Cbtc System Simulation And The Optimization Strategy

Communication Based Train Control system, CBTC, is one of the most important components of the moving block system in the urban rail transit system. The CBTC system performance analysis and the optimization are studied in this thesis, and meanwhile an urban rail transit train simulation system is developed for the test of the study, hereby it is called CBTC Simulation System. The CBTC Simulation System cannot only be used for the theory study but also as the design assistant in the real project of the train control system to improve the system performance and safety. The main contributions of this thesis are:Train speed control mathematical model is the basis of the train movement simulation. On the study of the IEEE1474.1recommended safety braking model, the kinematic based algorithm and the energy balance based algorithm are analyzed and compared with each other for the calculation of the over-speed protection function. The calculation speed is improved by synthesizing the two algorithms, i.e. choosing whichever algorithm in the different braking stage. Derived from the emergency trigger speed, full service braking speed profile, command speed profile and the train actual speed profile is established in the CBTC Simulation System. The speed regulation algorithm simulated and tested can be adopted in the train over speed protection system.In order to solve the problem that the system performance is impacted by increased train headway in the station area in an urban rail transit system, the calculation algorithm of train headway was analyzed and a headway optimization method was provided based on the platform speed restriction and the speed restriction area parameters adjustment for the CBTC system. In this method, an optimized train headway can be gotten from the relationship of platform speed restriction setting, train headway and travel speed. The relationship is obtained by a simulation. From the simulated and tested on the CBTC Simulation System, it is proved that this method can optimize the headway in the critical area of the system so that to improve the whole system performance.It is always a difficult task to calculate the train tracking headway in the mixed operation of CBTC mode train and Non-CBTC mode train. In order to solve this problem to calculate the headway in either the adjacent area of two different system control modes or a area with different control mode trains, a particular position and block area method, PBAM (Position-BlockArea Method), is introduced in this thesis. With this method, the CBTC Simulation System can calculation the headway for every particular position to produce the position-headway profile. The transfer track between depot/yard and the mainline is the typical area of the mixed mode train operation that is difficult to calculate the headway in the real project. By using the PBAM method in the CBTC Simulation System, the headway of the transfer track in every position can be precisely calculated and the position-headway profile can be provided to prove the current system design is acceptable or not.The precision of the energy consumption during the train movement is the basis of the algorithms for energy consumption optimization. This thesis studied the train energy consumption algorithm from the aspect of the CBTC train speed regulation. Since CBTC system calculates the train tracking/braking status in the train speed regulation algorithm and sends the current tracking/braking command and the effort to the train tracking/braking system, which determines the train energy consumption in the operation, this algorithm can have more precision and controllability. The regenerative braking energy is specifically described in the algorithm for the further study of the regenerative braking energy absorption.Satisfied the train speed regulation, energy saving and pollution reduction is another important study in the urban rail transit train control system. In this thesis, a genetic algorithm based train traction energy saving method is studied. The object is to reduce the train traction energy by the combinatorial optimization of the train speed profile in the inter-station section. The energy saving optimized speed profiles will be generated for each performance level. By the test of simulation, energy optimized speed profile can make the best use of the energy saving civil grade and avoid the frequent braking and tracking due to the inter-section speed restriction. The effective energy saving can be achieved for each performance level except in the rush hour that imposed the maximum train speed by the timetable. The energy optimized speed profile can make the best use of the energy saving civil grade and avoid the frequent braking and tracking due to the inter-section speed restriction.The CBTC simulation system design and the implementation are described in the last of the thesis. In order to avoid the dramatically modifying the original system structure and provide an open testing platform for the future advanced algorithm study, an ITDS model, Intelligent Train Dispatching System is designed in the system design level.