Dynamic Characteristics Analysis of Strain Wave Gearing Actuated by Magnetic Force

Abstract

　Leg support system have been studied to assist people with lower limb disabilities, but the weight is not enough for patients and caregiver. We have developed a lightweight magnetic strain wave gearing with high gear ratio for leg support system. In this paper, we propose dynamic characteristics analysis method for the gear. First, the magnetic force distribution on a flexspline is obtained as magnetic force database, through static magnetic analysis with finite element method. Next, dynamic behavior is calculated through multi flexible body dynamics with the finite element method, the direct solver, and the magnetic force database. The analyzed maximum torque is 3.34 Nm (input rotation angle: stepwise waveform at every 5 deg.). The measured torque is 3.36 Nm (input rotation angle: stepwise waveform at every 5~30 deg.). From these results, the validity of the proposed analysis method was clarified.