Brake Control Allocation Employing Vehicle Motion Feedback for Four-Wheel-Independent-Drive Vehicle

This paper uses the brake control allocation method for Electric Vehicles (EVs) based on system-level vehicle Reference Point (RP) motion feedback. The RP motion control is an alternative to the standard brake torque allocation methods and results in improved vehicle stability in both longitudinal and lateral directions without requiring additional measurements beyond what is available in EVs with ABS and ESP. The proposed control law simplifies the brake torque allocation algorithm, reduces overall development time and effort, and merges most of the braking systems into one. Additionally, the measured or estimated signals required are reduced compared to the standard approach. The system-level RP measurements and references are transformed into individual wheel coordinate systems, where tracking is ensured by actuating both friction torques and electric motor regenerative torques using a proposed brake torque blending mechanism. The whole control system is validated in simulations using the Simulink vehicle dynamic simulator and IPG Carmaker high-fidelity simulator, utilizing the CTU FEE EFORCE formula model. Finally, a brake HiL stand validation is presented.