A resonant accelerometer based on electrostatic stiffness and its closed-loop control method

摘要

Purpose - This paper aims to provide detailed information on the dynamic model and closed-loop control theory for a resonant accelerometer based on electrostatic stiffness, which is important for the design of this type of resonant accelerometer. Design/methodology/approach - After analysing the principles of the resonant accelerometer based on electrostatic stiffness, a dynamic model was built. According to the requirements of the closed-loop control, the control equations based on phase-locked technology were also built for the system. With the help of the averaging method, the system behaviour was analysed, and the equilibrium for the vibration amplitude was achieved. Findings - The theoretical analysis and simulation show that integral gain is critical to system stability. When it is larger than the critical point, the system stable time is shorter, but the frequency-tracking process fluctuates; if it is smaller than the critical point, the system stable time is longer, and the frequency-tracking process stabilizes a resonant accelerometer was fabricated with a bulk-silicon-dissolved process. With the above conclusions, the accelerometer was driven and tested with a sensitivity of 47 Hz/g for a single vibration beam. Originality/value - The dynamic model and the control theory for the resonant accelerometer based on electrostatic stiffness were presented in this paper. The simulation and experiment results agree well with the theoretical analysis.