules char acterised by a BIXX ID On every module you can have an help mes sage 21 7 USING LABVIEW O This chapter is to familiarise you with the LabVIEW environment in the context of Khepera use LabVIEW is a product of National Instruments http www nat inst com To this end the examples are presented in an increasing order of complexity Our advice is to follow the chronological order of presentation Please refer to the Lab VIEW manuals for more information about this software The following examples and the files distributed with this product are based on LabVIEW version 5 LabVIEW runs on your PC Macintosh or SUN workstations and can control the functionality of the Khepera robot using the serial communication protocol described in section 6 2 7 1 Hardware configuration Set your environment as illustrated in section 5 2 The jumpers must be set as showed in figure 21 to obtain the running mode 2 for more details on running modes please refer to section 3 1 3 Top view Figure 21 Settings of the jumpers for using LabVIEW and a serial connection at 19200 baud 7 2 Set up of the serial link To enable the exchange of information between your computer and the robot you have to configure the serial link of your host computer according to the osetting chosen on the Khepera robot Be sure that the connection cable is connected at both ends Khe
18. e host connector You can easily find this cable by your host computer dealer If your host computer RS232 port has a DB25 male con nector you can plug the interface module directly in it 15 Figure 18 Configuration for the communication between the robot and the host computer e Between the interface charger module and the power supply with the cable fixed to the power supply e Set the jumpers according to the desired running mode see Jumpers reset button and settings on page 5 Be careful that in running mode 0 the robot starts moving when powered e Plug the power supply to the wall socket To test the connection and the settings of the serial port do the following manipulations e Put the robot on a flat surface on which the robot can move around easily The battery switch must be OFF e Insert all jumpers like in figure 19 setting for the running mode 0 see Jumpers reset button and settings on page 5 Top view Figure 19 Settings of the jumpers for the demo mode 16 e Run a terminal emulator on your host computer for instance Hyper Termi nal on PCs Microphone on MACs tip on UNIX or minicom on linux see RS232 configuration on page 45 connected to the serial port on which you have connected the robot Configure your terminal as following 9600 Baud 8 bit 1 start bit 2 stop bit no parity e Plug the mural power supply to the main or if it is already connected reset the rob
19. e the software LabVIEW The appendix can be referred to as necessary Chapter 1 Gives an introduction to this manual and the Khepera robot Chapter 2 explains the contents of the package Chapter 3 explains the functionality of every item present in the pack age Chapter 4 explains how to make the first test of the robot after unpack ing Chapter 5 gives the standard working configurations Chapter 6 presents the serial communication protocol Chapter 7 is addressed to users of LabVIEW It shows simple virtual instruments VI to control the robot functionality and a little example of programming in this environment Appendix A details the commands of the serial communication protocol Appendix B details the connectors pinning Appendix C details how to open the robot which means disconnect the upper from the lower part and change the ROM Both these operations has to be made only if really necessary Appendix D gives some detail on the configuration of some common ter minal emulators Appendix E details the different running modes 1 2 Safety Precautions Check the unit s operating voltage before operation It must be identical with that of your local power supply The operating voltage is indicat ed on the nameplate at the rear of the power supply Don t plug or unplug any connector when the system is switched ON All connections including extension addition or disconnection must be made when the robot and the i
20. ements of the light reflected by a wall versus the distance to the wall for several sensors of the same kind and in the same conditions 11 3 1 7 Batteries The robot is equipped with 4 rechargeable Nickel Cadmium batteries with a capac ity of 180 mAh older versions can have 110 mAh This capacity allows the robot an autonomy of about 45 minutes in the basic configuration The battery can be charged with the interface charger module see Interface and charger module on page 13 There is no specific management of the battery charge level During a life cycle of the robot the battery discharges as indicated in figure 14 When the battery voltage is under 4 V the robot processor stops working correctly and the robot has no more control At this voltage there is still sufficient power to make the motors move which means that the robot can move without control Battery voltage V 5 35 IOF 4 End of robot life 4 5 4 0 33 3 07 1 1 1 1 1 1 1 i i i 0 5 10 15 20 25 30 35 40 45 Time min Figure 14 Battery discharge cycle 3 2 Cables and accessories The S cable 2 m long with a 6 pins connector allows the connection between the robot and the interface charger module to support the communication to the host compu ter see Interface and charger module on page 13 The recharging cable 0 5 m long with a 4 pins connector allows the connection between the robot and the interface charger module to recharge the
