This invention provides a vehicle motion control method and a vehicle
motion control apparatus capable of improving the behavior stability of a
vehicle. According to the vehicle motion control method, vehicle steering
characteristic is determined based on a behavior amount differentiated
value obtained by differentiating (S203) a slip angle differential value
which is a behavior amount of the vehicle which occurs around a z-axis in
the vertical direction with respect to the vehicle body (S205, S209).
Consequently, because the phase of the slip angle differential value is
progressed, the transition tendency of the steering characteristic, that
is, which the vehicle motion condition is moved to over-steer or
under-steer, can be obtained early. Therefore, the starting timing of the
steering control or drive power control of the vehicle can be accelerated
thereby improving the behavior stability of the vehicle.