| The researches on parallel mechanism began with a parallel mechanism called Stewart platform in 1965.For the past of forties years,there has been many different kinds of parallel machine tools and parallel robots which are developed to be used in many different fields.Parallel mechanism is proposed that and 1965 Stewart platform is put forward,after 40 years of research at home and abroad has been derived from various forms of parallel mechanism and the parallel machine tools or parallel robot in the form of application in industrial production.Because of the advantages of its structure,the parallel machine tool has the advantages of high rigidity,fast speed and large working space,so it is widely studied in China.Because of the deep research of parallel machine tools,Northeastern University developed a 3-DOF tripod,5-DOF tripod and 3-TPS hybrid machine tool.However,the control method of parallel mechanism could be very complicated due to its special structure.This paper do a deep research on the servo control method of a 3-TPT parallel mechanism from one axis to three axis by simulation in Simulink software and experiment.the main research contents of this paper are as follows:(1)Design and analyze the whole structure and hardware of the servo control system of 3-TPT parallel mechanism.(2)Establish the servo control system’s model of one axis according to the parameters of hardware of the servo system by Simulink software.Then use vector control whit PID to establish the current loop,and establish the position loop and speed loop with PID control method.(3)Adjust the parameters of PID in each loop of the servo system model established by the Simulink software.(4)Connecting the circuit of the servo system of one axis according to the structure of the hardware.Then,adjust the parameters of current loop,speed loop and position loop of servo system by using step and parabola as the input signal in the experiment.(5)Analyze the kinematics and dynamics of 3-TPT mechanism by using equations.Establish the whole simulation model of the control system 3-TPT mechanism including the kinematics and dynamics model and three axis servo control system.Adjust the parameters of PID with a circle curve as the input signal.Make the track of the moving platform as close as to the input track of platform in simulation through adjusting the PID parameters in each servo system. |
PDF Full Text Request