Electric all-wheel drive: enhancing vehicle dynamics and driving safety by wheel-individual torque distribution

The electrification of the drivetrain involves advantages in addition to the reduction of the CO2 emissions. By replacing the central engine unit by four electric motors situated close to the wheels, the number of control variables to actively influence the horizontal motion of such an electric vehicle increases compared to that of a conventional vehicle. The control structure presented in this paper uses these additional control variables for torque vectoring to enhance vehicle dynamics as well as driving safety. First, a desired vehicle behavior is realized which the driver himself is able to intuitively adjust by only a handful of parameters. Following this, the wheel -individual torques are distributed in such a way that the peak tire traction is reduced leading to a maximum in driving safety.