Controls Lab Interface ImprovementProject #06508Faculty Advisors: Dr. A. Mathew and Dr. D. Phillips

Project ObjectivesThis work focused on the improvement of the current laboratory setup used in the Control Systems Design course taught in the Electrical Engineering Department at the Rochester Institute of Technology. A new digital interface was designed to interface Simulink within MATLAB to the servo DC motor used in the lab. Two different software toolboxes were used and compared to generate code from a Simulink block diagram for a data acquisition card to act as the digital controller. The results from testing show that the digital control interface was successfully designed and built with both toolboxes.

Team Members:Michael AbbottNeil Burkell

Workstation

Ribbon Cable

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System Interface

Matlab and Simulink

Feedback Power Supply

33-100 DC Servo Motor

Interface Board

Measurement Computing PCI-

DAS1602/16 PCI Card

Block Diagram of Real Time Windows Target Design

Sponsored by the RIT EE Department

For more information see ourwebsite at http://edge.rit.eduor http://www.ee.rit.edu

Requirements

•Implement interface using existing Control Systems lab equipment•Use Simulink within MATLAB to control the DC motor•Interface must acquire position and velocity data of the motor•Verify digital interface results match those from current lab equipment•Design for extra inputs/outputs than required for a robust design•Easy for user to change the sampling time of the system from 300 ms to 1 ms

Project Design

Our design used two software solutions in order to meet our requirements. The xPC and Real Time Windows Target Toolboxes within MATLAB Real Time Workshop were used in order to control the servo DC motor. A PCI card (PCI-DAS1602/16) DAQ from Measurement Computing was used in order to interface the motor with the Simulink control algorithm. The servo DC motor board was examined and signals were traced in order to understand their purpose on the motor board. A printed circuit board was designed in order to provide the necessary connections between the PCI card and the servo DC motor. After the experiment has been run, the data from the motor is available on the host PC to be analyzed by the lab user.

Testing and Data Analysis

After the preliminary design of the interface, a mathematical model of the motor was created in order to simulate the interface. With these simulation results, velocity and position results from the digital interface were compared to simulation as well as results from servo DC motor control with the analog control board. Four different control algorithms were used to test the design as well as an implementation of a Fuzzy controller in order to control the servo DC motor.

Project Results

Results of the design testing showed similar results between the two design interfaces. The transient data of each interface design compared very well to simulation and current laboratory results. The xPC Target design showed better performance at high sampling rates as expected. For the scope of the undergraduate Control Systems Design course, the Real Time Windows Target Design meets all necessary requirements. Control of more complex systems would require the use of the xPC Target Design.

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Results for PI Controller (Results Shifted for Viewing Purposes)

Analog Control Board Result

Simulation Control Result

Digital Control MATLAB Real Time Workshop Result

Digital Control MATLAB xPC Target Result

Block Diagram ofxPC Target Design

xPC Host PC

RS-232

Ribbon Cable

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Work Bench

System Interface

Matlab and Simulink

Feedback Power Supply

33-100 DC Servo Motor

Interface Board

xPC Target PC

Measurement Computing PCI Card

System Block Diagram

Real TimeWorkshop

Simulink

Generated CCode

Real TimeWorkshop

DC Motor

PCI CardGenerated C

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xPC Kernel PCI Card

Host PC

Real Time Windows Target Toolbox

xPC Target Toolbox

InterfaceBoard

InterfaceBoard

Target PC