This paper presents an improved virtual coupling train set(VCTS)operation control framework to deal with the lack of opti-mization of speed curves in the traditional techniques.The framework takes into account the tem...This paper presents an improved virtual coupling train set(VCTS)operation control framework to deal with the lack of opti-mization of speed curves in the traditional techniques.The framework takes into account the temporary speed limit on the railway line and the communication delay between trains,and it uses a VCTS consisting of three trains as an experimental object.It creates the virtual coupling train tracking and control process by improving the driving strategy of the leader train and using the leader-follower model.The follower train uses the improved speed curve of the leader train as its speed refer-ence curve through knowledge migration,and this completes the multi-objective optimization of the driving strategy for the VCTS.The experimental results confirm that the deep reinforcement learning algorithm effectively achieves the optimization goal of the train driving strategy.They also reveal that the intrinsic curiosity module prioritized experience replay dueling double deep Q-network(ICM-PER-D3QN)algorithm outperforms the deep Q-network(DQN)algorithm in optimizing the driving strategy of the leader train.The ICM-PER-D3QN algorithm enhances the leader train driving strategy by an average of 57%when compared to the DQN algorithm.Furthermore,the particle swarm optimization(PSO)-based model predictive control(MPC)algorithm has also demonstrated tracking accuracy and further improved safety during VCTS operation,with an average increase of 37.7%in tracking accuracy compared to the traditional MPC algorithm.展开更多
This article discusses the detailed examination of the engineering design and implementation process for direct Train-to-Train(T2T)communication within a wireless train backbone network in the context of a virtual cou...This article discusses the detailed examination of the engineering design and implementation process for direct Train-to-Train(T2T)communication within a wireless train backbone network in the context of a virtual coupling scenario.The article proposed several critical aspects,including the optimization of transmission data requirements,which is essential to ensure that communication between trains is efficient and reliable.The design of the T2T wireless communication subsystem is discussed in detail,outlining the technical specifications,protocols,and technologies employed to facilitate wireless communication between multiple trains.Additionally,the article presents a thorough analysis of the data collected during real-world train experiments,highlighting the performance metrics and challenges encountered during testing.This empirical data not only validates the effectiveness of the proposed design but also serves as a crucial reference for future advancements in T2T wireless communication systems.By combining both theoretical principles and practical outcomes,the article offers insights that will aid engineers and researchers in developing robust and efficient wireless communication systems for next-generation train operations.展开更多
As the latest research direction of train-to-train communication,virtual coupling train formation technology has attracted the attention of many scholars.This paper studies the influence of time delay on the formation...As the latest research direction of train-to-train communication,virtual coupling train formation technology has attracted the attention of many scholars.This paper studies the influence of time delay on the formation of virtual coupled trains.We proposed a distributed PID controller,which means that trains can still form a stable fleet operation under the influence of communication delay and control delay.After modelling and analysis,the research uses Matlab to conduct simulation,involving two sets of experiments.Factors including speed,acceleration,position,position error,expected distance between adjacent trains and actual distance between adjacent trains are simulated.The results demonstrate that the distributed PID controller can effectively control the impact of time delay on the virtual coupling fleet.展开更多
In the research on the new generation of intelligent rail transit system,the prevention of train collision accidents is still a focus.Virtual coupling technology controls the running speed and interval distance of two...In the research on the new generation of intelligent rail transit system,the prevention of train collision accidents is still a focus.Virtual coupling technology controls the running speed and interval distance of two or more trains cooperatively through Trainto-Train(T2T)direct communication technology.The aim is to form a coordinated logical system and jointly complete the train control and dispatching.In this paper,a virtual coupling train formation control method based on the model predictive control(MPC)framework is proposed.From the establishment of the virtual coupling system,the construction of an MPC model and decoupling method,how to integrate virtual coupling technology into the rail transit train collision protection is studied.The safety and reliability of the system are calculated through fault tree and the method of constructing reliability function.The research shows that if virtual coupling technology is used for train collision protection,the overall safety and reliability of the train control system is improved.展开更多
