Ceramic Appnote 5426 - Galil Motion Control
Contents
1. ED L MG _RPX _TEX _ILX _MOX WT100 JP L bWSNFroOo ILO CP100 CT KIO 01 PR1000 BG XQ 0 0000 19 0000 0 0000 0 0000 934 0000 669 0000 0 0000 0 0000 1000 0000 684 0000 2 0406 0 0000 1000 0000 656 0000 4 6783 0 0000 1000 0000 429 0000 7 2166 0 0000 1000 0000 340 0000 9 8544 0 0000 1000 0000 83 0000 9 9982 1 0000 1000 0000 82 0000 9 9982 1 0000 11 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com CT FUNCTION Specifies the rate at which the integrator limit IL is incremented DESCRIPTION When the dead band is turned on CP between 0 and 32767 CT specifies how fast IL is incremented when the move is complete _BGn 0 but the error TE is still greater than the dead band CP IL will stop incrementing if it reaches 9 998 or if the absolute value of the error TE becomes less than the dead band CP Note The CT command is not available on Accelera series motion controllers ARGUMENTS CT n n n n n n n n or CTA n where n is an even integer in the range 0 to 126 0 2 4 124 126 O turns the IL increment off 2 increments IL fast and 126 is slow n Returns the value of the integrator limit rate for the specified axis USAGE DEFAULTS While Moving Yes Default Value 0 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _CTn contains the value of the int2. Commanded position and torque vs time KP0 KI0 KD0 K10 K20 K30 FC10 FN5000 PR10000 15 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com FN FUNCTION Distance from end of move when FC is engaged DESCRIPTION Adds a bias to the torque output TT proportional to the commanded velocity if the distance from the end of the move is less than FN FC is the same as FV but activated FN counts from the end of the move and both positive and negative values are allowed Bias in volts 1 22 10 FC commanded Velocity in counts s ARGUMENTS FN n n n n n n nn or FNA n where nis an integer in the range 0 to 2147483647 in counts n Returns the distance from the end of the move when FC is engaged for the specified axis USAGE DEFAULTS While Moving Yes Default Value 0 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _FNn contains the distance from the end of the move when FC is engaged for the specified axis RELATED COMMANDS FC Distance from end of move when FC is engaged FV Standard velocity feedforward gain EXAMPLES FCX 10 set distance selectable velocity feedforward gain to 10 FNX 1000 set distance from end of move when FC is engaged to 1000 counts 16 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax
3. galilmc com 4 ABI1 Driver and LS2 Ceramic Motor Setup The next page shows a setup diagram between a Galil ICM 1900 and a Nanomotion LS2 ceramic motor system The ABI Driver Box is a Nanomotion product and can be configured to accept a 10V control signal from a Galil Controller Since the Galil command signal is single ended it must be connected to the Vin input on the Driver Box and the Vin should be grounded If a product other than Nanomotion is used contact the motor manufacturer for connection information Note The ABI driver box requires a 5V low amp enable signal This means that the drive is enabled at OV and disabled at SV When ordering a Galil interconnect module be sure to specify the LAEN option If a high amp enable interconnect module is used contact Galil for modification information Inside the AB1 Driver box there is a dipswitch bank that needs to be configured for 10V analog mode These switches are on the AC1 Card and the necessary settings are shown in the following diagram See the AB1 Driver Box User Manual for more LLL imi jm S1 S2 S3 S4 S5 5S6 Dip Switch Settings for the ABI Driver Box 9 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com Encoder Wire Connections Encoder ICM 1900 Channel A MAX Channel A MAX Channel B MBX Channel
4. of the velocity profile 3 Response Graphs 3 1 Antifriction Bias Parameters ZP and ZN Of all the tuning parameters mentioned above the ceramic motors are most sensitive to the values of ZP and ZN Excessive values of ZP and ZN can cause motor vibration whereas limited values will cause position error The three pictures below show the performance of a Nanomotion LS2 ceramic motor with varying ZP values The blue lines represent the actual motor position and the green lines are the commanded position The program used to produce these screen shots was identical to the one written above Eistorage scopes STE File Edit Graph Terminal Help 1 Scope Primary Data x x MS Time E Actual Postion x Zoom Noma M Collecting for Secondary Secondary Data k a time sm Commanded Position x Normal bd Command String xo JV Stop After Scope Completes Start Collecting Status Scope data collection complete Oscillations due to a ZP value that s too large 5 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com storage scopes x File Edit Graph Terminal Help E Primary Data x Tie E Actual Poston x Zoom Noma IV Collecting for Secondary Secondary Data x Time F Commanded Position Normal Command String JV Stop After Scope Completes Start Collecting Stat
