Delayed Position Feedback Control On Suppressing Poll-in Instability Of A Typical Electrostatically Actuated Microsensor

In this article, an electrostatic actuated MEMS sensor is considered, at the same time considering vibration model with DC bias voltage and AC voltage drive. Firstly, the structure Vibration systems is simplified to one degree of freedom mass and spring and capacitance and damping vibration system. Consider a parallel plate capacitor in theory, In the case of no edge effect of parallel plate capacitor, electrostatic driving force of the system has been calculated. The electrostatic micro sensor dynamics system was established based on Newton's second law equation. To facilitate the study of electrostatic micro actuator of pull in phenomenon, on the system parameters are dimensionless, and analyze the effect of the change of system parameters of electrostatic MEMS sensor nonlinear motion.Secondly, considering MEMS sensor electrostatic pull-in phenomenon from static power, the electrostatic MEMS sensor system applied delayed position feedback, according to the stability theory and homoclinic orbits and heteroclinic orbits method obtained parameters lead to MEMS sensor power system the pull-in instability phenomenon of boundary conditions, master the delayed position feedback control mechanism to pull-in phenomenon. Will the Melnikov function method applied to single degree of freedom electrostatic MEMS sensor time delay control system, discuss the delayed position feedback parameters and the size of the balance of system instability, calculated to verify the sensor system pull-in phenomenon of boundary AC voltage.Then using fourth-order Runge Kutta method and point mapping method for the numerical simulated system has the chaos and safe basin erosion characteristics and complex control systems with time delay dynamics behavior with the evolution of the control parameters, thus validating the delayed position feedback control is effective.Finally, numerical simulation and analytical calculation show that:as long as in the positive feedback parameters and the hysteresis control and delayed position feedback to control the MEMS sensor structure of pull-in phenomenon has the ideal control effect. The time delay changes directly affect the AC voltage system pull-in phenomenon, effectively improves the anti-interference ability of the system.