Patent ID: 7949446
Filing Date: 2011-05-24
Classification: B60G

Abstract:
1. A body-roll restraining system for restraining roll of a body of a vehicle equipped with front-wheel-side suspension devices respectively provided for left and right wheels on a front side of the vehicle and rear-wheel-side suspension devices respectively provided for left and right wheels on a rear side of the vehicle, each of the suspension devices including (a) a suspension spring for elastically connecting a sprung portion and an unsprung portion and (b) a damper for generating a damping force with respect to a relative movement of the sprung portion and the unsprung portion, the system comprising: a front-wheel-side roll restraining device and a rear-wheel-side roll restraining device each of which is configured to generate a roll restraining force that functions as a force by which the sprung portion and the unspring portion corresponding to one of the left and right wheels approach toward each other while the sprung portion and the unspring portion corresponding to the other of the left and right wheels are separated away from each other, each of which has an actuator, and each of which is configured such that the roll restraining force is changeable owing to an operation of the actuator; and a controller which is configured to determine a target device-individualized roll restraining force that is the roll restraining force to be generated by each of the front-wheel-side roll restraining device and the rear-wheel-side roll restraining device and which is configured to control the operation of the actuator of said each of the front-wheel-side roll restraining device and the rear-wheel-side roll restraining device on the basis of the determined target device-individualized roll restraining force, wherein the controller includes a road-surface-unevenness-dependent-roll-restraining-force determining portion configured to determine a target road-surface-unevenness-dependent-roll restraining force that is the roll restraining force to be generated by both of the front-wheel-side roll restraining device and the rear-wheel-side roll restraining device, for restraining the roll of the body of the vehicle that arises from unevenness of a road surface on which the vehicle travels, wherein the road-surface-unevenness-dependent-roll-restraining-force determining portion is configured to determine the target road-surface-unevenness-dependent-roll restraining force according to a virtual roll behavior model set for restraining the roll of the body of the vehicle that arises from the unevenness of the road surface on which the vehicle travels, wherein the road-surface-unevenness-dependent-roll-restraining-force determining portion includes a roll-causing-force-reduction-type roll-restraining-force determining portion which employs a roll-causing-force reduction model as the roll behavior model for reducing a roll-causing force as a force to be generated by the suspension spring and the damper of each of the suspension devices and as a force that causes the roll of the body of the vehicle resulting from a relative displacement movement of the unsprung portions for the left and right wheels on the front side of the vehicle and a relative displacement movement of the unsprung portions for the left and right wheels on the rear side of the vehicle, the roll-causing-force-reduction-type roll-restraining-force determining portion configured to estimate, according to the roll-causing-force reduction model, a reduction force that is a difference between the roll-causing force to be actually generated by the suspension spring and the damper and the reduced roll-causing force and configured to determine the target road-surface-unevenness-dependent-roll restraining force on the basis of the estimation, wherein the roll-causing force contains components thereof: a front-wheel-side-spring-dependent roll-causing force generated by front-wheel-side springs that are the two suspension springs of the front-wheel-side suspension devices; a front-wheel-side-damper-dependent roll-causing force generated by front-wheel-side dampers that are the two dampers of the front-wheel-side suspension devices; a rear-wheel-side-spring-dependent roll-causing force generated by rear-wheel-side springs that are the two suspension springs of the rear-wheel-side suspension devices; and a rear-wheel-side-damper-dependent roll-causing force generated by rear-wheel-side dampers that are the two dampers of the rear-wheel-side suspension devices, and wherein the roll-causing-force reduction model is set so as to reduce at least one of the front-wheel-side-spring-dependent roll-causing force, the front-wheel-side-damper-dependent roll-causing force, the rear-wheel-side-spring-dependent roll-causing force, and the rear-wheel-side-damper-dependent roll-causing force, on the basis of a reduction ratio set for each of the at least one of the front-wheel-side-spring-dependent roll-causing force, the front-wheel-side-damper-dependent roll-causing force, the rear-wheel-side-spring-dependent roll-causing force, and the rear-wheel-side-damper-dependent roll-causing force.