Experimental analysis of spring hardening and softening nonlinearities in microelectromechanical oscillators

Micro-electro-mechanical systems or MEMS are used in a variety of today’s technology and can be modeled using equations for nonlinear damped harmonic oscillators. Mathematical expressions have been formulated to determine resonance frequency shifts as a result of hardening and softening effects in MEMS devices. In this work we experimentally test the previous theoretical analysis of MEMS resonance frequency shifts in the nonlinear regime. Devices are put under low pressure and swept through a range of frequencies with varying AC and DC excitation voltages to detect shifts in the resonant frequency. Mathematical models have predicted greater nonlinearities with higher AC amplitudes and spring softening with high DC voltages. Further research is being conducted to compare MEMS experimental data to earlier theoretical models. Our research will assist in confirming a more accurate model for MEMS devices, which could result in improved micro-technology in products such as gyroscopes, accelerometers, and displays.