21. esponding to the channel_number analog input The value 1024 corresponds to an analog value of 4 09 Volts J Configure the speed profile controller Format of the command J max_speed_left acc_left max_speed_right acc_right Format of the response jl Effect Set the speed and the acceleration for the trapezoidal speed shape of the position controller The max_speed parameter indicates the maximal speed reached during the displacement The unit for the speed is the pulse 10ms that corresponds to 8 mm s The unit for the acceleration is the pulse 256 10 ms 10 ms that correspond to 3 125 mm s2 At the reset these parameters are set to standard values max_speed to 20 acc to 64 speed max_speed time position end position start position time 37 K Read the status of the motion controller Format of the command KI Format of the response k T_left M_left E_left T_right M_right E_right Effect Read the status of the motion controller The status is given by three num bers for every motor T target M mode and E error T 0 means that the robot is still on movement T 1 means that the robot is on the target position M 0 means that the motor control is in the speed mode M 1 means that the control is in position mode M 2 means that the control is in PWM mode E indicates controller position or speed error L Change LED state Format of the command L LED_number acti
22. esponse sent by the Khepera to the host computer In all communications the host computer plays the role of master and the Khepera the role of slave All communications are initiated by the master The communication is based on two types of interactions one type of interaction for the set up of the robot for instance to set the running modes the transmission baudrate and one type of interaction for the control of the functionality of the robot for instance to set the speed of the motors to get the values of the sensors The inter actions allowing the set up of the robot are based on commands called tools The interac tions for the control of the robot functionality uses protocol commands and responses 6 1 The tools Here is the description of some basic tools run Starts a function stored in the ROM It has to be followed by the function name The functions available in the ROM can be listed with the list tool and have an identification string beginning with FU Some of the functions correspond to the running modes presented in the section 3 1 3 Using the run tool it is possible for instance to start the demo mode Braitenberg vehicle corresponding to the running mode 0 as described in section 3 1 3 typing run demo and return serial Sets the serial channel to a baud rate given as parameter For instance typing serial 19200 and return you set the baudrate to 19200 Baud help Shows t
23. f 255 T Send a message to an extension turret Format of the command T turret_ID command Format of the response t response Effect Send a command and return the response of the intelligent extension turret with turret_ID The list of turrets connected and their ID can be requested with the tool net The command parameter takes the same format as a standard command including an identification capital letter followed if necessary by numerical parameters separated by commas and terminated by a line feed The response takes the same format starting with the same letter but in lower case followed if necessary by numerical parameters separated by commas and terminated by a line feed The command and response formats are specific for every module R Read a byte on the extension bus Format of the command R relative_address Format of the response r data Effect Read the data byte available at the relative_address 0 63 of the exten sion bus W Write a byte on the extension bus Format of the command W data relative_address Format of the response wf Effect Write the data byte at the relative_address 0 63 of the extension bus 39 APPENDIX B CONNECTORS 4 Female connector 1 VCC Power supply 5V 2 RxD Serial receive data TTL levels 3 TxD Serial transmit data TTL levels 4 GND Power supply ground 5 GND Power supply ground same signal 6 GND Power supply ground Fi
24. ftware Microphone The main configuration panel is illustrated in figure 47 You have of course to choose the correct Connection Port where the Khepera is connected Communications Settings Method MicroPhone Standard w Cancel Modem Driver Standard v Port Settings Connection Port Baud Rate 39600 wv Data Bits Parity i Printer Modem Port Stop Bits Flow Control I warn if Port is in Use Figure 47 Microphone communications settings On LINUX you can use MINICOM where the settings can be adjusted running minicom s as root or by changing the settings with the CTRL A O command The cor rect settings are illustrated in figure 48 and figure 49 lelcome to minicom 1 75 Callin Pr Callout Progra IM MOS OLD CTRL A Z for help 9600 8N1 NOR Minicom 1 75 1996 VT102 Offline Figure 48 Serial port setting in MINICOM 46 xterm Modem and dialing parameter ing secseeees ATIT i ATDP IM MSOs Lo H I J IJ settee string F Dial time 2c62s4e0000040 P Auto baud detect No Delay before redial 5 Q Drop DTR to hangup Yes 10 R Modem has DCD line Return or Esc to exit CTRL A Z for help 9600 8N1 NOR Minicom 1 75 1996 VT102 Offline Figure 49 Modem settings in MINICOM On SUN a common tool is tip used on the dev ttya or dev ttyb ports More details are given in the manual man tip 47 APPENDIX E RUNNI
