EWB control based on the estimated clamping force

Abstract

This paper focuses on clamping force control of electronic wedge brakes without additional sensors for cost-effectiveness and system simplicity. Brake-by-wire systems can be used for enhanced, safe braking of intelligent and environmentally friendly vehicles such as gas-electric hybrid and electric vehicles. For implementation of the electronic wedge brake, the clamping force should be controlled properly even though model uncertainty and parameter variations exist due to the environment or system characteristics changes, e.g., temperature variations, pad wear, and nonlinear friction. In this paper, the electronic wedge brake is modeled to include the wedge dynamics as well as the nonlinearities such as backlash and friction in mechanical connections and clearance between the brake disk and pad. An on-line status monitoring algorithm using the simplified mathematical models is designed to estimate the mechanical system parameters. Based on the mechanical parameters estimated initially and the estimated clamping force, a sliding-mode control algorithm is proposed to achieve the robust control performance. The performance of the proposed monitoring and control algorithm is verified through simulations using Matlab/Simulink. Additionally, the proposed algorithm is validated experimentally using a hardware-in-the-loop simulation test bench equipped with the prototype electromechanical brake and electronic wedge brake.