Vehicle anti-lock control system and slip ratio vibration suppression method based on LQG controller

Abstract

The invention discloses a vehicle anti-lock control system and slip ratio vibration suppression method based on an LQG controller. By designing a brake torque threshold control unit, the output braketorque range output by a brake anti-lock control unit is subjected time-varying limiting, and the brake torque threshold control unit is composed of front and rear road surface adhesion coefficient estimation units, front and rear wheel ideal brake torque estimation units and front and rear wheel brake torque constraint units. The brake torque range is limited in the following control steps that 1, the front and rear road surface adhesion coefficient estimation units estimate front and rear road surface adhesion coefficients; 2, the front and rear wheel ideal brake torque estimation units determine front and rear wheel ideal brake torques through the polynomial fitting relation between the road surface adhesion coefficients and the brake torques; 3, upper and lower limit thresholds of thefront and rear wheel brake torques are set, so that the brake torques output by the LQG controller are subjected to limit constraint of the upper and lower limit thresholds, and then actual control signals of the brake torques output by the brake anti-lock control unit are obtained.

Description

technical field [0001] The invention belongs to the technical field of wheel slip rate control during vehicle braking, and in particular relates to a vehicle anti-lock braking control system based on an LQG controller and a slip rate shake suppression method. Background technique [0002] Vehicle anti-lock braking system (ABS) is an active safety control system that can prevent the car from locking and slipping during braking. Vehicles equipped with ABS make the wheels always in a better braking state, ensuring that the vehicle has a certain steering ability during the braking process, thereby improving the braking stability of the vehicle and reducing the risk of the vehicle under emergency braking conditions. probability of traffic accidents. [0003] As one of the core technologies in ABS, the slip rate control method plays a decisive role in the braking performance of the vehicle. Common slip rate control methods mainly include: PID control, sliding mode variable struc...

AI Technical Summary

Problems solved by technology

However, in actual engineering applications, the control torque signal output by the LQG controller needs to be realized through the brake pressure adjustment device of the hydraulic unit, which is subject to the oil pressure, friction consumption, and the output from the applied brake pressure to the actual brake torque. Due to a certain time delay and other reasons, the hydraulic unit cannot accurately execute the control instructions issued by the LQG controller, which eventually leads to a decline in the control effect of ABS in executing vehicle anti-lock braking control.

After research and analysis, it is found that when the LQG controller is used to control the hydraulic unit to perform anti-lock braking control, sometimes the phenomenon of excessive vibration of the wheel slip rate may occur

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