Nonlinear vibration for a micro electromagnetic harmonic drive system

In this paper, a nonlinear dynamics equation for a micro electromagnetic harmonic drive system is proposed considering nonlinearity caused by the molecule force applied to the flexible ring. Using the equations, the nonlinear resonant frequencies and the amplitude frequency characteristics of the drive system are investigated. Effects of the molecule force nonlinearity on the resonant frequencies and the amplitude-frequency characteristics and their changes along with system parameters are analyzed. Results show that the nonlinear effect of van der Waals forces on system vibration should be considered when the coil current and the radius of the flexible wheel are large, the thickness of the flexible wheel or the gap between the flexible wheel and the stator is small. The jump vibration zone of the flexible wheel reduces significantly with increasing the exciting current in the coil, the length of the flexible wheel, and the nonlinear parameter, or decreasing the thickness of the flexible wheel.