Tilt dynamics and control of narrow tilting electric vehicles considering driving torque difference

Abstract

Narrow electric vehicles are widely considered to be one of the ideal solutions for future mobility due to their flexibility, energy efficiency, small size, and light weight. Nonetheless, their reduced width presents challenges to vehicle stability, particularly at high speeds. Consequently, tilting vehicles are often designed to counteract the centrifugal force experienced while turning. The vehicle employs an active tilting actuator that moves the vehicle toward the inside of the curve during turns. However, the shock absorbers located between the driving wheels and the active tilting actuator can cause delays in the tilting response, resulting in more energy consumption and a suboptimal riding experience. To address this issue, this paper examines the effects of a driving torque difference between the two driving wheels on tilt dynamics and proposes a novel control strategy: using the torque difference to assist with tilt control. The effectiveness of this strategy is demonstrated through prototype experiments. Results indicate that the average response time for tilting and the maximum current of the tilting motor used for tilting are reduced by 65.46% and 30.84%, respectively. The method proposed herein suggests a promising solution to speed up the tilt angle response and reduce the energy consumption of the active tilting, in stark contrast with existing methods using a tilting motor only. This discovery is critical in understanding the impact of vehicle longitudinal driving torque on tilt dynamics.