A servo controller for an MTS machine Characterization Presentation David Schwartz & Uri goldfeld Supervisors : Dany Alkalay & Mony Orbach

Project Goal: Implementing a new control system for the MTS machine Located at the Material Mechanics Laboratory. Replacing the current controller with the noval 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

Material Testing Machine (MTS) General Description: Purpose – finding the strength of various materials Under static and dynamic loads. The machine does Tensile or compression static tests And fatigue testing under cyclic dynamic loads. Force is applied using a servo valve Actuator

Stress vs Strain

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

Commands Two action modes: 1.Force – usually used in static experiments.The feedback is through the LoadCell sensor which converts Force applied by the servo valve to voltage. 2.Displacement – usually used in dynamic experiments. The feedback is through the LVDT sensor which converts the position of the servo valve to voltage.

Controller necessity The machine’s input has to abide to certain limitations. Illegal input may be destructive. For Example : giving the servo valve too much acceleration will produce force that might break the machine. The controller has to pass through only legal commands, He will do it using an FSM that checks for irregularity In the given commands.

Tools and Techniques Development environment: Software LabView 7.1 software and toolboxes: Control system and simulation toolbox. State machine development toolbox. FPGA module and real-time capabilities. Hardware The MTS system Multifunction DAQ board. NI FPGA board NI PXI-7831R

assignmentsDates Learning LabView development environment and tools. On going Finding the servo valves transfer function H(s)=a(s)/b(s) using system identification techniques. Two weeks ”Reverse engineering” of the current MTS implementation. One week Defining systems nominal requirements and limitations. Two weeks Design a basic MTS servo system simulation in LabView. One week preliminary specifications of the experiment protocol GUI. One week Project Schedule