基于行星齿轮机构的功率分流式混合动力系统可利用双电机分別对发动机进行转速调节和转矩补偿,从而使得混合动力汽车(Hybrid electric vehide, HEV)的燃油经济性和排放性能得到显著提升。然而,单行星排功率分流式混合动力系统在行驶过...基于行星齿轮机构的功率分流式混合动力系统可利用双电机分別对发动机进行转速调节和转矩补偿,从而使得混合动力汽车(Hybrid electric vehide, HEV)的燃油经济性和排放性能得到显著提升。然而,单行星排功率分流式混合动力系统在行驶过程中会频繁产生功率循环现象,降低了系统整体工作效率。为了进一步提升燃油经济性,提出一种单行星排功率分流式混合动力系统构型优化设计方案。首先,对单行星排功率输出/输入式混合动力系统的运行特征以及拓扑结构进行分析,拆分并重组两种拓扑结构的连接关系,以生成基础拓扑结构方案。其次,基于基础拓扑结构方案探索全部的可行性拓扑结构,并对可行性拓扑结构进行组合以生成新的构型方案。最终采用基于动态规划(DP)算法的全局最优的控制策略对所生成的构型方案的最佳经济性和最佳动力性能进行仿真分析。结果表明,所提出的单行星排功率分流式混合动力系统构型优化方案能够有效提升整车综合行驶性能。展开更多
The cyber-physical space is a spatial environment that integrates the cyber and physical worlds to provide an intelligent environment for users to conduct their day-to-day activities. Mobile users and mobile objects a...The cyber-physical space is a spatial environment that integrates the cyber and physical worlds to provide an intelligent environment for users to conduct their day-to-day activities. Mobile users and mobile objects are ubiquitous in this space, thereby exerting tremendous pressure on its security model. This model must ensure that both cyber and physical objects are always handled securely in this dynamic environment. In this paper,we propose a systematic solution to be able to specify security policies of the cyber-physical space and ensure that security requirements hold in these policies. We first formulate a topology configuration model to capture the topology characteristics of the cyber and physical worlds. Then, based on this model, a Topology-Aware CyberPhysical Access Control model(TA-CPAC) is proposed, which can ensure the security of the cyber and physical worlds at the same time by adjusting permission assignment dynamically. Then, the topology configuration and TA-CPAC models are formalized by bigraphs and Bigraph Reactive System(BRS), respectively, allowing us to use model checking to rationalize the consequences of the evolution of topological configurations on the satisfaction of security requirements. Finally, a case study on a building automation access control system is conducted to evaluate the effectiveness of the proposed approach.展开更多
A method based on the metamorphic principle is proposed for the analysis of the configuration design of a space truss deployable mechanism. The configuration change and correspondent topological graphs and adjacency m...A method based on the metamorphic principle is proposed for the analysis of the configuration design of a space truss deployable mechanism. The configuration change and correspondent topological graphs and adjacency matrixes at different work-stage of the mechanism, which is helpful to completely understand the composition and change rules of the metamorphic mechanism, are analyzed to indicate the metamorphic relationship in one working cycle. Furthermore, the static distance matrix, dynamic distance matrix and stiffness matrix of the mechanism are derived to assess the ability of the designed configuration to reveal some of the topological characteristics like compactness, dynamic sensitivity and stiffness. Using this proposed method in a space truss deployable mechanism helps the designer to evaluate its performance at the conceptual stage of design and make a rapid, reasonable selection for configuration design, which provides means for processing its type of analysis by computer.展开更多
The existence of a single topologically protected edge state in the first bulk bandgap for acoustic/elastic valley Hall insulators(VHIs)with zigzag interface configurations(ZICs)is well known.However,in this work,we s...The existence of a single topologically protected edge state in the first bulk bandgap for acoustic/elastic valley Hall insulators(VHIs)with zigzag interface configurations(ZICs)is well known.However,in this work,we show that an ultra-broadband edgestate pair in this bandgap can be created using the inverse design by topology optimization.The valley Hall insulator design increases the operational bandwidth 121%compared with an existing valley Hall insulator from recent literature and exhibits extreme field confinement,where more than 99%of the field intensity is concentrated within three unit-cells from the interface.One-way propagation and topological robustness towards small cavity defects are confirmed for the full bandwidth.The exploitation of such edge-state pairs of valley Hall insulators opens an avenue for realizing broadband confined edge modes.In tests for disorder and bend defects,we show that the additional ZIC,with a different operational frequency interval,encountered at the defects,degrades the transmission for bend and disorder defects which may prove significant for the application of VHIs.Through an alternative topology optimization method based on two ZICs,we further increase their common operational bandwidth.展开更多
