Magnetic Suspension System Control Using Position and Current Feedback Team: Gary Boline and Andrew Michalets Advisors: Dr. Anakwa and Dr. Schertz
Applications of a Magnetic Suspension System Electromagnetic Suspension TrainFrictionless Magnetic Bearings
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
Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions
System Overview
Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions
High Level Block Diagram
Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions
Current Modeling Experimental Simulink Transfer Function Rate Limiter (nonlinear)
Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions
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
Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions
Position Controller Development Root Locus Attempts Block Diagram Simulation Data Scope Plots Performance Data vs. Specs
Position Controller Development Root Locus Open Loop Poles: , Closed Loop Poles: / j, , Expanded
Position Controller Development Block Diagram
Position Controller Development Step Response (simulation) 28% OS
Position Controller Development Step Response (xPC) ~30% OS
Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions
Microcontroller Implementation Improvements Input/Output Configuration System Timing Scope Plots Performance Data vs. Specs
Input/Output Configuration
D/A Converter Setup Volts (mV) Controller Output +2047FFF : : FF : :
Software Flowchart
Timing Improvements
Step Response Our Controller Past Controller
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
Outline Magnetic Suspension System Overview High Level Block Diagram Current Modeling Current Controller Attempts Position Controller Development Microcontroller Implementation Future Suggestions References Questions
Future Suggestions Lab bench space Modularize Code Design to realistic specs Anti-aliasing filters Design System Bottom Up, Current and Voltage Control Independently
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 Simulink, Version 6.1 (R14SP1), The MathWorks Inc., Natick, MA 01760, xPC Target Box, The MathWorks Inc., Natick, MA 01760, 2003.
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
Conclusion
Questions?