A threshold accelerometer based on a tristable mechanism

A threshold accelerometer based on a compliant tristable mechanism (TM) is developed. The accelerometer is capable of sensing two distinct inertial signals when acceleration thresholds are exceeded along one axis. This function allows the flexibility to detect two consecutive events with the expected threshold values of the stimuli or two level quasi-static acceleration thresholds. The TM is a series connection of two bistable mechanisms (BMs). An analytical model based on a chained beam constraint model (CBCM) is developed for design and characterization of the TM. Feasibility of the device is demonstrated by experiments. The developed analytical model for the TM is verified by finite element analyses and experiments. Detection accuracy and fault tolerance can be enhanced by the thresholds created by snap through behavior of the TM.