Nowadays, distributed optimization algorithms are widely used in various complex networks. In order to expand the theory of distributed optimization algorithms in the direction of directed graph, the distributed conve...Nowadays, distributed optimization algorithms are widely used in various complex networks. In order to expand the theory of distributed optimization algorithms in the direction of directed graph, the distributed convex optimization problem with time-varying delays and switching topologies in the case of directed graph topology is studied. The event-triggered communication mechanism is adopted, that is, the communication between agents is determined by the trigger conditions, and the information exchange is carried out only when the conditions are met. Compared with continuous communication, this greatly saves network resources and reduces communication cost. Using Lyapunov-Krasovskii function method and inequality analysis, a new sufficient condition is proposed to ensure that the agent state finally reaches the optimal state. The upper bound of the maximum allowable delay is given. In addition, Zeno behavior will be proved not to exist during the operation of the algorithm. Finally, a simulation example is given to illustrate the correctness of the results in this paper.展开更多
The Controller Area Network (CAN) is a well established control network for automotive and automation control applications. Time-Triggered Controller Area Network (TTCAN) is a recent development which introduces a ses...The Controller Area Network (CAN) is a well established control network for automotive and automation control applications. Time-Triggered Controller Area Network (TTCAN) is a recent development which introduces a session layer,for message scheduling,to the existing CAN standard,which is a two layer standard comprising of a physical layer and a data link layer. TTCAN facilitates network communication in a time-triggered fashion,by introducing a Time Division Multiple Access style communication scheme. This allows deterministic network behavior,where maximum message latency times can be quantified and guaranteed. In order to solve the problem of determinate time latency and synchronization among several districted units in one auto panel CAN systems,this paper proposed a prototype design implementation for a shared-clock scheduler based on PIC18F458 MCU. This leads to improved CAN system performance and avoid the latency jitters and guarantee a deterministic communication pattern on the bus. The real runtime performance is satisfied.展开更多
为了提高控制器局域网络(controller area network,CAN)通信的实时性,文章基于时间触发CAN(time-triggered CAN,TTCAN)协议,采用verilog硬件描述语言设计实现TTCAN总线控制器。该控制器可在经典CAN模式与TTCAN模式之间进行切换,同时兼...为了提高控制器局域网络(controller area network,CAN)通信的实时性,文章基于时间触发CAN(time-triggered CAN,TTCAN)协议,采用verilog硬件描述语言设计实现TTCAN总线控制器。该控制器可在经典CAN模式与TTCAN模式之间进行切换,同时兼容可变速率CAN(CAN with flexible data rate,CAN FD)协议下的高速通信。实验结果证明,相较于经典CAN总线控制器,该TTCAN总线控制器能够减少在高总线负载率下周期性报文的发送延时,在全波特率范围内且总线负载率大于等于60%的情况下,能够减少75%以上的CAN报文发送延时。展开更多
文摘Nowadays, distributed optimization algorithms are widely used in various complex networks. In order to expand the theory of distributed optimization algorithms in the direction of directed graph, the distributed convex optimization problem with time-varying delays and switching topologies in the case of directed graph topology is studied. The event-triggered communication mechanism is adopted, that is, the communication between agents is determined by the trigger conditions, and the information exchange is carried out only when the conditions are met. Compared with continuous communication, this greatly saves network resources and reduces communication cost. Using Lyapunov-Krasovskii function method and inequality analysis, a new sufficient condition is proposed to ensure that the agent state finally reaches the optimal state. The upper bound of the maximum allowable delay is given. In addition, Zeno behavior will be proved not to exist during the operation of the algorithm. Finally, a simulation example is given to illustrate the correctness of the results in this paper.
文摘The Controller Area Network (CAN) is a well established control network for automotive and automation control applications. Time-Triggered Controller Area Network (TTCAN) is a recent development which introduces a session layer,for message scheduling,to the existing CAN standard,which is a two layer standard comprising of a physical layer and a data link layer. TTCAN facilitates network communication in a time-triggered fashion,by introducing a Time Division Multiple Access style communication scheme. This allows deterministic network behavior,where maximum message latency times can be quantified and guaranteed. In order to solve the problem of determinate time latency and synchronization among several districted units in one auto panel CAN systems,this paper proposed a prototype design implementation for a shared-clock scheduler based on PIC18F458 MCU. This leads to improved CAN system performance and avoid the latency jitters and guarantee a deterministic communication pattern on the bus. The real runtime performance is satisfied.
文摘为了满足航空器经济性的制造需求,降低航空器内部的有效载荷,使用无线代替有线已经成为机载网络转型升级的重要方向,然而传统无线技术难以满足机载网络中时间敏感业务的实时性传输需求.因此,通过明确机载无线通信网络(airborne wireless communication network, AWCN)的应用特点,设计了AWCN结合机载骨干交换网络的混合拓扑架构;综合考虑了节点无冲突、信道无干扰、路径依赖与端到端时延需求,构建了时间触发的AWCN确定性调度应该满足的一阶逻辑形式;理论分析了不同信道数量下完成调度所需要的最少时隙数量与制约端到端时延的主要因素,并证明了稳态时数据流在网关处的信息年龄期望值;设计了基于整数规划的调度方法,并针对大规模网络中决策变量多、约束之间耦合性高而导致的求解效率低的缺陷,提出了一种增量式求解策略.最后,通过实验验证了确定性调度模型与理论分析的有效性,并讨论了不同调度影响因子对数据流总时延与调度规模的影响.
文摘为了提高控制器局域网络(controller area network,CAN)通信的实时性,文章基于时间触发CAN(time-triggered CAN,TTCAN)协议,采用verilog硬件描述语言设计实现TTCAN总线控制器。该控制器可在经典CAN模式与TTCAN模式之间进行切换,同时兼容可变速率CAN(CAN with flexible data rate,CAN FD)协议下的高速通信。实验结果证明,相较于经典CAN总线控制器,该TTCAN总线控制器能够减少在高总线负载率下周期性报文的发送延时,在全波特率范围内且总线负载率大于等于60%的情况下,能够减少75%以上的CAN报文发送延时。
