Hydraulic Control System Search On A3-UPS/S Parallel Mechanism

Parallel mechanism has many characteristics of high precision, good rigidity, large load capacity, etc. Electro-hydraulic servo drive system also has advantages of small space, large bearing capacity, fast response and wide-range speed regulation. Thus, applying electro-hydraulic servo system to parallel mechanism is so necessary for parallel mechanism to increase its load capacity, speed up its response characteristics and expanding its applicable range. Parallel mechanism driven by hydraulic have been widely used in fields of industry, ship craft and space flight, etc. As the same time, introduction of hydraulic drive increases the difficulty of the control of parallel mechanism, therefore, control strategy about hydraulic drive3-UPS/S parallel mechanism will be mainly studied.The mathematical model of kinematic positive and negative solution to3-UPS/S parallel mechanism and the mathematical model of valve control asymmetric cylinder hydraulic dynamic mechanism were established firstly in this paper, on this basis, transfer function of single-channel hydraulic system is further established, and the pressure, speed and pressure flow characteristics of power mechanism when it is in the forward and reverse movement are analyzed.Traditional PID control and neural network predictive control methods were adopted to single-channel of3-UPS/S parallel mechanism, control effect of this two methods which were applied to single-channel hydraulic system was analyzed by comparing simulation analysis.By the use of ADAMS、Simulink and AMESim, co-simulation model which includes mechanical dynamic model, electro-hydraulic servo system model and control strategy model of3-UPS/S parallel mechanism are established. According to co-simulation, the position tracking situation of three cylinders when the platform was in the motion is analyzed.Experiment platform of3-UPS/S parallel single-channel hydraulic systemis build. By using of dSPACE simulation system, joined the traditional PID control and neural network predictive control to the experiment platform for experiment research, the experiment result and simulation results are compared according to analysis. By the Labview, the pressure values of the two cavities of the hydraulic cylinder which was in the forward and reverse motion were collected to verify the correctness of the pressure characteristic analysis.