Estimation of vehicle side slip angle using hybrid observer

The vehicle side slip angle is an important matter of vehicle stability control, and it is usually obtained by estimation method today. A hybrid observer is proposed to estimate the vehicle side slip angle in this paper. The hybrid observer includes three parts: a state-space observer, a kinematics integration module and a weight distribution module. The weighting distribution module includes a vehicle stability detection module and a fuzzy controller. We use the phase plane method to detect the stable status of the vehicle. Then, we use the fuzzy controller to calculate the weight of the state-space observer based on the status of the vehicle stability. Through the weight of the state-space observer, the hybrid observer integrates the state-space observer method and kinematics integration method together and makes full use of the advantage of the two methods. And in order to reduce the integration error of the kinematics integration module, we use the Kalman filter to handle the signals that the sensor measured. So, the hybrid observer can work well in the whole area of the tire. The simulation results show that the hybrid observer can achieve the precise estimation results whether the vehicle is in linear area or in the nonlinear area.