25. ght measurements 9 Reflected light measurements 10 Batt ries sereset di ea E e done edue se 12 Cables and accessories ununun unnn urrunen 12 Powersupply 24 3Ne es owen bash se aie na ont s 12 Interface and charger module 4 13 Software support floppy disks 0 13 Unpacking Test si2s26c2sneeoks een ed bees ge ua weNeRe 14 CONNCCHONS 4 cc30ceeGadYeceseheee desta kee ese heeae 14 Charging configuration 00 00 14 Configuration for robot computer communication 15 The serial communication protocol 00 18 Thetools s2c53 4 064 Soden hd ei a i es oe tae ee 18 The control protocol 0 0 0 cee eee eee 19 Testing a simple interaction 000 20 Using Lab VIEW 2 1234 eee ose be ee tee wev es base tous 22 Hardware configuration 0 002 e eee 22 Set up of the serial link 2 csoecnsd conor ene an 22 MOtOFS seuran regdeur a e EE E e aces 24 SONSOOS ora roer aes E EAA EEE ERa EE 27 Braitenberg s vehicle 22s4 02eveesegbdeveeeudere ese 28 Advanced programming 0s eee eee ee 30 SOUSOIS vers hekaoe et eR teeee eee hve EE Ea 31 Example of Braitenberg s vehicle 32 Referents oaeoi acakan daaa a oa E AE a 33 Appendix A Communication protocol to control the robot 34 Appendix B Connectors 0 0 eee eee 40 Appendix C How to open the robot and change the ROM
26. gure 35 Serial line S connector RED placed on the CPU board and on the interface charger module Female connector 1 GND Ground 2 V Charger input voltage 3 NTC Temperature measurement 4 NTC Temperature measurement Figure 36 Battery recharger connector placed on the motor sensors board and on the charger module Pin Signal Pin Signal 1 Reset 41 D15 2 VCCEst 42 AO 3 GND 43 Al 4 VCC 44 A2 5 GND 45 R W 6 VRef 46 CSExt 7 GNA 47 FI 18 D8 48 IRQ6 19 D9 49 MISO 20 D10 50 MOSI 21 Dil 51 SCK 22 D12 52 CSCOM 23 D13 53 TxD 36 CH3 54 RxD 37 CH4 55 A3 38 CH5 56 A4 39 PAI 57 A5 40 D14 Figure 37 K extension bus pinning 40 DB25 female connector Not connected Not connected Transmit data data from PC to Khepera Not connected Receive data data from Khepera to PC Not connected Not connected Not connected Not connected Not connected Not connected Not connected Ground Not connected Data Carrier Detect from Khepera to PC always set to 12 Not connected Not connected Not connected Not connected Not connected Not connected Not connected Not connected Not connected Not connected Figure 38 RS232 connector placed on the interface charger module Male connector Female connector cable Front view Side internal view Side internal view Front view O GND Ground external 8 5V Power supply internal Figure 39 Power supply connector of the inte
27. he help message of the modules available in the ROM A parameter can be used to indicate a need of help on a particular item help list gives an help message for the list tool help demo gives an help message on the demo func tion mentioned above list Gives the list of all the tools functions protocol commands 18 and other modules available in ROM For every item listed you get an ID a name a description and a version The ID is composed by four letters The first two letters define the fam ily of the module IDs starting by TA define tasks running on Khepera FU functions that can be executed with the run command PR protocol commands TO tools like this one and BIT BIOS components k team Gives a short description of the K Team active members net Gives an information about the intelligent extension turrets installed on the robot For each item listed you get a name an ID to be used to address the turret see also the command T in appendix A a description and a revision memory Gives an information about the memory used by the system restart Resets the robot This action is equivalent to a hardware reset process Gives the list of all processes running on Khepera in parallel to the serial communication protocol management sfill Starts a Motorola S format downloader This downloader does not start the execution of the code at the end of
28. he set up effective 48
29. ion of the two wheels as described above The position given as target will be reached using a trapezoidal speed profile as described in section 3 1 5 of this manual The target position can be given to the robot with the Control_position VI illustrated in figure 26 Also here the commands can be made moving the slider or entering the desired position in the digital display placed between the sliders and their names Control_position Spt Application Font Next position Next position motor lett motor right a z e d a 100000 100000 T000 T000 20000 20000 25000 25000 o 25000 25000 So000c S0000 75000 7T5000 E 100000 T Figure 26 Control_position panel 2 sliders controlling the position to reach for every wheel As described in section 3 1 5 of this manual every displacement in position control mode will be made following a precise speed profile The parameters of this speed profile can be configured using the VI Conf_pos_param showed in figure 27 For each motor you can set acceleration and maximal speed Deceleration will be set identical to acceler ation Figure 27 shows default values 26 Conf_pos_param Serial port ef re max speed_lett acceleration_lett Figure 27 Conf_pos_param panel all the parameters of the speed profile can be controlled To test the position control please start setting to 0 the two position counters of the two wheels using
