Intelligent emergency service system based on wireless sensor and actuator networks

An intelligent emergency service（ IES） system is designed for indoor environments based on a wireless sensor and actuator network（ WSAN） composed of a gateway, sensor nodes, and a multi-robot system（ MRS）. If the MRS receives accident alarm information, the group of robots will navigate to the accident sites and provide corresponding emergency services.According to the characteristics of the MRS, a distributed consensus formation protocol is designed, which can assure that the multiple robots arrive at the accident site in a specified formation. The prototype emergency service system was designed and implemented, and some relevant simulations and experiments were carried out. The results showthat the MRS can successfully provide emergency lighting and failure node replacement services when accidents happen. The effectiveness of the algorithm and the feasibility of the system are verified.

Improved control of distributed parameter systems using wireless sensor and actuator networks:An observer-based method

In this paper,the control problem of distributed parameter systems is investigated by using wireless sensor and actuator networks with the observer-based method.Firstly,a centralized observer which makes use of the measurement information provided by the fixed sensors is designed to estimate the distributed parameter systems.The mobile agents,each of which is affixed with a controller and an actuator,can provide the observer-based control for the target systems.By using Lyapunov stability arguments,the stability for the estimation error system and distributed parameter control system is proved,meanwhile a guidance scheme for each mobile actuator is provided to improve the control performance.A numerical example is finally used to demonstrate the effectiveness and the advantages of the proposed approaches.

A Localized Inter-Actuator Network Topology Repair Scheme for Wireless Sensor and Actuator Networks

Node failure is one of the most severe problems that wireless sensor and actuator networks(WSANs) have to deal with. The failure of actuator nodes, in particular, may result in substantial consequences such as network partitioning, incorrect and incomplete decision execution for WSANs. This paper proposes an efficient localized scheme, called LANTR, to repair the damaged topology of inter-actuator network while single actuator node paralyzes. For the failure of an ordinary actuator node, LANTR can rapidly repair the topology through relocating only one-hop neighbors of the failure node, meanwhile, keep the original topology structure as much as possible. Given the magnitude of cut vertex actuators playing on the connectivity, LANTR designs a novel method for each cut vertex to select out a specific guardian node with the minimum degree or minimum cumulative degree from its neighbors, which can reduce the repair influence on the original topology and effectively reduce the coverage loss rate. The performance of the proposed scheme is evaluated and compared with several existing representative topology repair schemes, and the results indicate that LANTR can more effectively and efficiently repair the topology of inter-actuator networks.

Zigbee Based Wireless Sensor and Actuator Network for Service Robot Intelligent Space

Wireless sensor and actuator network is the key technology of service robot intelligent space. This paper is concerned with design and implementation of a ZigBee based wireless sensor and actuator network (hereinafter referred to as ZWSAN), which has been applied in our service robot intelligent space successfully. Firstly, a simplified ZigBee stack applied to ZWSAN is proposed and the primitives of the stack are illustrated after a short overview of ZigBee protocols. Then the implementation of hardware module and software stack is introduced in detail as well as several representative devices integrated into ZWSAN, including environmental sensors for environmental perception, home devices controllers for device control, embedded speech recognition module for speech control, IMU module for abnormal behaviors detection and laser robot control for service robot navigation. An application example is described to demonstrate how the devices in ZWSAN to provide service cooperatively. Finally, we conclude this paper and discuss the future directions.

Dynamic Coverage with Wireless Sensor and Actor Networks in Underwater Environment

This paper studies the problem of dynamic coverage with wireless sensor and actor networks (WSANs) in underwater environment. Different from most existing works, the WSANs consist of two kinds of nodes, i.e., sensor nodes (SNs) which cannot move autonomously and actor nodes (ANs) which can move autonomously according to the performance requirement. The problem of how to coordinate two kinds of nodes to facilitate dynamic coverage in underwater environment is challenging due to their heterogeneous capabilities. To reduce redundancy of communication links and improve connectivity between ANs and SNs in underwater WSANs, a min-weighted rigid graph based topology optimization scheme is first developed, such that the underwater communication energy consumption can be saved. With the optimized topology, a dynamic coverage strategy is proposed to improve the coverage among SNs and ANs for underwater WSAN where underwater fluid motions are considered. Furthermore, it is proved that the network coverage area is connected by using the min-weighted rigid graph. Finally, simulation results are presented to show the effectiveness of the main results. © 2014 Chinese Association of Automation.

