Nonlinear Dynamics of Lateral Electrostatic Gap Closing Actuators for Applications in Inchworm Motors

We present a nonlinear dynamics model for lateral electrostatic gap closing actuators (GCAs) operated in air and underwater. We factor in finger bending and the release phase’s initial velocity over prior work, and we systematically study the effect on GCA pull-in and release time by varying both the finger length and the release spring constant. Simulation results are then compared to experimental data with good conformity. We also apply this dynamics model to optimize electrostatic inchworm motors for drive frequencies up to 40 kHz and speeds up to 415 mm/s, over 11× faster than what has been previously reported. [2021-0197]

Keywords: Gap closing actuators, electrostatic inchworm motors, MEMS, dynamics