Design of a path generating compliant mechanism using a novel rigid-body-replacement method

Flexure-hinge compliant mechanisms have developed rapidly in precision engineering and robotics, especially in the context of micro aerial vehicles, where researchers employ such mechanisms for generating flapping-wing paths. This paper focuses on the design of a fully compliant mechanism for generating different bio-inspired 3D wing paths. A novel design algorithm was developed based on the rigid-body replacement method. The rigid-body replacement typically involves searching a rigid-body mechanism that accomplishes the desired path and converting it into a compliant mechanism by replacing the rigid joints with flexural hinges or using the Pseudo-Rigid-Body model. In the new method, the 3D mechanism was designed in two perpendicular planes. First, the main path was developed using the four-bar mechanism synthesis methods. Then, the mechanism was dynamically designed by flexural elements in the other plane. The governing dynamic equations were derived, and the main parameters were investigated. The mechanism was prototyped by the SCM (Smart Composite Manufacturing) process. For verification, the wing path was captured by a high-speed camera and compared with the analytical path.