【作者】 连承飞；

【导师】 张荣标；

【作者基本信息】 江苏大学 ， 控制理论与控制工程， 2008， 硕士

【摘要】 目前,温室环境测控系统通信方式普遍采用的是基于485总线或CAN总线的有线通信方式。而有线通信方式存在线缆错综复杂,安装维护难度大,成本高等缺点。利用无线传感器网络实现数据传输是解决温室环境测控系统通信问题的有效方法。因此,实现温室等设施农业低成本低功耗的无线传感网络测控系统是设施农业急需解决的前沿课题。针对当前温室测控系统信息传输技术存在的问题,根据温室环境具体结构特征提出变结构自组织无线传感网络体系物理结构和逻辑结构,并确定了系统通信频率、汇聚节点覆盖半径及传感器节点睡眠时间等组网关键技术参数,构建动态星型的温室测控系统无线传感器网络框架。综合分析现有的无线传感器网络硬件节点设计情况,根据温室测控系统特点进行低成本低功耗的硬件选择,完成主要包括无线通信模块、节点位置模块、显示模块和RS-232串口通信模块的硬件电路设计。利用高性能频谱分析仪GSP-830调试2.4G高频无线通信模块,确定了其匹配网络电路的相关参数,能够保证无线通信模块在各工作频段达到相应的频谱要求,实现无线节点的多频段可靠通信。由于低成本的无线通信模块物理层以及MAC层协议简单,自身并不具备复杂网络的通信能力,借鉴IEEE802.15.4协议,结合选定的动态星型无线传感器网络框架特点,在该通信模块固有帧结构的基础上进行帧扩展设计,扩充完善网络通信协议,研究了传感器节点、控制节点和汇聚节点的通信算法,解决移动汇聚节点在移动过程中与覆盖范围内传感节点、控制节点的连接问题,动态形成自组织星型网络。研究结果表明,通过汇聚节点的移动来动态组成二级子网的动态星型无线传感器网络通信方法,随着汇聚节点的移动以及一级子网内二级子网数量的增加,有效缩短了点对点之间的通信距离,网内传感器节点通信能耗急剧变小,并且当导轨长度增加时,系统内通信能耗增速较慢,具有很好的节能效果,延长了网络更换电池的周期。最后论文在总结全文工作的基础上,对进一步研究提出了建议和展望。本文研究内容得到了国家“863”高技术研究发展计划的资助,项目编号2006AA10Z258。更多还原

【Abstract】 Nowadays, cable communication based on 485 bus and CAN bus is adopted widely in measuring and controlling system for greenhouse. But the cable communication manner has several disadvantages such as complex line, difficult maintenance and high cost. It is an effective method for solving the communication problems of greenhouse measuring and controlling system to utilize wireless sensor network to realize data transmission. Hence, the realization of low-cost low-power greenhouse measuring and controlling system based on wireless sensor network is an important task which needs to be solved urgently.To solve the problems of information transmission technology for greenhouse measuring and controlling system, propose systematic physical and logical framework of changing structure ad-hoc wireless sensor network according to practical structural characters in greenhouse. At the same time ascertain key technological parameters of the network including systematical communication frequency, the covered radius of sink nodes and sleeping time of sensor nodes etc, establish a dynamic star frame of wireless sensor network. Synthetically analyzing existing hardware nodes of wireless sensor network, select low-cost low-power components and design hardware circuit composed of wireless communication module, position module, display module and RS-232 serial communication module. Through debugging 2.4G wireless communication module with high-performance spectrum analyzer GSP-830, matching networks circuit parameters are determined which achieves multi-frequency credible communication among nodes. The low-cost wireless communication module, whose protocol including physics layer and MAC layer is too simple, cannot organize complex network by itself. Therefore, it’s necessary to design extended frame in order to perfect network protocol through considering IEEE 802.15.4 and selected dynamic star wireless sensor network. Moreover, communication algorithm of the nodes including sensor nodes, control nodes and sink nodes is provided which settles the connection problem among nodes.Research results show that the communication method of dynamic star wireless sensor network which dynamic second-class sub-network is formed during sink nodes move reduces the point-to-point communication distance and saves energy effectively when the number of second-class sub-network in the same first-class increases. Besides the communication energy consumed in system increases less slowly when the length of the rail increases. Hence, the communication method prolongs the period of redeploying batteries in the network.This paper is supported by the national 863 high technology research and development program "Research on greenhouse measuring and controlling system of new-style changing structure ad-hoc wireless sensor networks(serial number: 2006AA10Z258)".更多还原