Electrified railways are becoming a popular transport medium and these consume a large amount of electrical energy.Environmental concerns demand reduction in energy use and peak power demand of railway systems.Further...Electrified railways are becoming a popular transport medium and these consume a large amount of electrical energy.Environmental concerns demand reduction in energy use and peak power demand of railway systems.Furthermore,high transmission losses in DC railway systems make local storage of energy an increasingly attractive option.An optimisation framework based on genetic algorithms is developed to optimise a DC electric rail network in terms of a comprehensive set of decision variables including storage size,charge/discharge power limits,timetable and train driving style/trajectory to maximise benefits of energy storage in reducing railway peak power and energy consumption.Experimental results for the considered real-world networks show a reduction of energy consumption in the range 15%–30%depending on the train driving style,and reduced power peaks.展开更多
With the increasing railway vehicle speed, pantograph--catenary （PAC） system has become an important part as its incidents still stand among the prin- cipal causes of railway traffic interruption. Indeed, when a rai...With the increasing railway vehicle speed, pantograph--catenary （PAC） system has become an important part as its incidents still stand among the prin- cipal causes of railway traffic interruption. Indeed, when a rail vehicle moves, the pantograph should constantly press against the underside of the catenary. Nonetheless, it is difficult to get around the complexity of the physical interaction between the pantograph and the contact wire, which could deteriorate the quality of the electricity transfer. Thus, PAC system performances could dramati- cally be reduced because of bad current collection. Therefore, in this paper, we present an output feedback solution in order to design an active control of PAC system. The proposed solution is based on the backstepping control and an adaptive observer that estimates both the （unknown） catenary parameters and the system state. All synthesis steps are given and the closed-loop analysis shows asymptotic tracking behavior regardless of the time-vary- ing catenary stiffness. Furthermore, a numerical example shows that the PAC contact can be regulated with desired effect.展开更多
In this paper we analyze connectivity of one-dimensional Vehicular Ad Hoc Networks where vehicle gap distribution can be approximat- ed by an exponential distribution. The probabilities of Vehicular Ad Hoc Network con...In this paper we analyze connectivity of one-dimensional Vehicular Ad Hoc Networks where vehicle gap distribution can be approximat- ed by an exponential distribution. The probabilities of Vehicular Ad Hoc Network connectivity for difference cases are derived. Furthermore we proof that the nodes in a sub-interval [z1, z1 ＋ △z] of interval [0,z],z 〉 0 where all the nodes are independently uniform distributed is a Poisson process and the relationship of Vehicle Ad hoc Networks and one-dimensional Ad Hoc networks where nodes independently uniform distributed in [zl, z1 ＋ △z] is explained. The analysis is validated by computing the probability of network connectivity and comparing it with the Mont Carlo simu- lation results.展开更多
As the basis of location-based services(LBS),positioning is one of the most essential parts in intelligent transportation systems(ITS).Although global positioning system(GPS)has been widely used in vehicle positioning...As the basis of location-based services(LBS),positioning is one of the most essential parts in intelligent transportation systems(ITS).Although global positioning system(GPS)has been widely used in vehicle positioning,it can not achieve lane level positioning accuracy.Motivated by the mature ranging technologies such as radar and ultra-wideband(UWB),several cooperative positioning(CP)methods have been proposed to enhance the accuracy and robustness of GPS.In this paper,we proposed a twostage CP algorithm that combines multidimensional scaling(MDS)and Procrustes analysis for vehicles with GPS information.Specifically,the optimized MDS based on the scaling by majorizing a complicated function(SMACOF)algorithm is first proposed to get the relative coordinates of vehicles which can tackle measurements of different error distributions,then Procrustes analysis is carried out to transform the relative coordinates of vehicles to their absolute coordinates based on GPS information.All the computations are performed at the mobile edge computing node(MECN)for the request of ultra-reliable and low latency communications(URLLC).Simulation results validate that the proposed algorithm can greatly improve the positioning accuracy and robustness for vehicles.展开更多
文摘Electrified railways are becoming a popular transport medium and these consume a large amount of electrical energy.Environmental concerns demand reduction in energy use and peak power demand of railway systems.Furthermore,high transmission losses in DC railway systems make local storage of energy an increasingly attractive option.An optimisation framework based on genetic algorithms is developed to optimise a DC electric rail network in terms of a comprehensive set of decision variables including storage size,charge/discharge power limits,timetable and train driving style/trajectory to maximise benefits of energy storage in reducing railway peak power and energy consumption.Experimental results for the considered real-world networks show a reduction of energy consumption in the range 15%–30%depending on the train driving style,and reduced power peaks.
