压电爬行平台高精度步长控制调速方法

A High Precision Step-Controlled Speed Regulation Method for the Piezoelectric Crawling Stage

压电爬行平台是实现微纳尺度运动控制的重要执行器,其调速精度直接影响定位的准确性.然而,压电爬行平台在开环调速中常采用频率控制调速方法,并未考虑压电致动率相关特征对单步步长的影响,因此导致压电爬行平台的速度公式失准,使运动的定位精度受到损害.为解决此问题,本文提出高精度步长控制调速方法.该方法能够结合速度公式,在定频率下使用电压-单步位移特性对步长精准建模,通过调节切向压电叠堆的电压信号峰峰值控制步长大小,从而忽略率相关特征的影响,满足压电爬行平台调速精度需求.实验证明,在压电爬行平台的倍速控制对比中,高精度步长控制调速方法的控制效果显著优于传统频率控制调速方法.在2.0秒定时长的终点位置处,两组对照实验的开环定位误差率分别从9.642%和17.01%减小至0.282%与0.729%.

The piezoelectric crawling stage is a significant actuator to micro/nano-scale motion control,determining the positioning accuracy by its speed regulation’s precision.However,in the open-loop fast response speed control,the piezoelectric crawling stage often adopts a frequency-controlled speed regulation method.The method cannot compensate for the rate-dependent characteristics of piezoelectric ceramics,causing the periodic motion step size to be influenced by the frequency,ultimately leading to a degradation in the positioning accuracy of the piezoelectric crawling stage.To address this issue,this paper proposes a high precision step-controlled speed regulation method for the piezoelectric crawling stage.This method can combine the velocity formula,control the step length through the peak-to-peak value of the shear piezoelectric stack voltage signal based on the voltage-displacement relationship at a certain frequency,thereby ignoring the influence of rate-dependent characteristics and meeting the speed regulation requirements.Experiment demonstrates that the high precision step control speed regulation method are superior to the traditional frequency-controlled speed regulation method,with the open-loop position error of piezoelectric crawling stage reduced from 9.642%and 17.009%to 0.282%and 0.729%,respectively.