Estimation of vehicle lateral velocity

Two techniques for the estimation of vehicle lateral velocity using state observers are considered. The first method uses a physical model of the vehicle handling. The physical model based observer produces noise free lateral velocity estimates, but can be sensitive to changes in the vehicle parameters. It produces reliable estimates in the vehicle linear handling region only. We show that the observer gain can be selected to make the observer insensitive to certain parameter variations. The second method uses a kinematic model relating longitudinal velocity, lateral velocity, longitudinal acceleration, lateral acceleration and yaw rate. This model contains no vehicle parameters, and hence the kinematic model based observer is unaffected by changes in the vehicle parameters. The observer produces reliable lateral velocity estimates throughout the linear and nonlinear handling regions, the estimates however are more noisy than those produced by the physical model based observer. The techniques are compared using simulated data for manoeuvers in the linear and nonlinear handling regions of the vehicle.