A constant-force bistable micromechanism

A constant-force bistable micromechanism (CFBM) allowing force regulation and overload protection is developed. When an unknown force is suddenly applied to a microdevice equipped with a CFBM and the unknown force exceeds a critical force of the CFBM, the CFBM can snap to its other stable equilibrium state to safeguard the device. The bistability of the mechanism originates from combined compression and bending of its beam structures. Prototypes of the CFBM are fabricated and tested. A device for obtaining the in-plane force-displacement characteristics of the CFBM is developed. The performance of the CFBM is verified by experiments. Sophisticated sensors and control system for force regulation of microsystems can be eliminated using the developed CFBM.