文摘With the increasing railway vehicle speed, pantograph--catenary （PAC） system has become an important part as its incidents still stand among the prin- cipal causes of railway traffic interruption. Indeed, when a rail vehicle moves, the pantograph should constantly press against the underside of the catenary. Nonetheless, it is difficult to get around the complexity of the physical interaction between the pantograph and the contact wire, which could deteriorate the quality of the electricity transfer. Thus, PAC system performances could dramati- cally be reduced because of bad current collection. Therefore, in this paper, we present an output feedback solution in order to design an active control of PAC system. The proposed solution is based on the backstepping control and an adaptive observer that estimates both the （unknown） catenary parameters and the system state. All synthesis steps are given and the closed-loop analysis shows asymptotic tracking behavior regardless of the time-vary- ing catenary stiffness. Furthermore, a numerical example shows that the PAC contact can be regulated with desired effect.
基金supported by National Science Fund for Distinguished Young Scholars (No.60525110)National 973 Program (No. 2007CB307100, 2007CB307103)+2 种基金National Natural Science Foundation of China (No. 60902051)Chinese Universities Scientific Fund (BUP-T2009RC0505)Development Fund Project for Electronic and Information Industry (Mobile Service and Application System Based on 3G)
文摘In this paper we analyze connectivity of one-dimensional Vehicular Ad Hoc Networks where vehicle gap distribution can be approximat- ed by an exponential distribution. The probabilities of Vehicular Ad Hoc Network connectivity for difference cases are derived. Furthermore we proof that the nodes in a sub-interval [z1, z1 ＋ △z] of interval [0,z],z 〉 0 where all the nodes are independently uniform distributed is a Poisson process and the relationship of Vehicle Ad hoc Networks and one-dimensional Ad Hoc networks where nodes independently uniform distributed in [zl, z1 ＋ △z] is explained. The analysis is validated by computing the probability of network connectivity and comparing it with the Mont Carlo simu- lation results.
基金This work was supported in part by the National Key Research and Development Program of China(2019YFB1600100)in part by the Foundation of Shaanxi Key Laboratory of Integrated and Intelligent Navigation under Grant SKLIIN-20190103.
文摘As the basis of location-based services(LBS),positioning is one of the most essential parts in intelligent transportation systems(ITS).Although global positioning system(GPS)has been widely used in vehicle positioning,it can not achieve lane level positioning accuracy.Motivated by the mature ranging technologies such as radar and ultra-wideband(UWB),several cooperative positioning(CP)methods have been proposed to enhance the accuracy and robustness of GPS.In this paper,we proposed a twostage CP algorithm that combines multidimensional scaling(MDS)and Procrustes analysis for vehicles with GPS information.Specifically,the optimized MDS based on the scaling by majorizing a complicated function(SMACOF)algorithm is first proposed to get the relative coordinates of vehicles which can tackle measurements of different error distributions,then Procrustes analysis is carried out to transform the relative coordinates of vehicles to their absolute coordinates based on GPS information.All the computations are performed at the mobile edge computing node(MECN)for the request of ultra-reliable and low latency communications(URLLC).Simulation results validate that the proposed algorithm can greatly improve the positioning accuracy and robustness for vehicles.
