Forces for electromechanical integrated electrostatic harmonic drive

In this paper, electromechanical coupled force between flexible ring and stator for the drive is given and defined in Fourier series form. Using displacement function, basic equations of the internal forces and displacements are presented. The displacement function is defined in Fourier series form and three equivalent differential equations are obtained. From the three differential equations, above displacement function and the equations of the internal forces and displacements are given. By boundary condition, undetermined coefficients of above equations are obtained. The relationship between average radial displacement and voltage is given by iterative computation. The internal force distributions in the flexible ring are obtained. Changes of the internal forces along with drive parameters are analyzed. Results show: there is an extreme voltage, after which the flexible ring will be buckled and it will contact with stator. The six internal forces in the flexible ring are variable and their distributions are different. Bending moments and torque are much smaller than internal forces. The flexible ring radius, clearance between ring and stator, etc. has obvious influences on internal forces of the flexible ring. In order to reduce internal forces in the flexible ring, larger radius, smaller thickness and clearance, and proper voltage should be used.