Vehicle stability in 4 wheel drive(4WD) vehicles has been pursued by torque split based
technology and brake based technology. The brake based methods are essentially brake maneuver
strategies using the active control of the individual wheel brake. By comparison, the torque split
based technologies realize stability by varying the traction torque split through powertrain to create
an offset yaw moment. In the 4WD hybrid electric vehicle adopting separate front and rear motor,
the vehicle stability enhancement algorithm using the rear motor control has some advantages such
as faster response, braking energy recuperation, etc. However, since the left and right wheels are
controlled by the same driving and regenerative torque from one motor, stability enhancement only
by the front and rear motor control has a limitation in satisfying the required offset yaw moment.
Therefore, to obtain the demanded offset yaw moment, a brake force distribution at each wheel is
required. In this paper, a vehicle stability control logic using the front and rear motor and electrohydraulic
brake(EHB) is proposed for a 4WD hybrid electric vehicle. A fuzzy control algorithm is
suggested to compensate the error of the sideslip angle and the yaw rate by generating the direct
yaw moment. Performance of the vehicle stability control algorithm is evaluated using ADAMS and
MATLAB Simulink co-simulation.