Research on skid control of small electric vehicle (effect of regenerative braking system in skidding condition)

In recent years, electric vehicles have come to be widely used. Most of small electric vehicles only provide seat belts as safety equipment., the vehicle using In-wheel motor system as driving unit in particular have no space for an antilock braking system, which is a basic skid control system. For the same reason, small electric vehicles using In-wheel motor system employ a mechanical braking system rather than a hydraulic braking system. Although the mechanical system is compact, the stiffness of the system is smaller than that of the hydraulic braking system, and the responsiveness of the braking force of the mechanical system is low. Therefore, small electric vehicles may be considered that they lack driving safety. The purpose of the present study is to improve the safety of small electric vehicles. In this report, the effects of regenerative brake and Anti-lock brake system for braking performance were examined. A hybrid simulation model comprising velocity and the pressure of the brake fluid in the brake piping by the characteristic curve method was constructed for the hydraulic and mechanical systems. The braking pressure of the braking unit, which includes the antilock braking unit modeled by the lumped constant model, was controlled to compensate for the small stiffness value of the mechanical braking system. © 2011 The Japan Society of Mechanical Engineers.