Research On Kinematics Calibration Of 3-UPU Parallel Mechanism

With the continuous development of the industrial economy,the competition among countries in the world is still the competition of the manufacturing industry.The proposal of "Made in China 2025" has promoted the development of traditional manufacturing in the direction of intelligence and high precision.Among them,the parallel mechanism as the core unit is used in the parallel machine tool to show its excellent performance.The research object of this paper is a kind of unaccompanied two-turn and one-shift 3-UPU parallel mechanism,which can rotate around a fixed point and has a huge application prospect in machine tools.Mainly carry out motion calibration research to improve the accuracy of terminal motion.The research content is as follows:First,according to the structural characteristics of the mechanism itself,the kinematics inverse solution relationship is established,the residual matrix under n groups of poses is constructed,the accuracy model of the mechanism is established based on the closed-loop vector chain,and the error source that affects the motion accuracy of the parallel mechanism is analyzed.Based on the accuracy model,the factors that affect the motion accuracy of the end effector of the mechanism are analyzed,including 23 errors,and the mapping relationship between the corresponding errors on the end motion is established,and the effect of a single error source on the end effector is obtained.The mapping relationship of the end error when the three branches change within the same error range.According to the actual situation of the error,a histogram of the error distribution of the three degrees of freedom is obtained.Afterwards,generalized simulations are carried out on the influence of the mechanism error,and finally the dynamic error of the mechanism is classified and analyzed.A kinematic calibration method for improving the quantum particle swarm optimization algorithm is proposed,and four test functions are used to verify that the improved quantum particle swarm optimization algorithm has higher calculations than the difference algorithm,particle swarm algorithm,and quantum particle swarm algorithm.Accuracy and convergence speed,and explain the kinematics calibration process of the parallel robot,design the objective function to be calibrated,and again use the traditional intelligent algorithm genetic algorithm,simulated annealing algorithm,and improved algorithm to obtain the parameters of the three optimization algorithms The identification value again proves that the optimized quantum particle swarm optimization algorithm has higher identification accuracy.Using a laser tracker and kinematics calibration test to calibrate the full parameters of3-UPU,it is proved that the 3-UPU parallel mechanism has the highest sensitivity to errors in the degree of freedom of movement.After calibration,the motion accuracy of the end effector is improved by more than an order of magnitude.,The experimental data and the calibrated exercise effect verify the effectiveness of the improved algorithm and the correctness of the experimental method.