Electrostatic comb drive actuators with variable gap: nonlinear dynamics at primary resonance

This paper provides an extensive study of the nonlinear dynamics of a variable gap electrostatic comb-drive. The resonant response, as well as the force response of the comb-drive were obtained and analyzed taking into account mechanical and electrostatic nonlinearity of the system. A significant influence of nontrivial equilibrium position of the comb-drive on frequency and force response of the system is demonstrated. Using numerical methods of bifurcation theory, continuation of the resonant operating mode is performed in terms of DC and AC voltage variables. The result obtained makes it possible to determine the range of excitation voltage values that provide the required vibration amplitude in the resonant mode. The influence of the second stationary electrode on the dynamics of the system is investigated. The significant influence of this factor on the resonant-mode characteristics is revealed.