A Comprehensive Model for Adhesion Control System of Wheel and Rail

This paper presents the movement dynamic of the train and the relationship between the speed of wheel and train, as well as a discussion about the concept of wheel slip. There are two different operation regions designated as creep and wheel spin areas for wheel slip. Creep and wheel spin areas have stable and unstable characteristics, respectively. Wheels and rails are constructed from iron, and thus the friction between them is negligible. Therefore, operation point of speed control system may be in either creep or wheel spin areas. The place of the operation point depends on the values of driving torque compared with the value of maximum adhesion torque. As described, in this article too, in order to minimize the acceleration time, the best operation point is maximum adhesion point. To provide a situation to study algorithms of adhesion control, this paper presents a complete model for simulation the adhesion control. Adhesion coefficient is a non-measurable quantity; therefore, an estimator, previously used, for its estimation is used. The traction motor, which is used in this study, is an induction motor. The speed control system of this traction motor is field-oriented control. The presented model is used in operation in creep/wheel spin area and on maximum adhesion point. The simulation results approve the model.