Estimating Road Angles With the Knowledge of the Vehicle Yaw Angle

摘要

This paper presents a method of estimating road angles using state observers and threentypes of sensors (lateral acceleration sensors, longitudinal velocity sensors, and suspensionndisplacement sensors). The proposed method differs from those in most existingnliterature in three aspects. First, a “full-state” vehicle model is used to describe nonlinearnvehicle dynamics on a sloped road. Second, “switching observer” techniques arenused to suggest suitable sensors and to construct state observers. Lastly, the road anglesnare described by three Euler angles, and two of them are estimated simultaneously. Thenanalysis indicates that (1) road angles affect vehicle dynamics through components of thengravitational force acting on the vehicle body. These gravitational forces can be correctlynestimated with an estimation accuracy less than 7.5%, even when road angles vary withntime. (2) Those road angles can be correctly estimated only when the vehicle yaw anglenis known.