Design And Implementation Of An Embedded System Based Motion Controller For 6-DOF Parallel Mechanisms

In this dissertation, a application specific motion controller is designed. It is used to implement real-time, accurate control of Subreflector Adjusting Mechanism. The Stewart platform is used as a subreflector adjusting mechanism. The motion controller can achieve the six degrees-of-freedom movement of the Stewart platform based on the six servo motor control. Considering the multi-axis synchronous movement and the actual application environment, CAN bus is decided to build the fieldbus network and to complete the design of the movement control system, that with short frame transmission, low interference rate, high transmission efficiency.This dissertation, according to the function of the motion controller and the composition of control system, propose a design scheme of special motion controller. The control system consists of PC, special motion controller, servo drives, electric cylinder, Stewart platform, sensors, etc. User send control commands to motion controller by PC interface. The motion controller to complete the command parsing, status acquisition, control algorithm processing. The motion controller sends motion control commands to servo drivers by CAN bus, realize the precise movement of parallel mechanism. It also can obtain relevant data and status of equipments by CAN bus.This dissertation complete the overall designed of the control system, describes and assigns the function of control system.By studying the principles of parallel machanism, kinemaatics analysis of 6-DOF parallel mechanism is completed. Forward and inverse solution algorithms are impemented, and integrated into the motion controller.In the control system, the design of CANopen protocol stack is completed, through the analysis and research of CAN bus and high-level protocol CANopen. According to control requirements, configuration of servo drivers is completed, the function of CANopen protocol is assigned,The functional design of motion control is completed, which includes the FPGA and ARM part. The FPGA is used to complete the limit switch sampling, SSI sensors sampling, SPI communication, code conversion, and other functions. As the main control past, ARM is used to complete driver design of hardwares, to implement theCANopen protocol stack, to complete integration of forward and inverse solution algorithms, to design the motion control program, to protect the mechanism, to call and control other modules of control system.Finally, a series of tests on the motion controller, and field experiments of Subreflector Adjusting Mechanism, the feasibility and accuracy of motion controller is validated.