Multi-stable devices are systems that have multiple different stable equilibrium states. This behavior results from the nonlinearity of the system. Multi-stable MEMS devices are used in many applications and are realized using various operating principles such as geometric structure nonlinearity or non-linear actuation.
In this work, a multi-stable electromechanical system is realized in a MEMS device, that is constructed from several double-sided comb-drive actuators. The fingers of the double-sided comb-drive actuators do not overlap in the initial state. This is in sharp contrast to common double-sided comb-drive transducers in which fingers overlap during the entire stroke. Due to the nonconventional design of the new comb-drives, the electrostatic forces are a non-linear function of motion. This nonlinearity induces instability in the electromechanical response of the non-overlapping double-sided comb-drive transducers. By using several of these transducers, a multi-stabile device is implemented. The nonlinearity of the electrostatic forces is determined by the voltages applied to the comb-drive transducers, which enables the tuning of the stable states.
In this work, the functionality of such multi-stable devices is investigated, using simple models, numerical analysis, and experimental characterization of test devices that were designed for this purpose.
