Methodology Of Energy-efficient Freight Train Optimization And Intelligent Control

Rail transportation has the advantages of large transport capacity,high speed,small pollution,high efficiency,safety,and punctuality.It is gradually becoming the main channel of the economy and the basic framework of modern urban transportation.At present,China's high-speed rail network construction has been gradually built.The function of the original railway will gradually transferred to the freight,to form a more efficient,safe and efficient freight channel.With the increasing attention to the issue of energy security and environmental protection,rail transportation energy saving is becoming more and more important,especially the speed profile optimization and the speed intelligent tracking control of freight trains with electric locomotive has important academic significance and engineering application value.Freight train is a complex system with high energy consumption,large inertia,poor operating environment,which is difficult to control.Its operation is closely coupled with the complex environment,and forms a more complicated nonlinear,multi constraint and multi objective time varying process.This thesis takes the freight train with electric locomotive as the research object,focusing on the task of tracktion energy saving,carry out the research work as the following:Freight train integrated model construction:Based on the existing models,the thesis makes a detailed analysis of the tracktion force,motion equations,and the modeling of the constraint conditions of the train system.According to the characteristics of the control object,the model is improved by using the method of piecewise linearization,fuzzy logic and multi modal modeling.An integrated model which can accurately reflect the characteristics of train operation is constructed.At the same time,it has enriched the traditional modeling methods,and has opened up a new approach for the modeling of complex systems.Energy consumption sensitivity analysis of train operation:This thesis carried out simulations and analysis on the main factors that affect the energy consumption of train operation,directly reflect the influence degree of various factors on energy consumption,so that to facilitate the overall evaluation of all the various factors as the basis for decision making.This thesis proves that the optimal coasting relationship in certain accuracy is a region rather than a point,and it put forward the concept of optimal switching regoin.The paper also draws a conclusion that the full use of the scheduled running time is the key to the optimization.Train Speed profile optimization algorithm design:Based on four phase's operation strategy theory,the thesis put forward the six mode theory.In particular,the thesis proposes a speed profile optimization algorithm based on adaptive resolution and bidirectional iteration,which can quickly determine modal sequences and the switching points in the distance and time dimension,and then precisely adjust the switching points in the given neighbourhood of optimal switching region in accordance with the principle of make full use of the scheduled running time.For the not too long steep slope,the thesis proposes a local approximation approach to transform the complex global optimization problem into a relatively simple local optimization problem.Train running speed tracking control algorithm design:According to the freight train's characteristics of large lag and nonlinear,based on given target profile,the thesis adopts the method of traction force feed forward,which effectively relieve the problem of slow convergence of train speed.It adopts the method of adaptive traction output limitation,so that restrains the speed overshoot effectively,and solves the problems of overspeed brake without increasing the safety speed margin.Combined with a multimodal combined control strategy,the thesis put forward the MM-FPID and MM-FPID+BPNN control algorithms to achieve accurate,efficient and stable train speed tracking control.Computer simulation software package design:Based on the energy-efficient train optimization and intelligent speed tracking control method,a computer simulation platform is designed,so that the effect of simulation and optimization can be visually displayed.The simulation platform can provide a helpfull simulation tools for the relevant scientific research,and can provide theoretical guidance and reference for the production planning,optimization and adjustment in the actual railway production.From the researches on the above problems,the thesis reveals the influence of coasting impact on energy consumption,and the influence of regenerative braking on the optimal coasting relationship.It plays an effective complement and improvement to the existing theory of energy-efficient train operation.It explores the relationship between the energy consumption and the scheduled running time,line condition,running speed,traction characteristic and so on.It presents a speed profile optimization method of simple,fast,accurate,efficient,and easy to engineering,and provides a tracking object for the train speed tracking control.The train speed tracking controller overcomes the large lag and nonlinear characteristics of the train system,and achieves accurate,efficient and stable speed tracking about the target speed profile.The system is simple,efficient and robust,and has a good performance in the engineering sense.It will play a positive role in promoting the operation of freight trains from the semi auto driving mode to an intelligent automatic driving mode.