Enhancing real-time performance via controlled actor relocation in wireless sensor and actor networks

Actors'relocation is utilized during the network initialization to enhance real-time performance of wireless sensor and actor networks(WSANs)which is an important issue of WSANs.The actor deployment problem in WSANs is proved NP-Hard whether the amount of actors is redundant or not,but to the best of our knowledge,no effective distributed algorithms in previous research can solve the problem.Thus two actor deployment strategies which need not the boundary control compared with present deployment strategies are proposed to solve this problem approximately based on the Voronoi diagram.Through simulation experiment,the results show that our distributed strategies are more effective than the present deployment strategies in terms of real-time performance,convergence time and energy consumption.

基于多反应节点下WSANs路由协议研究

针对多个反应节点环境中现有无线传感器网络路由协议不能完全满足无线传感反应网络(WSANs)对能耗和实时性需求的问题,利用J-Sim对WSANs的仿真功能,设计并实现适应单反应节点选择模式的WSANs路由协议BHOER,给出仿真数据及性能分析,实验结果表明,BHOER较好地满足WSANs的应用需求。

WSANs中基于竞拍和iMesh的服务发现方法

针对无线传感器和执行器网络中服务发现问题,提出一种融合距离敏感的最新信息网格和竞拍协议的服务发现方法。首先,当传感器接收到事件信息时,使用i Mesh算法交叉查找附近的执行器,在垂直和水平方向发送搜索消息,找出有可能是最接近的执行器;然后,利用本地化竞拍聚合协议寻找出最接近的执行器对事件执行相应措施;最后,将所提方法与基本i Mesh和Quorum方法在两种场景下(连通的执行器网络和随机部署)进行对比,利用距离敏感服务发现效率和通信成本作为评估指标。仿真结果表明,找到最接近的执行器是可行的,相比于其他方法,获得了最高的发现率且通信成本较低。

SAS模式下WSANs路由协议的分析与研究

针对SAS模式下现有WSNs(Wireless Sensor Networks)路由协议不能很好地满足WSANs(Wireless Sensor and Actor Net-works)应用的需求的问题,利用J-Sim对WSANs的仿真功能,设计并实现了适应SAS模式的WSANs路由协议BHOER,同时给出了仿真数据及性能分析,实验结果表明BHOER很好地满足了WSANs的路由需求。

基于分布式估计及任务分配的WSANs协同机制

针对无线传感器/执行器网络中的传感器-执行器和执行器-执行器协同工作问题,分别提出了一种分布式的解决方案。根据传感器与执行器的部署情况,传感器-执行器协同工作可归结为一个多源信息估计及融合问题。基于这个特点,设计了一种能在传感器和执行器上并行运行的联邦滤波器。同时考虑到时间、能量、控制指标等要求,提出了一种基于事件驱动机制的执行器任务分配机制来协同执行器之间的工作。仿真表明所提算法能够满足控制系统的性能要求。

Active structures integrated with wireless sensor and actuator networks： a bio-inspired control framework

One of the main problems in controlling the shape of active structures （AS） is to determine the actuations that drive the structure from the current state to the target state. Model-based methods such as stochastic search require a known type of load and relatively long computational time, which limits the practical use of AS in civil engineering. Moreover, additive errors may be produced because of the discrepancy between analytic models and real structures. To overcome these limitations, this paper presents a compound system called WAS, which combines AS with a wireless sensor and actuator network （WSAN）. A bio-inspired control framework imitating the activity of the nervous systems of animals is proposed for WAS. A typical example is tested for verification. In the example, a triangular tensegrity prism that aims to maintain its original height is integrated with a WSAN that consists of a central controller, three actuators, and three sensors. The result demonstrates the feasibility of the proposed concept and control framework in cases of unknown loads that include different types, distributions, magnitudes, and directions. The proposed control framework can also act as a supplementary means to improve the efficiency and accuracy of control frameworks based on a common stochastic search.

Node coordination mechanism based on distributed estimation and control in wireless sensor and actuator networks

Wireless sensor and actuator networks （WSANs） have a wide range of applications. To perform effective sensing and acting tasks, multiple coordination mechanisms among the nodes are required. As attempt in this direction, this paper describes collaborative estimation and control algorithms design for WSANs. First, a sensor-actuator coordination model is proposed based on distributed Kalman filter in federated configuration. This method provides the capability of fault tolerance and multi-source information fusion. On this basis, an actuator-actuator coordination model based on even-driven task allocation is introduced. Actuators utilize fused sensory information to adjust their action that incur the minimum energy cost to the system subject to the constraints that user＇s preferences regarding the states of the system are approximately satisfied. Finally, according to system requirements, a distributed algorithm is proposed to solve the task allocation problem. Simulations demonstrate the effectiveness of our proposed methods.

