Dynamic behavior analysis of a planar four-bar linkage with three clearance joints

In practice, clearances in the joints are inevitable due to tolerances, and defects arising from design and manufacturing. It is noteworthy that in the presence of clearance at a joint, a mechanism gains some additional, uncontrollable degrees of freedom which are the source of error. Moreover, joints undergo wear and backlashes and so cannot be used in precision mechanisms. In this study, the dynamic behaviour of a planar mechanism with revolute joints, in the presence of clearances is investigated. A continuous contact force model, based on the elastic Hertz theory together with a dissipative term, is used to evaluate the contact forces. And then, the dynamic characteristics of planar mechanical system with revolute joint clearance are analyzed based on the new contact model. Numerical results for four-bar linkage with three revolute clearance joints are presented and discussed.