5. 2 e www galilmc com
6. 3 mar aas GALIL Application Note 5426 Tuning Ultrasonic Ceramic Motors This application note gives some tips for tuning ultrasonic ceramic motors using Galil s ceramic motor special firmware It also includes a brief description of how to connect a Galil Controller to the Nanomotion Brand LS2 Ceramic Motor Galil s ceramic motor firmware is available for a one time 400 fee and is highly recommend for optimum ceramic motor performance 1 COMMAND SUMMARY wincssscccssensstsncssncsevensscsnsescectaconsescsennvessntssietsevedsvonsescetsnsssseccesanvevencsdbatdevonsscs 2 2 TUNING e E E E E E 2 21 SERVO LOOP UPDATE RATE TM sesssecesssssecssscececssnseceensnsesenessesssnseeecnsnsecsesssesseneeeeessnseesens 2 22 ANTIFRICTION BIAS PARAMETERS ZP AND ZN 3 2 3 DEAD BAND PARAMETERS DS AND DB 3 2 4 MOTOR OFF DEAD BAND CP ANDCT ie 3 25 PID GAINS K1 K2 K3 AND KP KI KD i 4 2 6 FEEDFORWARD GAINS FC FN FV FA i 5 3 RESPONSE GRAPHS vessssscccccssssatsossccessassscctsnssscevestunssseoossnes cosonsedeansscessnssinsedessenssecosevennessedsesensedesuseeses 5 3 1 ANTIFRICTION BIAS PARAMETERS ZP AND ZN 5 3 2 DISTANCE SELECTABLE VELOCITY FEEDFORWARD GAIN FC FN 7 3 3 MOTOR OFF DEAD BAND CP ANDCT ii 8 4 AB1 DRIVER AND LS2 CERAMIC MOTOR SETUP u sssscssscsssscsssccsscccsssc
7. 916 626 0102 e www galilmc com K1 FUNCTION P gain during motion DESCRIPTION K1 is the proportional gain in effect when the profiler is commanding motion RP is changing When no motion is commanded RP constant KP is in effect Some systems will oscillate when holding position unless the gains are lowered ARGUMENTS K1 n n n n n n n n or K1A n where n is a number in the range 0 to 1023 875 with a resolution of 1 8 n Returns the value of the P gain during motion for the specified axis USAGE DEFAULTS While Moving Yes Default Value 6 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _K1n contains the value of the P gain during motion for the specified axis RELATED COMMANDS KP Proportional gain when holding position K2 Integral gain during motion K3 Derivative gain during motion EXAMPLES K1X 10 set X axis P gain in effect during motion K2X 1 set X axis I gain in effect during motion K3X 100 set X axis D gain in effect during motion KPX 6 set X axis P gain in effect when holding position KIX 0 set X axis I gain in effect when holding position KDX 64 set X axis D gain in effect when holding position 17 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com K2 FUNCTION I gain during motion DESCRIPTION K2 is the integral gain in effect when the profiler is comm
8. B MBX Index INX Index INX Note Some linear encoders may not have an index channel ICM AMP 1900 MOCMDX AMPENX 48 V DC Power Supply 48V GND Vin PET _ ENABLE Nanomotion Motor P N LS2 JEPOoUF Jeau LHOd O I INO HYOLOIN xog HIAIHC LAY 10 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com 5 Command Reference CP FUNCTION Dead band within which the motor is shut off MO DESCRIPTION After a move is complete _BGn 0 and the absolute value of the position error TE becomes less than the dead band CP the motor is turned off SH must be issued before further motion can be commanded CT can be used to increment the integrator limit to ensure that the motor reaches the dead band ARGUMENTS CP n n n n n n n n or CPA n where n is an integer in the range 0 to 65535 in counts If n gt 32768 the feature is disabled n Returns the value of the dead band for the specified axis USAGE DEFAULTS While Moving Yes Default Value 65535 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _CPn contains the value of the dead band for the specified axis RELATED COMMANDS CT Specifies the rate at which the integrator limit IL is incremented EXAMPLES ESRAV DMC1842 Rev 1 0n CM F TORAS
