Modelling and optimization of compound lever-based displacement amplifier in a MEMS accelerometer

Abstract

Compliant mechanisms have been realized as a potential tool to enhance the sensitivity of MEMS accelerometers through displacement amplification. In this article, optimization of a compound lever-based compliant mechanism has been carried out for the inclusion in MEMS accelerometer. The compliant displacement amplifier has been studied using the pseudo-rigid body approach and expressions for the displacement and fundamental natural frequency have been derived for the MEMS accelerometer. Further, for a range of values of the selected parameters, a detailed comparison has been made between the outcomes of the considered pseudo-rigid body-based approach and FEA simulations. Based on the derived mathematical model, optimization has been carried out for the best performance of the MEMS accelerometer. Using switched capacitor-based signal conditioning, output voltage has been calculated for the given input signal. Performance of displacement amplifier based MEMS accelerometer has been compared with the conventional one for sensitivity and nonlinearity. In this work, using a comparatively smaller size of proof mass, the higher figure of merits has been achieved in terms of natural frequency and amplified displacement of sense comb fingers.