Research Of Vehicle Sideslip Angle Observation Method On The Basis Of Steering Torque

Vehicle sideslip angle is critical for many active safety systems such as Vehicle Dynamics Stability Control System(DSC), yaw stability control, rollover prevention and lane departure avoidance. However, it is almost impossible to obtain the parameter directly without applying complex and expensive sensors or devices. Therefore, estimation of vehicle sideslip angle based on the parameter on the basis of the easily observed physical quantities. is an important topic. Because steering torque signal has more rapid and direct response compared with the steering angle signal during the process of steering. Nowadays, electric power steering System has become the focus of researching. Because the steering torque signal is to be obtained the vehicle equipped with EPS, so the method based on the vehicle equipped with EPS has more practical utility. Due to the limitation of the linear tire model itself, the estimation method has good accuracy only in the linear region.But the vehicle stability control system can be triggered only in extreme conditions.So, during the research of the estimation of the sideslip angle of the vehicle equipped with(EPS),this paper proposes the estimation method applying he extended Kalman filter(EKF), in which the nonlinear tire model in extreme conditions of the vehicles is considered on the basis of the extended Kalman filter(EKF).The main content is as follows:(1)Because lots of estimation methods are based on steering angle, this article illustrates a EKF estimation method on the basis of steering torque.(2)The motivation is proposed on the basis of comparison between the transfer functions of estimating methods, including the method based on steering torque and that on steering angle.We can conclude that the method based on steering torque have better accuracy in the low steering frequency in the process of steering.(3)The comparison of the two methods in different steering frequency from the simulations of the ramp input,double-lane change maneuver and slalom maneuver validates that the estimation based on steering torque have better accuracy in nonlinear condition.(4)Through the comparison of estimation value obtained from the two methods in real vehicle experiments with the standard value obtained from the DGPS, the results validates that the estimation based on steering torque have better accuracy in nonlinear condition.