Crack Detection Method On Flexure Hinges Of 3-RRR Compliant Mechanism

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.The object of the research is to(1) propose a new method to detect the location of cracked compliant mechanism based on Pesudo Rigid Body Model (PRBM) and (2) validate the method through numerical simulation and experimental test-bed.Firstly, kinematic and dynamic model will be established through PRBM. Secondly, cracked dynamic model will be established based on healthy one. Thirdly, driving torque between healthy and cracked mechanism will be used to identify the location of cracked flexure hinges. Finally, numerical simulation and experimental validation about the planar 3-RRR compliant mechanism will be introducedThe conclusion of the research is that (1) the crack detection method is effective and correct to detect existence or position of the cracked hinge on the compliant mechanism and (2) static and dynamic input signal have been proved to be effective on crack detection method, and the format of the detecting result is depended on the input signal’s format.