30. k e Plug the power supply to the wall socket only when these connections are established The charger will perform some measurements and then start to charge These oper ations can take 10 minutes if the batteries are hot after long use or too discharged When charging the charging indication led is ON If the led does not switch ON after 10 minutes unplug and re plug the power supply The led is switched OFF at the end of the charging process The charging time for an empty battery is about 40 minutes At this moment you can unplug the power supply and remove the charger cable When charging the battery can be hot 50 C This is nor mal 5 2 Configuration for robot computer communication This configuration allows the communication between the robot and a host compu ter through a serial link On the host computer side the link is made by a RS232 line The interface module converts the RS232 line into the S serial line available on the robot The following connections must be made e Between the robot and the interface charger module by the S serial cable This cable also supports the power supply of the robot This external power supply is available when the general battery switch is OFF If the switch is ON the robot uses its own batteries for power supply e Between the interface module and the host computer by a standard RS232 cable This cable is not in the package because there are several standards at the level of th
31. l The unit of displacement correspond to 0 08mm Get_position Position motor left fs Serial port aF MoDem Position motor right fs 7 Figure 24 Get_position panel 2 indicators show the position of each wheel To test the functionality of this module just click on the double arrow to start the recurrent running mode At this moment the VI will show you the actual position of each wheel To change the position of the wheel use the Motors VI as described above and observe the result on the Get_position VI To set the position counter to a given value you can use the Set_position VI The Get_speed VI display the speed of each wheel This value is computed on the robot based on the information of the position and the time Get_speed Spt Application Font al Speed motor lett Serial port Speed motor right pd b Figure 25 Get_speed panel 2 indicators show the speed of each wheel 25 To test the functionality of this module just click on the double arrow to start the recurrent running mode At this moment the VI will show you the actual speed of each motor To change the speed of the motors use the Motors VI as described above You can also try to set the motor speed to 5 using the Motors VI then slow down the wheels with your fingers and look to the result on the Get_speed VI It is also possible to give to the robot a position to reach expressed using the posi t
32. n empty battery is about 45 minutes See Charging configu ration on page 14 for more details The S RS232 interface this interface allows the connection between the robot S serial line and a host computer over a RS232 port Two connec tors are available a standard female DB25 the interface module is a DCE for the RS232 link toward the host computer and a S six pins connector for the link toward the robot The link towards the robot also powers the robot if the battery switch is OFF See Configuration for robot computer communication on page 15 for more detail on this working configuration 3 5 Software support floppy disks Three 3 5 floppy disks contain all the modules for interfacing the Khepera robot with LabVIEW on PC Macintosh and SUN see Using LabVIEW on page 22 The software LabVIEW is a product of National Instruments and is not included in the package 13 4 UNPACKING TEST O After unpacking it is important to test the functionality of the robot A test that uses most of the possible functionnalities is available with the running mode 0 a Braiten berg vehicle see Jumpers reset button and settings on page 5 To obtain this running mode operate as following e Put the robot on a flat surface without danger for the robot Water edge of the table or metallic objects have to be considered as dangerous for the robot Be aware that the robot will move rather quickly and cover long
33. nterface are switched OFF Otherwise damages can occur Switch OFF the robot if you will not use it for more than a day Disconnect the power supply removing it from the wall socket Do not open the robot separate upper from lower part if you do not have been ex plicitly allowed Disconnect the CPU to the sensory motor board only if you have been allowed by a spe cific documentation Perform this operation following carefully the instructions given in appendix C Do not manually force any mechanical movement Avoid to force by any mechanical way the movement of the wheels or any other part Avoid to push the robot in a way that forces the wheels If you have any question or problem concerning the robot please contact your Khepera dealer 1 3 Recycling Think about the end of life of your robot Parts of the robot can be recycled and it is important to do so It is for instance important to keep Ni Cd batteries out of the solid waste stream When you throw away a Ni Cd battery it eventually ends up in a landfill or municipal incinerator These batteries which contain heavy metals can contribute to the toxicity levels of landfills or incinerator ash By recycling the Ni Cd batteries through recycling programs you can help to create a cleaner and safer environment for genera tions to come For those reasons please take care to the recycling of your robot at the end of its life cycle for instance sending back the robot to the manufact
