UC45-controller for multi-channel actuators
Contents
1. Figure 5 6 Warning on calibration period e SNR Signal to Noise Ratio in dB e Low cut off frequency at 3dB in Hz e High cut off frequency at 3dB in Hz 3 CALIBRATION e For SG75 CEDRAT TECHNOLOGIES 24 32 Version 1 3 25 09 2012 UC45 Product and Warranty information o Strain gages gain in um V o Amplifier Gain in V V o System Gain in pm V Strain Gages Gain um V Amplifier Gain V V System Gain um Y 1 36 1 22 1 57 Figure 5 7 675 data s e For ECS75 o Gain in um V o Linearity error in Gain um V Linearity error 90 20 00 0 5 Figure 5 8 ECS75 Data s If there are no TEDS associated to the board the TEDS section will disappear and an indicator TEDS NOT AVAILABLE will appear 5 5 General command section On the bottom side the screen is composed of several buttons to manage some information SAVE PARAMETERS RELOAD DEFAULT LOCAL HELP EMERGENCY STOP Figure 5 9 Bottom section of the HMI General command section eRUNNING NO COMMUNICATION button indicates the state of the software o RUNNING No error o NO COMMUNICATION A problem is occurred or the communication is temporary not available Figure 5 10 RUNNING NO COMMUNICATION button a No Communication b Running e SAVE PARAMETERS button permits to save the current parameters in the computer so that they can be reloaded later on using the RELOAD button Warning The saved parameters are stored in the RAM memory so they can o2. eeeee Re Renee 18 4 1 Software Installation eese 18 4 1I Re ired egulpmehts uoto de resume E dE 18 4 1 2 JistiTmeJust llatioh onere TRE ate Deae oda atte ne obti ome a dates demande 18 4 2 Hardware connections eese eerte nnne ntes 19 5 HIGHLY DYNAMIC AND PRECISE MOTION 45 SOFTWARE 20 Od InfPoGUCcblolssocenetespe dette RERO Dette op EUER dreatbu Gis dr unt ui MEE reste Ud 20 g2 CONMECTION Sec LIO uus neo ert DET E u IDE IN dose MR eni 21 5 3 Parameters SECTION uu eeeccesscesccsscccsscccsssececccsssecsssecessecessesessecessesesseeenss 22 5 4 Transducer Electronic Data Sheet TEDS eese 24 5 5 General command section esent nnennes 25 DO SMN Y DN Rc 27 6 OPERATING INSTRUCTIONS 000 cece cece cee eee 28 6 L Step DY Step instructions e seti ecc ae eI eroe teg sec 28 6 2 Standalone apbIICGl ION sioe rasta een e ai eU nta itd doeet 29 0 5 Singlestroubleshootilg ooi ne eb cO Eb ated scele 29 7 FIRMWARE UPGRADE eeeeee RR II I een 30 TECHNICAL SPECIFICATIONS ee ccc nenne 31 9 INSPECTION UPON RECEIPT eeee eren 32 UC45 Product and Warranty information TABLE OF CONTENTS CEDRAT TECHNOLOGIES 3 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 1 INTRODUCTION The UC45 board uses a microcontroller to provide ful
3. LI max T U max loaded 1 N fr Figure 2 14 Displacement Vs Frequency A s U max unloaded U max loaded The default value is A s 1 and in general A s gt 1 As the A s is in the feedback loop the gain will not appear directly on the output measurement Calibration of the As on HDPM45 1 If you can measure the displacement of the actuator u integrated in the system then As ua uo Where uo Maximum Free Displacement of the actuator at 170V 2 If you can t measure the displacement of the actuator u integrated in the system then As Vinput Vsc75 Where VInput 8 5V Vse75 Output pk pk voltage from the SG75 in open loop End of calibration of the As on HDPM45 2 2 Method of operation with the UC45 controller The previous theories can be exactly applied on the UC45 controller The basis of this controller includes the possibility to change the PID parameters and the stabilizing filters The operator can analyze the behavior of the system to adjust the parameters of the loops via the USB link When the control parameters are adjusted on the computer they are automatically saved in a non volatile memory The UC45 can then be operated stand alone without computer interface X Caution In factory the configuration is set to predefined parameters This configuration is robust stable but gives a slow response in closed loop If a faster response time is needed the controller should be optimized to the mechan
4. 1 3 25 09 2012 UC45 Product and Warranty information Figure 4 1 Destination directory D aS License Agreement You must accept the license s displayed below to proceed CONTRAT DE LICENCE LOGICIEL NATIONAL INSTRUMENTS GUIDE D INSTALLATION LE PRESENT DOCUMENT EST UN CONTRAT AVANT DE T L CHARGER LE LOGICIEL ET OU DE FINALIBER LE PROCESSUS D INSTALLATION VEUILLEZ LIRE ATTENTIVEMENT LE PR SENT CONTRAT EN T L CHARGEANT LE LOGICIEL ET OU CLIQUANT SUR LE BOUTON PERMETTANT DE FINALISER LE PROCESSUS D INSTALLATION VOUS SOUSCRIVEZ AUX CLAUSES DU PR SENT CONTRAT ET ACCEPTEZ D TRE LI PAR LE PR SENT CONTRAT SI VOUS NE VOULEZ PAS DEVENIR PARTIE AU PRESENT CONTRAT NI ETRE LI PAR L ENSEMBLE DE SES CLAUSES ET CONDITIONS VEUILLEZ CLIQUER SUR LE BOUTON QUI ANNULE LE PROCESSUS D INSTALLATION N INSTALLEZ PAS ET N UTILISEZ PAS LE LOGICIEL ET RETOURNEZ CELUI CI DANS LES TRENTE 30 JOURS DE SA R CEPTION ACCOMPAGN DE TOUS LES DOCUMENTS CRITS QUI LE COMPL TENT AINSI QUE DE LEURS EMBALLAGES A L ENDROIT OU VOUS LES AVEZ OBTENUS TOUS LES RETOURS SERONT SOUMIS ALA POLITIQUE DE NI ALORS EN VIGUEUR EN MATIERE DE RETOURS 1 D finitions Dans le pr sent Contrat les mots suivants ont les significations indiqu es xl si nem mmi m accept the License Agreements C do not accept the License Agreements lt lt Back Next gt gt Cancel Figure 4 2 License
