Patent ID: 7725226

Claim:
A suspension system comprising: a front roll stiffness changing device comprising a front stabilizer bar with an actuator that changes roll stiffness on a front-wheel side of a vehicle; a rear roll stiffness changing device comprising a rear stabilizer bar with an actuator that changes roll stiffness on a rear-wheel side of the vehicle; and a roll stiffness distribution control device that controls the roll stiffness distribution between the front-wheel side and the rear-wheel side by controlling the front and rear roll stiffness changing devices based on respective front and rear target roll stiffness corresponding amounts determined in independent front and rear target roll stiffness determining portions, respectively, and defining a predetermined roll stiffness ratio between the front and rear wheel sides, wherein the roll stiffness distribution control device further includes: front and rear actual roll stiffness correspondence amount obtaining devices for obtaining an actual roll stiffness correspondence amount on the front and rear wheel sides, respectively; actuator driving performance insufficiency determining means for determining an insufficiency if the front or rear actual roll stiffness correspondence amount differs from the respective target front or rear roll stiffness correspondence amount by a set amount or greater; and a dependent target roll stiffness determining portion that, when an actuator driving performance insufficiency is determined in one of the front or rear roll stiffness changing devices, determines a target roll stiffness correspondence amount of the other of the front or rear roll stiffness changing devices, according to an actual roll stiffness correspondence amount obtained by the corresponding actual roll stiffness correspondence amount obtaining device on the side where the driving performance is determined to be insufficient such that the target roll stiffness corresponding amount on the side where the driving performance of the actuator is reduced, such that the roll stiffness distribution ratio between the front and rear wheel sides is maintained in an appropriate range despite an insufficiency of one of the driving actuators.