An Approach to Vehicle Brake-By-Wire Optimal Control Tracking Strategy

In this paper, an optimal control tracking strategy for a brake-by-wire system is developed and tested on a laboratory setup consisting of a driving motor, clutch and gearbox system, rotating inertia and an electro-mechanical brake actuator. The presented brake by wire system consists of a brake pedal sub-system connected to the electro-mechanical brake actuator through an electronic control module handling the optimal control logic. A mathematical model of the proposed brake-by-wire control system is presented. The presented mathematical model is simulated and validated against the experimental data. The good agreement between both simulation results and experimental validates the mathematical model. The validated mathematical model is then used to test the proposed optimal control tracking strategy against different levels of disturbances that are difficult to emulate in the laboratory. The developed control logic ensures optimal control effort of the electro-mechanical brake actuator and, at the same time, efficient tracking between the brake pedal command and the braking deceleration profile. Consequently, the introduced logic plays a major role in keeping the tracking between the braking system command and its output as high as possible while not sacrificing the power supply (i.e. high drained electric current) in case of emergency situations. This provides acceptable braking performance while maximizing the system battery life and protects the brake actuator driver against high current.