Research On Control Methods Of High-speed Parallel Manipulators

Impelled by the keen market requirement from electronics and pharmaceutical industry, where pick-and-place operations at very high speed and precision are basic conditions, this dissertation presents an integrated methodology to improve the movement speed and accuracy for the parallel manipulators, including dynamics analysis, trajectory planning, control strategy and confirmatory experiments on Delta prototype machine. The following achievements have been accomplished.For the goal of ensuring minimum summation of the maximum absolute deviation for each joint between complete and simplified dynamics model, a new method about allocating proportionality of driven chain quality has been proposed. Through analyzing the relationship between allocating proportionality, simplified dynamics model for Delta prototype machine has been obtained and proved to be effective.Aiming at typical operating conditions and motion path, the planning has been completed in operation space by selecting some suitable laws of motion. After comparisons of these laws according to themselves movement characteristics and motion effective torque considered, an optimum law of motion for pick-and-place operated by parallel manipulators has been immobilized.With the method of simulation in Simulink soft, simulation results for the parallel manipulator system by using PID control, fuzzy PID control and computed torque control have been obtained. Taking the tip tracking errors into consideration, a control strategy for parallel manipulator systems has been confirmed preliminary.To verify control effects with the kinematics control strategy employed, the experiments have been carried out. The results show that obvious deviation between experiments results and simulation results with the kinematics control strategy in consideration of the dynamic characteristic of high-speed parallel manipulators. Therefore, it will be important and imperative to carry forward researches about dynamics control strategy and the related experiments.The work achieved in the dissertation is significant and valuable for enriching promoting the control strategy on high-speed parallel manipulators and expanding its application in automatics industries.