Multi-Objective Based Research In Optimization Strategy Of Heavy Haul Trains

With the development of heavy haul transportation technology, driver’s operation level is more and more important. At present, drivers of heavy haul trains usually refer to manipulate cue cards and operation schematic diagram to grasp the safety of the operation line. Drivers also can rely on their own experience to control reasonably. But a large number of experiment results are required to summarize the manipulate cue cards and operation schematic diagram, and the driver’s manipulating level has a lot of limits. Therefore, starting from the multi-objective train operation, this paper adopts the method of theoretical analysis and simulation calculation to study the optimized operation of heavy haul trains. The guidance speed curve which generated from this study can help drivers drive more efficiently.Based on heavy haul trains, this paper analyzes the forces of the train in the operation process according to the basic principles of train traction calculation. Then motion equation can be established to describe the relationship among the train speed, time and distance.After analyzing the train operation targets and rules, the multi-objective train optimized operation model is established. The evaluation function of heavy haul trains considers the targets of train traction energy consumption, operation time and stability. The importance of each target is determined by the corresponding weight value. The constraint conditions of the train operation consider the train limit speed, the traction and braking force and the energy conservation. The train operation curve can be numerically calculated by using quadratic programming.In order to set the weight value of multi-objective evaluation function, this paper analyzes all the control targets’influences to the train track. According to the analysis of the influence between the target information which includes weight value and target speed, and train information, including the train coasting distance, run time and change of traction, the weight adjustment strategy is summarized and weight adjustment formula is obtained. The actual operation requirements of Daqin line are used as the constraints to verify the weight adjustment strategy. The contrast of the train simulation curve and actual operation curve proves that the multi-objective optimization control algorithm can satisfy the requirements of train safety, punctuality, energy saving and stationarity. On the other hand, the simulation optimization curve is in accord with the heavy haul train optimization operation strategy. In addition, a local improvement algorithm is proposed to solve the problem of the cycle braking in long descending gradient. Based on the results of multi-objective optimization, this paper makes further optimization on the long descending gradient problem, which is more suitable to the actual needs.