Robust Tracking Control of a Magnetically Suspended Rigid Body

This study is an application of H-inf and mu-synthesis for designing robust tracking controllers for the Large Angle Magnetic Suspension Test Facility (LAMSTF). The modeling, design, analysis, simulation and testing of a control law that guarantees tracking performance under external disturbances and model uncertainties is investigated. The type of uncertainties considered and the tracking performance metric used is discussed. This study demonstrates the tradeoff between tracking performance at low frequencies and robustness at high frequencies. Two sets of controllers were designed and tested. The first set emphasized performance over robustness while the second set traded off performance for robustness. Comparisons of simulation and test results are also included. Current simulation and experimental results indicate that reasonably good robust tracking performance can be attained for this system using a multivariable robust control approach.