9. Yes Default Value 0 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _ZNn contains the value of the negative antifriction bias for the specified axis RELATED COMMANDS ZP Positive antifriction bias OF Offset EXAMPLES ZNX 1 set negative antifriction bias on X to 1 volt ZPX 1 set positive antifriction bias on X to 1 volt 20 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com ZP FUNCTION Positive antifriction bias DESCRIPTION ZP adds a positive open loop voltage to the controller s command signal when the position error is positive ARGUMENTS ZP n n n n n n n n or ZPA n where n is a number in the range 0 to 9 999 volts with a resolution of 0 0003 n Returns the value of the positive antifriction bias for the specified axis USAGE DEFAULTS While Moving Yes Default Value 0 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _ZPn contains the value of the positive antifriction bias for the specified axis RELATED COMMANDS ZN Positive antifriction bias OF Offset EXAMPLES ZNX 1 set negative antifriction bias on X to 1 volt ZPX 1 set positive antifriction bias on X to 1 volt 221 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 010
10. anding motion RP is changing When no motion is commanded RP constant KI is in effect Some systems will oscillate when holding position unless the gains are lowered ARGUMENTS K2 n n n n n n n n or K2A n where n is a number in the range 0 to 2047 875 with a resolution of 1 128 n Returns the value of the I gain during motion for the specified axis USAGE DEFAULTS While Moving Yes Default Value 0 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _K2n contains the value of the I gain during motion for the specified axis RELATED COMMANDS KI Proportional gain during motion KI Integral gain when holding position K3 Derivative gain during motion EXAMPLES K1X 10 set X axis P gain in effect during motion K2X 1 set X axis I gain in effect during motion K3X 100 set X axis D gain in effect during motion KPX 6 set X axis P gain in effect when holding position KIX 0 set X axis I gain in effect when holding position KDX 64 set X axis D gain in effect when holding position 18 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com K3 FUNCTION D gain during motion DESCRIPTION K3 is the derivative gain in effect when the profiler is commanding motion RP is changing When no motion is commanded RP constant KD is in effect Some systems will oscillate when holding position unl
11. c com 2 2 Antifriction Bias Parameters ZP and ZN Once the TM has been set the next step is to adjust the antifriction bias parameters ZP and ZN The procedure for finding an acceptable ZP value is detailed below Turn the motor off with the MO command Set KP KD KI KI K2 and K3 to zero Set the motor in the middle of travel and define the position as zero DP 0 Turn the motor back on with the SH command Implement a positive position error by setting IP 50 Increment the value of ZP by 0 1 Volt until the motor makes a significant jump in the forward direct more than 2 or 3 counts The current motor position can be queried with the TP command and the error comes from the TE command Once the motor jumps reduce the value of ZP by 40 8 Repeat this procedure for the ZN command but make sure to use IP 50 for a negative position error 9 Due to inconsistencies in the Ceramic strip the necessary anti friction bias may vary over the full travel of the motor It may be helpful to find the minimum values of ZP and ZN in order to have better overall performance Neo 09 Oa WA 2 3 Dead band Parameters DS and DB With the antifriction biases set the next step is adjusting the dead band parameters DS and DB These values can be adjusted according to the users liking but DB must be greater than or equal to DS Also if the user sets a very small dead band it is more likely that the motor will oscillate This is because h
12. cssccsssesssssssnsssssnees 9 5 COMMAND REFERENCE savcsccsiccossssssconsssosstecosescessssacsesscssscesssnassonecsosssvcsonsessasesecsrssasssevonsaccenessesees 11 CP sides lance ea alain 11 Csa nl 12 y D o AE E ETE E ETE EENE A AE E E E E A AATE EA A AE EE T 13 DSi allinea ea 14 FC cain e ia a 15 PEN ili 16 CRCR ER RE A E 17 E AEA AE RE IR SRO OR ROERO OR PEA ARIETE RTRT RIA RO I CONE LORI 18 Rici 19 ZN Linee leone 20 ZIP ano ria ra 21 sls Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com 1 Command Summary The commands associated with the ceramic firmware are as follows ZP and ZN Antifriction Bias parameters that add an open loop voltage to the controller s command signal when there is position error The ZP provides a positive voltage when the error is positive and ZN provides negative voltage when the error is negative DS and DB Dead band with hysteresis parameters The DS specifies the range in encoder counts in which the PID and antifriction Bias are turned off and the DB specifies the range in which they are turned back on This is done when there is no profiled motion CP and CT Dead band with IL increment and motor shut off The CP specifies the error dead band at the end of a move in which the amplifiers will be disabled The CT increments the integrator limit to insure that the motor reaches this final range Note T
