Wireless communication-enabled Cooperative Adaptive Cruise Control(CACC)is expected to improve the safety and traffic capacity of vehicle platoons.Existing CACC considers a conventional communication delay with fixed ...Wireless communication-enabled Cooperative Adaptive Cruise Control(CACC)is expected to improve the safety and traffic capacity of vehicle platoons.Existing CACC considers a conventional communication delay with fixed Vehicular Communication Network(VCN)topologies.However,when the network is under attack,the communication delay may be much higher,and the stability of the system may not be guaranteed.This paper proposes a novel communication Delay Aware CACC with Dynamic Network Topologies(DADNT).The main idea is that for various communication delays,in order to maximize the traffic capacity while guaranteeing stability and minimizing the following error,the CACC should dynamically adjust the VCN network topology to achieve the minimum inter-vehicle spacing.To this end,a multi-objective optimization problem is formulated,and a 3-step Divide-And-Conquer sub-optimal solution(3DAC)is proposed.Simulation results show that with 3DAC,the proposed DADNT with CACC can reduce the inter-vehicle spacing by 5%,10%,and 14%,respectively,compared with the traditional CACC with fixed one-vehicle,two-vehicle,and three-vehicle look-ahead network topologies,thereby improving the traffic efficiency.展开更多
A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the ...A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the vibrated velocity in the stern plate and main engine foundations is tested during the trial trip. Then, the excited force of the propeller and main engine is derived using the vibrated velocity and admittance matrix.Based on the excited force, the cabin-simulated vibrated velocity is compared with the tested vibrated velocity, and the tolerance is within the allowable scope in engineering. Loading the excited forces on the boundary element model, the distribution characteristics of sound level underwater are analyzed. Then, forces excited by the main engine and propeller are loaded on the model, and the contribution ratio of excitation sources to underwater acoustic radiation is analyzed. The result provides a reference for vibration assessment in the early stage and control in the late stage.展开更多
Predictive cruise control(PCC)is an intelligence-assisted control technology that can significantly improve the overall performance of a vehicle by using road and traffic information in advance.With the continuous dev...Predictive cruise control(PCC)is an intelligence-assisted control technology that can significantly improve the overall performance of a vehicle by using road and traffic information in advance.With the continuous development of cloud control platforms(CCPs)and telematics boxes(T-boxes),cloud-based predictive cruise control(CPCC)systems are considered an effective solution to the problems of map update difficulties and insufficient computing power on the vehicle side.In this study,a vehicle-cloud hierarchical control architecture for PCC is designed based on a CCP and T-box.This architecture utilizes waypoint structures for hierarchical and dynamic cooperative inter-triggering,enabling rolling optimization of the system and commending parsing at the vehicle end.This approach significantly improves the anti-interference capability and resolution efficiency of the system.On the CCP side,a predictive fuel-saving speed-planning(PFSP)algorithm that considers the throttle input,speed variations,and time efficiency based on the waypoint structure is proposed.It features a forward optimization search without requiring weight adjustments,demonstrating robust applicability to various road conditions and vehicles equiped with constant cruise(CC)system.On the vehicle-side T-box,based on the reference control sequence with the global navigation satellite system position,the recommended speed is analyzed and controlled using the acute angle principle.Through analyzing the differences of the PFSP algorithm compared to dynamic programming(DP)and Model predictive control(MPC)algorithms under uphill and downhill conditions,the results show that the PFSP achieves good energy-saving performance compared to CC without exhibiting significant speed fluctuations,demonstrating strong adaptability to the CC system.Finally,by building an experimental platform and running field tests over a total of 2000 km,we verified the effectiveness and stability of the CPCC system and proved the fuel-saving performance of the proposed PFSP algorithm.The results showed that the CPCC system equipped with the PFSP algorithm achieved an average fuel-saving rate of 2.05%-4.39%compared to CC.展开更多
Marine services-ranging from ocean tourism and maritime transport to public marine services-have become a powerful driver of China’s ocean economy.In 2024,the country’s gross ocean product(GOP)exceeded 10 trillion y...Marine services-ranging from ocean tourism and maritime transport to public marine services-have become a powerful driver of China’s ocean economy.In 2024,the country’s gross ocean product(GOP)exceeded 10 trillion yuan(US$1.4 trillion)for the first time,with marine services contributing 6.28 trillion yuan(US$880 billion),or 59.6 percent of the total.Among them,marine tourism and maritime transport accounted for the lion’s share.展开更多
