Research On Motion Control Of Electric Drive Small 6-DOF Parallel Platform

The 6-DOF parallel platform has gradually increased in industrial production and life due to its advantages of compact structure,small volume and large rigidity,with capacious development prospect.6-DOF parallel platform by electric driver is more and more widely applied because of its advantages of energy conservation and environmental protection.Motion control is a prerequisite for the accurate execution of motion trajectory on a six-degree-of-freedom platform.Therefore,it is of great significance to study the motion control of electrically driven 6-DOF parallel motion platform.This paper summarizes the development of 6-DOF parallel kinematics platform at home and abroad,and the motion control of the 6-DOF parallel platform by electric driver is studied.In this paper,the structure design of 6-DOF parallel platform driven by electric driver is carried out.The overall structure of the platform consists of upper platform,lower platform,upper hook hinge,lower hook hinge and middle electric cylinder.And the three-dimensional modeling of the platform is designed by using Solidworks,and the model of stepping motor and driver are matched.The type selection calculation of the screw and the checking of the stability of the compression rod are carried out and the physical prototype of the platform is built.The transfer function of the system is established,and the stability and response characteristics of the system are analyzed.The improved Kutzbach-Grubler formula is used to define the structure of the two-end Hooke hinge with electric cylinder in the middle to verify the basic condition that the platform exists six degrees of freedom.In order to describe conveniently,the dynamic and static coordinate systems of the platform are established.The translation matrix and the rotation matrix are established through the translation and rotation transformation,and the homogeneous transformation matrix of the platform is derived.The inverse kinematic position model of the platform is established through the vector relation of the member,and the velocity and acceleration equations are obtained by the vector derivation.Based on the mathematical model,the inverse kinematics solution algorithm is designed,and the simulation model of the platform is established in the Matlab/Simulink environment by the path generation module,the rotation matrix module,the matrix connection module,the leg length calculation module,the upper Hook hinge vector module,the lower Hook hinge vector module and the matrix shaping module,and the motion simulation of the platform is carried out.The simulation results of the platform under the motion state of single degree of freedom and multi-degree of freedom are obtained.,which laid the foundation for the subsequent control programming.Using the motion control card as the driving amplifier,and the circuit diagram of the control system and the corresponding program block diagram are designed based on the driving characteristics of ADT-856 motion control card and LabVIEW programming software,the control interface and corresponding program block diagram of electrically driven 6-DOF parallel motion platform are developed,and the functions and characteristics of each component are introduced in detail.The state of the platform under different presupposition and pose is obtained through the motion demonstration test.Compared with the simulation results,the data obtained and verified the correctness and feasibility of the simulation and control program.