Estimation of Vehicle Lateral Velocity With a Nonlinear Sliding-Mode Observer

Abstract

Stability and high maneuverability are important in modern vehicles. To achieve good stability and high maneuverability, it is necessary to have realtime information on the states of the vehicle. In this context, information on the longitudinal velocity, lateral velocity and yaw rate is more important than any others. While the longitudinal velocity and yaw rate can be directly measured with sensors, the lateral velocity is indirectly measured by integrating the lateral acceleration measured with an accelerometer. This paper proposes a nonlinear sliding-mode observer to estimate the lateral velocity and compares its performance with that of a conventional method of integrating the lateral acceleration. Its performance is measured through computer simulations of driving automobile of 8 degrees of freedom with a nonlinear tire model. The proposed sliding-mode observer performs as well as the conventional method. In comparison with the conventional method. it obtains the information on lateral velocity without costly accelerometers.