1. Magnetic Suspension System Control Using Position and Current Feedback Team: Gary Boline and Andrew Michalets Advisors: Dr. Anakwa and Dr. Schertz

2. Applications of a Magnetic Suspension System Electromagnetic Suspension TrainFrictionless Magnetic Bearings

3. Determine if Current Feedback can be utilized to improve performance No success with Current Feedback Develop New Position Controller Design Methods Implement: xPC & Coldfire Summary

4. Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions

5. System Overview

6. Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions

7. High Level Block Diagram

8. Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions

9. Current Modeling Experimental Simulink Transfer Function Rate Limiter (nonlinear)

10. Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions

11. Current Controller Attempts State-space Current with Lag, Lead, or Lag/Lead Noise Problems Current Feed-forward Current Error Feed-forward Based on Proportion to Position Position Integrator ‘integrates’ current term out

12. Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions

13. Position Controller Development Root Locus Attempts Block Diagram Simulation Data Scope Plots Performance Data vs. Specs

14. Position Controller Development Root Locus Open Loop Poles: 1.0321, 0.9689 Closed Loop Poles: 0.9704+/-0.0077j, 0.8550, 0.3888 Expanded

15. Position Controller Development Block Diagram

16. Position Controller Development Step Response (simulation) 28% OS

17. Position Controller Development Step Response (xPC) ~30% OS

18. Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions

19. Microcontroller Implementation Improvements Input/Output Configuration System Timing Scope Plots Performance Data vs. Specs

20. Input/Output Configuration

21. D/A Converter Setup Volts (mV) Controller Output +2047FFF : : 0800 -17FF : : -2047000

22. Software Flowchart

23. Timing Improvements

24. Step Response Our Controller Past Controller

25. Step Response Results Our Controller Max Amplitude : 0.2Vpp Overshoot : 47% Settling Time : 240 ms Past Controller Max Amplitude : 0.5Vpp Overshoot : 36% Settling Time : 560 ms Advantages: Faster System Disadvantages: Larger overshoot, Less input amplitude, Less stability

26. Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions

27. Future Suggestions Lab bench space Modularize Code Design to realistic specs Anti-aliasing filters Design System Bottom Up, Current and Voltage Control Independently

28. References Jose A Lopez and Winfred K. N. Anakwa, “Identification and Control of a Magnetic Suspension System using Simulink and Dspace Tools”, Proceedings of the ASEE Illinois/Indiana 2003 Sectional Conference, March 27, 2004, Peoria, Illinois, U.S.A. Feedback Inc., 437 Dimmocks Mill Road, Hillsborough, North Carolina 27278. http://www.fbk.com Simulink, Version 6.1 (R14SP1), The MathWorks Inc., Natick, MA 01760, 2004. xPC Target Box, The MathWorks Inc., Natick, MA 01760, 2003.

29. Conclusion Determined Current Feedback not viable State Space Classical Designed New Position Controller Root Locus Simulation and xPC Implemented Design on Microcontroller Timer Driven Faster System Bring back focus Step back up from lower level Project importance at beginning Balance additional content

30. Conclusion

31. Questions?