Influence of joint clearance on kinematic and dynamic parameters of mechanism

Abstract

Kinematic joints for dynamic analysis of multi-body mechanical systems assumed ideal or perfect. However, in a real mechanical kinematical joint clearance is always present. Such clearance is necessary for the component assemblage and to allow the relative motion between the connected bodies. This clearance is inevitable due to the manufacturing tolerances, material deformations, wear, and imperfections. The presence of such joint clearance degrades the performance of mechanical systems in virtue of the contact and impact forces that take place at the joint. Contact analysis is a computational bottleneck in mechanical design where the contact changes. Manual analysis is time-consuming and prone to error. To address these problems, a geometrical contact analysis method based on kinematic simulation, using CAD software is developed. An equivalent kinematic linkage mechanism is constructed according to contact position of pin and hole assembly. Results of kinematic and dynamic analysis of a four bar linkage with joint clearance shows that the contribution of joint forces at slower input speed also degrades the performance of mechanism.