Evaluation of an Active Steering System

Adrian Rodriguez Master Thesis Abstract A steering aid system called active steering is evaluated by simulating different driving events. The active steering solution, which is taken from a scientific paper, has been implemented in Matlab/Simulink. A vehicle model, also implemented in Matlab/Simulink, is used to form a total system and to compare the two systems: a conventional vehicle and a controlled vehicle. The input to the vehicle model is the steering wheel angle performed by the driver. Simulations are made for a constant speed and a specific changeable road adhesion coefficient. The control system takes the yaw rate as input and derives a steering angle contribution to be added to the drivers command. The motivation for this work is to understand and characterize the response of a vehicle with a complementary steering system. Specific driving events are considered for the simulations such as a wind force disturbance and a severe double lane change. The response of the controlled vehicle is similar to the response of the conventional vehicle for nominal driving, but the steering aid system reduces the effect of wind force disturbances. Improved stability is obtained for the vehicle during slippery road driving.