压电微动工作台的位移复合控制

为解决稳态精度和稳定性之间的矛盾,提高压电陶瓷执行器的控制性能,进而提高其驱动的微动工作台的定位精度,构造了一种前馈补偿同反馈调节相结合的复合控制算法。其中,前馈补偿为基于压电陶瓷执行器迟滞非线性模型的前馈控制,通过自学习算法来实现,用来补偿压电陶瓷执行器的迟滞非线性,提高对参考位移信号的跟踪能力;反馈调节为PID反馈控制,用来进一步校正前馈补偿没有消除的偏差以及由模型的不确定性所引起的误差,且为了减小积分饱和作用以及微分对扰动的敏感性,对PID算法进行了改进,使之成为一种变系数积分与加权微分的PID算法。试验验证了该算法的有效性,并将该算法同其他控制算法——开环控制、前馈控制、PID 反馈控制进行了对比试验研究,结果表明,复合控制算法比其他控制算法具有更好的性能。

DISPLACEMENT COMPOUNDING CONTROL OF PIEZOELECTRIC MICRO-MOTION WORKTABLE

A compounding control method with feedforward compensation and feedback control is presented in order to balance the accuracy and stability, improve the performance of piezoelectric ceramic actuator, and then to get high positioning accuracy for micro-motion worktable drived by piezoelectric ceramic actuator. Feedforward compensation is feedforward control based hysteresis model of piezoelectric ceramic actuator and is realized through self-learning algorithm, the aim of which is to compensate piezoelectric hysteresis and improve tracking ability to reference displacement signal. Feedback control is PID control, which eliminates the residual error of feedforward compensation and the error caused by uncertainty of model. Moreover, traditional PID control is improved to be variable-coefficient integrals and weighted differential PID to decrease the integral saturation and differential sensitivity to disturbance. This compounding control method is validated by experiments and compared with other control strategies, such as open loop control, feedforward control and PID control. The results demonstrate that the motion worktable under compound control has better performance than other control strategies.