A high-reliability acceleration switch based on a compliant bistable mechanism

Acceleration switches play a crucial role as control devices in the inertial control system. Their ability to make reliable contact and close has a direct impact on the safety and stability of the entire system. This paper presents the design of a passive bistable acceleration switch. The design is based on the switching characteristics of a three-segment fully compliant bistable mechanism (TSFCBM) and the principle of frictional vibration reduction, aiming to improve system stability and reliability through friction damping. Firstly, the nonlinear stiffness of the TSFCBM and the static design relationship of the bistable acceleration switch are analyzed. Secondly, a dynamic model of the bistable acceleration switch under the coupling action of multiple forces, such as inertial force, friction damping force, and elastic force, is established. Then, dynamic characteristic simulations and experiments are conducted. The relative error between the simulation results and the experimentally measured switch closing threshold is less than 6.7 %. Moreover, once the switch is closed, it remains in the closed state even when the acceleration signal disappears, demonstrating good threshold characteristics and reliability of the bistable characteristic switch. Next, based on the above, the features of the half-sine wave acceleration signal that enable the bistable acceleration switch to close stably are further analyzed. Finally, a mathematical model between pulse width and amplitude on the closure boundary is obtained, thereby providing a theoretical basis for the threshold design of the bistable acceleration switch.