On the optimization of compliant force amplifier mechanisms for surface micromachined resonant accelerometers

Abstract

The present work deals with the optimization of a compliant force amplifier mechanism in a surface micromachined resonant accelerometer. Figures of merit including noise floor and scale factor are critically dependent on the gain of the force amplifier mechanism, and hence optimization of the force amplifier mechanism is necessary. The optimization is constrained by limitations imposed by the manufacturing process and the device geometry. The force amplifier mechanisms in this work are initially designed using continuum topology optimization. The results of topology optimization are seen to depend strongly on the size of the design space, output and input stiffnesses and boundary conditions. The results of the topology optimization are converted to beam element models that are used for a further shape and size optimization. Single-stage force amplification factors greater than 100 are obtained from the results of the optimization process.

Performance of compliant mechanisms applied to a modified shape accelerometer of single and double layer

“…Other structures have been developed to increase the displacement obtained in several accelerometers, such as mechanical amplifier, which can transform the displacement applied to the input in an amplified version of it, obtained at the output of the system. Mechanical amplifiers can have very simple geometries, as lever devices [12][13][14]. More complex devices are also implemented, such as the Displacementamplifying Compliant Mechanism (DaCM) shown in [15].…”

Characterization of a Mechanical Motion Amplifier Applied to a MEMS Accelerometer

“…Mechanical amplifiers employing systems of microlevers have already been used in previous studies for various micromachined systems [18]- [25]. However, there have been only very few studies on the application of such mechanisms in inertial sensors [23]- [25].…”

“…However, there have been only very few studies on the application of such mechanisms in inertial sensors [23]- [25]. Although deflection amplification has been implemented in accelerometers before, its application using microlevers is new in these devices.…”

Dynamic and Quasi-Static Simulation of a Novel Compliant MEMS Force Amplifier by Matlab/Simulink

“…Recent studies on compliant mechanisms are focused on novel designs (Kosa et al, 2010), new developed methodologies and optimization in topology (Chour & Jyhjei, 2006;Krishnan & Ananthasuresh, 2008;Pedersen & Seshia, 2004), size and shape (Krishnan & Ananthasuresh, 2008) or the use of finite element methods . Compliant micro mechanisms enable mechanical or geometric benefit meaning that the ratio of output force to input force and the ratio of output displacement to input displacement, respectively, and both mechanical and geometric advantage (MA and GA, respectively) are formulized as follows;…”