5. EMERGENCY STOP Figure 5 2 Human Machine Interface description Each section is named which helps the operator to know what kind of parameter is modified 5 2 Connection Section On the left side the screen is composed of twelve possible boards maximum number The software search automatically the boards and the operator can choose the board he wanted to change the parameters CONNECTION pw Figure 5 3 Left section of the HMI Connection section CEDRAT TECHNOLOGIES 21 32 Version 1 3 25 09 2012 UC45 Product and Warranty information Until the connection is not established correctly button RUNNING NO COMMUNICATION stay in the state NO COMMUNICATION nothing else can be done except EMERGENCY STOP 5 3 Parameters section On the right side the screen is composed of four sections where the operator could pass different parameters for the numeric PID controller 1 Chi Ch Ch3 TEDS Command Applied Voltage Y External WW Loop Sensor Invert MM E e A Sensibility GENERAL Gas Qm fr E I D 199 8 Jp ritat 20000 0 004 0 006 CONTROL x rf gud icm 0 002 0 008 M i J zw z w 0 32000 0 01 Filter type actuator o Internal In this case the command is issued from the Applied voltage command The operator can select the voltage that he would like to send on the actuator between 1 to 7 5 Volts o External In this case the c
6. and stability to the system by preventing overshoot On the following frequency response the impact of each term is traced Effect of the I term Effect of the P term Effect of the D term Magnitude dB 8B 8 8 h3 e Phase deg 90 ii ld ti 10 10 10 10 10 10 10 10 Frequency Hz Figure 2 2 Frequency response of a PID controller CEDRAT TECHNOLOGIES Dg Version 1 3 25 09 2012 UC45 Product and Warranty information Generally the PID regulator can be written with the following formulae de t dt y t e t x P etre Dx With the jo operator y jo Dx joy Ix jo P E J jo Where y jo is the output of the regulator e jc is the input of the regulator or the error Generally to suppress high frequency noise the D term is limited with a 1 order low pass filter to limit the high frequency gain Impact of the terms Closed loop Rise time Overshoot Settling time Final error SEE IMEM Increase Small change ea Eliminate b Small change Small change Figure 2 3 Impact of the different parameters on the output To learn more please see below 82 1 3 amp 5 sections Added filter A PID controller can be followed with a filter to limit the impact of the resonant frequency of the actuator Two factory tuned types of filters are implemented in the controller e The first one is a 2 order low pass filter which has a low cut off frequency to reduce with
7. but phase lag at low frequency filter filter filter Practically unstable Stable is Cut off Stable is Cut off stable with a simple frequency below Fr 3 frequency equals Fr model Phase lag Phase lag Transient response Practically unstable Low response time Fast response time to a step stable with a simple model Figure 2 12 Table of behavior of the loop with different filers If the operator wants to reduce the phase lag the controller is designed without stabilizing filters In this case the PID terms must be correctly optimized to increase the phase gain margin This condition of operation is not really easy to tune and must be used with caution This methodology can be applied directly on other kind of control loop vibration control servo speed with only a modification of the sensor block the regulator 2 1 3 2 A Calibration For people who need a good resolution and who use loaded actuator this section gives some details to use the A sensibility A L mm l 0 Figure 2 13 A s in the position control loop CEDRAT TECHNOLOGIES 15 32 Version 1 3 25 09 2012 UC45 Product and Warranty information If the actuator is loaded the difference between the tension max of loaded and non loaded actuator will be big The A sensibility permits to adjust the gain in the feedback loop to avoid this problem Without this gain adjustment the control will saturate near the tension limits U
8. button appears 3 When the connections are ok the program reads the parameters of the boards During this time the RUNNING NO COMMUNICATION button is a the state NO COMMUNICATION 4 When the connections are ok the program reads the parameters of the boards During this time the RUNNING NO COMMUNICATION button is at the state NO COMMUNICATION D The parameters are now enabled and the operator can change each parameter 6 Choose the type of command Internal and External We recommend to check the command signal on an oscilloscope 7 Don t forget to switch on the CA45 power supply with the mechanical switch in the front panel of the CA45 to provide the power supply to the mechanism 8 For first time we recommend to adjust Low and High with a small Delta voltage to limit the amplitude of the mechanism able to create damage on the mechanism 9 Adjust PID parameters Filter parameter with your application We recommend remaining in open loop during the modification of these parameters to avoid a typing error and so a bad parameter 10 Close the loop by clicking on OL CL button Now the mechanism is controlled in position with the programmed parameters on the HMI If you hear a sound from the mechanism click immediately on the OL CL button to pass in open loop The closed loop is unstable Change the PID and Filter parameters to be stable 11 To change the type of command between Internal or External we recommend to be in Open loop
9. by clicking on the OL CL button before selecting the new type 12 To stop the mechanism the operator must click on the Emergency Stop button CEDRAT TECHNOLOGIES 28 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 6 2 Stand alone application When the UC45 controller must be configured in a stand alone controller click on the REMOTE LOCAL button to pass from a LOCAL configuration to a REMOTE configuration The controller works continuously but no change can be done In this configuration the USB link can be disconnected To modify a parameter reconnect the USB link and click on the REMOTE button to pass in LOCAL connection the HMI and the UC45 controller dialogue together again The REMOTE LOCAL button must be pushed when the operator is sure that no new modification of parameters will be done 6 3 Single troubleshooting Launch the Highly dynamic and precise motion 45 software with the button on the top and left side L HDPM45v15 vi Fichier Edition Ex cution Outils Fen tre Aide C Figure 6 1 The software is not running ku HDPMA5v15 vi Figure 6 2 The software is running The Ue controller doesn t respond AUNI Check the power supply of the rack the power must be in on state Check the USB link Verify the COM address of the board Run the Highly dynamic and precise motion 45 software with the button on the top and left side of the screen The Re
