Steering control of high speed vehicles: dynamic look ahead and yaw rate feedback

A popular automatic steering control approach for passenger cars is to decouple the yaw motion from lateral motion by using yaw rate feedback. It will be shown in this paper that by re-defining the control position at a frequency-dependent distance ahead of the vehicle, the yaw dynamics can also be decoupled. The resulting system dynamics with this dynamic look-ahead scheme can be simplified into a double-integrator vehicle dynamics with a constant, open-loop gain. It is further shown in this paper that even though the simplified system dynamics obtained from the dynamic look ahead scheme appears similar to that from the decoupling approach using yaw rate feedback, the hidden (unobservable) dynamics of the closed control loop is fundamentally different