Virtual coupling(VC) is an emerging technology for addressing the shortage of rail transportation capacity. As a crucial enabling technology, the VC-specific acquisition of train information, especially train followin...Virtual coupling(VC) is an emerging technology for addressing the shortage of rail transportation capacity. As a crucial enabling technology, the VC-specific acquisition of train information, especially train following distance(TFD), is underdeveloped.In this paper, a novel method is proposed to acquire real-time TFD by analyzing the vibration response of the front and following trains, during which only onboard accelerometers and speedometers are required. In contrast to the traditional arts of train positioning, this method targets a relative position between two adjacent trains in VC operation, rather than the global positions of the trains. For this purpose, an adaptive system containing three strategies is designed to cope with possible adverse factors in train operation. A vehicle dynamics simulation of a heavy-haul railway is implemented for the evaluation of feasibility and performance. Furthermore, a validation is conducted using a set of data measured from in-service Chinese high-speed trains. The results indicate the method achieves satisfactory estimation accuracy using both simulated and actual data. It has favorable adaptability to various uncertainties possibly encountered in train operation. Additionally, the method is preliminarily proven to adapt to different locomotive types and even different rail transportation modes. In general, such a method with good performance, low-cost, and easy implementation is promising to apply.展开更多
The emerging virtual coupling technology aims to operate multiple train units in a Virtually Coupled Train Set(VCTS)at a minimal but safe distance.To guarantee collision avoidance,the safety distance should be calcula...The emerging virtual coupling technology aims to operate multiple train units in a Virtually Coupled Train Set(VCTS)at a minimal but safe distance.To guarantee collision avoidance,the safety distance should be calculated using the state-of-the-art space-time separation principle that separates the Emergency Braking(EB)trajectories of two successive units during the whole EB process.In this case,the minimal safety distance is usually numerically calculated without an analytic formulation.Thus,the constrained VCTS control problem is hard to address with space-time separation,which is still a gap in the existing literature.To solve this problem,we propose a Distributed Economic Model Predictive Control(DEMPC)approach with computation efficiency and theoretical guarantee.Specifically,to alleviate the computation burden,we transform implicit safety constraints into explicitly linear ones,such that the optimal control problem in DEMPC is a quadratic programming problem that can be solved efficiently.For theoretical analysis,sufficient conditions are derived to guarantee the recursive feasibility and stability of DEMPC,employing compatibility constraints,tube techniques and terminal ingredient tuning.Moreover,we extend our approach with globally optimal and distributed online EB configuration methods to shorten the minimal distance among VCTS.Finally,experimental results demonstrate the performance and advantages of the proposed approaches.展开更多
Mode-localized sensors have attracted significant attention due to their exceptional sensitivity and inherent ability to reject common-mode noise.This high sensitivity arises from the substantial shifts in resonator a...Mode-localized sensors have attracted significant attention due to their exceptional sensitivity and inherent ability to reject common-mode noise.This high sensitivity arises from the substantial shifts in resonator amplitudes induced by energy confinement in weakly coupled resonators.Despite their promising attributes,there has been limited research on the mechanisms of energy confinement.This paper presents both qualitative and quantitative analyses of energy confinement within weakly coupled resonators and concludes them as the concept of modal dominance.This concept elucidates that mode frequencies are predominantly dictated by the natural frequencies of the internal resonators,facilitating spatial energy confinement.Based on this modal dominance,a novel concept of virtually coupled resonators is proposed,which obviates the need for physical coupling structures.Instead,energy confinement is achieved through a frequency offset between two independent resonators,resulting in a similar amplitude ratio output and enhanced sensitivity.To further enhance performance,a double-closed-loop control scheme is developed for virtually coupled resonators,expanding the bandwidth in comparison to weakly coupled resonators.Experimental results validate the feasibility of virtually coupled resonators and the double-closed-loop control,demonstrating a 2.7-fold improvement in amplitude ratio sensitivity and at least a four-fold enhancement in bandwidth relative to weakly coupled resonators with identical parameters.展开更多
Virtual coupling is a novel technology that enables trains to run closely together without physical connections through communication and automation systems.The paper addresses an adaptive polynomial approximation alg...Virtual coupling is a novel technology that enables trains to run closely together without physical connections through communication and automation systems.The paper addresses an adaptive polynomial approximation algorithm for the cooperative control of high-speed trains(HSTs)under virtual coupling.It aims to solve the cooperative tracking control problem of HST formation operations under various scenarios,including known and unknown parameters.To enable the HST formation system to achieve cooperative operation while ensuring an appropriate spacing distance,the tracking errors of displacement and speed throughout the entire operation converge to zero.The proposed control strategy focuses on adopting polynomial approximation to handle unknown parameters,which are estimated via adaptive laws.Additionally,the unknown parameters of the HSTs are estimated online through adaptive laws.Experimental results verify the effectiveness of this method.展开更多
基金supported by the National Natural Science Foundation of China under Grant 52162050.