10. its roll off of 40dB decade the impact of the resonant frequency of the actuator This filter is well adapted for static applications where a low bandwidth is required e The second one is a 2 order notch filter placed at the resonant frequency of the actuator see the next paragraph for more detail This filter is well adapted for applications which require more bandwidth In any case these filters increase the time response of the actuators to reach the desired position CEDRAT TECHNOLOGIES 8 32 Version 1 3 25 09 2012 UC45 Product and Warranty information Bode Diagram Bode Diagram 20 ry TT er 0 TT 0 eee edet oe oe 7 n n Hi i E S dri m z diri S 100 Sdn n L 5 5 iE n b JH SS eee eee ae Ce ee ee DH EAZ 4 200 iil Laul iil iit ite 90 IT i 45 L r 1 r T87077 7 3 fF aS TU T ee ee oe ee ee mis e ee D te hi WN T oq D 111 Ne toe re te 2 i e d B8 i a o D e E ge E H ee 2b ce H 2e d 2 3 ae 2 3 4 5 10 10 10 10 10 10 10 10 10 10 Frequency Hz Frequency Hz Figure 2 4 Frequency response of different ideal filters low pass filter and Stop band filter The low pass filter is a 2 order low pass Butterworth filter described with the following formulae Out jo _ l 7 im y2 In jo Lae ere ee jo f With o the cut off pulsation of the filter and z the damping The stop band filter is a 2 order stop band Butterworth filte
11. means that for any bounded input over any amount of time the output will also be bounded This is known as BIBO stability see also Lyapunov stability If a system is BIBO stable then the output cannot blow up i e become infinite if the input remains finite Mathematically this means that for a causal linear system to be stable all of the poles of its transfer function must satisfy some criteria depending on whether a continuous or discrete time analysis is used e In continuous time the Laplace transform is used to obtain the transfer function A system is stable if the poles of this transfer function lie in the closed left half of the complex plane I e the real part of all the poles is less than or equal to zero e Indiscrete time the Z transform is used A system is stable if the poles of this transfer function lie on or inside the unit circle I e the magnitude of the poles is less than or equal to one The study of the stability of the loop must be realized in parallel of the study of the performance A good choice in term of performance can bring an unstable system The study of the stability is directly linked to the open loop transfer function The following diagram shows an alternative representation of a feedback loop Output s gt Output s Figure 2 8 General representation of a feedback loop The stability is the study of the equation 1 G s H s 2 0 with G s the plant in line with the controller and
12. the applied voltage on the actuator Each channel can be selected and modified with the Channel button In a 3 channels configuration the operator can select independently the parameters of each channel for the GENERAL CONTROL FILTER and DRIVER sections CEDRAT TECHNOLOGIES 23 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 5 4 Transducer Electronic Data Sheet TEDS TEDS is a compact set of data describing sensor calibration characteristics if there is any Two kinds of sensor can be expected SG75 or ECS75 For more details on those sensors see the user manuals dedicated to the relative sensor Chi Ch2 Ch3 TEDS Ch 1 Serial Number UC45 Channel UC45 i i CONTROLLER 11 030 1 i Sensor Serial Number Last Calibration Calibration Period month SG75 09 001 02710 2012 24 GENERAL SNR dB Low cut off frequency 3d6 Hz High cut off frequency 3d6 Hz 70 0 15000 Strain Gages Gain um Y Amplifier Gain V V System Gain um V 1 36 1 2 1 57 CALIBRATION Figure 5 5 TEDS section 1 CONTROLLER e Serial Number of the associated UC45 e Channel of the associated UC45 2 GENERAL e Sensor SG75 or ECS75 e Serial number of the sensor e Last Calibration DD MM YYYY e Calibration period in month If the calibration is near to be passed or is passed a warning will appear to prevent the user Cedrat Technologies recommands a recalibration This does not mean that the system is not working properly
13. 8 Bode Diagram Magnitude abs i mE Eo SS Phase dea Frequency Hz Figure 2 7 Modal identification of a mechanism In first approximation for quasi static application the driver is a pure gain You should integrate the current limitation when the system requires bandwidth Dread Lon In A sensor can be represented with a pure gain If you use a strain gages sensor from Cedrat Technologies S675 board this gain is defined as Out Maximal _ stroke Sensor Jo In Maximal _input _ voltage Numerical application For an APA120ML the maximum stroke is 120um and the maximum voltage order is 8 5V The gain is 70833 V m The study can be realized in continuous domain in which the controller is represented by a continuous transfer function without frequency limitation from the sample rate of the loop or in discrete domain where the controller is digitalized and represented with CEDRAT TECHNOLOGIES 11 32 Version 1 3 25 09 2012 UC45 Product and Warranty information a z transfer function In this case the loop includes the sample amp hold and the quantization of the analogue to digital converter and the digital to analogue converter The aim of the control is to increase the accuracy the settling time without destabilizing the loop The last point is very important and must follow a specific study Stability in control theory often
