Continuous flow intersection(CFI)is one of the most important unconventional intersection design(UID)modes.This kind of intersection transfers left-turn movements to secondary intersections to obtain a 2-phase signal ...Continuous flow intersection(CFI)is one of the most important unconventional intersection design(UID)modes.This kind of intersection transfers left-turn movements to secondary intersections to obtain a 2-phase signal control scheme at main intersection,so the traffic efficiency at main intersection is greatly improved.To further exploit the traffic efficiency of continuous flow intersection,the coordination of main and secondary intersection signals is theoretically studied,and an optimal timing model for general use is proposed.The optimal timing model can effectively coordinate primary and secondary intersection signal timings and produce the most effective signal timing schemes for main and secondary intersections to great extent reduce vehicle delay and improve intersection capacity,and can ensure reliable operation of primary and secondary intersections in practical application.Based on the delay compositions and their characteristics of CFI,the delay and queue process evolution with the signal offset of main and secondary intersections and the corresponding scene are analysed.Then,the method for solving optimal offset between main and secondary intersections is given by optimal analysis to simplify the solving procedure of the model.In the end,an arterial intersection in Nanchang is studied as a case of how to apply the CFI channelization design to a conventional intersection and how to apply the optimal timing model to generate the coordinate timing scheme,and the micro traffic simulation is used to evaluate the traffic benefit.The result shows that(1)the optimal timing scheme can effectively reduce delays and queues and improve the intersection capacity;(2)the model calculation agrees well with the simulation result,which proves that the signal timing model is effective and accurate.展开更多
There are various analyses for a solar system with the dish-Stirling technology.One of those analyses is the finite time thermodynamic analysis by which the total power of the system can be obtained by calculating the...There are various analyses for a solar system with the dish-Stirling technology.One of those analyses is the finite time thermodynamic analysis by which the total power of the system can be obtained by calculating the process time.In this study,the convection and radiation heat transfer losses from collector surface,the conduction heat transfer between hot and cold cylinders,and cold side heat exchanger have been considered.During this investigation,four objective functions have been optimized simultaneously,including power,efficiency,entropy,and economic factors.In addition to the fourobjective optimization,three-objective,two-objective,and single-objective optimizations have been done on the dish-Stirling model.The algorithm of multi-objective particle swarm optimization(MO P S O)with post-expression of preferences is used for multi-objective optimizations while the branch and bound algorithm with pre-expression of preferences is used for single-objective and multi-objective optimizations.In the case of multi-objective optimizations with post-expression of preferences,Pareto optimal front are obtained,afterward by implementing the fuzzy,LINMAP,and TOPSIS decision making algorithms,the single optimum results can be achieved.The comparison of the results shows the benefits of MOPSO in optimizing dish Stirling finite time thermodynamic equations.展开更多
This paper presents an optimized equivalent consumption minimization strategy(ECMS) for four-wheel-drive(4 WD) hybrid electric vehicles(HEVs) incorporating vehicle connectivity. In order to be applicable to the 4 WD a...This paper presents an optimized equivalent consumption minimization strategy(ECMS) for four-wheel-drive(4 WD) hybrid electric vehicles(HEVs) incorporating vehicle connectivity. In order to be applicable to the 4 WD architecture, the ECMS is designed based on a rule-based strategy and used under the condition that a certain propulsion mode is activated. Assuming that a group of 4 WD HEVs are connected and position information can be shared with each other, we formulate a decentralized model predictive control(MPC) framework that compromises fuel efficiency, mobility, and inter-vehicle distance to optimize the velocity profile of each individual vehicle. Based on the optimized velocity profile, an optimization problem considering both fuel economy and battery state of charge(SOC) sustainability is formulated to optimize the equivalent factors(EFs) of the ECMS for HEVs over an appropriate time window. MATLAB User Datagram Protocol(UDP) is used in the codes run on multiple computers to simulate the wireless communication among vehicles, which share position information via UDP-based communication, and dSPACE is used as a software-in-the-loop platform for the simulation of the optimized ECMS. Simulation results validate the control effectiveness of the proposed method.展开更多