文摘This paper presents an improved virtual coupling train set(VCTS)operation control framework to deal with the lack of opti-mization of speed curves in the traditional techniques.The framework takes into account the temporary speed limit on the railway line and the communication delay between trains,and it uses a VCTS consisting of three trains as an experimental object.It creates the virtual coupling train tracking and control process by improving the driving strategy of the leader train and using the leader-follower model.The follower train uses the improved speed curve of the leader train as its speed refer-ence curve through knowledge migration,and this completes the multi-objective optimization of the driving strategy for the VCTS.The experimental results confirm that the deep reinforcement learning algorithm effectively achieves the optimization goal of the train driving strategy.They also reveal that the intrinsic curiosity module prioritized experience replay dueling double deep Q-network(ICM-PER-D3QN)algorithm outperforms the deep Q-network(DQN)algorithm in optimizing the driving strategy of the leader train.The ICM-PER-D3QN algorithm enhances the leader train driving strategy by an average of 57%when compared to the DQN algorithm.Furthermore,the particle swarm optimization(PSO)-based model predictive control(MPC)algorithm has also demonstrated tracking accuracy and further improved safety during VCTS operation,with an average increase of 37.7%in tracking accuracy compared to the traditional MPC algorithm.
基金supported by the National Key R&D Program of China(2021YFF0501103).
文摘This article discusses the detailed examination of the engineering design and implementation process for direct Train-to-Train(T2T)communication within a wireless train backbone network in the context of a virtual coupling scenario.The article proposed several critical aspects,including the optimization of transmission data requirements,which is essential to ensure that communication between trains is efficient and reliable.The design of the T2T wireless communication subsystem is discussed in detail,outlining the technical specifications,protocols,and technologies employed to facilitate wireless communication between multiple trains.Additionally,the article presents a thorough analysis of the data collected during real-world train experiments,highlighting the performance metrics and challenges encountered during testing.This empirical data not only validates the effectiveness of the proposed design but also serves as a crucial reference for future advancements in T2T wireless communication systems.By combining both theoretical principles and practical outcomes,the article offers insights that will aid engineers and researchers in developing robust and efficient wireless communication systems for next-generation train operations.
文摘As the latest research direction of train-to-train communication,virtual coupling train formation technology has attracted the attention of many scholars.This paper studies the influence of time delay on the formation of virtual coupled trains.We proposed a distributed PID controller,which means that trains can still form a stable fleet operation under the influence of communication delay and control delay.After modelling and analysis,the research uses Matlab to conduct simulation,involving two sets of experiments.Factors including speed,acceleration,position,position error,expected distance between adjacent trains and actual distance between adjacent trains are simulated.The results demonstrate that the distributed PID controller can effectively control the impact of time delay on the virtual coupling fleet.
基金International Joint Laboratory of China-Laos Railway Engineering under the"the Belt and Road"Initiative of Science and Technology Innovation of Shanghai Municipal Science and Technology Commission(Grant No.21210750300)Research on key technologies of intelligent operation and maintenance of rail transit"for local capacity building of Shanghai Municipal Science and Technology Commission(Grant No.20090503100).
文摘In the research on the new generation of intelligent rail transit system,the prevention of train collision accidents is still a focus.Virtual coupling technology controls the running speed and interval distance of two or more trains cooperatively through Trainto-Train(T2T)direct communication technology.The aim is to form a coordinated logical system and jointly complete the train control and dispatching.In this paper,a virtual coupling train formation control method based on the model predictive control(MPC)framework is proposed.From the establishment of the virtual coupling system,the construction of an MPC model and decoupling method,how to integrate virtual coupling technology into the rail transit train collision protection is studied.The safety and reliability of the system are calculated through fault tree and the method of constructing reliability function.The research shows that if virtual coupling technology is used for train collision protection,the overall safety and reliability of the train control system is improved.
基金supported by the National Natural Science Foundation of China(52222217,52388102,52372435)the Major Science and TechnologyProject of China Energy(GJNY-22-7)
文摘Virtual coupling(VC) is an emerging technology for addressing the shortage of rail transportation capacity. As a crucial enabling technology, the VC-specific acquisition of train information, especially train following distance(TFD), is underdeveloped.In this paper, a novel method is proposed to acquire real-time TFD by analyzing the vibration response of the front and following trains, during which only onboard accelerometers and speedometers are required. In contrast to the traditional arts of train positioning, this method targets a relative position between two adjacent trains in VC operation, rather than the global positions of the trains. For this purpose, an adaptive system containing three strategies is designed to cope with possible adverse factors in train operation. A vehicle dynamics simulation of a heavy-haul railway is implemented for the evaluation of feasibility and performance. Furthermore, a validation is conducted using a set of data measured from in-service Chinese high-speed trains. The results indicate the method achieves satisfactory estimation accuracy using both simulated and actual data. It has favorable adaptability to various uncertainties possibly encountered in train operation. Additionally, the method is preliminarily proven to adapt to different locomotive types and even different rail transportation modes. In general, such a method with good performance, low-cost, and easy implementation is promising to apply.
