Locomotive Speed Measuring Method And Its Applications In The Adhesion Control

The low accuracy of the current train speed measurement caused the problem of low efficiency of adhesion force control. How to choose a more effective program based on the specific situation of rail transport in order to achieve high-precision speed measurements and high-efficiency adhesion control is an important and difficult task.Information of speed and position is important for train control and train operation safety. For a dynamic system such as train, speed and position are requisites to control driving, braking, acceleration and de-acceleration, if it is to get high operation efficiency and safety. As adhesive force, which exists between rail and wheel, is the ultimate power that drives train, it is a great advantage to make an excellent use of it. In fact, good use of adhesion force can not only enhance a train's accelerative performance, cut short its brake distance and improve its passenger's comfort, but also reduce wheel skip and skid significantly and results in greatly extended wheel and rail life. In recent years, with the application of AC drive and the advent of high speed train, adhesion control system has been invented to make high adhesion utilization possible.This thesis studies train speed measurement and its application for adhesion control. Four parts can be roughly seen in the paper. In the first part, the principle of speed measurement is discussed, several speed measurement methods are introduced and a Doppler-Effect based radar speed detector is designed and analyzed in detail. The second part of the paper focuses on railway adhesion and its relationship with train speed, introducing wheel skip/skid detection method, discussing a main stream adhesion control scheme and stressing the importance of speed accuracy for excellent adhesion control. Fuzzy control is discussed in the third part and, based on the result of part 2, a fuzzy adhesion controller is proposed. Finally, in the fourth part, simulation is used to validate the effectiveness of the designed fuzzy adhesion controller, and its high performance is fully demonstrated by the simulation results.