基于电容传感器的精密压电微位移系统研究

Research on Precision Piezoelectric Micro-displacement System Based on Capacitance Sensor

摘要:

利用高精度的电容传感器设计了一种带有位移反馈的压电陶瓷精密微位移系统,极大地矫正了压电陶瓷的非线性。设计了高精度的位移检测电路,实时采集电容传感器的电容量并转换成数字信号反馈给DSP,形成位移信息的闭环。结合带有前馈补偿的PID闭环控制策略,矫正压电陶瓷的非线性特性,进而实现微位移系统精密定位。对设计研制的微位移系统进行试验测试,结果表明:位移检测电路的电容分辨率可达0.000 1pF,微位移系统定位精度优于5nm,校正后迟滞误差低于1.0%。

Abstract:

A precision micro-displacement system with displacement feedback was designed by high-precision capacitive sensor, which greatly corrects the nonlinearity of piezoelectric ceramics. A high-precision displacement detection circuit was designed to collect the capacitance of the capacitive sensor in real time and convert it into a digital signal to the DSP to form a closed loop of the displacement information. By combining with the PID closed-loop control strategy with feed forward compensation, the nonlinear characteristics of piezoelectric ceramics were corrected, and the precision displacement of micro-displacement system was realized. The results show that the capacitance resolution of the displacement detection circuit can reach 0.0001pF, and the positioning accuracy of micro-displacement system is better than 5nm, and the hysteresis error after correction is less than 1.0%.