Crack Detection Method on Flexure Hinges of 3-RRR Compliant Mechanism

Abstract

Abstract. The planar 3-RRR compliant mechanism is a piezoelectric (PZT) actuator driven 3DOF parallel micro-motion device. It is widely used in micro-electromechanical systems, biotechnology engineering and aerospace. However, crack easily occurs on flexure hinge because alternate loading over a long period of time, which will compromise mechanism's accuracy. This paper presents a method for crack detection based on the pseudo rigid body model (PRBM). Particularly, the location of cracked hinge can be identified from the obtained force's variation on piezoelectric actuator of healthy and cracked configurations, while theirs elongation remaining the same. This research has good uses including fault diagnosis, facility for the real-time control and optimization of design of a compliant mechanism.

Modelling and verification of fatigue damage for compliant mechanisms

“…2; since the crack effect is coupled with the motion of mechanism. Recently, we have investigated the methodologies for the crack detection of compliant mechanisms: Gu et al 23 proposed a pseudo rigid body model to represent a crack in a 3-RRR mechanism driven by PZT actuators. A crack was located by measuring the force and vibration over actuators.…”