Electric and mechanical brake cooperative control method for FRID EVs under various severe road conditions

This paper describes an electric and mechanical brake cooperative control method suitable for front and rear wheel independent drive type electric vehicles (FRID EVs) for various severe road conditions with low friction coefficient (μ) like icy roads and split-μ roads. The brake cooperative control method is proposed based on the analysis results of vehicle behavior at the time of braking on split-μ roads which is the most dangerous operation. In the proposed control method, brake force is controlled so as to suppress the imbalanced torque of lateral force occurring between left and right wheels other than the lateral force required for revolution. This control is done considering the big difference in the response speed between the electrical and mechanical brakes. Here, it is confirmed through simulations and experiments that stable brake performance is obtained with the proposed brake cooperative control method which properly uses a mechanical brake and electrical brake according to the slip ratio value under various severe road environments.