Piezoelectric Motor And Force Feedback Controlling Of Parallel Platform

Parallel platform has many advantages like high rigidity,high carrying capacity and low inertia force of terminal element.And it is also used in robots,machine manufacturing,aerospace and entertainment facilities areas.In assembling of precision instrument,parallel platform also has some application prospects.Electromagnetic motor and hydraulic device are used as the driving element in traditional parallel platform.In recent years,with the developing of micro-special motor,ultrasonic motor is used in various parallel platform gradually.Ultrasonic motor(USM)has perfect performance and characteristics like low speed,high torque,quick response,self-lock while power off,and it can be used in magnetic field.Firstly,a parallel platform with 6-UPS mechanical structure is designed,and it takes ultrasonic motor as driving element to solve the problem that traditional parallel platform can't work in magnetic field.Secondly,theoretical analysis of the 6-UPS parallel platform is made,including inverse kinematics solution and static analysis.The transform relationships of pose and branched chain length are obtained,and they are the theoretical basis of control algorithm.And then the trajectory planning for parallel platform is made by interpolation method and trapezoidal curve method to ensure smooth running.Thirdly,the control system consisted of PC and DSP is designed to guarantee the function of manual adjustment and automatic adj ustment.An error compensation method of parallel mechanisms based on MBGD algorithm and a new PID controller model based on SGD-Momentum algorithm are presented,optimizing the response time and convergence rate of this system.And then some hardware circuits are designed,to ensure system integrity and reliability.Finally,the experimental prototype is manufactured,and the experiment data is gathered to validate the results of theoretical analysis and control algorithm.And the zero-position information of encoder is used to confirm the initial pose,reducing the zero-shift risk.This paper shows that the high-precision motion of 6-UPS parallel platform with ultrasonic motor can be assured,and solves the problem that traditional parallel platform can't work in magnetic field.The application scenario of parallel platform is broadened.