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A major deficiency of piezoelectric actuators is that their open-loop control accuracy is seriously limited by hysteresis. In this paper, a novel mathematical model is proposed to describe hysteresis precisely and a new parameter called turning voltage is introduced. It was found experimentally that the shapes of hysteresis curves are decided by the value of the turning voltage. A computer-based inverse control approach under open-loop operation based on the mathematical model was applied to suppress the inherent hysteresis to within ±1% full span range of a stack piezoelectric actuator and the performance of the piezoelectric actuator is noticeably improved.

The compact precise tilt positioning mechanism (PTPM) determines the performance of inter-satellite optical communication systems. This paper presents a novel structural design of a PTPM in which the tilt movement is implemented by the elastic deformation of a flexure ring. The flexure ring promises zero friction and zero clearance. The stiffness model of the flexible ring was built based on an analysis of the structural mechanics. Then a dynamic model is presented based on the Lagrange equation. A modal analysis and an experimental investigation were performed. The error between the three methods is less than 10%.

The need for a precision fast positioning technique is drawing significant attention from optical engineering, semiconductor industry, biotechnology, and nanotechnology, etc. This paper presents a novel piezoelectric (PZT) actuated precision fast positioning system (PFPS), which consists of a control module, PZT driving module, a precision fast positioning mechanism (PFPM), and a micro-displacement measure module. It controls the tilt and piston movements quickly and precisely. The driving, mechanism and measure integrative model of the PFPS has been built. The methods of digital proportional integral differential (PID) feedback control and self-tuning fuzzy PID control are studied. Simulation results prove that the proposed self-tuning fuzzy PID controller has good dynamic and static performances. A dynamic performance test system has been established. The experimental results confirm the validity of the design and the theoretical analysis of the PFPS.