14. Agreement ziSixi Psi SSS ET Start Installation Review the following summary before continuing Upgrading HDPM45v11 Files Adding or Changing National Instruments system components Overall Progress Currently installing HDPM45v11 Part 1 of 1 Click the Next button to begin installation Click the Back button to change the installation settings Save File lt lt Back Next gt gt Cancel Figure 4 3 Starting Installation 2 After this installation is finished an other driver will be install automatically and then restart your PC 3 Connect your PC with the UC45 by USB cable see 4 2 and power on the rack 4 Now the operator can run the software HDPM45_vxx exe which is normally on your desktop 4 2 Hardware connections The hardware connection permits the connection of the UC45 controller to a computer in order to be able to adjust the configuration Connect the controller with the provided USB cable using the USB port on the controller front panel If you have too many boards you can use a USB hub to connect all the boards to the computer CEDRAT TECHNOLOGIES 19 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 5 HIGHLY DYNAMIC AND PRECISE MOTION 45 SOFTWARE 5 1 Introduction In this paragraph we describe how to use the Highly dynamic and precise motion 45 software with a pair piezo actuator sensor The software provided with the UC45 permits to
15. CEDRAT TECHNOLOGIES Innovation in Mechatronics Y UC45 controller for digital control of actuators PRODUCT AND WARRANTY INFORMATION t HDPM45v15 vi Highly dynamic and Q CEDRAT Precise motion 45 Main chan Loo CONNECTION Comman d Applied Voltage V A Sensor Invest A Sensibility cma a a ams GENERAL o gt 31 P I D JE E ew l a a o 20000 004 0 006 CONTROL n x f 25000 0 00 Sets 2 5000 amp 7 j J f gt ey woes X H4 3 HE 3 0 0 01 Filter type Frequency filter 1 Frequency filter 2 m ees FILTER Ny Lowpass Order 2 wr Hz 2000 Hz o 2 v io TAI Opere 50 75 So 75 25 V 100 as M 100 DRIVER RUNS A 125 A 125 ll 0 DA 150 Low 20 150 High 20 7 50 v fio SAVE PARAMETERS RELOAD DEFAULT LOCAL HELP EMERGENCY STOP Version 1 4 Date 25 09 2012 CEDRAT TECHNOLOGIES URL www cedrat technologies com 59 Chemin du Vieux Ch ne Inovall e Email actuator cedrat tec com F 38246 MEYLAN Cedex Phone 33 0 4 56 58 04 00 FRANCE Fax 33 0 4 56 58 04 01 UC45 Product and Warranty information CAUTION READ BEFORE OPENING For safety purposes these instructions must be read before use of this product This numeric controller is dedicated to control actuators with specific regulators The operator must read the user manual related to the driver used CA45 LA75 SA75 or LA24 before powerin
16. H s the sensor G s H s is called the open loop transfer function Instability occurs when the denominator in Figure 10 becomes zero In other words when G s H s 1 This equation can be resolved with mathematic formulae but it is easier to trace in the frequency domain the module and the argument of this transfer function e Pnare real negative stable system e Pnare complex with real negative parts critically stable system CEDRAT TECHNOLOGIES 12 32 Version 1 3 25 09 2012 UC45 Product and Warranty information e Pnare imaginary complex gt Unstable system Recalling that O dB is equivalent to unity 1 can be written as OdB 180 We introduce the Bode diagram as a representation in the frequency domain of the module and argument of a transfer function The open loop method works by estimating two measures of stability or margins The first is phase margin or PM Find PM by locating the frequency where the loop gain is O dB Gain margin or GM is similar Find the frequency where the open loop phase is 180 and then measure the gain Since the system will be unstable at OdB 180 the GM is OdB less the gain gt Example Open loop transfer function and their margins Module dB Phase deg Figure 2 9 Frequency response of the open loop transfer function Bode diagram G s 1 G S H s optimize the response to a step we analyze the transfer function Output G s Input jy G s H s To optimize the regu
17. OGIES 32 32 Version 1 3 25 09 2012
18. adjust its control configuration At first the software make a research of the several boards which could be connected During this first step a button LOADING appears This first step can be 1 or 2 minutes long Figure 5 1 First step During a second step the software will read the parameters on the boards a button NO COMMUNICATION appears When those two steps are ok the Human Machine Interface is ready to use the button RUNNING appears The screen is cut in three areas e The first one on the left manages the several boards e The second one on the right manages the regulator with some parameters that the operator can change e The last one on the bottom of the screen includes several main commands to manage the state of the software CEDRAT TECHNOLOGIES 20 32 Version 1 3 25 09 2012 UC45 Product and Warranty information Peles Highly dynamic and CEDAT Precise motion 45 TECHNOLOGIES Ch2 Ch3 TEDS Loo Command Applied Voltage V xi irem A Sensibility GENERAL External V 0 Close gt Off P I D 20000 0 004 0 006 CONTROL f Y 6 10000 b b 2 8 5000 4 eJ z eJ 0 10 0 32000 0 0 01 25000 0 002 0 008 ej Filter type Frequency filter 1 Frequency filter 2 FILTER Lowpass Order 2 y 100 He 1 inn Hz EN NND AT ME A amd 100 25 ed 100 ep o 125 4 b 20 150 Low 20 150 High viis SAVE PARAMETERS RELOAD DEFAULT LOCAL HELP
