Front and rear wheel independent drive type electric vehicles (FRID EVs) with outstanding running performance suitable for next-generation electric vehicles

The safety and running performance of front and rear wheel independent drive type electric vehicles (FRID EVs) for use as advanced, next-generation electric vehicles (EVs) is clarified under severe running conditions, with particular focus on energy saving control performance and braking and cornering performance on low-friction coefficient (n) roads. The running performance of FRID EVs, which could not be obtained from the propulsion power generating systems of the EVs developed until now, is produced from propulsion power generating systems that can mutually or independently control the driving and braking forces of the front and rear wheels. The first energy saving control performance was obtained by applying the driving forces (torques) corresponding to the friction coefficient between the tire and road surface to the front and rear wheels while estimating the friction coefficient and the load movement occurring during acceleration. Outstanding braking and cornering performance is obtained by optimizing the relationship between the longitudinal and lateral forces acting on the tires so as to prevent an imbalanced torque between the left and right wheels from occurring, based on the friction circle principle. These outstanding functions were verified by undertaking tests performed under various running conditions using a prototype FRID EV.