Dynamic analysis of a resonant comb-drive micro-actuator in linear and nonlinear regions

The nonlinear behavior of a resonant comb-drive micro-actuator was characterized using a theoretical model and compared with the numerical results and experimental data. It has been experimentally noticed that the displacement amplitude in the nonlinear region became less than that in the maximum possible linear region. Therefore, the maximum linear displacement of an actuating comb that maintains the sinusoidal harmonic motion was obtained using the theoretical model, in which the total electrostatic force was linearized using a sinusoidal shape. The displacement amplitude and the phase delay were used as convergence parameters, and the maximum linear displacement was found when the displacement amplitude of the sinusoidal motion reaches its maximum value while satisfying the convergence criteria. We then present a general model of the maximum linear displacement for variable comb dimensions. The theoretical result was compared with the numerical and experimental results, and they are within the errors of 7.2 and 11.5%, respectively. The more softening effects were experimentally noticed in the sweeping up frequency than in the sweeping down frequency.