Research on Thermal Recession Compensation Method of Disc Brakes

If a car is braked frequently or at high speed, the thermal decay of brake system performance appears, which reduces the braking performance of the car. To compensate brake moment reduction during braking at thermal decay of brake system, a compensation strategy of brake moment is designed by using “feedforward +PID feedback” to pressure at wheel braking cylinder. The trigger and exit conditions of the strategy for the wheel cylinder pressure are proposed based on the threshold. A vehicle model consisting braking system is established if a vehicle runs at straight line, and the braking distance and braking acceleration are estimated, the results shown that the thermal decay compensation control strategy proposed in this paper can reduce the braking distance and braking time. A braking system experiment if a car runs at straight line is carried out, it demonstrates that if temperature of a disc brake is higher than 300°C, the thermal decay will occur, and friction coefficient decreases by 16.7% compared with the nominal friction coefficient. Brake thermal decay compensation strategy proposed in this paper can enhance braking safety performance if thermal decay happens.