Motion characteristics of pointing mechanism with clearance in consideration of wear

For the accurate prediction of the joint dynamic wear, the coupling factors of clearance, friction and abrasion were considered. The dynamic problems and abrasion problems of the two-dimensional space pointing mechanism were studied, which considered the factors of clearance, friction and abrasion. Using the Newton Euler' s law, the dynamic model of the two-dimensional space pointing mechanism with clearance was constructed by embedding the clearance variables. Based on the Archards wear model, by finding the wear depth at different positions of the moving contact surface and reconstructing the surface morphology of the kinematic pair, the dynamic characteristics of the pointing mechanism with clearance were analyzed in the process of wear, and the change laws of the contact collision force and the tangent friction force at the joints were obtained; the dynamic fitting variables method and the discrete processing method were used to fit the correspondences between the clearance and contact force, and the running time and the relative slip velocity of the kinematic pair with clearance, and the dynamic wear mathematical model was established; furthermore, the predicted service lives of the two-dimensional pointing mechanism are 12 591.92 hours and 764.44 hours under the tracking mode and the attitude adjustment mode. The work in this thesis provided the theoretical base for the ontology design, manufacture and application of the two-dimensional pointing mechanism.