Vibration Suppression of Reduction-Geared In-Wheel-Motor by Joint Torque Control Using Load-Side Encoder

In-wheel-motors (IWMs) are attracting considerable attention as drive-train for electric vehicles owing to their high motion performance, because of the absence of drive shafts compared with on-board motors. A large motor torque with limited mounting space and low-cost IWMs expect a geared drive-train, however, collisions of gear teeth cause vibration and deteriorate control performance and ride comfort. In order to suppress vibration, reduction-geared IWMs (RG-IWMs), which are IWMs with gears, are modeled as two-inertia system with deadzone model for backlash and joint torque control using both motor-side and load-side encoders for the two-inertia system is applied that our research group proposed previously. Simulations and experiments demonstrate that joint torque of RG-IWMs can be precisely controlled, vibration by collisions can be sufficiently suppressed, and the number of gear collision can be reduced during an acceleration situation. We expect that this research solves the critical problem of RG-IWMs, that is, vibration caused by gear collisions, and realizes the practical and commercial use of IWMs.