| The high-speed railway has been developed significantly in the past decade,and high-speed trains have become an important role in transportation.With the construction of large railroad projects such as Sichuan-Tibet line,high-speed trains are suffering from more complex trackside terrain and worse weather.High-speed trains are prone to insufficient stability thus derail and overturn when running through strong crosswind areas,viaducts,tunnels,canyons,high embankments as well as passing by each other at high speed.Safety is an indispensable boundary,so how to Position,velocity and attitude determination of high-speed trains accurately in real-time,how to assess the impact of severe weather(especially crosswind)on the safety of train running,and how to effectively monitor and warn against severe weather are the key issues that need to be solved.The main work of this study is therefore arranged as follows.(1)Optimization of the multi-source high-speed train Position,velocity and attitude determination system.By using multi-source information fusion technology and high-precision positioning technology based on trajectory matching,Position,velocity and attitude determination system for high-speed trains operating safely in complex environment is constructed.The GNSS subsystem,the SINS subsystem and the trajectory matching-based high-precision positioning method of the combined system are optimized respectively;the GNSS/SINS,SINS/ODO and trajectory matching high-speed train Position,velocity and attitude determination system is constructed.The full-scale tests under complex environment show that the optimized GNSS/SINS coupled system eliminates the effects of short-term limitations of GNSS,and the position,horizontal posture and heading accuracies are better than 5 cm,0.2° and 1°,respectively,which improves the accuracy and applicability of the combined system.(2)Optimization of the multi-source fusion algorithm for the high-speed train Position,velocity and attitude determination system.The optimized ECKF sequential fusion algorithm is proposed.To guarantee the accuracy and real-time performance of the high-speed train Position,velocity and attitude determination system,the filtering accuracy and complexity of EKF and CKF are compared.Then,the characteristics of the state model and the measurement model of the combined system are analyzed,based on which,the ECKF sequential fusion algorithm is proposed,and the CKF is used to update the state and the EKF to update the measurement.The numerical results show that the accuracy of the ECKF sequential fusion algorithm is 34% higher than that of the EKF,and the execution time is 32% lower than that of the CKF.Both the accuracy and the real-time performance of the combined system are ensured.(3)Study of transient aerodynamic characteristics of high-speed trains under crosswinds.Based on CFD and train aerodynamics theory,a 3D CFD coupled model of train-bridge-wind barrier is established employing URANS turbulence model.Numerical simulation is used to calculate the transient aerodynamic characteristics of the train passing through the bridge in the crosswind region,and the optimal height of the wind barrier is analyzed when the train passes through the bridge under the proof of various wind barriers at different speeds in crosswind region.The results show that the risk of train overturning in the crosswind region increases with its speed,and the optimal height of the wind barrier is 4 m.Wind tunnel tests are also performed to verify the accuracy of the numerical simulations.(4)Proposing a simplified MBSD fast simulation method for high-speed trains that combines full-scale test and numerical simulations to improve the reliability and efficiency of the safety assessment of train running.Based on the train MBSD theory,a simplified MBSD fast simulation method for high-speed trains combining full-scale test and numerical simulations is proposed to improve the reliability and efficiency of the safety assessment method for high-speed trains running in crosswinds regions(including the 90° yaw angle).A simplified full-scale test is undertaken on an existing line to collect train information about operation,vibrations,track irregularities,and meteorological parameters,the collected data are used for feature extraction,and some optimized sub-models for vehicle posture,vehicle vibrations,track irregularities,wind characteristics,etc.are established,which are used to replace the less efficient sub-models in the MBSD model and perform the MBSD simulation.Finally,taking the posture data of a train collected from the full-scale test for MBSD fast simulation as an example,the optimized train posture sub-model and the transient aerodynamic characteristics of the train are loaded into the train MBSD model simultaneously for fast simulation to accurately assess the safety of train operation under crosswinds,thus verifying the feasibility of MBSD fast simulation using simplified full-scale data and assessing the safety of train operation.(5)Design of high-speed train running safety monitoring and warning system based on intelligent sensing and monitoring technologies.Using high cost-effective microelectromechanical inertial sensors,high-precision GNSS chips and powerful processors with edge computing capability,design a speed measurement and positioning subsystem and a posture measurement subsystem suitable for the safe operation of high-speed trains in complex environments.Based on the theory of resonant ultrasound,a high-precision ultrasonic wind speed and direction sensor is developed;a low-power optical rain/snow/fog/temperature/humidity integrated sensor is also developed based on the optical principle,and an intelligent meteorological monitoring and wind speed and direction warning subsystem is designed.Finally,build a high-speed train operation safety monitoring and warning system.It actively tracks the running speed,running posture,real-time position of high-speed trains and collects track irregularities;meanwhile,it monitors the meteorological parameters such as wind speed and direction along the line and provides timely warning.It not only provides data support for the fast simulation of MBSD of high-speed trains,but also protects the efficient and safe operation of single trains and train groups on the line.110 Figures,20 Tables,232 References... |
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