Dynamics Characteristics Analysis of Multi-Link Mechanism Considering Various Disturbance Factors

Abstract

Disturbance factors such as clearance, wear, and elastic deformation of components severely constrain accuracy and stability of mechanism, and further lead to chaotic phenomena, seriously affecting dynamic of mechanism. The main purpose of this paper is to establish a multi-body system dynamics model of a multi-link mechanism that considers coupling effects of clearance, wear, and elastic deformation of rods, accurately predicting the wear characteristics, dynamic response, and nonlinear characteristics. Firstly, a wear model for clearance of the rotating pair was established based on the Archard model. Secondly, establish a model of flexible rods based on Absolute Node Coordinate Formula. Then, Lagrange multiplier method was used to establish exact dynamic equation considering coupling effects of clearance, wear, and elastic deformation of component. Finally, influence of different parameters on dynamic and wear characteristics were analyzed, and nonlinear characteristics were studied through phase diagrams, Poincaré maps, and maximum Lyapunov exponents. The results indicate that wear intensifies irregularity of clearance surface contour, leading to an increase in the instability of dynamic response and a decrease in motion accuracy. Excessive clearance value, and fast driving speed can both lead to increased wear of motion pair, resulting in decreased stability of mechanism and enhanced chaos.