Failsafe Drive Performance of Electric Vehicles with the Structure Driven by the Front and Rear Wheels Independently

Failsafe performance is clarified for electric vehicles (EVs) with the drive structure driven by front and rear wheels independently. A simulator based on the four-wheel model which can be applied to various types of drive systems like four in-wheel motor drive type EVs is used for the clarification. Yaw rate and skid angle which are related to drivability and steerability of vehicles and which further influence the safety of vehicles during runs are analyzed under the condition that one of the motor drive systems fails while cornering on wet roads. In comparison with four in-wheel motor drive type EVs, it is confirmed that the EVs with the structure focused on here have little change of the yaw rate and hardly any dangerous phenomena appear which would cause an increase in the skid angle of vehicles even if the front or rear wheel drive system fails when running on wet roads with low friction coefficient. Moreover, the failsafe drive performance of the EVs with the above structure is verified through experiments using a prototype EV.