Approximate Inverse Simulation of an Active Steering System Including Steering Wheel Reaction

In contrast to studies on active front wheel steering in which the vehicle responses to specified steering inputs are examined, this paper includes an artificial driver model control system which is adjusted to force all vehicles, with and without active steering, to accomplish the same lane change maneuver to a good approximation. The driver model essentially accomplishes an “inverse simulation” allowing one to see what the driver steering input must be in order to change lanes with various vehicles. In addition, the simulation is based on a bond graph model including steering system dynamics of a particular type of active steering so that the reaction moment that the driver would feel can be computed. Using the model following concept for active steering, it is shown that the driver steering input corresponds closely to that required of the reference model while the total steering input to the road wheels (including the contribution of the active system) corresponds to what the driver would have had to supply to accomplish the lane change if there were no active steering control. In the cases studied, the model following controller seems to function effectively as a stability augmentation system and the reaction moment due to the active steering does not seem to be of a magnitude that would be disturbing to the driver.