基金supported by the National Natural Science Foundation of China under Grant U21A20449in part by Jiangsu Provincial Key Research and Development Program under Grant BE2021013-2。
文摘Wireless communication-enabled Cooperative Adaptive Cruise Control(CACC)is expected to improve the safety and traffic capacity of vehicle platoons.Existing CACC considers a conventional communication delay with fixed Vehicular Communication Network(VCN)topologies.However,when the network is under attack,the communication delay may be much higher,and the stability of the system may not be guaranteed.This paper proposes a novel communication Delay Aware CACC with Dynamic Network Topologies(DADNT).The main idea is that for various communication delays,in order to maximize the traffic capacity while guaranteeing stability and minimizing the following error,the CACC should dynamically adjust the VCN network topology to achieve the minimum inter-vehicle spacing.To this end,a multi-objective optimization problem is formulated,and a 3-step Divide-And-Conquer sub-optimal solution(3DAC)is proposed.Simulation results show that with 3DAC,the proposed DADNT with CACC can reduce the inter-vehicle spacing by 5%,10%,and 14%,respectively,compared with the traditional CACC with fixed one-vehicle,two-vehicle,and three-vehicle look-ahead network topologies,thereby improving the traffic efficiency.
文摘A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the vibrated velocity in the stern plate and main engine foundations is tested during the trial trip. Then, the excited force of the propeller and main engine is derived using the vibrated velocity and admittance matrix.Based on the excited force, the cabin-simulated vibrated velocity is compared with the tested vibrated velocity, and the tolerance is within the allowable scope in engineering. Loading the excited forces on the boundary element model, the distribution characteristics of sound level underwater are analyzed. Then, forces excited by the main engine and propeller are loaded on the model, and the contribution ratio of excitation sources to underwater acoustic radiation is analyzed. The result provides a reference for vibration assessment in the early stage and control in the late stage.
基金Supported by National Key Research and Development Program of China(Grant No.2021YFB2501000).
文摘Predictive cruise control(PCC)is an intelligence-assisted control technology that can significantly improve the overall performance of a vehicle by using road and traffic information in advance.With the continuous development of cloud control platforms(CCPs)and telematics boxes(T-boxes),cloud-based predictive cruise control(CPCC)systems are considered an effective solution to the problems of map update difficulties and insufficient computing power on the vehicle side.In this study,a vehicle-cloud hierarchical control architecture for PCC is designed based on a CCP and T-box.This architecture utilizes waypoint structures for hierarchical and dynamic cooperative inter-triggering,enabling rolling optimization of the system and commending parsing at the vehicle end.This approach significantly improves the anti-interference capability and resolution efficiency of the system.On the CCP side,a predictive fuel-saving speed-planning(PFSP)algorithm that considers the throttle input,speed variations,and time efficiency based on the waypoint structure is proposed.It features a forward optimization search without requiring weight adjustments,demonstrating robust applicability to various road conditions and vehicles equiped with constant cruise(CC)system.On the vehicle-side T-box,based on the reference control sequence with the global navigation satellite system position,the recommended speed is analyzed and controlled using the acute angle principle.Through analyzing the differences of the PFSP algorithm compared to dynamic programming(DP)and Model predictive control(MPC)algorithms under uphill and downhill conditions,the results show that the PFSP achieves good energy-saving performance compared to CC without exhibiting significant speed fluctuations,demonstrating strong adaptability to the CC system.Finally,by building an experimental platform and running field tests over a total of 2000 km,we verified the effectiveness and stability of the CPCC system and proved the fuel-saving performance of the proposed PFSP algorithm.The results showed that the CPCC system equipped with the PFSP algorithm achieved an average fuel-saving rate of 2.05%-4.39%compared to CC.
文摘Marine services-ranging from ocean tourism and maritime transport to public marine services-have become a powerful driver of China’s ocean economy.In 2024,the country’s gross ocean product(GOP)exceeded 10 trillion yuan(US$1.4 trillion)for the first time,with marine services contributing 6.28 trillion yuan(US$880 billion),or 59.6 percent of the total.Among them,marine tourism and maritime transport accounted for the lion’s share.
