Brakes in railway trains have a variety of forms such as air brake,eddy current brake and aerodynamic brake.Their primary functions areto slow down and stoptrains,so asto ensure safe and efficient train movement.Brake...Brakes in railway trains have a variety of forms such as air brake,eddy current brake and aerodynamic brake.Their primary functions areto slow down and stoptrains,so asto ensure safe and efficient train movement.Brakes are indispensable and safety-critical systems for all types of railway trains including passenger(high-speed,metro,tram,etc.)and freight(heavy-haul,intermodal,etc.)trains.Safe and efficient railway operations require a good understanding of brakes from various parties including drivers,maintenance crews,manufacturers,and design engineers.Research helps to expand and deepen the knowledge about railway train brakes.Brake modelling and simulation date back to the pre-digital age.However,it remains a challenging topic to today due to many reasons including their nonlinear dynamic nature,complex devices,and the limits regarding parameter determination.展开更多
Train braking performance is important for the safety and reliability of railway systems. The availability of a tool that allows evaluating such performance on the basis of the main train features can be useful for tr...Train braking performance is important for the safety and reliability of railway systems. The availability of a tool that allows evaluating such performance on the basis of the main train features can be useful for train system designers to choose proper dimensions for and optimize train＇s subsystems. This paper presents a modular tool for the prediction of train braking performance, with a par- ticular attention to the accurate prediction of stopping distances. The tool takes into account different loading and operating conditions, in order to verify the safety require- ments prescribed by European technical specifications for interoperability of high-speed trains and the corresponding EN regulations. The numerical results given by the tool were verified and validated by comparison with experimental data, considering as benchmark case an Ansaldo EMU V250 train--a European high-speed train--currently developed for Belgium and Netherlands high-speed lines, on which technical information and experimental data directly recorded during the preliminary tests were available. An accurate identification of the influence of the braking pad friction factor on braking performances allowed obtaining reliable results.展开更多
The present work focused on the application of innovative damping technologies in order to improve railway vehicle performances in terms of dynamic stability and comfort. As a benchmark case-study, the secondary sus- ...The present work focused on the application of innovative damping technologies in order to improve railway vehicle performances in terms of dynamic stability and comfort. As a benchmark case-study, the secondary sus- pension stage was selected and different control techniques were investigated, such as skyhook, dynamic compensation, and sliding mode control. The final aim was to investigate which control schemes are suitable for optimal exploitation of the non-linear behavior of the actuators. The performance improvement achieved by adoption of the semi-active dampers on a standard high-speed train was evaluated in terms of passenger comfort. Different control strategies have been investigated by comparing a simple SISO （single input single output） regulator based on the skyhook damper ap- proach with a centralized regulator. The centralized regulator allows for the estimation of a near optimal set of control forces that minimize car-body accelerations with respect to constraints imposed by limited performance of semi-active actuators. Simulation results show that best results is obtained using a mixed approach that considers the simultaneous applications of model based and feedback compensation control terms.展开更多
文摘Brakes in railway trains have a variety of forms such as air brake,eddy current brake and aerodynamic brake.Their primary functions areto slow down and stoptrains,so asto ensure safe and efficient train movement.Brakes are indispensable and safety-critical systems for all types of railway trains including passenger(high-speed,metro,tram,etc.)and freight(heavy-haul,intermodal,etc.)trains.Safe and efficient railway operations require a good understanding of brakes from various parties including drivers,maintenance crews,manufacturers,and design engineers.Research helps to expand and deepen the knowledge about railway train brakes.Brake modelling and simulation date back to the pre-digital age.However,it remains a challenging topic to today due to many reasons including their nonlinear dynamic nature,complex devices,and the limits regarding parameter determination.
文摘Train braking performance is important for the safety and reliability of railway systems. The availability of a tool that allows evaluating such performance on the basis of the main train features can be useful for train system designers to choose proper dimensions for and optimize train＇s subsystems. This paper presents a modular tool for the prediction of train braking performance, with a par- ticular attention to the accurate prediction of stopping distances. The tool takes into account different loading and operating conditions, in order to verify the safety require- ments prescribed by European technical specifications for interoperability of high-speed trains and the corresponding EN regulations. The numerical results given by the tool were verified and validated by comparison with experimental data, considering as benchmark case an Ansaldo EMU V250 train--a European high-speed train--currently developed for Belgium and Netherlands high-speed lines, on which technical information and experimental data directly recorded during the preliminary tests were available. An accurate identification of the influence of the braking pad friction factor on braking performances allowed obtaining reliable results.
文摘The present work focused on the application of innovative damping technologies in order to improve railway vehicle performances in terms of dynamic stability and comfort. As a benchmark case-study, the secondary sus- pension stage was selected and different control techniques were investigated, such as skyhook, dynamic compensation, and sliding mode control. The final aim was to investigate which control schemes are suitable for optimal exploitation of the non-linear behavior of the actuators. The performance improvement achieved by adoption of the semi-active dampers on a standard high-speed train was evaluated in terms of passenger comfort. Different control strategies have been investigated by comparing a simple SISO （single input single output） regulator based on the skyhook damper ap- proach with a centralized regulator. The centralized regulator allows for the estimation of a near optimal set of control forces that minimize car-body accelerations with respect to constraints imposed by limited performance of semi-active actuators. Simulation results show that best results is obtained using a mixed approach that considers the simultaneous applications of model based and feedback compensation control terms.
