Control System Of A Micro-positioning Stage Actuated By Piezoelectric Actuators

The piezoelectric actuator is a prefect micro-positioning drive element. Because of its good performance, it was broadly used in applications that require precise position control. However the position response of piezoelectric actuator shows strong hysteresis, creep and nonlinearity. These defects make it difficult to control. This paper employed piezoelectric actuators to drive a 3-DOF micro-positioning stage to improve the performance of the stage. The following aspects have been studied.Based on theoretical research of the actuation mechanism, the characteristic of the P239.40 piezoelectric actuator was tested. An experimental setup of piezoelectric actuator was designed, which included piezoelectric actuators, strain gauge sensor integrated into the actuator, sensor signal-conditioning module, A/D and D/A modules, power supply modules, and computer. To eliminate the hysteresis, creep and nonlinearity of the piezoelectric actuator, the conventional PID control method and parameters self-tuning fuzzy PID control method were developed respectively. Their control conceptions and principles were described; their control algorithms were compiled in Lab VIEW environment, and the control interfaces were designed. In addition, the control results of this two control methods were analyzed and compared to each other by experiment. The experimental results indicated that the system had dynamic performance and steady-state precision, and can achieve 10nm precision with the range of 60μm by using parameters self-tuning fuzzy PID control.Finally, the 3-DOF micro-positioning stage driven by three piezoelectric actuators was introduced. The stage can realize 3-DOF micro positions by controlling each of actuators. The experimental shows that the positioning precisions of the stage X-axis, Y-axis and θ_Z rotation achieved 0.200μm, 0.225μm and 0.009mrad respectively.This dissertation will provide theoretical and practical experience for the further research of micro-positioning stage, and will be helpful to promote the development of micro-positioning technology.