19. effect of the resonant frequency of the actuator In the case of the actuator is characterized with a low quality factor this filter can be bypassed and only an adjustment of the PID parameters can optimize the behavior of the loop A PID controller attempts to correct the error between a measured process variable and a desired set point by calculating and then outputting a corrective action that can adjust the process accordingly It is used to ensure an optimum response behavior of the actuator to its input commands reducing error in velocity acceleration and mainly in position PID regulator P Proportional Gain This term determines the overall responses of a system to position errors providing an output signal proportional to the error at any time low proportional gain provides a system which is very stable without oscillation i e stable has low stiffness and possibility large position errors under load A high proportional gain provides high stiffness and small position errors under load but may be unstable I integral Gain This term helps the system to eliminate positional errors but in static condition by increasing the output to the actuator until the error reduces to zero This error is added or integrated over time and eventually the controller generates a sufficient output to reduce it A low Integral gain may allow positional error at rest which depends on the static load D Derivative Gain this term provides damping
20. g the UC45 controller Only qualified personnel should work on or around this equipment and only after becoming thoroughly familiar with all warnings safety notices and procedures contained here in The successful and safe operation of this equipment is dependent on proper handling installation and operation A qualified person is one who is familiar with the installation construction and operation of the equipment and the hazards involved In addition he she has the following qualifications e is trained and authorized to energize de energize clean and ground equipment in accordance with established practices e is trained in the proper care and use of protective equipment in accordance with established safety practices This pictograms A is placed to focus the attention on potential hazards CEDRAT TECHNOLOGIES 2 32 Version 1 4 25 09 2012 1 INTRODUCTION 2245 han chose dees een a e eee da eene ee 4 e GENERAL THEORY rb eroi EU b e LTLOEVEDeRURE d TRENDS 5 2d Theory OFC coHttol 00D ceste doti oce wein 5 2 1 1 The different FUNCTIONS seo rote PR quies wee pe wase usiee ties on 5 21 2 Definition of the regulator oio rb RARE Peu deba dua AV EE A 7 2 1 3 Advanced performances osito EURO PbRtau EN EUR PE Eni inaa EN Rp 10 2 2 Method of operation with the UC45 controller 16 HARDWARE DESCRIPTION eeee ee err rre 17 4 INSTALLING INSTRUCTIONS
21. he kind of filter is inline with the PID regulator o Low pass Order 2 is a filter based on a 2 order low pass filter In this case only the frequency filter 1 can be change o Notch Order 2 is a filter based on a 2 order stop band filter In this case only the frequency filter 1 can be change o Notch Order 4 is a filter based on a 4 order stop band filter In this case only the frequency filter 1 can be change o 2 Notches Order 2 are two filters based on a 2 order stop band filter In this case the frequency filter 1 and the frequency filter 2 can be change o None indicates that no filter is added with the PID controller eFrequency filter 1 2 are integers and can be adjust between 50 to 2000 Hz 4 DRIVER e Low indicates the lowest limitation of the voltage output of the driver e High indicates the highest limitation of the voltage output of the driver The limitation can be adjusted between 20 to 150V These values are correct if the offset of the driver is adjusted at O Volt To verify place the command in the internal mode section General and check the value of the driver with an oscilloscope Turn if necessary the offset potentiometer of the CA45 see user manual of CA45 for additional information Li We recommend when you tune the regulator to place the Low and High commands with small amplitudes to limit a potential risk of damage on the actuator during an instability phase by limiting the amplitude of
22. integrator term slow down the time response of the system gt Example Impact of the stabilizing filters on open loop closed loops transfer function transient responses of a piezo actuator a PID regulator and some stabilized filters Open loop response Closed loop response Transient response EN Figure 2 11 Frequency response of the open loop transfer function closed loop transfer function and transient response a without filter b with Low pass filter c with Notch filter i F pn m Doe A snc irr d ups r ri Loco Ziebis T Yre 1 eet F Numerical application Input Data APA400M with 5Ogr Q 100 Load 50gr Fr 340Hz 10 First case with a low pass filter fc 100Hz 2nd order Results With P 0 1 I 250 Overshoot 20 Stability 5dB 60 Fc in closed loop 100Hz CEDRAT TECHNOLOGIES 14 32 Version 1 3 25 09 2012 UC45 Product and Warranty information Modification PID parameters P 0 1 I 300 Overshoot 40 Stability 3dB 45 Fc 100Hz The low pass filter fixes the cut off frequency of the closed loop The I term doesn t play a large role after the cut off frequency of the low pass filter Modification Cut off frequency of the low pass filter 300Hz Stability 4dB 20 Fc 150Hz The system is not really stable Second case with a Notch filter Fc Fr 2nd order Results With P 0 1 I21000 amp D 1e 4 Overshoot is reduced Settling time 3ms Stability 11dB 56 Fc 200Hz