基金supported by the National Natural Science Foundation of China(52372310)the State Key Laboratory of Advanced Rail Autonomous Operation(RAO2023ZZ001)+1 种基金the Fundamental Research Funds for the Central Universities(2022JBQY001)Beijing Laboratory of Urban Rail Transit.
文摘The emerging virtual coupling technology aims to operate multiple train units in a Virtually Coupled Train Set(VCTS)at a minimal but safe distance.To guarantee collision avoidance,the safety distance should be calculated using the state-of-the-art space-time separation principle that separates the Emergency Braking(EB)trajectories of two successive units during the whole EB process.In this case,the minimal safety distance is usually numerically calculated without an analytic formulation.Thus,the constrained VCTS control problem is hard to address with space-time separation,which is still a gap in the existing literature.To solve this problem,we propose a Distributed Economic Model Predictive Control(DEMPC)approach with computation efficiency and theoretical guarantee.Specifically,to alleviate the computation burden,we transform implicit safety constraints into explicitly linear ones,such that the optimal control problem in DEMPC is a quadratic programming problem that can be solved efficiently.For theoretical analysis,sufficient conditions are derived to guarantee the recursive feasibility and stability of DEMPC,employing compatibility constraints,tube techniques and terminal ingredient tuning.Moreover,we extend our approach with globally optimal and distributed online EB configuration methods to shorten the minimal distance among VCTS.Finally,experimental results demonstrate the performance and advantages of the proposed approaches.
基金supported by the National Science Foundation of China(No.52435012 and No.52475606)the National Key Research and Development Program of China(No.2023YFB3208800)+2 种基金Innovation Capability Support Program of Shaanxi(No.2024RS-CXTD-7)the Key Research and Development Program of Shaanxi Province(2024GX-YBXM-193)the Fundamental Research Funds for the Central Universities.
文摘Mode-localized sensors have attracted significant attention due to their exceptional sensitivity and inherent ability to reject common-mode noise.This high sensitivity arises from the substantial shifts in resonator amplitudes induced by energy confinement in weakly coupled resonators.Despite their promising attributes,there has been limited research on the mechanisms of energy confinement.This paper presents both qualitative and quantitative analyses of energy confinement within weakly coupled resonators and concludes them as the concept of modal dominance.This concept elucidates that mode frequencies are predominantly dictated by the natural frequencies of the internal resonators,facilitating spatial energy confinement.Based on this modal dominance,a novel concept of virtually coupled resonators is proposed,which obviates the need for physical coupling structures.Instead,energy confinement is achieved through a frequency offset between two independent resonators,resulting in a similar amplitude ratio output and enhanced sensitivity.To further enhance performance,a double-closed-loop control scheme is developed for virtually coupled resonators,expanding the bandwidth in comparison to weakly coupled resonators.Experimental results validate the feasibility of virtually coupled resonators and the double-closed-loop control,demonstrating a 2.7-fold improvement in amplitude ratio sensitivity and at least a four-fold enhancement in bandwidth relative to weakly coupled resonators with identical parameters.
基金supported in part by the National Natural Science Foundation of China(Grant Nos.62203246 and 62003127)Shandong Provincial Natural Science Foundation(Grant No.ZR2024QF041)the Natural Science Foundation of Hebei Province(Grant No.F2023202060)。
文摘Virtual coupling is a novel technology that enables trains to run closely together without physical connections through communication and automation systems.The paper addresses an adaptive polynomial approximation algorithm for the cooperative control of high-speed trains(HSTs)under virtual coupling.It aims to solve the cooperative tracking control problem of HST formation operations under various scenarios,including known and unknown parameters.To enable the HST formation system to achieve cooperative operation while ensuring an appropriate spacing distance,the tracking errors of displacement and speed throughout the entire operation converge to zero.The proposed control strategy focuses on adopting polynomial approximation to handle unknown parameters,which are estimated via adaptive laws.Additionally,the unknown parameters of the HSTs are estimated online through adaptive laws.Experimental results verify the effectiveness of this method.
