Stabilizing the Steering Weave Mode

The steering weave mode is explained with the aid of slip angle diagrams and a third order mathematical model. Nonlinear simulations show why the weave mode is not noticed during normal driving, and that it is worse with large amplitude maneuvers beyond the linear range of lateral tire force curves. A steering stabilizing method is described, in which transient torques are applied to the steering system using feedback from the instantaneous dynamic state of the vehicle. The steering stabilizer operates by reducing the phase difference between steer angle and steering torque, thereby damping the weave mode and reducing overshoot. The driver has a better torque feel, and the vehicle is more stable if the driver releases the steering wheel, both of which are expected to be beneficial. Suggestions for implementing the steering stabilizer are described.