Abstract
This paper presents an optimal brake force distribution strategy of a highspeed train. The brake system of a high-speed train has to provide not only high reliability and safety but also brake performance such as reducing friction area of the disc pad, minimizing temperature increase of rail, and maximizing brake efficiency. In response to such requirements, generally, combinations of three different types of the brake system, which are the regenerative brake, the contact brake such as the pneumatic brake, and the non-contact brake such as eddy-current brake, are installed into the high-speed train. In this paper, we use a model of the brake dynamics of the high-speed train which includes the dynamics of the electric regenerative brake, the pneumatic brake, the eddy-current brake, and the train body. In case of the conventional brake force distribution strategy, the regenerative brake and the eddy-current brake take the primarily responsibility of generating brake force; and the pneumatic brake provides only the assisting brake force. However, in case when the eddycurrent brake is used excessively, temperature increase of the rail may result in bending the rail and turning over the train. To solve this problem, this paper proposes an optimal distribution strategy of brake force. This cost function for the optimization consists of abrasion rate of a disc pad, and temperature growth of the rail. These terms are significantly associated with the brake performance and reliability. The brake dynamics and the proposed control strategy are programmed and simulated by Matlab/Simulink. The simulation results illustrate the validity and reliability of the proposed control strategy.
Keywords: High speed train, Brake force distribution, Least square method, Object function, Lagrange multipliers