Research And Design Precision Driving Control System Of Three Dimensions

Vast majority of piezoelectric actuators applied to the field of precision drive are importedproducts, in china. In order to improve our precision drive technology, scanning probe microscopysystem (SPM) was set up, which has been widely used in nano-manufacturing filed. The componentsof SPM are metal core piezoelectric fiber (MPF) as the core component, piezoelectric precisionmotion platform and so on. MPF is a new piezoelectric actuator. The open-loop transfer function ofMPF was established by testing step response, hysteresis characteristic and voltage-displacementcurve were also tested. Piezoelectric precision motion platform is widely used in precision drive filed.Its open-loop transfer function was established by testing step response, hysteresis characteristic wasalso tested. Because the two drive components both have hysteresis characteristic, hysteresiscompensation is necessary. In view of the existing hysteresis models, or can not describe asymmetricpiezoelectric actuator hysteresis, or model parameters identification are too complex, a modifiedMaxwell hysteresis model was proposed. Not only the parameters of this new model identification areeasy, but also it can describe the asymmetric hysteresis well. In order to verify the accuracy andfeasibility of the new hysteresis model, three kinds of hysteresis compensation experiments on MPFand piezoelectric precision motion platform are designed, such as open-loop control, PID control, andcomposite closed-loop control. Experimental results show that the hysteresis characteristic of the twoactuators has been well compensated, positioning accuracy of MPF is better than10nm, positioningaccuracy of platform is better than38nm. Because classic control system of SPM does not take intoaccount the hysteresis characteristic of piezoelectric actuators, the new hysteresis model was appliedto the new control system of SPM in this paper. Three kinds of voltage driving signals were used inscanning erperiments and comparing the three experimental results.