基金Supported by the Natural Science Foundation of Shanghai(No.17ZR1431800)。
摘要Continuous flow intersection(CFI)is one of the most important unconventional intersection design(UID)modes.This kind of intersection transfers left-turn movements to secondary intersections to obtain a 2-phase signal control scheme at main intersection,so the traffic efficiency at main intersection is greatly improved.To further exploit the traffic efficiency of continuous flow intersection,the coordination of main and secondary intersection signals is theoretically studied,and an optimal timing model for general use is proposed.The optimal timing model can effectively coordinate primary and secondary intersection signal timings and produce the most effective signal timing schemes for main and secondary intersections to great extent reduce vehicle delay and improve intersection capacity,and can ensure reliable operation of primary and secondary intersections in practical application.Based on the delay compositions and their characteristics of CFI,the delay and queue process evolution with the signal offset of main and secondary intersections and the corresponding scene are analysed.Then,the method for solving optimal offset between main and secondary intersections is given by optimal analysis to simplify the solving procedure of the model.In the end,an arterial intersection in Nanchang is studied as a case of how to apply the CFI channelization design to a conventional intersection and how to apply the optimal timing model to generate the coordinate timing scheme,and the micro traffic simulation is used to evaluate the traffic benefit.The result shows that(1)the optimal timing scheme can effectively reduce delays and queues and improve the intersection capacity;(2)the model calculation agrees well with the simulation result,which proves that the signal timing model is effective and accurate.
基金This research was supported by the Scientific Research Foundation of Wuhan University of Technology(No.40120237)the ESI Discipline Promotion Foundation of WUT(No.35400664).
摘要There are various analyses for a solar system with the dish-Stirling technology.One of those analyses is the finite time thermodynamic analysis by which the total power of the system can be obtained by calculating the process time.In this study,the convection and radiation heat transfer losses from collector surface,the conduction heat transfer between hot and cold cylinders,and cold side heat exchanger have been considered.During this investigation,four objective functions have been optimized simultaneously,including power,efficiency,entropy,and economic factors.In addition to the fourobjective optimization,three-objective,two-objective,and single-objective optimizations have been done on the dish-Stirling model.The algorithm of multi-objective particle swarm optimization(MO P S O)with post-expression of preferences is used for multi-objective optimizations while the branch and bound algorithm with pre-expression of preferences is used for single-objective and multi-objective optimizations.In the case of multi-objective optimizations with post-expression of preferences,Pareto optimal front are obtained,afterward by implementing the fuzzy,LINMAP,and TOPSIS decision making algorithms,the single optimum results can be achieved.The comparison of the results shows the benefits of MOPSO in optimizing dish Stirling finite time thermodynamic equations.
基金supported by the National Hi-Tech Research and Development Program of China(Grant No.2015BAG17B04)China Scholarship Council(Grant No.201506690009)U.S.GATE Program
摘要This paper presents an optimized equivalent consumption minimization strategy(ECMS) for four-wheel-drive(4 WD) hybrid electric vehicles(HEVs) incorporating vehicle connectivity. In order to be applicable to the 4 WD architecture, the ECMS is designed based on a rule-based strategy and used under the condition that a certain propulsion mode is activated. Assuming that a group of 4 WD HEVs are connected and position information can be shared with each other, we formulate a decentralized model predictive control(MPC) framework that compromises fuel efficiency, mobility, and inter-vehicle distance to optimize the velocity profile of each individual vehicle. Based on the optimized velocity profile, an optimization problem considering both fuel economy and battery state of charge(SOC) sustainability is formulated to optimize the equivalent factors(EFs) of the ECMS for HEVs over an appropriate time window. MATLAB User Datagram Protocol(UDP) is used in the codes run on multiple computers to simulate the wireless communication among vehicles, which share position information via UDP-based communication, and dSPACE is used as a software-in-the-loop platform for the simulation of the optimized ECMS. Simulation results validate the control effectiveness of the proposed method.