【摘要】：糧食存儲是糧食安全的重要環(huán)節(jié),每年由于不當?shù)谋O(jiān)管導(dǎo)致糧食在存儲環(huán)節(jié)損耗不容小覷,因此做好科學儲糧顯得尤為重要。隨著通信、電子技術(shù)在糧倉現(xiàn)場中的應(yīng)用,數(shù)字化糧情測控系統(tǒng)大大提升了糧食存儲的管理質(zhì)量和效率。但目前主流的糧情測控系統(tǒng)仍然存在著功能簡單、系統(tǒng)的兼容性差、數(shù)據(jù)傳輸速率低以及抗干擾能力差等問題,而這些問題的關(guān)鍵在于無線網(wǎng)絡(luò)傳輸。針對這些問題,結(jié)合無線傳感器網(wǎng)絡(luò)技術(shù)、無線Mesh網(wǎng)絡(luò)技術(shù)、傳感器技術(shù)、智能控制技術(shù)、嵌入式應(yīng)用開發(fā)技術(shù)等,設(shè)計了一種基于無線Mesh網(wǎng)絡(luò)的糧情測控系統(tǒng),分為數(shù)據(jù)采集控制子系統(tǒng)、Mesh網(wǎng)絡(luò)傳輸子系統(tǒng)和主機子系統(tǒng)。該系統(tǒng)針對無線網(wǎng)絡(luò)傳輸?shù)年P(guān)鍵問題,結(jié)合糧倉現(xiàn)場的建筑特點和數(shù)據(jù)業(yè)務(wù)需求,采用了兩級無線網(wǎng)絡(luò)傳輸結(jié)構(gòu)。其中,一級無線網(wǎng)絡(luò)傳輸結(jié)構(gòu)為基于470MHz的Si4432模塊組建的單跳無線傳感器網(wǎng)絡(luò),用于各倉中傳感器節(jié)點向其所屬分機匯聚數(shù)據(jù);二級無線網(wǎng)絡(luò)傳輸結(jié)構(gòu)為主干網(wǎng)傳輸結(jié)構(gòu),采用無線Mesh網(wǎng)絡(luò)技術(shù)進行設(shè)計,以實現(xiàn)各分機糧情數(shù)據(jù)和視頻業(yè)務(wù)數(shù)據(jù)向主機子系統(tǒng)的高速率、穩(wěn)定傳輸。論文的主要工作概括如下:1、在數(shù)據(jù)采集子系統(tǒng)中,針對傳感器節(jié)點功耗高的問題,采用Si4432射頻模塊的睡眠機制,并對Rx-On時間參數(shù)進行優(yōu)化,實現(xiàn)分機對所轄傳感器節(jié)點能夠穩(wěn)定、快速的喚醒。針對多倉傳感器由于同頻干擾的問題無法實現(xiàn)同時向所屬分機進行數(shù)據(jù)上傳的問題,在研究和測試Si4432射頻模塊最小正交子信道帶寬的基礎(chǔ)上,設(shè)計了無線信道劃分機制,實現(xiàn)了多倉傳感器同時向所屬分機進行數(shù)據(jù)上傳,提升了現(xiàn)場整體的測控效率。針對分機軟件設(shè)計,采用了基于嵌入式Linux平臺的多線程機制,實現(xiàn)了對Si4432通信線程、網(wǎng)絡(luò)通信線程、無線Mesh網(wǎng)絡(luò)線程以及設(shè)備信息同步線程的高效管理。針對視頻監(jiān)控設(shè)備的設(shè)計,采用了 EPOLL機制,實現(xiàn)對實時采集子模塊、動態(tài)物體監(jiān)控報警子模塊以及通信子模塊的高效管理。2、在Mesh網(wǎng)絡(luò)傳輸子系統(tǒng)中,針對無線傳感器網(wǎng)絡(luò)數(shù)據(jù)匯聚速率低的問題,結(jié)合Mesh網(wǎng)絡(luò)傳輸技術(shù)和糧庫的特殊網(wǎng)絡(luò)拓撲,設(shè)計了一種基于多正交子信道分配的骨干網(wǎng)傳輸機制,并進行了基于NS2平臺的仿真。該機制能夠提升骨干網(wǎng)的穩(wěn)健性,并且仿真結(jié)果表明該機制能夠滿足視頻業(yè)務(wù)等現(xiàn)場數(shù)據(jù)傳輸?shù)膸捄蛯崟r性要求。3、針對主機子系統(tǒng)的設(shè)計,在嵌入式ARM+Linux平臺上搭載了本地服務(wù)器、web服務(wù)器、流媒體服務(wù)器以及數(shù)據(jù)庫,實現(xiàn)對環(huán)境檢測,視頻查看,報警圖片查看、報警信息的瀏覽以及智能化控制,能夠?qū)崿F(xiàn)與云服務(wù)器無縫對接。
[Abstract]:Grain storage is an important link of food security. Due to improper supervision and management, the loss of grain in storage is not to be underestimated, so it is particularly important to do a good job of scientific grain storage. With the application of communication and electronic technology in the field of grain storage, the management quality and efficiency of grain storage are greatly improved by the digital grain condition measurement and control system. However, there are still some problems such as simple function, poor system compatibility, low data transmission rate and poor anti-interference ability in the current mainstream grain condition measurement and control system. The key of these problems is wireless network transmission. Aiming at these problems, combining wireless sensor network technology, wireless Mesh network technology, sensor technology, intelligent control technology, embedded application development technology and so on, a grain condition measurement and control system based on wireless Mesh network is designed. It is divided into data acquisition and control subsystem, mesh network transmission subsystem and host subsystem. Aiming