Method for operating an active roll support system of a motor vehicle
A method for operating an active roll support system of a motor vehicle, in which a roll moment distribution is regulated below a sideslip angle threshold on the basis of an actual grip reserve of a rear axle relative to a front axle of the motor vehicle. A wheel load is acquired for each of the wheels of the front axle and for each of the wheels of the rear axle and the acquired wheel loads are used as feedback variables in a control loop for regulating the roll moment distribution to calculate the actual grip reserve of the rear axle and compare it with a target grip reserve of the rear axle and from this determine a control deviation for adapting the roll moment distribution.
1 . A method for operating an active roll support system of a motor vehicle, in which a roll moment distribution is regulated below a sideslip angle threshold on a basis of an actual grip reserve of a rear axle relative to a front axle of the motor vehicle, said method comprising:
(a) acquiring, by plural sensors of the motor vehicle, a wheel load for each wheel of the front axle and for each wheel of the rear axle while the motor vehicle is being driven;
(b) calculating a grip potential available for longitudinal and lateral forces for each of the wheels of the front axle and for each of the wheels of the rear axle using at least a tire temperature and a wheel camber;
(c) calculating a currently available grip potential of the front axle from the grip potentials of the wheels of the front axle, and calculating a currently available grip potential of the rear axle from the grip potentials of the wheels of the rear axle;
(d) calculating, by a controller of the motor vehicle, the actual grip reserve of the rear axle by calculating a difference between the currently available grip potential of the rear axle and the currently available grip potential of the front axle;
(e) calculating, by the controller, a target grip reserve of the rear axle based on at least an accelerator pedal position and brake pressure;
(f) comparing, by the controller, the actual grip reserve of the rear axle with the target grip reserve of the rear axle;
(g) determining, by the controller, based on the comparison at step (f), a control deviation for adapting the roll moment distribution; and
(h) adjusting, by the controller, the roll moment distribution and the actual grip reserve of the rear axle based on the target grip reserve of the rear axle while the motor vehicle is being driven.
2 . The method according to claim 1 , further comprising using the accelerator pedal position, the brake pressure, and at least one of the following variables to calculate the target grip reserve of the rear axle: driving speed, lateral acceleration, change in lateral acceleration, longitudinal wheel load transfer, sideslip angle, coefficient of friction of the tires and driving program.
3 . The method according to claim 1 , further comprising controlling the roll moment distribution as a function of the sideslip angle and a driving speed when the sideslip angle threshold is exceeded.
4 . The method according to claim 1 , further comprising using a variable sideslip angle threshold which is set as a function of the driving mode.
5 . The method according to claim 1 , wherein the method further comprises:
acting on the wheel suspension of each of the wheels of the front axle and the rear axle according to the adjustment of the roll moment distribution and the actual grip reserve.
6 . The method according to claim 1 , wherein the wheel load for each wheel of the front axle and for each wheel of the rear axle are used as feedback variables in a control loop for regulating the roll moment distribution.