Vehicle motion control system

A vehicle motion control system to be installed on a vehicle having a plurality of wheels that include a single front wheel, a right wheel and a left wheel, the single front wheel being disposed in a front portion of the vehicle, the right and left wheels being disposed in respective right and left portions of the vehicle and located on a rear side of the single front wheel, said control system being configured to control motion of the vehicle, said control system comprising:

• a rollover-probability judging portion configured to judge whether or not a vehicle-body acceleration of a body of the vehicle falls in a high rollover-probability region that is defined as a region in which a probability of rollover of the vehicle is high;
• and
• a rollover-prevention control executing portion configured, when it is judged by said rollover-probability judging portion that the vehicle-body acceleration falls in the high rollover-probability region, to execute a rollover prevention control for controlling the motion of the vehicle so as to reduce the probability of rollover of the vehicle,
• wherein said rollover-probability judging portion is configured to obtain a direction and a magnitude of the vehicle-body acceleration by composing a longitudinal acceleration that is a component of the vehicle-body acceleration in a longitudinal direction of the vehicle and a lateral acceleration that is a component of the vehicle-body acceleration in a width direction of the vehicle,
• and wherein said rollover-probability judging portion is configured to judge whether or not the vehicle-body acceleration falls in the high rollover-probability region that is defined by a threshold whose amount varies depending on the direction of the vehicle-body acceleration, the threshold being represented by a straight line connecting the front and left wheels and a straight line connecting the front and right wheels.