23. iors of the loop in terms of accuracy speed The UC45 controller is compatible with the different drivers of the standard product and is integrated on the racks of the standard product up grading the front face of the drivers with an USB interface The dimensions of board are 50mm x 70mm for a weight of 0 05Kg CEDRAT TECHNOLOGIES 4 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 2 GENERAL THEORY The UC45 controller is used to control multi pairs of actuators sensors using feedback loops with dedicated regulators It includes ADC and DAC converters to sample the analog signals and perform the control law digitally Before connecting the UC45 controller the operator will find in the next paragraph the behaviors of each function of the regulator 2 1 Theory of a control loop 2 1 1 The different functions The basic scheme of one channel control loop is the following It includes some regulators based on analogue digital converters and a robust PID controller al Lx SN ees ie Er J i Sorte Sep A D e E Discrete Time Dace LATS Dirver leat Transke Fen Rouge Diseret Bleu Continu Fi gure 2 1 Schematic of a basic digital control loop In this example the displacement of a PPA6OL piezo actuator is controlled each block is represented with an input and an output to model the behavior of the reality The control loop includes the following blocs e The actuator and its d
24. ism Be careful to verify the stability in closed loop when adjusting the controller Cedrat Technologies can help you optimizing the controller CEDRAT TECHNOLOGIES 16 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 3 HARDWARE DESCRIPTION The UC45 controller is a board that is integrated on a standard product The only difference with a standard product is the USB type B interface on the front panel 2 1 el 3 4 Figure 3 1 USB B Type on the front panel You will need a USB cable with a B Type and a A type to connect to your computer 1 2 3 4 Figure 3 2 USB A Type on the front panel The USB cable will be delivered with the UC45 product by CEDRAT TECHNOLOGIES CEDRAT TECHNOLOGIES 17 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 4 INSTALLING INSTRUCTIONS This paragraph describes the different instructions to connect the UC45 controller and to install the computer software At the same time the operator must connect the mechanism to the rack following the instruction in the user manual LA75 Linear amplifier for piezoelectric actuators Product and warranty information or the user manual of the driver in use LA24 SA75 DO NOT CONNECT THE USB DRIVER ON THE PC BEFORE INSTALLING THE SOFTWARE 4 1 Software Installation 4 1 1 Required equipments You must install the Software on the following Personal Computer configuration Change in in the regi
25. lation of the impact of the disturbance the operator must analyze the next transfer function The study of the performances is based on the study of in closed loop To Disturbance _ l Input 4 G S H s In any case if GH 1 then Input Output for the first equation and Disturbance Input Example Correlation in closed loop Bode Diagram mtt wit EEH ap f GADfiim 0r irit is inn SEAL iX Pit 6 Wi EET ARES E CPI elt D B Y E 3 AQ X Uk eS x Ni 1 m een De ee i 5 tT SNH 095 E Li 0 9 E Magnitude dB P CA T Phase deg CEDRAT TECHNOLOGIES 13 32 Version 1 3 25 09 2012 UC45 Product and Warranty information Figure 2 10 a Frequency response of the closed loop transfer function b transient response We recommend using dedicated software like MATLAB Simulink from The MATHWORKSQ to trace the different Bode diagrams and transient responses In an actuator with a large peak at its resonant frequency high quality factor the PID regulator is generally not sufficient to stabilize the closed loop and the state of the art is to add in line a specific filter defined above On the following Bode diagram we Show the impact of stabilizing filters on a standard analogue PID controller coupled with a piezo actuator The stability can be assured with the low pass filter and the placement of the cut off frequency below the resonant frequency of the actuator A low pass filter or an
26. ly digital control of actuators at a rate of 10kHz with a resolution of 16 bits It includes a digital PID controller followed by a digital filtering cell The type of the output filtering cell can be changed notch of order 2 notch of order 4 low pass of order 2 or double notch of order 2 for multi mode controlling It can also be chosen to have no output filter Simply connect the UC45 to the USB port of a computer and all the control parameters can be modified online using an easy Labview interface Once the parameters set it can be disconnect from the computer and it will run autonomously keeping the control parameters even after reboot Uncoupled multi channel control is possible by using several UC45 boards up to 3 stacked on a multi channel driver Thanks to the multi channel converters coupled double channel control is possible for the specific case of the XY stages using Eddy Current Sensors ECS75 Due to the digital nature of the processing the UC45 has the capability to be adapted to a broad range of other control situations without needing hardware modifications Thus it can be adapted to specific actuators requiring a particular control scheme or a hybrid controller With the UC45 controller Cedrat Technologies provides a free NI licenses software which includes a setup section to modify the parameters of the control loop With a dedicated regulator the operator can change the different parameters to optimize the behav
27. mote button is in REMOTE state and so the controller is in stand alone configuration To change a parameter or display a curve this button must be in a LOCAL configuration The actuator doesn t move 1 The power is supplied when the mechanical switch in the front panel of the CA45 In this case Protect LED of the CA45 must be lighted CEDRAT TECHNOLOGIES 29 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 2 The Type command is in Internal position with O Volts applied Pass the type command in External position and applied a 1Hz 0 1V square signal on the BNC input connector of the CA45 A little noise must be heard 3 The type command is in External position but no signal is send on the BNC input 4 In CL position the Parameters of the regulator are O The CL OL button doesn t respond 1 The possibility to pass from Closed loop in Open loop can be managed by the mechanical switch in the front panel of the CA45 For being able to manage the CL OL button on the software the mechanical switch has to be on the state Servo ON 7 FIRMWARE UPGRADE The application can be upgraded with a new version of software directly from our Web site An installation sequence as the first installation described in paragraph 4 1 2 is NOT necessary only the download of the file named HDPM45 vxx exe is necessary We recommend contacting us and going on our website to download the latest version of the software http w
