Parametric vibration for electromechanical integrated electrostatic harmonic drive

In this paper, the electromechanical coupled force between flexible ring and stator of the drive system is presented. The radial displacement of the flexible ring subjected to electric field force is obtained. A critical voltage is found beyond which the flexible ring and the stator will make contact. Considering the ring contacting with the stator as a curved beam fixed at ends, an electromechanical coupled dynamic equation of the drive system is developed. From the equation, the natural frequencies and vibrating modes of the drive system are given. The periodic variable voltage is expressed as disturbance on natural frequency of the drive system and the forced response of the drive system to voltage excitation is investigated. Using Laplace transformation, the forced frequency response of the drive system to voltage excitation is obtained as well. Changes of the forced frequency response along with drive parameters are discussed. Influences of the linear excitation caused by changing boundary angle on the system vibrations are also investigated. The response frequencies are dependent on exciting frequency and natural one. As the exciting frequency is close to the natural frequency of the drive system, the resonance occurs. The flexible ring radius, clearance between the ring and stator, etc. has obvious influences on the frequency responses of the drive system.