A new nonlinear observer of sideslip angle with unknown vehicle parameter using the dual unscented Kalman filter

To improve the stability control of automotive engineering, the vehicle dynamic information, including vehicle motion states and key parameters of vehicle dynamic, is essential. Especially, the sideslip angle, an important variable of the vehicle state, is difficult to measure directly for technology or economic reason. What´s more, some key parameters of vehicle system, such as the mass of vehicle, may vary significantly front one journey to the others, and require real-time estimation. This article is designed to propose a new nonlinear observer which can derive the state and unknown parameter of the vehicle dynamic system. This observer is based on the nonlinear double track model, in which the Dugoff model is used to describe the relation between the tire road force and the sideslip angle. The dual unscented Kalman filter is employed to get the states and the key parameters in the observe: Simulation results indicate that the new nonlinear observer works effectively and has big potential benefit in the real vehicle dynamic system.