Robust control design for automatic steering based on feedback of front and tail lateral displacement

This paper describes a robust control design for automatic steering of passenger cars. Previous studies [1,2] showed that reliable automatic driving at highway speed may not be achieved under practical conditions with look-down reference systems which use only one sensor at the front bumper to measure the lateral displacement of the vehicle from the lane reference. An additional lateral displacement sensor is added here at the tail bumper to overcome this problem. The control design is performed stepwise: First, an initial controller is determined using the parameter space approach in an invariance plane. This controller is then refined to accomodate practical constraints. The performance and robustness of the final controller was verified experimentally at California Path.