Modeling and simulation study of the steer by wire system using bond graph

Steer by wire (SBW) systems have many merits over traditional power steering systems in fuel efficiency, space efficiency, security and comfort by virtue of eliminating the mechanical link between the steering wheel and the front wheel. This paper aims at modeling the mechanical parts, the steering wheel motor, the front wheel motor and electronic control unit (ECU) of the SBW System by bond graph approach and simulating complete system dynamic behavior regarding vehicle maneuverability and stability and driver's steering feel. With the model built by Matlab/Simulink, the simulation results have demonstrated that the SBW system enables the steering wheel motor to generate desirable reactive torque and the front wheel motor to provide an appropriate angle of front wheel for the driver's steering torque and at different vehicle speed. The simulation also shows that it possible to control the vehicle behavior along with steering responsiveness characteristic by changing parameter values of SBW system variables. The work in the paper will help to guide further researches on control algorithm of the SBW system.