文摘基于行星齿轮机构的功率分流式混合动力系统可利用双电机分別对发动机进行转速调节和转矩补偿,从而使得混合动力汽车(Hybrid electric vehide, HEV)的燃油经济性和排放性能得到显著提升。然而,单行星排功率分流式混合动力系统在行驶过程中会频繁产生功率循环现象,降低了系统整体工作效率。为了进一步提升燃油经济性,提出一种单行星排功率分流式混合动力系统构型优化设计方案。首先,对单行星排功率输出/输入式混合动力系统的运行特征以及拓扑结构进行分析,拆分并重组两种拓扑结构的连接关系,以生成基础拓扑结构方案。其次,基于基础拓扑结构方案探索全部的可行性拓扑结构,并对可行性拓扑结构进行组合以生成新的构型方案。最终采用基于动态规划(DP)算法的全局最优的控制策略对所生成的构型方案的最佳经济性和最佳动力性能进行仿真分析。结果表明,所提出的单行星排功率分流式混合动力系统构型优化方案能够有效提升整车综合行驶性能。
基金supported by the National Natural Science Foundation of China(Nos.61772270,61602262,and 61602237)Jiangsu Natural Science Foundation of China(No.BK20170809)+1 种基金the National High-Tech Research and Development(863)Program of China(No.2015AA015303)Science Foundation of Nanjing Institute of Technology(No.YKJ201420)
文摘The cyber-physical space is a spatial environment that integrates the cyber and physical worlds to provide an intelligent environment for users to conduct their day-to-day activities. Mobile users and mobile objects are ubiquitous in this space, thereby exerting tremendous pressure on its security model. This model must ensure that both cyber and physical objects are always handled securely in this dynamic environment. In this paper,we propose a systematic solution to be able to specify security policies of the cyber-physical space and ensure that security requirements hold in these policies. We first formulate a topology configuration model to capture the topology characteristics of the cyber and physical worlds. Then, based on this model, a Topology-Aware CyberPhysical Access Control model(TA-CPAC) is proposed, which can ensure the security of the cyber and physical worlds at the same time by adjusting permission assignment dynamically. Then, the topology configuration and TA-CPAC models are formalized by bigraphs and Bigraph Reactive System(BRS), respectively, allowing us to use model checking to rationalize the consequences of the evolution of topological configurations on the satisfaction of security requirements. Finally, a case study on a building automation access control system is conducted to evaluate the effectiveness of the proposed approach.
基金supported by the Science and Technology Commission of Shanghai Municipality under Grant No. 06dz22105
文摘A method based on the metamorphic principle is proposed for the analysis of the configuration design of a space truss deployable mechanism. The configuration change and correspondent topological graphs and adjacency matrixes at different work-stage of the mechanism, which is helpful to completely understand the composition and change rules of the metamorphic mechanism, are analyzed to indicate the metamorphic relationship in one working cycle. Furthermore, the static distance matrix, dynamic distance matrix and stiffness matrix of the mechanism are derived to assess the ability of the designed configuration to reveal some of the topological characteristics like compactness, dynamic sensitivity and stiffness. Using this proposed method in a space truss deployable mechanism helps the designer to evaluate its performance at the conceptual stage of design and make a rapid, reasonable selection for configuration design, which provides means for processing its type of analysis by computer.
基金supported by the China Scholarship Council(CSC)the Danmarks Grundforskningsfond(Grant No.DNRF147)。
文摘The existence of a single topologically protected edge state in the first bulk bandgap for acoustic/elastic valley Hall insulators(VHIs)with zigzag interface configurations(ZICs)is well known.However,in this work,we show that an ultra-broadband edgestate pair in this bandgap can be created using the inverse design by topology optimization.The valley Hall insulator design increases the operational bandwidth 121%compared with an existing valley Hall insulator from recent literature and exhibits extreme field confinement,where more than 99%of the field intensity is concentrated within three unit-cells from the interface.One-way propagation and topological robustness towards small cavity defects are confirmed for the full bandwidth.The exploitation of such edge-state pairs of valley Hall insulators opens an avenue for realizing broadband confined edge modes.In tests for disorder and bend defects,we show that the additional ZIC,with a different operational frequency interval,encountered at the defects,degrades the transmission for bend and disorder defects which may prove significant for the application of VHIs.Through an alternative topology optimization method based on two ZICs,we further increase their common operational bandwidth.
