Development Of Rail Vehicle Derailment Detection And Early Warning System

With the rapid development of rail transit in China,the problem of rail vehicle derailment has attracted more and more attention.At present,most countries at home and abroad use derailment coefficient and wheel load reduction rate to evaluate the risk of rail vehicle derailment,and have developed some devices to detect rail vehicle derailment.However,the study found that in the actual driving process of the vehicle,the vehicle whose derailment coefficient exceeds the safety evaluation standard does not necessarily derail,and the derailment coefficient does not exceed the safety evaluation standard,but the derailment occurs,and this phenomenon is particularly prominent when the vehicle is unloaded.This shows that the derailment coefficient and the wheel load reduction rate cannot accurately reflect whether the vehicle is derailed.This paper will start with the key characteristic physical quantities when the rail vehicle has derailment risk.Firstly,the key characteristic physical quantities are defined through experiments and previous studies.Then,grasping the characteristics of key characteristic physical quantities,a simple and effective detection scheme is adopted to design a curve compensation algorithm for the superelevation problem generated when the train passes the curve.Finally,the critical threshold of train derailment characteristic physical quantity is determined by combining virtual simulation with field experiment,and finally the rail vehicle derailment detection and early warning system is developed.The system can realize early warning of vehicle derailment risk,so as to protect the safety of passengers and vehicles.The rail vehicle derailment detection and early warning system is studied through virtual simulation and field experiments.The following four problems are solved and relevant conclusions are drawn :(1)Aiming at the problem of which characteristic physical quantities will change significantly when the rail vehicle is derailed,through the combination of experiments and previous studies,it is concluded that when the risk of derailment occurs,the lateral acceleration and roll angle of the axle box of the rail vehicle bogie near the wheelset will change significantly,which shows that it is effective and reasonable to use the lateral acceleration and roll angle as the characteristic physical quantities to judge the derailment of the rail vehicle.(2)In view of the huge loss caused by the current rail vehicle derailment,combined with the limited conditions of the existing experimental line of Shanghai Institute of Technology,the derailment detection and early warning system is designed to detect the risk of derailment of the vehicle bogie in real time.When the designed derailment detection and early warning system is arranged on the bogie of the experimental line,it is found that the derailment detection system can detect the risk of derailment of the bogie in real time by letting the bogie run.(3)Aiming at the problem of whether the designed rail vehicle derailment detection system can accurately detect the current state of the rail vehicle,the vehicle model is built by combining the VI-Rail of the simulation experiment and the G programming language written by Lab VIEW is used to process the simulation data and the existing experimental line is used for field experiments.It is concluded that the designed and improved derailment detection and early warning system can accurately detect the current line,especially the curve section.Because the curve compensation algorithm is designed to solve the influence of superelevation,the current status of the rail vehicle can be accurately located and detected in real time.If there is a risk of derailment,combined with the design of the early warning system can make the rail vehicle emergency braking and alarm.In summary,the rail vehicle derailment detection and early warning system studied in this paper is of great significance for engineering research.The advantage of this system is that it can detect whether the vehicle is currently derailed in real time,and solve the derailment hazard caused by time lag.Real-time detection of the current state of the vehicle by positioning can not only improve the response efficiency of the rail vehicle in the event of derailment risk,improve the safety of rail vehicle operation,but also provide constructive suggestions for future research on vehicle-related detection,laying a good foundation for engineering applications.