Rolling Stability Control Based on Electronic Stability Program for In-wheel-motor Electric Vehicle

In this paper, a novel robust rolling stability control (RSC) based on electronic stability program (ESP) for electric vehicle (EV) is proposed. Since EVs are driven by electric motors, they have the following four remarkable advantages: (1) motor torque generation is quick and accurate; (2) motor torque can be estimated precisely; (3) a motor can be attached to each wheel; and (4) motor can output negative torque as a brake actuator. These advantages enable high performance three dimensional vehicle motion control with a distributed in-wheel-motor system. RSC is designed using two-degree-of-freedom control (2-DOF), which achieves tracking capability to reference value and disturbance suppression. Generally, RSC and YSC are incompatible. Therefore, ESP, which is composed of estimation system(S1) and integrated vehicle motion control system(S2) is proposed. A distribution ratio of RSC and YSC is defined based on rollover index (RI) which is calculated in S1 from rolling state information. The effectiveness of proposed methods are shown by simulation and experimental results.