34. on speed of 9600 Baud Same as mode 1 but with the communication speed of 19200 Baud wy Same as mode but with the communication speed of 38400 Baud 4 User application mode start an application stored into the EPROM you can add to the standard modules if any 5 Downloading mode in this mode the robot waits for a program to be transferred and executes it when downloaded S format 9600 Baud 6 Same as mode 5 but with the serial link at 38400 Baud 7 Test of the functionality of the robot The result of successive tests is given on the serial link 9600 Baud The serial link set up is always 8 bit 1 start bit 2 stop bit no parity Only the baud rate changes The set up of the jumpers can be changed at any time If the robot is run ning it is necessary to reset it to make the set up effective The reset button can be used at any time to reset the robot 3 1 4 The S serial line The S serial line is an asynchronous serial line with TTL levels 0 5V An inter face is necessary to connect this line to a standard RS232 port This interface is included in the interface charger module present in the package see Interface and charger mod ule on page 13 The S serial line can power the robot The length of the S serial cable should be limited to two meters for proper operation 3 1 5 Motors and motor control Every wheel is moved by a DC motor coupled with the wheel through a 25 1 reduction gear An incremental en
35. on_number Format of the response N Effect Perform an action on one of the two LEDs of the robot Possible actions are 0 turn OFF 1 turn ON 2 change status The LED number 0 is the lateral one the LED number 1 is the frontal one N Read proximity sensors Format of the command NII Format of the response n val_sens_left_90 val_sens_left_45 val_sens_left_10 val_sens_right_10 val_sens_right_45 val_sens_right_90 val_sens_back_right val_sens_back_left Effect Read the 10 bit values of the 8 proximity sensors section 2 1 6 2 from the front sensor situated at the left of the robot turning clockwise to the back left sensor O Read ambient light sensors Format of the command O Format of the response o val_sens_left_90 val_sens_left_45 val_sens_left_10 val_sens_right_10 val_sens_right_45 val_sens_right_90 val_sens_back_right val_sens_back_left Effect Read the 10 bit values of the 8 light sensors section 2 1 6 1 from the front left sensor turning clockwise to the back left sensor 38 P Set PWM pulse width modulation Format of the command P pwm_motor_left pwm_motor_right Format of the response pi Effect Set the desired PWM amplitude see Motors and motor control on page 6 for more details on the two motors The minimum PWM ratio is 0 0 The maximal forward ratio 100 correspond to a value of 255 The maximal backwards ratio 100 correspond to a value o
36. ontrol of the speed or position of the motor setting the correct PWM value according to the real speed or position read on the incre mental encoders target trajectory position position position PID position gt generator a j aror controller control A A f g d speed 3 spere 5 speed PID control error controller S a Po dx dt g A PWM automatic control rr y switching yy pulse PWM PWM lt _ _ _ counter generator 4 increments encoder Figure 6 Structure of the motor controllers and levels of user access Both DC motors can be controlled by a PID controller executed in an interrupt rou tine of the main processor Every term of this controller Proportional Integral Deriva tive is associated to a constant setting the weight of the corresponding term Kp for the proportional Kj for the integral Kq for the derivative The motor controller can be used in two control modes The speed and the position modes The active control mode is set according to the kind of command received If the controller receives a speed control command it switches to the speed mode If the con troller receives a position control command the control mode is automatically switched to the position mode Different control parameters Kp Kj and Kq can be set for each of the two control modes Used in s
37. or more informa tion about these particular devices please refer to the documentation of the sensor manu facturer The exact part name is SFH900 2 and the manufacturer is SIEMENS This sensor device allows two measures e The normal ambient light This measure is made using only the receiver part of the device without emitting light with the emitter A new measure ment is made every 20 ms During the 20 ms the sensors are read in a sequential way every 2 5 ms The value returned at a given time is the result of the last measurement made The light reflected by obstacles This measure is made emitting light using the emitter part of the device The returned value is the difference between the measurement made emitting light and the light measured without light emission ambient light A new measurement is made every 20 ms During the 20 ms the sensors are read in a sequential way every 2 5 ms The value returned at a given time is the result of the last measurement made The output of each measurement is an analogue value converted by a 10 bit A D converter The following two sections 3 1 6 1 and 3 1 6 2 illustrate the meaning of this 10 bit values 3 1 6 1 Ambient light measurements The measurement of the ambient light versus the distance of a light source has the following shape 500 3 Dark 400 7 300 4 200 gt Measured value 1004 0 l l l l 0 50 100 150 200 250 Distance to the light source mm
38. ot pressing on the reset button Your terminal should display ROM of minirobot KHEPERA The transmit data Robot TxD on the interface module green lamp should blink after reset If the robot does not respond as indicated the green led does not blink after reset check the points mentioned above and retry If the green led blinks but your com puter does not show any message check the configuration of your serial port and termi nal emulator as well as the connection between interface charger module and host computer 17 6 THE SERIAL COMMUNICATION PROTOCOL O The serial communication protocol allows the complete control of the functionnal ities of the robot through an RS232 serial line It correspond to running modes 1 to 3 see Jumpers reset button and settings on page 5 The connection configuration necessary to use these functionnalities is presented in the section 5 2 of this manual The configura tion baudrate as well as data start stop and parity bits of the serial line of your host computer must correspond to the one set on the robot with the jumpers running modes 1 to 3 always 8 bit 1 start bit 2 stop bit no parity The communication between the host computer and the Khepera robot is made sending and receiving ASCII messages Every interaction is composed by e A command sent by the host computer to the Khepera robot and followed by a carriage return or a line feed e When needed a r
