Research On The Control Method Of Precise Positing For The Piezoelectic Moving Platform

A3-DOF precision positioning stage system driven by the linear ultrasonic motor(LUSM) hasbeen designed to meet the requirement of multi-dimensional nanometer level positioning offlexure-based precision mechanism.LUSM is a novel motor utilizing the mechanical vibration that is generated by the inversepiezoelectric effect of piezoelectric ceramics.Through the friction between the stator and the promoter,the slight vibration of elastic body converts to linear motion of the promoter. Because of its fastresponse, self-locking when power off and no motion of conversion mechanism, it is suitable to beapplied to precision positioning platform, to get higher positioning accuracy and resolution.Firstly, the new motor is used as a drive unit. With a high-precision linear rolling guide and ahigh-resolution grating encoder, a linear precision platform is established. It has the followingfeatures:simple stuctur, high guiding accuracy and good retention.Secondly, TMS320F28335is selected as a lower computer for real-time control, grating encoderas position feedback element returns movement data through the DSP, LABVIEW is applied todevelop the host computer software. The movement date of linear ultrasonic motor can be multiplecollected, displayed, processed and saved.Thirdly, LUSM with the advantage of its high move-resolution when stimulated by ultra-short pluse,this paper introduces a high precise position control strategy named stepping-position control methedand the factors that influence position precision are analyzed. In order to make the motor in thecontinuous operation can be smooth and fast when running to the target position,PID algorithm isapplied, the repetition positioning accuracy of the single precision positioning stage is less than1μmunder different distancese and the movement is smooth,fast and robust, this system can realize the3-DOF move, have a rotation angle of [0,3rad], the range of movement is [-5mm,5mm;-5mm,5mm].The system is widely used in research of precision processing and micro-nano operation.