13. egrator limit rate for the specified axis RELATED COMMANDS CP Dead band within which the motor is shut off MO EXAMPLES HARAY DMC1842 Rev 1 0n CM F R S ED L MG _RPX _TEX _ILX _MOX WT100 JP L WNro ILO CP100 7C T2 KTO 0T PR1000 BG XQ 0 0000 19 0000 0 0000 0 0000 934 0000 669 0000 0 0000 0 0000 1000 0000 684 0000 2 0406 0 0000 1000 0000 656 0000 4 6783 0 0000 1000 0000 429 0000 7 2166 0 0000 1000 0000 340 0000 9 8544 0 0000 1000 0000 83 0000 9 9982 1 0000 1000 0000 82 0000 9 9982 1 0000 The CT command is not available on Accelera series motion controllers 13 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com DB FUNCTION Range in which PID and antifriction bias are turned on on band DESCRIPTION When the absolute value of the error TE is greater than DB the torque output TT will be set back to normal reflecting KP KD KI ZP and ZN This is used to avoid oscillation when holding position DB should be set greater than or equal to DS ARGUMENTS DB n n n n n n n n or DBA n where n is an integer in the range 0 to 32767 n Returns the value of the on band for the specified axis USAGE DEFAULTS While Moving Yes Default Value 0 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _DBn contains the value of the on band for the spec
14. ess the gains are lowered ARGUMENTS K3 n n n n n n n n or K3A n where n is a number in the range 0 to 4095 875 with a resolution of 1 8 n Returns the value of the D gain during motion for the specified axis USAGE DEFAULTS While Moving Yes Default Value 64 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _K3n contains the value of the D gain during motion for the specified axis RELATED COMMANDS KI Proportional gain during motion K2 Integral gain during motion KD Derivative gain when holding position EXAMPLES K1X 10 set X axis P gain in effect during motion K2X 1 set X axis I gain in effect during motion K3X 100 set X axis D gain in effect during motion KPX 6 set X axis P gain in effect when holding position KIX 0 set X axis I gain in effect when holding position KDX 64 set X axis D gain in effect when holding position 19 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com ZN FUNCTION Negative antifriction bias DESCRIPTION ZN adds a negative open loop voltage to the controller s command signal when the position error is negative ARGUMENTS ZN n n n n n n n n or ZNA n where n is a number in the range 9 999 to 0 volts with a resolution of 0 0003 n Returns the value of the negative antifriction bias for the specified axis USAGE DEFAULTS While Moving
15. he CT command is not available on Accelera series motion controllers K1 K2 and K3 Second set of PID gains that are active during motion FC and FN Distance selectable velocity feedforward gain The FC specifies the positive or negative feedforward gain and FN specifies the distance from the end of the move that FC is engaged 2 Tuning For the sake of tuning ultrasonic ceramic motors it is strongly recommended that the user purchase Galil s WSDK software The storage scopes in WSDK make it easy to view position error command position and torque levels during commanded moves The alternative to WSDK is using interrogation commands like TE Tell Error to monitor the response of the motor 2 1 Servo Loop Update Rate TM After downloading the firmware special onto the controller the first step is to reduce the TM value to 250 or lower if possible The TM command controls the servo update rate the smaller the value the faster the update rate See the controller manual appendix for the lowest TM value available Be aware that all speed and acceleration parameters will be altered i e for TM 500 the motor velocities will be twice as much as they were for TM 1000 Lowering the value of TM allows the PID and other tuning parameters to sample more often thus having better control over the motor 2 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilm
16. ified axis RELATED COMMANDS DS Range in which PID and antifriction bias are turned off EXAMPLES DSX 100 set off band on X axis to 100 counts DBX 200 set on band on X axis to 200 counts 13 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com DS FUNCTION Range in which PID and antifriction bias are turned off off band DESCRIPTION When the absolute value of the error TE is less than DS the torque output TT will be set to the offset OF the contributions of KP KD KI ZP and ZN are set to zero This is used to avoid oscillation when holding position DB should be set greater than or equal to DS ARGUMENTS DS n n n n n n n n or DSA n where n is an integer in the range 0 to 32767 n Returns the value of the off band for the specified axis USAGE DEFAULTS While Moving Yes Default Value 0 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _DSn contains the value of the off band for the specified axis RELATED COMMANDS DB Range in which PID and antifriction bias are turned on EXAMPLES DSX 100 set off band on X axis to 100 counts DBX 200 set on band on X axis to 200 counts 14 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com FC FUNCTION Distance selectable velocit
17. igh static friction makes it difficult for the motor to settle in a very small position window 2 4 Motor Off Dead Band CP and CT If the user needs to completely eliminate oscillation at the end of a profiled move then the DS and DB may not be sufficient The alternative is to use the CP command to disable the amplifier when the motor is within a target distance of the final position Once the amplifier is disabled the idea is that motor s static friction will hold the load in place However if the static friction is not strong enough the motor will be free to drift without Galil Control Therefore if the user wants control to be restored when the motor ventures outside of the dead band he will need to use the DS and DB commands instead The CT command is used along with the CP command to set the rate at which the integrator limit IL will be incremented in order to achieve the target distance Because the amplifiers are disabled when using the CP command the user will have to issue the SH command before beginning another move To disable the CP command enter a negative value as the operand i e CP 5 Note The target range specified by the CP command only takes effect when the controller has finished the profiled move This means that if the motor is following Be Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com the profile very cl
18. lter Scope Completes Status Scope data collection complete Motor response without the use of FC and FN WA storage Scopes Efe Eck Gaph Terminal Help Primary Data fx x Vs Tire x Actual Position z Zoom Nemal Collecting for Secondary Secondary Data k tm si Commanded Postion Nomnat z Command String I Stop Alte Scope Completes Statue Scope data colection complete Motor response with FC and FN ey Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com 3 3 Motor Off Dead Band CP and CT The final two screen shots demonstrate the use of CP and CT The example shows a 500 count move with a motor that doesn t follow the profile very accurately The CP distance has been set to 20 and the CT is also 20 Notice in the second picture that the motor slowly approaches the target range and stops without reaching 500 counts From then on there is no motion because the amplifier is disabled The second picture isn t meant to show better motor response but rather to demonstrate the use of CP and CT Obviously the 20 count dead band is an over exaggeration Profiled move using CP and CT Note The CT command is not available on Accelera series motion controllers 8 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www
19. nd the type of amplifier used Typically it s best to increase the differential gains to the brink of instability and then adjust the proportional and integrator gains for better motor performance and accuracy The differential gains will always be greater than the proportional gains and the proportional gains are usually greater than the integrator gains For point to point moves it is advised to set a negative integrator limit i e IL 9 99 so that the integrator is frozen during the profiled move This prevents profile overshoot and motor oscillation s Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com 2 6 Feedforward Gains FC FN FV FA In addition to the PID parameters the program above can also be used to set the FV FC and FN commands As with any standard firmware the FV Feedforward Velocity command applies a bias voltage to the amplifier during a profiled move The FC works the same way as the FV except that it may have negative values and can be selectively enabled at n counts before the end of the move Typically this function is enabled during the deceleration phase of the motion with negative values of FC This will decelerate the motor faster thereby reducing the chance for a target overshoot The FA Feedforward Acceleration command can also be used to provide bias voltage during the acceleration and deceleration ramps
