A Four-Wheel Steer-by-Wire Control Method Based on the Guaranteed Cost Control Theory

Based on front wheel steering vehicles, the ideal yaw rate model was constructed. Four-wheel (4W) steer-by-wire control model of two-degree-of-freedom (DOF) was taken as the study object, according to characteristics of vehicle constant speed and steady-state conditions, the zero sideslip angle and idea yaw rate were regarded as conditions to solve 4W steer-by-wire feed-forward controller. Taking vehicle mass, moment of inertia and tire cornering stiffness as control model perturbation items, the guaranteed cost control theory was adopted to design feedback controller. For simulation tests, the input method of angle step was used to evaluate performances of the system model tracking ideal states. The track of snake lane was chosen to make real vehicle road tests. The results show that controllers have a good tracking accuracy for ideal states of vehicle.