39. peed mode the controller has as input a speed value of the wheels and controls the motor to keep this wheel speed The speed modification is made as quick as possible in an abrupt way No limitation in acceleration is considered in this mode Used in position mode the controller has as input a target position of the wheel an acceleration and a maximal speed Using this values the controller accelerates the wheel until the maximal speed is reached and decelerates in order to reach the target position This movement follows a trapezoidal speed profile as described in figure 7 The input values and the control mode of this controller can be changed at every moment The controller will update and execute the new profile in the position mode or control the wheel speed following the new value in the speed mode A status of the con troller indicates the active control mode the phase of the speed profile on target or in movement and the position error of the controller speed max_speed time position target position start position time Figure 7 Speed profile used to reach a target position with a fixed acceleration acc and a maximal speed max speed 3 1 6 Infra red proximity sensors Eight sensors are placed around the robot and are positioned and numbered as shown in figure 8 Figure 8 Position of the 8 IR sensors These sensors embed an infra red light emitter and a receiver F
40. pera and inter face that the robot is powered power adaptor then start LabVIEW and open the Set up virtual instrument called VT present in your floppy disk The panel illustrated in figure 22 should appear 22 serial flow control ete Serial port input HON OFF MODEM AEST baudratel Wipe and nake j z _19200 input alt Hiv HShk output XON XOFF output HW Handshake output alt Hi HShk Figure 22 Set up panel for serial link initialisation Now select the serial port on which the robot is connected This selection depend on which port you use and the type of computer you have This choice must be made for every module that you will use Then click once on the run arrow at the top of the window A stop icon appears for a few seconds after what the front panel returns to its initial state That s all The serial link with Khepera is set to 19200 baud It will remain so until you quit LabVIEW 23 7 3 Motors We will now control the displacement of the robot Be sure that the serial link has been correctly installed then open the Motors VI present on the floppy disk Now your screen displays the following panel Figure 23 Motors panel 2 sliders controlling the speed of each wheel Before to move the robot you must learn how to stop it Different means are avail able Starting from the most efficient e Press the reset button on the robot once e P
41. rface charger module 41 APPENDIX C HOW TO OPEN THE ROBOT AND CHANGE THE ROM 3 Changing the ROM of Khepera needs very fine operations The complete sequence of actions is described in this appendix Please follow very carefully these instructions A wrong action can cause mechanical damages to your Khepera robot We do assume no responsibility for your wrong manipulations The ROM is situated inside the robot To change it please e Disconnect the robot from the power supply or the battery charger switch the robot OFF e Open the robot by separating the CPU board to the motor sensors board Be very careful in this operation and follow the indications given in figure 40 and figure 41 GOOD BAD Figure 40 Good and bad way to remove a CPU board from the basic motor and sensor board To do this operation without damages to the pins the CPU board must be disconnected carefully and all pins have to be disconnected together This can be made using a big plastic screwdriver and operating between the CPU board and the white motor blocks Open some millimetres right then left then right and be very careful CPU board Motor sensors board Figure 41 Be very careful opening the robot The tool should not damage electronic components The tool should make the effort directly to the green print board or on stable mechanical parts like the white motor boxes indicated in the figure 42 e When the CPU and mo
42. robot Some exchange parts are also included in the package 4 new tires 10 jumpers 3 3 Power supply A transformer provides the power supply to the interface module and if the battery switch of the robot is OFF to the robot itself The connection between the power supply and the interface charger module is made by the power supply jack see Interface and charger module on page 13 SAFETY PRECAUTION The power supply must be connected to the wall socket only when all other connections are already made 12 3 4 Interface and charger module Power supply jack RS232 Charging O E Recharging connector Robot RxD O ae Robot TxD O S serial line connector Figure 15 The interface charger module This module supports the interface between the robot and the host computer the power supply of the robot from the S serial line cable and the charge of the battery To work the module needs to be connected to the power supply The following features are present in this module e The battery charger a four pins connector allows the connection with the Khepera robot to charge its battery When charging the robot must be disconnected to all other systems and switched OFF Avoid to recharge full batteries this can cause damages It would be optimal to discharge the robot completely leave the robot swathed on before recharging it During the charging period a yellow led indicates the activity The charg ing time for a
