COMPENSATION OF RESONANCE AND HYSTERESIS IN HIGH PRECISION POSITION CONTROL SYSTEM

Abstract

TWO MAJOR PROBLEMS ASSOCIATED WITH MANY HIGH PRECISION POSITION CONTROL SYSTEMS ARE RESONANCE AND HYSTERESIS. RESONANCE PROHIBITS THE INCREASE OF SYSTEM BANDWIDTH, AND THEREBY, REDUCES THE SPEED OF RESPONSE. ON THE OTHER HAND, HYSTERESIS IS AN INHERENT NONLINEAR CHARACTERISTIC OF PIEZOELECTRIC ACTUATOR. THE WORK OF THIS THESIS IS TO ANALYZE AND COMPENSATE THESE TWO MAJOR PROBLEMS OF THE ACTUATORS USED IN MANY APPLICATIONS. ACTUATORS OF HARD DISK DRIVE HEAD POSITIONING SYSTEM, I.E., VCM ACTUATOR AND PIEZOELECTRIC MICRO-ACTUATOR ARE USED AS THE EXPERIMENTAL PLATFORM FOR THIS WORK. FOR RESONANCE COMPENSATION, FIRSTLY, AN ADAPTIVE RESONANCE COMPENSATOR IS PRESENTED HERE TO SUPPRESS THE RESONANCE OF VCM ACTUATOR. SECONDLY, A FEEDBACK RESONANT CONTROLLER IS USED TO COMPENSATE THE RESONANT MODES OF PIEZOELECTRIC MICRO-ACTUATOR. THE DESIGN IS BASED ON MIXED PASSIVITY, NEGATIVE-IMAGINARY, AND SMALL-GAIN THEOREM. FOR HYSTERESIS COMPENSATION, A NEW RATE-DEPENDENT DIRECT INVERSE HYSTERESIS COMPENS