Output-Feedback Control of Electromagnetic Actuated Micropositioning System with Uncertain Nonlinearities and Unknown Gap Variation
Mohammad Al Saaideh, Almuatazbellah Boker, Mohammad Al Janaideh
Abstract
This paper investigates the output feedback tracking control of the motion system driven by an electromagnetic actuator with uncertain nonlinearities and unknown gap variation, considering only the measured output position. The output feedback control is based on two cascade high-gain observers combined with a full state feedback control that is based on the backstepping approach. In this work, the observer of two cascaded high-gain observers with different speeds is considered; the faster one estimates the output position and velocity of the motion system and feeds a virtual nonlinear output to estimate the magnetic flux and nonlinear hysteresis of the reluctance actuator. We show that the equilibrium point of the full state feedback control system under full knowledge of the system information is globally asymptotically stable. The simulation results show that the output feedback control achieves the tracking control objective and recovers the performance of the state feedback control. Also, the simulation results show the robustness of the output feedback control for unknown variations in the air gap and unknown external disturbances.