A servo controller for an MTS machine Midterm Presentation David Schwartz & Uri goldfeld Supervisors : Dany Alkalay & Amir Reoven Supervisors : Dany Alkalay & Amir Reoven

Quick Reminder Project Goals:  Implementing a new control system for the MTS machine Located at the Material Mechanics Laboratory.  Replacing the current controller with the novel one.

Currently we have the old system with a built in controller: We will replace the old controller using LabView: FPGALabView We configure an FPGA NI board using LabView to replace the old controller

The control loop PID controller MTS + - Command LVDT The machine is controlled in a closed loop. The control loop is modeled as an SISO LTI system. Load cell 1 2 Force = 1 Displacement=2

Project stages Stage 1(Done): System identification of the complete system System identification of the complete system including the controller including the controller This stage was necessary in order to set a base line and see what is the required behavior of the controlled system and to compare it to the system behavior with our controller

Stage 1’s stages Learning LabView deeply Learning LabView deeply Learning MatLab System identification tool Learning MatLab System identification tool Finding the 3dB point of the system Finding the 3dB point of the system Finding Overshoot% and T settling and T rise_time Finding Overshoot% and T settling and T rise_time Finding dominant poles ( W n and  ) Finding dominant poles ( W n and  ) Working with function generator while controlling it using LabView Working with function generator while controlling it using LabView Finding Bode plot Gain + Phase of the system Finding Bode plot Gain + Phase of the system

LabView I/O card 6036 Agilent Waveform generator The measurement system RS232 MTS

Using LABVIEW Send waveform properties To signal generator via RS232 Read generator’s output signal and mts’ output signal via sampling card Do preliminary calculations (such as gain and phase) Write to file for further Post processing with matlab

Stage 1’s details Finding the 3dB point of the system: Finding the 3dB point of the system: we used 2 techniques we used 2 techniques first: 3dB= T rise_time /0.35 = 3.02Hz first: 3dB= T rise_time /0.35 = 3.02Hz second: inserting sin wave in up going Freq and checking when the gain is 1/ sqrt(2) = 5.3Hz second: inserting sin wave in up going Freq and checking when the gain is 1/ sqrt(2) = 5.3Hz Finding O.S%, T settling and T rise_time : Finding O.S%, T settling and T rise_time : We made the proper VI that checks O.S and We made the proper VI that checks O.S and rise_time while in matlab we calculate T settling rise_time while in matlab we calculate T settling We input a square wave and do all the testing on the response We input a square wave and do all the testing on the response

Step response to 1Hz rectangular wave of 1Volt Sampling rate is 1KHz: T rise_time =106ms O.S%= 0.5% T settling = 140ms

Finding dominant poles ( W n and  ): Finding dominant poles ( W n and  ): O.S% and T settling determine the dominant poles and the poles came out: O.S% and T settling determine the dominant poles and the poles came out:  critical damp  n =

Finding Bode plot Gain + Phase of the system Finding Bode plot Gain + Phase of the system This was done with a VI that ran on Freq. between 0.01Hz to 60Hz and sampling the Gain and Phase for each Freq. This was done with a VI that ran on Freq. between 0.01Hz to 60Hz and sampling the Gain and Phase for each Freq.GainPhase

Stage 2(in progress now) Stage 2(in progress now) doing system identification on the controller himself and testing for his transfer function and other characteristics. doing system identification on the controller himself and testing for his transfer function and other characteristics. Stage 3 Stage 3 after having the controller we will implement it in LabView, Then replace the old controller with ours and simulate the system with the LabView controller. after having the controller we will implement it in LabView, Then replace the old controller with ours and simulate the system with the LabView controller.

Time Table assignmentsDates Defining systems nominal requirements, interlocks and limitations. On going Building the controller in LabView using system identification tools. Two-Three weeks Design a basic MTS servo system simulation in LabView. One week Simulating our controller and comparing to previous full system Two-Three weeks preliminary specifications of the experiment protocol GUI. One week Project Book and final presentation for part B One-Two weeks