Closed Loop Yaw Control of Vehicles Using Magneto-Rheological Dampers 2000-01-0107

A new vehicle suspension control system that enhances vehicle stability and handling in fast evasive maneuvers performed close to the limit of adhesion is evaluated. The central idea is to use continuously variable magneto-rheological (MR) dampers to distribute the damping forces between front and rear axles in order to bring the vehicle yaw rate as close as possible to the desired yaw rate. This mitigates the vehicle oversteer or understeer tendencies during quick transient maneuvers. The basic principle of system operation is explained using known dynamic properties of MR dampers, vehicles and tires. The available control authority and the effect of MR damper settings on vehicle yaw response is then evaluated using computer simulations. The results of vehicle tests are presented. They demonstrate the benefits of the proposed control method in terms of improved vehicle response and reduced driver steering effort.