Road Adhesion Coefficient Estimation Based on Second-Order Linear Extended State Observer

In order to estimate different road adhesion coefficients, a new method based on the second-order linear extended state observer is proposed to improve the active safety and driving stability of vehicles. The vehicle single-wheel driving dynamics model and single-wheel braking dynamics model are built with analyzing the driving and braking processes of the vehicle. The controllers of ASR and ABS are designed by using sliding mode structure control, and the chattering phenomenon of sliding mode control is eliminated by the saturation function. The road adhesion coefficient can be estimated by the second-order linear extended state observer in real time with the wheel speeds, and driving torque and braking torque are used as input variables. The simulation results show that the road adhesion coefficient estimation method based on the second-order linear extended state observer can accurately identify the adhesion coefficient of different roads in the presence of external interference and has strong robustness. At the same time, it also provides a reference for the design of the stability control system of unmanned vehicles.