Strategy Of Parameters Optimization Based On Vibration Suppression Of Manipulator With Pivot Clearances Coupling Induced Vibration

In the series manipulator,the existence of the clearance between the hinges is inevitable,that will lead to the deterioration of the dynamics performance.In this paper,the 3R series manipulator with clearances is taken as the object of study,based on the derivation of the dynamic equation of the manipulator,the vibration suppression effect of the multi clearances manipulator is realized from the precision and the quality optimization.The main work of this paper has the following aspects:(1)The joint clearance are described,analyzed the advantages and disadvantages of spring damping model and light bar model,combined spring damping model and light bar model,aiming at the possibility of space manipulator's joints in touch motion interference,kinematics equation of manipulator with clearances is proposed by using the dynamics equation and the D'Alembert's principle.The obtained model is more accord with the engineering practice,and the derivation process is relatively simple.(2)Under the same driving speed,the dynamic response characteristics of the manipulator with different joint clearances are also distinctly different.The effect of the joint precision which close to the base on the end of the arm is larger than that of the far base.The accuracy of the joint clearance from the near base to the end of arm is IT7/IT8/IT9,and the vibration amplitude is significantly lower than that of IT8/IT8/IT8 clearance accuracy combination and IT9/IT8/IT7.The simulation analysis can provide a theoretical basis for the joint clearance precision design of the industrial robot manipulator.(3)Based on the dynamic equation,the influence of the weight of the rod on the dynamics of the manipulator with clearances is analyzed.Through the selection of different manufacturing materials,the quality of the rod is adjusted in order of descending.The simulation results show that the quality of the rod near the base is heavy and the end effector is with lower weight can achieve the vibration suppression effect.Within a certain acceleration range,if the acceleration of the drive is small(lengthening the simulation time),we can reduce the quality of the rod in order to achieve the effect of vibration suppression of the manipulator by reducing the end effector to the base.(4)The optimization model is established by combining precision optimization with quality optimization.The precision of the model is IT7/IT8/IT9,from the end of the base to the end of the manipulator.Through the selection of different manufacturing materials,the quality of the rod is adjusted in order of descending.The kinematic and dynamic parameters of the manipulator with clearances are analyzed in terms of working stroke and return stroke.Simulation results show that the combination of the twooptimization methods is better than single parameter optimization,and finally achieves the optimization effect.