28. nly be recalled during the same session of the HDPM45 If the HDPM45 is stopped the parameters can not be reloaded eRELOAD button permits to call back the parameters saved using the SAVE PARAMETERS button e DEFAULT button permits to call back the initial factory parameters e LOCAL REMOTE button permits to work in stand alone configuration CEDRAT TECHNOLOGIES 25 32 Version 1 3 25 09 2012 UC45 Product and Warranty information o REMOTE The UC45 controller works alone and the USB link is disable In this case the HMI is disconnected from the UC45 controller To reconnect the HMI with the UC45 controller click again on the LOCAL button to enable the USB link o To disconnect the USB link start by clicking on the REMOTE button and disconnect the physical link in a second time To reconnect the controller to the USB link start by connecting the physical link and in a second time select the LOCAL button a owe d Figure 5 11 LOCAL REMOTE button a LOCAL action b REMOTE action e HELP button permits to find the user manual at screen in pdf format e EMERGENCY STOP permits to stop the software CEDRAT TECHNOLOGIES 26 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 5 6 Summary Each parameter are summarized in the following table including their states Name Range Connection Section Parameters Section Po 0 t0 10 resolution te Do Oto tee resolution te 5 SSS Filter type Low
29. ommand is issued from the Input BNC connector of the CA45 to command the actuator This command must be adjusted between 1 to 7 5 Volts e Applied voltage command is used to send on the actuator directly a static command in Volt between 1 to 7 5V e OL CL is a command to close or to open the control loop OL indicates that the controller works in open loop and CL indicates that the controller works in closed loop i e the regulator is on with the parameters in the control section e Sensor Invert is used to invert the data s sensor eA Sensibility is used to adjust the sensitivity of the feedback sensor CEDRAT TECHNOLOGIES Frequency filter 1 Frequency filter 2 FILTER Lowpass Order 2 wr 100 Hz 1000 He 20 V IN i gu a a u DRIVER o J i g d CES 20 iso Low 2 150 High yrs Figure 5 4 Right section of the HMI parameter section eCommand is a selector to chose between two possible command to send to the 22 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 2 CONTROL eP I D commands adjust the PID parameters as described in the previous paragraphs o The P parameter can be adjusted between O to 10 by step of 1 o The I parameter can be adjust between O to 32000 by step of 1 o The D term can be adjusted between O to 1e 2 by step of 1 The command can be sent by rotating the button or by writing the number independently 3 FILTER eFilter type indicates t
30. onal configuration of your PC if it is not the case Settings Controls Panel Regional and language Options Customize Decimal symbol Your screen cannot be higher than 1200 per 800 pixels The installation is simple A unique CD or a download on Cedrat website http www cedrat com en mechatronic products software download html 0 includes the installation of the drivers to dialogue with the UC45 and the installer for the application software It contains the autonomous application too 4 1 2 First time installation 1 The operator has to run the Ww setup exe following the giving indications MEMEEEEEE LL CSIBSIBIBEEIS E aix CE NMNME 5 x piai ax Destination Director Select the primary in stellata n directory s ongly recommende ds ihe exit plas ograms befor isin Die Applic ao deside n the ba ckground suc ds virus sca All software will be installed in the following locations To install software into a utilities might cause the nstaler to take lon nger r than average elo complete different location s click the Browse button and select another directory C toss Directory for HDPM45v11 C Program Files HDPM 45s11 Browse Please wait while the installer initializes M Directory for National Instruments products C Program Files N ational Instruments Browse lt lt Back Next gt gt Cancel CEDRAT TECHNOLOGIES 18 32 Version
31. pass Order 2 Notch Order 2 Notch Order 4 2 Notchs Order 2 None TEDS 0 0 0 Serial Number UC45 S Channel UC45 ooo S Serial Number of sensor Jo SNRindB 000000 S Calibration for SG75 Strain Gages gain um V Amplifier Gain V V System Gain um V Calibration for ECS75 Gain in um V Linearity error in 76 General command section S O RUNNING NO COMMUNICATION Display the state of the communication between the PC and the boards SAVE PARAMETERS Save the parameters at the screen RELOAD Call back the parameters from the SAVE PARAMETERS action DEFAULT Call back initial parameters HELP Display a short form of the user manual REMOTE The USB link is disable and the HMI is disconnected from LOCAL REMOTE the UC45 controller LOCAL The USB link is enable and the HMI is connected to the UC45 controller EMERGENCY STOP Figure 5 12 Summarize table of each parameter CEDRAT TECHNOLOGIES 27 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 6 OPERATING INSTRUCTIONS In this paragraph we give some operating instructions to avoid damages on the mechanism for a first time user 6 1 Step by step instructions 1 Power on the rack by switch on the rear connector If the rack is not powered on the UC45 microcontroller is not supplied and the HMI is not connected to the microcontroller 2 Wait until the software is searching the boards LOADING
