斐索干涉仪中压电陶瓷的非线性校正

Nonlinear Correction of Piezoelectric Ceramic in Fizeau Interferometer

相移器是斐索干涉仪的核心部件,其关键为压电陶瓷(PZT)致动器,而其迟滞非线性特性严重影响了相移精度,对光学元件的形貌检测造成不利影响。该文首先设计了PZT的控制系统,利用National Instruments(NI)动态数据采集设备(PCIe-6321)、LabVIEW系统及电压放大器组成电压驱动系统产生驱动信号,利用电阻式应变仪、惠斯通电桥作为位移传感器采集位移;其次,提出了一种多项式模型及基于PZT传递函数的前馈开环校正算法对PZT进行建模及校正;最后,在实验系统上对该算法进行了验证。实验结果表明,校正后,相移器的相移误差可被改善,校正前、后位移差小于10%。该系统可有效校正非线性,从而降低非线性相移对测量结果的影响,满足检测光学元件面形的高精度要求。

The phase shifter is the core component of Fizeau interferometer and the key component is piezoelectric ceramic actuator.However,the piezoelectric ceramic actuator has hysteresis and nonlinear characteristics which seriously affects the precision of the phase shifter and adversely affects the surface shape detection of optical components.Therefore,a control system of PZT is designed,which uses the National Instruments(NI)dynamic data acquisition equipment(PCIe-6321),LabVIEW system and voltage amplifier to form a voltage drive system to generate drive signals,and uses the resistance strain gauge and Wheatstone bridge as the displacement sensor to collect the displacement.Secondly,a polynomial model is established and a feedforward open-loop correction algorithm based on the PZT transfer function are proposed to model and correct the PZT.Finally,the algorithm was verified on the experimental system.The experimental results show that the phase shift error of the phase shifter can be improved,and the difference between uncorrected and corrected displacement is less than 10%.The system can effectively correct the hysteresis nonlinear characteristic of piezoelectric ceramic actuator,so as to reduce the influence of nonlinear phase shift on the measurement results and meet the high precision requirements of detecting optical element surface shape and system.