The Research Of Modeling And Control Based On Micro- Displacement Stage Driven By Piezoelectric Actuator

Micro-positioning technology is an important support technology in the field of super precision machining, precision drive and precision measurement, etc.Piezoelectric ceramics with piezoelectric effect that can produce nanoscale expansion deformation, has been widely as the driver of the micro displacement platform.But the inherent characteristics of the micro displacement platform such as creep characteristic, hysteresis characteristics and dynamic characteristic which greatly influence the positioning precision of the micro displacement platform. This article mainly based in the piezoelectric ceramics as a drive and the flexible hinge as a support rail which used in the micro displacement platform as the research object. This paper designed the PC control software based on Piezoelectrically microPositioning stage, then researched the model and control according to the hysteresis characteristics and dynamic characteristics of the Piezoelectrically microPositioning stage. Concrete research contents has the following several aspects.1.For the type of XP-611 Piezoelectrically microPositioning stage, we set up the experimental system of it. Experiment system is composed of the following working module:displacement sensing module, driving power supply module, Piezoelectrically microPositioning stage, computer control system.2.Based on the experimental system,the paper written data collection procedures in Labview development environment and analysed the characteristics of Piezoelectrically microPositioning stage. The analysis results show that the creep property of Piezoelectrically microPositioning stage had smaller influence on positioning accuracy and creep property can be ignored on the condition of low positioning accuracy. The hysteresis property and dynamic property of Piezoelectrically microPositioning stage had a greater influence on the positioning accuracy. When the Piezoelectrically microPositioning stage working in small range and low-speed, hysteresis property and dynamicproperty was not obvious. When the Piezoelectrically microPositioning stage was under the condition of slow positioning mainly reflected hysteresis characteristics, dynamic performance is not obvious.However, the Piezoelectrically microPositioning stage was under the condition of a wide range and rapid positioning,dynamic property and hysteresis property were all reflected greatly and had a strong impact on the positioning accuracy.3.Considering the dynamic property and hysteresis property of Piezoelectrically microPositioning stage, established the mathematical model of it. Hysteresis property of modeling adopted PI model, the threshold r was determined by method of inhomogeneous threshold, weight coefficients were identified under the condition of fitting load curve offline at the beginning and then corrected under working conditions of Piezoelectrically microPositioning stage. Dynamic modeling adopted second-order system, the parameters of transfer function model determined by frequency analysis method. Through the precise Piezoelectrically microPositioning stage platform, the model parameters of second-order system and PI hysteresis model had been identified.4.The CMAC neural network which has fast response characteristics introduced into the control based on Piezoelectrically microPositioning stage. Incorporating the CMAC neural network control and traditional PID control, the paper designed CMAC-PID compound controller based on Piezoelectrically microPositioning stage. PID control and CMAC-PID compound control are simulated respectively by the matlab. Writting the PC control program based on Piezoelectrically microPositioning stage under the development environment of Labview and carrying out tracking experiment contrast about two kinds of control methods.Through the analysis of the simulation and experimental data, it was concluded that CMAC and PID hybrid control was effective for control of Piezoelectrically microPositioning stage.