Effects of joint clearance on the dynamics of a partly compliant mechanism: Numerical and experimental studies

• Joint clearance is inevitable and makes the mechanism performance worse.
• Compliant and articulated mechanisms having joint clearance are investigated.
• Vibrations of mechanisms are compared to each other for different scenarios.
• Pseudo joint in mechanism with clearance decreases the uncertainties in motion.
• Flexural pivot in compliant mechanism has a suspension effect for impact mode.

Compliant mechanism has got at least one flexible member between conventional rigid links. It is a good choice for decreasing the number of movable joints and also their clearance effects. In articulated mechanisms, clearance is inevitable due primarily to the design, manufacturing and assembly processes or a wear effect. Also, it plays a crucial role and has a significant effect on the mechanism stability and the performances of whole system. In this study, both numerical and experimental investigations are carried out to analyze the effects of joint clearance on partly compliant and conventional articulated mechanisms. Bearings' and links' vibrations are considered to determine what is the main contribution of small flexural pivot on compliant mechanism having joint clearance? Five accelerometers have been located at different points to measure the vibrations on system during the mechanism motion. The results show that the joint clearance makes the mechanism performance worse. The flexibility of flexural pivot has a clear suspension effect to minimize the undesired outputs of joint clearance on mechanisms. Also, small-length flexural pivot is an important tool to prevent the separation between journal and bearing by constituting a force-closed kinematic pair in a joint with clearance.