Sliding mode lane keeping control based on separation of translation and rotation movement

The lane keeping problem of automatic driving for vehicles was studied based on the simplified linear lateral dynamic model which was divided into a translation subsystem and a rotation subsystem. The rotation subsystem was defined as an inner loop and the translation subsystem was defined as an outer loop. With the separation design strategy of inner loop and outer loop, a kind of angle stable controller was designed to make the rotation subsystem stable. The inner angle stable subsystem was driven by the outer translation subsystem which was controlled by the error signal of vehicle position. The inner loop was cascaded with outer loop and both loops were designed by the sliding mode method. At last, detailed numerical simulations were done and simulation results were compared with other three methods to explain the physical meanings of design and its three advantages.