ROBUST FORCE CONTROL FOR A MAGNETICALLY LEVITATED MANIPULATOR USING FLUX-DENSITY MEASUREMENT

This paper demonstrates, theoretically and experimentally, the idea of magnetic force control in magnetically levitated systems using flux d ensity measurements. The force is determined by measuring the flux den sity in the airgap from a Hall-effect sensor. A simple magnetic levita tion system which consists of a U-shaped electromagnet and a manipulat or is developed for demonstration. A state feedback controller and H-i nfinity controller are used together to increase robustness and speed performance of the force controlled system, and they are implemented i n real time using a digital signal processor with 16-bit A/D and D/A c onverters. Simulation and experimental results for robust stability, d isturbance/noise rejection and asymptotic tracking are presented.