20. osely within the target window then the amplifier will be disabled before the IL begins to increment Note The CT command is not available on Accelera series motion controllers 2 5 PID gains K1 K2 K3 and KP KI KD In order to adjust the two sets of PID the user will need to write and download a program similar to the one below A DPO B IP500 AMX WT25 TP 5 AMX WT250 JP B EN When executed this program will increment the ultrasonic motor back and forth 500 counts The WT250 will leave 250 servo samples of dwell between the IP commands and will allow for the motor to settle after each increment Using the Storage Scopes in WSDK the user can graph Actual and Commanded Position on the same display This will show how well the motor is following the profiled position for the given PID gains The KI K2 and K3 values take effect when the controller is producing a motion profile The K1 is the proportional gain K2 is the integrator gain and K3 is the differential gain When the motion profile is complete the KP KI and KD are the effective gains Due to static friction and the mechanics of the piezo strips ultrasonic motors have very nonlinear motion characteristics Having two sets of PID allows the user to better compensate for these non linear effects and make the motor more responsive The values of the PID gains will vary greatly depending on the TM value of the controller the resolution of the encoder a
21. us Scope data collection complete Position error due to a ZP value that s too small Elstorage scopes NO Eile Edit Graph Terminal Help Tee Primary Data Actual Poston xi IV Collecting for Secondary Secondary Data x a time F Commanded Position Normal Command String JV Stop After Scope Completes Start Collecting Status Scope data collection complete Motor response with the proper ZP value 6 Galil Motion Control Inc e 3750 Atherton Road e Rocklin CA 95765 USA e 800 377 6329 e Ph 916 626 0101 e Fax 916 626 0102 e www galilmc com 3 2 Distance Selectable Velocity Feedforward Gain FC FN Although not as sensitive the values of FC and FN are also very important in optimizing ceramic motor performance Below are two screen shots that demonstrate motor response with and without the use of FC and FN Again the program used to produce these screen shots is the same as the previous tests The value of FN was set to 100 so that FC would be applied 100 counts prior to the end of the profiled move The FC has been set to 20 because the motor lags behind the profile It will be necessary in most other systems to apply a negative FC to prevent the motor from leading the profile M storage Scopes io I D x Efe Eck Graph Terminal Help Actual Position x Zoom Norma Collecting for Secondary Secondary Data Commanded Poston Noma Command String TT Stop A
22. y feedforward gain DESCRIPTION Adds a bias to the torque output TT proportional to the commanded velocity if the distance from the end of the move is less than FN FC is the same as FV but activated FN counts from the end of the move and both positive and negative values are allowed Bias in volts 1 22 10 FC commanded Velocity in counts s ARGUMENTS FC n n n n n n n n or FCA n where n is an integer in the range 8191 to 8191 n Returns the value of the distance selectable velocity feedforward gain for the specified axis USAGE DEFAULTS While Moving Yes Default Value 0 In a Program Yes Default Format Command Line Yes Controller Usage ALL CONTROLLERS OPERAND USAGE _FCn contains the value of the distance selectable velocity feedforward gain for the specified axis RELATED COMMANDS FN Distance from end of move when FC is engaged FV Standard velocity feedforward gain EXAMPLES FCX 10 set distance selectable velocity feedforward gain to 10 FNX 1000 set distance from end of move when FC is engaged to 1000 counts ee Storage Scopes File Edit Graph Terminal Help 1 Scope 2 Scopes 3 Scopes I 4 Scopes Continuous Scope 1000 h 7 T 1 First Scope x Commanded Position Zoom Normal 750 500 Second Scope x Torque A i i i 400 600 sio 1o00 2e0m Noma x Command String DPO0 BGX I Stop After Scope Completes Start Collecting
Download Pdf Manuals
Related Search