32. position control of a PPA6OL piezo actuator with a strain gage position sensor The next figure represents this position loop al Lx Source Step A sD Cametti in Table fiesta Rouge Diseret Bleu Sort iru A a D Converiseuri Figure 2 6 Schematic of a Position control loop CEDRAT TECHNOLOGIES 10 32 Version 1 3 25 09 2012 UC45 Product and Warranty information Before analyzing the behavior of the loop a first step is the definition of the model and its accuracy In quasi static condition a model of the piezo actuator with its fundamental mode can be used see Application Note on the numerical control from the standard catalogue of piezo actuators drivers amp controllers 2007 u Nc H je H V ilt rie jo m c jo This transfer function represents the displacement of the actuator in function of the applied voltage on the ceramics This transfer function of course is linear and doesnt take into account the creep effect or the intrinsic hysteresis If necessary we suggest to use simulation software to include these nonlinearities X Caution When high settling time is required the elementary model is not enough to be used in the complete model We suggest a modal identification from Finite Element Model software of the mechanism or a hardware in the loop identification process to take into account the other modes at higher frequency System tf apax Frequency Hzy 15 1 __ Magnitude abs 0 066
33. r described with the following formulae 2 J0 44 Out j QO r B e 2 e men ae E eae ees a a O O With o the centre pulsation of the filter and z the damping To learn more please see below 82 1 3 amp 5 sections CEDRAT TECHNOLOGIES 9 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 2 1 3 Advanced performances 2 1 3 1 Control For people who want to understand the impact of such filters described below frequency type PID parameters this section gives some details inputs to study the behavior of the control loop and the impact of these elements and how the operator must analyze the loop DESIRED REFERENCE REFERENCE REFERENCE ERROR SIGNAL or OUTPUT or INPUT Controller ACTUAL REFERENCE or FEEDBACK Reference Sensor Figure 2 5 Schematic of a feedback loop A common process begins with the study of the behavior in open loop and in closed loop In this case we will define the phase and gain margins with additional filters working as stabilizing filters The steps to optimize the closed loop are the following 1 Definition of the models with the different blocks constituting the entire loop continuous plant acquisition treatment drivers sensors 2 Choice of the type of regulator with analyze in open loop and closed loop in the frequency and transient domains 3 Tests in the real world To develop theses stages we will use the example of the
34. river in this case the LA75x driver The sensor and its conditioner These parts are called the continuous plants and have a continuous behavior in opposite of digital behavior Two analogue to digital converters including the anti aliasing filters These blocs are characterized by sample and hold and quantization functions the quantization is function of the resolution of the A D converter for the UC45 16bits Those converters are used to sample the analogue orders and feedback signals e A digital to analogue converter with 16bits resolution to convert the digital command in an analogue command applied on the actuator This bloc is generally characterized with the maximum range and the resolution in terms of bits The regulator which computes the error between the command and the real position monitored by the sensor applied through a specific controller an order The controller is computed to maintain a closed loop stable with the desired performances accuracy speed CEDRAT TECHNOLOGIES 5 32 Version 1 3 25 09 2012 UC45 Product and Warranty information A A Sensibility gain to adjust sensibility of the data s sensor see 2 1 3 2 CEDRAT TECHNOLOGIES 6 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 2 1 2 Definition of the regulator A feedback controller is implemented in the regulator It includes a PID regulator in series with a dedicated filter A filter is placed inline to limit the
35. ww cedrat technologies com CEDRAT TECHNOLOGIES 30 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 8 TECHNICAL SPECIFICATIONS In the following table we summarize the technical performances of the UC45 References 15 15 5 Vdc 2 per board Sampling time 100us Frequency 10KHz A D converters 4 channels 16 bits 10V optional 5 channels 12 bits 0 5V 2 channels 16 bits 10V Filter cell minimum cut off 2 order Low pass filter 50 2000 Hz frequency maximum cut off 2 order stop band filter 150 2000 Hz frequency Two 2 order stop band filter in serial independently tuneable 150 2000 Hz 4 order stop band filter 150 2000 Hz No filter 50 mm x 70 mm 0 05 Kg Figure 8 1 Technical specifications of the UC45 board CEDRAT TECHNOLOGIES 31 32 Version 1 3 25 09 2012 UC45 Product and Warranty information 9 INSPECTION UPON RECEIPT This product has been inspected and shown to operate correctly at the time of shipment as verified by the Factory Verification Form that accompanies the power supply Immediately upon receipt of the product it should be inspected carefully for any signs of damage that may have occurred during shipment If any damage is found a claim should be filed with the carrier The package should also be inspected for completeness according to the enclosed packing list If an order is incorrect or incomplete contact your distributor CEDRAT TECHNOL
Download Pdf Manuals
Related Search