压电微动工作台的位移自感知控制

Displacement Control of Piezoceramic Micro-motion Worktable Using Self-sensing

使用自感知方法测量压电微动工作台的位移,省去独立传感器,构成位移自感知控制系统。压电陶瓷执行器晶片上的自由电荷中包含执行器的位移信息,据此提出基于积分器的压电执行器位移自感知方法,并设计了获取执行器晶片上自由电荷的积分器电路。该方法使得自感知电路的调节和感知信号的获取变得容易,可克服电桥法自感知电路阻抗不易匹配的不足。将该位移自感知方法作为压电微动工作台控制系统的反馈方式,并为提高工作台的动静态性能,构造一种前馈补偿同反馈调节相结合的复合控制算法,实现了自感知复合控制。试验验证了自感知复合控制的有效性,并将该控制方法同其他控制方法——前馈控制、独立传感器常规PID反馈控制、独立传感器复合控制进行了对比试验研究,结果表明自感知复合控制具有独立传感器复合控制的良好性能。

A self-sensing actuator without independent sensor is used to measure displacement of a piezoceramic micromotion worktable, and a displacement self-sensing control system is made. For a piezoceramic actuator, the free charges on the wafer surfaces contain the displacement information of the actuator, thus based on the integrator circuit, the displacement self-sensing for the piezoceramic actuator is proposed and also the integrator circuit is designed. This self-sensing method greatly facilitates circuit adjustment, easy to acquire sensitive signal and avoids the shortcoming of impedance mismatching met in bridge circuit. The self-sensing displacement is the feedback signal of control system of piezoceramic micro-motion worktable. In order to improve the static and dynamical performance of the piezoceramic micro-motion worktable, the compounding control method by combining feedforward control and feedback control is designed. The comparison experiments are performed in order to contrast the self-sensing compounding control with other control methods, such as the forwardfeed control, the PID control with independent sensor and the compounding control with independent sensor. The experimental results show that self-sensing compounding control has the same good performance of compounding control with independent sensor.