| Open loop mechanism is widely used in engineering equipment,such as industrial robot,space manipulator,etc.Especially the application demand of open-loop mechanism,which is represented by industrial robot is exploding under the background of the economic structure transformation and the rising trend of labor cost in manufacturing industry.Therefore,the in-depth research and innovative development of open loop mechanism have very important theoretical and practical significance.Many factors influence the dynamic performance of the open-loop mechanical system,and the joint clearance is one of the most urgent issues among the numerous factors to be solved.This work systematically analyzed the dynamic performance of an open loop mechanism with multiple clearance joints,and verified by experiment results.The main contents are as follows:The motion and force transmission laws of the open loop mechanism with multiple clearance joints were studied.Using the improved massless method,dynamic model of the mechanism with multiple DOF and clearance joints was established to solve the difficult dynamic equations.According to the structural characteristics of the spatial revolute joint,the dynamic model of open loop mechanism with spatial revolute clearance joint was established and the dynamic equation solving method was discussed.The effects of gravitation,clearance joint location and spatial revolute clearance joint on the dynamic characteristics of open loop mechanism with multiple DOF and clearance joints were analyzed,which provides a theoretical basis for improving the reliability and stability of open loop mechanisms.It is an effective control strategy to investigate the nonlinear factors like joint clearance by the neural network internal model control algorithm.Finally,an open loop mechanism experiment platform containing joint clearance was built.A axis trajectory measurement method was proposed,which successfully verified the dynamic model of open loop mechanism with clearance joint. |
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