Real-time estimation method of road adhesion coefficient under braking working condition

Abstract

The invention relates to a real-time estimation method of a road adhesion coefficient under a braking working condition. According to the real-time estimation method disclosed by the invention, a two-wheeled vehicle braking dynamics model, an ideal braking torque controller and a road adhesion coefficient observer are adopted, wherein the two-wheeled vehicle braking dynamics model consists of a full vehicle model and a tire model; based on the two-wheeled vehicle braking dynamics model, a saturation function and an integral switching surface are adopted to redesign a sliding mode controller, so that a shake problem is solved, and the ideal braking torque controller is set up. Based on the two-wheeled vehicle braking dynamics model and the ideal braking torque controller, a second order linear extended state observer is adopted to design the road adhesion coefficient observer and to observe an extended state quantity which is relevant with an adhesion coefficient, and then the real-time estimation of the road adhesion coefficient is completed. According to the real-time estimation method disclosed by the invention, the quantity of design parameters is small, the calculating efficiency is high, and the modes of the saturation function and the integral switching surface are adopted to solve the shake problem which is controlled by a sliding mode variable structure; the road adhesion coefficient observer adopts the second order linear extended state observer, so that the robustness is strong.

Description

technical field [0001] The invention relates to the field of active safety control of automobiles, in particular to a method for real-time estimation of road surface adhesion coefficient under braking conditions. Background technique [0002] At present, most of the existing cars are equipped with advanced driver assistance systems, such as emergency avoidance system (ECA), adaptive cruise control system (ACC), anti-lock braking system (ABS), traction force control system (TCS) and Electronic Stability Program (ESP), etc., these assisted driving systems can greatly improve the safety and stability of vehicle driving. The advanced driver assistance system can automatically adjust the control logic according to the change of the road surface adhesion coefficient, so as to maximize the performance of the control system, and real-time and accurate road surface adhesion coefficient is a necessary prerequisite for realizing active safety control. [0003] For the acquisition meth...

AI Technical Summary

Problems solved by technology

Compared with the Kalman filter algorithm and the double-extended Kalman filter algorithm, the extended state observer method can avoid solving the cumbersome Jacobian matrix under the premise of ensuring high calculation accuracy, but it does not consider the load under braking conditions. transfer, and there are many design parameters, the calculation efficiency is not high

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