43. rs 1 and 4 and 90 degree corresponds to the two side sensors numbers 0 and 5 The result type single is added to the value 10 0 The sum of the left sensors 3 4 and 5 corresponds to motor right 0 The sum of the right sensors 0 1 and 2 corresponds to motor left 1 These two values are then formatted 132 and send to the motors The computation needed is simple and fast enough to control Khepera in real time without big delays However displaying Motors and Sensors panels is a computational expensive operation If you want Khepera to move faster close these pan els but don t close the Braitenberg panel 8 REFERENCES O Braitenberg84 Braitenberg V Vehicles Experiments in synthetic psychology MIT Press 1984 Mondada93b Mondada F Franzi E and Ienne P Mobile robot miniaturisation a tool for investigation in control algorithms ISER3 Kyoto Japan 1993 National91 National Instruments LabVIEW manuals for the release 5 january 1998 33 APPENDIX A COMMUNICATION PROTOCOL TO CONTROL THE ROBOT S This communication protocol allows complete control of the functionnalities of the robot through a RS232 serial line The connection configuration needed is presented in section 5 2 The set up of the serial line of your host computer must correspond to the one set on the robot with the jumpers running modes 1 to 3 The protocol is constituted by commands and responses all in standard A
44. sponse of the sensor 1100 H black plastic 1000 4 900 s i green styropor E 800 A z ss pink sponge 3 p gt se S 700 a white plastic p99 grey plastic i 0 3 mn wood 1 5 400 S 300 wood 2 x 200 ee rA copper 100 0 Distance to the wall mm Figure 11 Measurements of the light reflected by various kinds of objects versus the distance to the object 10 The directionality of the sensor measurement is illustrated in Figure 10 these sen sors have a very large field of view Obstacle Angle 15 mm Measured reflection value Sensor 0 10 7 i T T T T 2 oo oD 9 fs 9 9 a a a GS SK GC A Angle Figure 12 Typical response of a proximity sensor for an obstacle 7 mm in width at a distance of 15 mm The measurement is given versus the angle between the forward orientation of the robot and the orientation of the obstacle The characteristics of the different physical sensors can change in a large range Figure 13 shows the measurements made on six sensors of the same robot placed in iden tical conditions Small differences of conditions vertical orientation of the sensor ambi ent light conditions colour of the floor can bring additional differences 1100 1000 sensor 1 o 900 sensor 2 3 E 800 sensor 3 g 700 sensor 4 lt 600 sensor 5 ne 500 sensor 6 D 5 400 a 300 200 100 0 10 20 30 40 50 6 Distance to the wood wall mm Figure 13 Typical measur
45. the Set_position VI or resetting the robot At this moment you can try the Control_position VI setting a distance of 1000 on both sliders and running the VI once clicking on the run arrow The robot should move forward showing an accelera tion a fixed speed and then a deceleration Test other movements keeping both left and right displacements identical to move on a line To start other kinds of trajectory bring back the robot to the 0 position or use the Set_position VI to reset the counter Then use the Conf_pos_param VI to set the left maximal speed to 10 the left acceleration to 32 and keeping the values of the right tra jectory to the default value indicated in figure 27 Run the VI once to make these values effective Then set on the Control_position VI the goal position of the left wheel to 1000 and the goal position of the right wheel to 2000 Run the VI once and observe the trajectory of the robot The robot should make a circular trajectory 7 4 Sensors In its basic version Khepera has eight infra red sensors as described in section 3 1 6 You will now easily understand their characteristics Be sure of the set up of the serial link then open the Sensors VI that you have on the floppy disk You should see on your screen the panel illustrated in figure 28 27 Sensors Figure 28 Sensors panel 8 gauges displaying the infra red values Each proximity
46. the download To download and execute a code please use the sloader function started by the command run sloader 6 2 The control protocol To control the functionnalities of the Khepera robot motors sensors etc a set of command are implemented in the control protocol Also in this case the communication with the Khepera robot is made sending and receiving ASCII messages Every interac tion between host computer and Khepera is composed by e A command beginning with one or two ASCII capital letters and followed if necessary by numerical or literal parameters separated by a comma and terminated by a carriage return or a line feed sent by the host computer to the Khepera robot e A response beginning with the same one or two ASCII letters of the com mand but in lower case and followed if necessary by numerical or literal parameters separated by a comma and terminated by a carriage return and a line feed sent by the Khepera to the host computer In all communications the host computer plays the role of master and the Khepera the role of slave All communications are initiated by the master The protocol commands are 18 and a complete description is given in Appendix A 19 6 3 Testing a simple interaction To better understand both tools and protocol commands we propose to do a very simple test as following e Set the jumpers to select the running mode 1 see Jumpers reset button and settings on page 5
