Dynamic modeling and analysis of hybrid driven multi-link press mechanism considering non-uniform wear clearance of revolute joints

The multi-link press mechanism is developing in the direction of high speed and high precision. However, the non-uniform wear of joint clearance seriously affects the output motion accuracy of mechanism. In order to accurately predict the impact of wear clearance on precision press mechanism, this paper takes the hybrid drive seven-bar press mechanism as an example, a method of dynamic modeling and analysis for the press mechanism with non-uniform wear clearance is developed. First, the contact force and friction force at the clearance are solved based on the L-N model and modified Coulomb friction model respectively, and the dynamic model of press mechanism with clearances is developed by Lagrangian multiplier method. Then, the wear characteristics of joint clearance are predicted by Archard model. Finally, the influences of factors such as wear times, friction coefficient and driving velocities on wear characteristics of kinematic pair and the dynamic response of press mechanism are discussed respectively. This study offers a theoretical basis for dynamic behavior prediction of press mechanism with multiple non-uniform wear clearances, and lays a foundation for the design and manufacture of high-precision press.