Dynamics Response and Non-linear Characteristics Analysis of Complex Planar 2-DOF Mechanism with Revolute Clearances

There are clearances in mechanism because of manufacture and assembly error, which reduces operation life and working accuracy of mechanism and has a great impact on dynamical responses. At the moment, research in this area mainly focuses on single degree-of-freedom mechanism considering one clearance, while research of multi-DOF mechanism considering multi-clearance is less. With the purpose of studying the dynamical characteristics of complex multi-DOF mechanism with multi-clearances, a dynamic model was developed. The dynamic responses of 2-DOF mechanism with two clearances under different positions, values, and numbers of clearance were analyzed. The displacement, velocity, acceleration, collision force, and the axis trajectory at clearance were then given. In addition, there is a limited amount of literature on chaotic phenomena, which mainly focuses on the chaotic phenomena of end-effector of mechanism. But in this paper, the non-linear characteristics were analyzed by chaotic phenomenon of clearance joint, then chaotic phenomenon was identified by Poincaré mappings and phase diagrams. Bifurcation diagrams were given. The results will offer a reliable technical support for the study of dynamical responses of planar mechanisms and the analysis of chaotic phenomena.