【摘要】：建筑受外力作用、機械設(shè)備運行都會產(chǎn)生振動信號。而這些振動信號中含有大量的結(jié)構(gòu)和設(shè)備運行狀態(tài)信息,通過分析這些振動信息可以很好的了解其運行狀態(tài),在其出現(xiàn)細微故障但不至于產(chǎn)生較大隱患前將故障診斷出來,可以避免故障隱患帶來的較大損失。因此振動信號的采集與分析十分必要。目前有線式振動信號采集與分析儀器已經(jīng)比較成熟和完善,但是對于無線傳輸?shù)恼駝有盘柌杉难芯窟�不夠成熟和完善,因此本文進行了基于WIFI的振動信號采集儀的研究。本文深入分析和研究了 LwIP協(xié)議棧的基本原理與實現(xiàn)方法,并根據(jù)振動采集儀儀上行發(fā)送的振動信號數(shù)據(jù)量大,下行發(fā)送的指令數(shù)據(jù)量小的特點對LwIP協(xié)議棧進行了改進。通過裁剪協(xié)議棧中不必要的功能,優(yōu)化協(xié)議棧阻塞窗口值的更新算法,采樣數(shù)據(jù)指針的傳遞方式,提高了振動信號數(shù)據(jù)的發(fā)送效率。硬件設(shè)計上,本文設(shè)計了一種多類型可編程傳感器接口電路,可編程設(shè)置信號接入類型,如單端電壓輸入、差分電壓輸入、ICP輸入、交直流耦合。能夠接入位移、ICP加速度和速度傳感器等多種類型的傳感器。采用24位高精度A/D,使采樣具有較高幅值相對精度。采樣頻率和通道增益可編程控制,為增益和采樣率控制提供了硬件保證。設(shè)計了 SDIO__WIFI模塊接口電路,使信號可實現(xiàn)WIFI無線傳輸。軟件設(shè)計上,移植了實時操作系統(tǒng)uC/OS-Ⅱ和改進了 LwIP協(xié)議棧。實現(xiàn)了基于wifi的振動數(shù)據(jù)上傳和配置命令接收。同時,設(shè)計了 ARM和計算機端數(shù)據(jù)采集的通訊協(xié)議,實現(xiàn)了電路參數(shù)的配置和采樣數(shù)據(jù)的有效傳輸。根據(jù)輸入信號的特征,改變采集通道的增益以及A/D的采樣頻率,提高了信號采集精度和傳輸效率。通過最終測試,本文設(shè)計的振動信號采集儀可以很好的實現(xiàn)各項功能。能夠通過指令切換不同的傳感器模式,能夠?qū)崿F(xiàn)0～40kHz頻率范圍內(nèi)的振動信號的采集,采樣幅值相對精度不大于0.2%,WIFI傳輸距離空曠環(huán)境中可達100m。同時系統(tǒng)在改進LwIP協(xié)議棧后的WIFI的傳輸速率最大可以達到4.5Mbps、丟包率不超過0.01%,明顯改善了振動數(shù)據(jù)量大時發(fā)送速率低的問題。
[Abstract]:The building is subjected to external force, mechanical equipment operation will produce vibration signal. These vibration signals contain a large amount of structure and equipment running state information. By analyzing these vibration information, we can understand the running state of the vibration signals, and diagnose the faults before there are minor faults but not big hidden dangers. Can avoid the fault hidden trouble brings about the big loss. So it is necessary to collect and analyze the vibration signal. At present, the wireline vibration signal acquisition and analysis instrument has been relatively mature and perfect, but the research of wireless transmission vibration signal acquisition is not mature and perfect. Therefore, the research of vibration signal acquisition instrument based on WIFI is carried out in this paper. In this paper, the basic principle and implementation method of LwIP protocol stack are deeply analyzed and studied, and the LwIP protocol stack is improved according to the characteristics of large amount of data of vibration signal sent up by vibration collector and small amount of instruction data sent down. By clipping unnecessary functions in the protocol stack, the algorithm of updating the blocking window value of the protocol stack is optimized, and the transfer mode of the sampling data pointer is obtained, which improves the transmission efficiency of the vibration signal data. In hardware design, a multi-type programmable sensor interface circuit is designed, which can be programmed to set the type of signal access, such as single-terminal voltage input, differential voltage input, ICP input, AC / DC coupling. Can access displacement, ICP acceleration and velocity sensors and other types of sensors. The 24 bit high precision A / D is used to make the sampling have higher amplitude relative precision. The programmable control of sampling frequency and channel gain provides hardware guarantee for gain and sampling rate control. The interface circuit of SDIO__WIFI module is designed to realize WIFI wireless transmission. In software design, the real-time operating system uC/OS- 鈪，

本文編號：2409406