A Study of Control Methods for the Braking System on Passenger Multiple Units

As well known, the mechanical (friction, pneumatic) brake system on trains contains some non-linear elements. So it has been difficult to control the speed or acceleration of trains according to desired patterns. This paper reviews our research on the control method of the physical performance of train running such as acceleration (deceleration) by mechanical braking devices. One of our approaches is the introduction of the feedback control into the brake control system. Mathematical models of non-linear elements in the brake system and some effective methods of controller design are proposed with both simulation and experimental results. Another approach is the real time estimation of the friction forces between a brake shoe and a wheel tread. Friction has severe non-linearity; however it can not be measured easily on running trains. We propose the introduction of the onboard real-time estimation method of friction coefficients using the speed information which can be obtained easily in the existing brake system.