WSANs中基于可靠性最大化的报文实时投递方案

无线传感反应器网络(WSANs)中现有的报文投递方案可靠性不足,不适用于数据率互不相同的网络场景.为此,提出一种基于可靠性最大化的报文实时投递方案.报文投递问题被分解为两个子问题:基于子周期的时隙分配问题和基于时隙的传输调度问题.第1个子问题被转化为一个线性整数规划问题,并给出一种具有多项式时间复杂度的求解方法.对于第2个子问题,文中证明是否存在最优可行调度取决于求解前一子问题时获得的时隙分配向量中的元素次序,然后给出一种可行时隙分配方案求解算法.仿真结果表明,本文算法可保证每个设备即使在不同的报告周期内也可实现基本相同的报文投递率,这一特性对于维持控制系统的稳定性具有重要作用.

WSN/WSAN中的时间同步算法研究

无线传感器网络实现了人类对现实世界的观测,由于网络中节点可以单独监测,因此在这样的网络中节点间需要时间同步,以确定事件发生的顺序。阐述了WSN时间同步的相关问题,并从同步报文传递方式的角度详细介绍了几种时间同步算法;从定性和定量两个方面对算法进行了比较。在此基础上,针对WSAN的新特点提出算法融合的设计思想。

基于WSAN的AGVS控制系统模型研究

给出了一种基于无线传感反应网络的自动导引搬运车系统的结构,研究了该系统的控制模型,提出了把无线传感器网络作为控制系统观测器的方法,在此模型基础上讨论了传感器节点模型和定位算法,最后制定了分布式动态路径规划策略。

WSAN中基于改进分布式竞拍的执行器任务分配算法

针对无线传感器执行器网络(WSAN)中的执行器任务分配问题,提出一种基于改进分布式竞拍的任务分配算法。该算法通过计算完成每个任务的效用以及执行器完成任务的代价,得出任务分配方案。算法改进了竞拍过程中响应树的构造方式,并在执行器效用值的计算过程中引入了匹配度的概念,以此来适应动态变化的网络环境。仿真结果表明,本方法均衡了网络能耗、减少了数据包的转发数量和任务完成时间。

基于QPSO的WSAN中执行器优化部署研究

为了提高WSAN的工作效率,在量子粒子群算法的基础上,提出一种WSAN中执行器节点的优化部署策略。该策略中多个粒子群在独立搜索解空间的同时,以一定的通信频率共享最优值。仿真结果表明,该部署策略可提高节点的实时覆盖率,并与最新的WSAN部署策略进行了对比。

WSAN中基于节点分区的能耗均衡路由协议

传感器节点能量消耗不均衡,是影响无线传感器/执行器网络寿命的关键问题之一。文章提出基于节点分区的能耗均衡路由协议(ERPNP),该协议在保证网络连通性的基础上,通过簇内传感器节点分区、传感器节点到执行器节点路由选择、执行器节点到sink节点路由选择等步骤,使传感器节点的发射功率尽可能的小,同时下一跳节点距离执行器节点越来越近,即选择较多节点较小发射功率的传输路径,避免选择较少节点较大发射功率的传输路径,利用较多节点分担传输能量,均衡节点能耗,提高网络寿命。仿真实验表明,相比于传统协议,ERPNP协议能够显著延长网络生存时间。

基于模拟退火的WSAN多设定值调度算法

针对无线传感器/执行器网络中多用户设定值对动态物理过程状态实时控制的问题,提出一种解决多设定值调度的算法。设计调度模型和动态物理过程的状态空间模型,在卡尔曼滤波最优估计前提下,运用模拟退火算法逐步计算最优控制,以得到全局最优控制。仿真结果表明,与基于二次规划的多设定值调度算法和跨层优化调度算法相比,该算法具有更快的收敛速度、更好的系统稳定性、更强的实时处理能力。

WSAN多反应节点多传感节点模型的数据传输算法

无线传感反应网络由传感节点和反应节点组成,传感节点将监测到的数据发送到反应节点时,通常采用单反应节点传输模型或多反应节点传输模型。针对最近为提高系统容错能力而提出的一种新的多反应节点多传感节点模型,提出了传感节点发送数据到反应节点的基于组播的新算法。实验证明这种算法可以有效地降低数据传输能耗,从而在提高网络容错能力的同时,改善系统的能量有效性。