at the key problem of wireless network transmission, the system combines the building characteristics of granary and the demand of data service, and adopts the two-level wireless network transmission structure. Among them, the primary wireless network transmission structure is a single-hop wireless sensor network based on Si4432 module of 470MHz, which is used to aggregate data from sensor nodes in each warehouse to its extension, and the secondary wireless network transmission structure is a backbone network transmission structure. The wireless Mesh network technology is adopted to realize the high speed and stable transmission of the grain and video service data from each extension to the host subsystem. The main work of this paper is summarized as follows: in the data acquisition subsystem, aiming at the problem of high power consumption of sensor nodes, the sleep mechanism of Si4432 radio frequency module is adopted, and the Rx-On time parameters are optimized. The extension can wake up the sensor nodes stably and quickly. In view of the problem that multi-warehouse sensors can not upload data to their extension simultaneously due to the same frequency interference, a wireless channel partition mechanism is designed based on the research and test of the minimum orthogonal sub-channel bandwidth of Si4432 RF module. The multi-warehouse sensor can upload data to its extension at the same time, and improve the efficiency of field measurement and control. Aiming at the extension software design, the multithreading mechanism based on embedded Linux platform is adopted to manage the Si4432 communication thread, network communication thread, wireless Mesh network thread and device information synchronization thread efficiently. Aiming at the design of video surveillance equipment, EPOLL mechanism is adopted to realize the efficient management of real-time acquisition sub-module, dynamic object monitoring and alarm sub-module and communication sub-module. It is used in the Mesh network transmission subsystem. Aiming at the problem of low data convergence rate in wireless sensor networks, combining with Mesh network transmission technology and special network topology of grain depot, a backbone network transmission mechanism based on multi-orthogonal sub-channel allocation is designed, and the simulation based on NS2 platform is carried out. The mechanism can improve the robustness of the backbone network, and the simulation results show that the mechanism can meet the bandwidth and real-time requirements of video traffic and other field data transmission, aiming at the design of host subsystem. The local server, streaming media server and database are mounted on the embedded ARM Linux platform to realize environment detection, video viewing, alarm picture viewing, alarm information browsing and intelligent control. Can achieve seamless docking with cloud server.
【學位授予單位】：安徽大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN929.5;TP212.9;TP274

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