一种适用于无线传感器网络节点设计的低功耗技术

无线传感器网络集成了传感器、嵌入式计算和通信技术,具有广阔的应用前景。由于传感节点的硬件资源有限,如何采取有效措施降低网络的能耗以延长其工作时间是一个关键的问题。介绍无线传感器网络节点的硬件构成及协议构成,从节点软硬件设计等方面介绍无线传感器网络节点相关的低功耗设计方法。     

基于单片机的无线传感器网络的通信节点设计

针对无线传感器网络中的远距离透明数据双向传输及带地址透明数据双向传输的要求,构建了基于c8051f020单片机的无线传感器网络通信节点。并详细论述无线接收模块及c8051f020的配置以及通信程序的设计方法。实验结果表明:相对于传统的无线传感器网络的通信节点系统的可靠通信距离明显增大,并且能够稳定、准确地对接收到的信息进行处理、发送,鲁棒性很高。     

基于CC2530的无线传感器网络节点设计

在简要介绍无线传感器网络和ZigBee技术的基础上,设计了以CC2530芯片为核心的星状结构的ZigBee无线传感器网络,包括协调器和终端设备。着重介绍了终端设备的供电模块设计以及协调器设备通过USB接口与计算机进行通信的解决方案。     

基于ZigBee技术的数据采集系统的设计

作为一种短距离通信技术,ZigBee以其低成本和低功耗成为无线传感器网络的一种理想数据传输方法。基于无线传感器网络的数据采集系统在工农业中有广泛的用途。基于ZigBee协议,设计并实现了无线传感器网络中的终端节点、数据采集节点和系统的监控软件,同时采用ZigBee协议在网络路由的基础上实现了传感器网络的组网和传输。为了保证数据参数的安全性,在无线传感器网络中采用LBlock算法实现受信任的安全协议。实验表明,该数据采集系统能够实时采集和监控多种信息数据。     

无线传感器网络安全的分析研究

分析无线传感器网络的特点和面临的安全威胁,在此基础上提出无线传感器网络安全的解决方案,有效的解决了无线传感器网络中通信的机密性、可靠性、完整性及时效性等安全需求,并指出无线传感器网络安全研究的发展方向。     

基于DSC-MIMO的无线传感器网络通信策略研究

由于无线传感器网络节点能量补充受到限制,降低传感器节点功耗成为提高能效的重点。在现有硬件条件下,主要节能方法为改变通信方式和减少数据传输量。目前,无线传感器网络通信策略一般采用GCMIMO。基于国内外研究现状,采用虚拟多入多出技术和分布式信源编码对通信策略进行改进,减少了数据长度,降低了无线传感器网络能效。设计了改进的DSC-MIMO分配算法,并利用Matlab软件进行能效仿真。研究表明:与GCMIMO和CIMO相比,DSC-MIMO通信策略能量效率最高,节能效果明显。     

一种无线烟雾传感器节点的设计与实现

无线传感器网络是当前信息领域中研究的热点之一,可用于特殊环境实现信号的采集、处理和发送;介绍无线烟雾传感器节点的设计与实现,以CC2430芯片为核心,利用烟雾传感器设计硬件电路,并通过无线收发模块与网络协调器和上位机通信达到实时监控;讨论和提出烟雾传感器节点的低功耗设计并描述系统的软件架构及实现方法。系统具有较高的实用性和可靠性,成本低,功耗低,具有良好的应用前景。     

基于波导技术的无线地下传感网通信系统研究与实现

针对传统地下无线磁感应通信系统信道路径损耗较大,无法满足无线地下传感器网络较远距离的实际通信需求的问题,建立了基于磁感应波导技术的磁感应通信系统模型,分析了中继波导线圈偏离理想位置时所引入的额外路径损耗对整个磁感应通信系统信道性能的影响,设计了地下无线磁感应通信系统,搭建了实验测试平台,实验结果表明,该系统引入中继波导线圈能够有效解决信道路径损耗较大的问题,有效延长无线通信距离,为无线地下传感器网络的应用提供重要参考。     

第四十五讲：基于工业无线技术的智慧路灯照明控制系统设计

考虑电力线载波和ZigBee通信方式在路灯控制系统可靠性和实时性方面的不足,本文提出了一种面向路灯控制的长链式工业无线传感器网络系统。该系统采用时间同步方式解决无线传感器网络中隐藏终端的问题,同时通过可变半径动态路由的方法来适应外界环境对无线传感器网络通信质量和通信距离的影响,提高了网络的可靠性。在此基础上,本文进行了路灯节点控制器的硬件设计和软件设计。在实际道路上的测试结果表明,该系统的可靠性和实时性较现有的电力线载波和ZigBee通信方式的控制系统有明显提高。     

分布式网络传感器综述及其在无线局域网中应用的问题探讨

随着通信技术、嵌入式计算技术和传感器技术的飞速发展和日益成熟,具有感知能力、计算能力和通信能力的微型传感器应运而生。由这些微型传感器构成的分布式无线传感器网络(Distributed Sensor Network,DSN)成为近年来一个重要的研究领域。文章介绍分布式网络传感器、无线局域网的发展历程,并分析其面临解决的一系列问题。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.     

OPTIMIZATION METHOD ON IMPELLER MERIDIONAL CONTOUR AND 3D BLADE

An optimization method for 3D blade and meridional contour of centrifugal or mixed-flow impeller based on the 3D viscous computational fluid dynamics (CFD) analysis is proposed. The blade is indirectly parameterized using the angular momentum and calculated by inverse design method. The design variables are separated into two categories: the meridional contour design variables and the blade design variables. Firstly, only the blade is optimized using genetic algorithm with the meridional contour remained constant. The artificial neural network (ANN) techniques with the training sample data schemed according to design of experiment theory are adopted to construct the response relation between the blade design variables and the impeller performance. Then, based on the ANN approximated relation between the meridional contour design variables and impeller performance, the meridional contour is optimized. Fewer design variables and less calculation effort is required in this method that may be widely used in the optimization of three-dimension impellers. An optimized impeller in a mixed-flow pump, where the head and the efficiency are enhanced by 12.9% and 4.5% respectively, confirms the validity of this newly proposed method.     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...