47. tor board are disconnected remove the ROM The ROM is situated on the bottom of the CPU board as indicated in figure 42 Figure 42 ROM position on the bottom side of the CPU board e To extract the EPROM operate carefully as with the robot There are two access holes that make the extraction possible as indicated in figure 43 Figure 43 Location of the access holes for the extraction of the ROM e Use a specific extraction tool to push out the EPROM very carefully and in a parallel way as indicated in figure 44 ARARARARANARAAN GOOD DAMAGE BAD Figure 44 Correct and wrong ROM extraction operation On the left the ROM extraction tool 43 e Finally plug the new EPROM Be careful about the orientation given by a corner of the ROM as showed in figure 45 Ey A Figure 45 One corner of the chip define its orientation e Assemble again CPU and motor sensors board Be sure to completely insert the connectors to ensure a good contact 44 APPENDIX D RS232 CONFIGURATION O On PCs a common terminal emulator is Hyper Terminal Figure 46 shows the con figuration panel set for a communication speed of 9600 baud on COM 1 COM1 Properties EES Port Settings Bits per second Data bits Parity Stop bits Flow control Advanced Restore Defaults Figure 46 Hyper Terminal configuration panel 45 On MAC you can use the so
48. turn or LF line feed indicates CR and LF A Configure Format of the command A Kp Ki KdI Format of the response af Effect Set the proportional Kp integral Ki and derivative Kd parameters of the speed controller At the reset these parameters are set to standard val ues Kp to 3800 Ki to 800 Kd to 100 B Read software version Format of the command BI Format of the response b version_of_BIOS version_of_protocol Effect Give the version of the software present in the EPROM of the robot C Set a position to be reached Format of the command C pos_left pos_right Format of the response c Effect Indicate to the wheel position controller an absolute position to be reached The motion control perform the movement using the three con trol phases of a trapezoidal speed shape an acceleration a constant speed and a deceleration period These phases are performed according to the parameters selected for the trapezoidal speed controller command J The maximum distance that can be given by this command is 2 23 2 pulses that correspond to 670m The unit is the pulse that corresponds to 0 08mm The movement is done immediately after the command is sent In the case another command is under execution speed or position con trol the last command replaces the precedent one Any replacement tran sition follows acceleration and maximal speed constraints 35 D Set speed Format of the
49. urer or to your local dealer Thanks for your contribution to a cleaner environment 2 UNPACKING AND INSPECTION O Figure 1 Position of the different parts in the bag Open the bag and check each item in the box against figure 1 1 The documentation you are reading now 2 Power supply 3 Interface and charger module 4 Three disks with the software modules VIs for LabVIEW on SUN on Macintosh on PC 5 Cables Serial S Battery 6 Spare parts tires and jumpers 7 Your Khepera robot in the basic version 3 THE ROBOT AND ITS ACCESSORIES O 3 1 The Khepera miniature robot 3 1 1 Overview Top view Side view Bottom view Figure 2 Position of some parts of the robot Make an external inspection of the robot Note the location of the following parts 1 LEDs Serial line S connector Reset button Jumpers for the running mode selection Infra Red proximity sensors Battery recharge connector ON OFF battery switch Second reset button same function as 3 OenANNMN BW PY 3 1 2 ON OFF battery switch Bottom view 0 Qim OFF lt gt ON Figure 3 Position of the Battery power supply ON OFF switch It allows the user to switch the battery of the robot ON or OFF When ON the robot is powered by the Ni Cd internal batteries In this case the robot cannot be powered by an external supply When OFF
50. ut the value 0 for each speed using the sliders Don t forget that these new values will only be taken into account at the next execution i e click on the arrow e Click on the button labelled Stop You have also to click on the arrow again so that the robot takes your last decision into account Before trying to give another values to the motors click again on the button to de select this option This last option is the best way to stop the robot You control directly each one of the motors by simply putting the desired speed values in the corresponding slider This can be made moving the slider or entering the desired speed in the digital display placed between the sliders and their names 24 Possible values are constrained only on the sliders between 20 and 20 so to take care of the mechanics To transmit your order to the robot just click once on the arrow You can change the values and click on the arrow again to validate your choice You see that the robot continues moving at the same speed until new values are send If you are getting bored with clicking on the arrow try one click on the double arrow Click on the stop icon to stop the execution The robot has two incremental encoders on the wheels Using these sensors it is possible to measure the displacement and the speed of each wheel at every moment The VI Get_position ask for the content of the increment counter which represent the dis placement of the whee
Download Pdf Manuals
Related Search