【作者】 黄勇；

【导师】 孙晓松；

【作者基本信息】 重庆大学 ， 机械电子工程， 2004， 硕士

【摘要】 近年来,超声波测距技术得到了越来越广泛的应用,这是主要是由于超声波测距对被测介质不产生干扰,无污染、无泄漏、无腐蚀,同时具有安装维护简易,可靠性高等特点。但是,现有的普通超声波测距仪一般只能对测量的距离进行简单的数字化显示,不能把数据进行存储并进行分析。而且不能根据采样得来的数据进行控制或不能对参数进行改变,或者存在成本较高的缺点。针对这一现状,本论文较为系统的分析了超声波测距原理,并根据实际需要,设计了基于对采样的数据进行分析和远程监控的超声波测距系统,该系统可通过台式机进行动画显示和超声测距仪参数的远程设置。超声波液位远程监控系统能够在远方的控制中心实现远程数据采集、监视和控制。它降低了人工劳动强度,减少了人工监控所耗费的物力和财力,同时也提高了测量精度,避免了人工读数所引起的误差。本文以超声波液位远程监控系统为研究对象,主要研究和探讨了以下几个方面的内容:一、对用于检测的超声波特点进行了系统的阐述,并对超声波测距原理中的脉冲回波法进行了分析,同时对超声波二次反射进行了分析,指出了二次反射的意义;提出了超声波测距原理中的盲区、近限和远限的问题以及在系统为了避免这些近限和远限所采取的措施。二、对远程通信特点进行了深入的研究,并针对超声波液位远程监控系统的通信特点进行分析,采用了适合该系统的电话线路连接方式,并对它作了较为深入的研究和对它的软件设计作了详细的介绍。三、对于超声波频率的实现途径进行了深入的分析,并选定了适合系统的实现方案;对超声波传播时间的测量进行了分析,并对盲区的问题进行了讨论,结合实际情况给出了本系统的盲区;对影响超声波声速最大的温度进行了测量,根据本实验的具体情况,选用了适合本系统的温度传感器芯片;对下位机的远程通信进行了详细的描述,分析并给出了RS232电平与TTL电平的转换电路,并结合本系统将超声波传播时间和环境温度传送到上位机中;四、上位机将接收到数据进行计算,根据计算地结果进行简单地动画显示,并将接收到的数据进行存储,以便进行分析、误差校正等。最后本文还给出了实验结果和实验数据,并对超声波测距的误差作了较为深入的研究,对误差的产生作了较为详细的介绍并提出一些避免误差的措施。更多还原

【Abstract】 In recent years, the technology of ultrasonic measuring distance is more and more widely applied, this is the reason that the ultrasonic measuring distance does not disturb the measuring object, and no polution, no divulge, no corrosion, and at the same time can be simply fixed and asserted. But the forthcoming normal apparatus of ultrasonic measuring distance only can simply digitally display measuring distance does not preserve and analyse the data. Furthermore, according to the data it can not control and change the parameters, or it’s cost price is more high. Aim to the condition, this paper scientifically analyses the principal of the ultrasonic measuring distance, and according to actual requirement, devises ultrasonic measuring distance system which is aimed for analysing the obtained data and remote controlling and supervising. This system can activitily display and remotely transform the parameter of the apparatus of ultrasonic measuring distance through the computer. The ultrasonic remote monitoring and controling system for liquid level can realize the remote data’s collection, supervising and controling. It lowers the people labor strength, and reduces the waste of the material and the financial power which is given rise to by artificial supervision and control, at the same time, increases the measuring accuracy, and avoids the deflection which is caused by the artificial reading data.This paper which makes ultrasonic remote supervising and controling system for liquid level as research object , mainly studies and discusses several aspects as following:Firstly, it not only systematically describes the feature of the ultrasonic wave which is used to check, and analyse the reverted pulse wave method of the principle of ultrasonic measuring distance, but also analyse the second reflexion of ultrasonic, and points out the second reflextion meaning; explouds the problem of blind zone, the last limitation and the outermost limitation of the principal of ultrasonic measuring distance and the solution of the last and outermost limitation.Secondly, it thoroughly researchs the characteristics of the remote communication, aiming to the characteristics of ultrasonic remote supervising and controlling system of liquid level, we adopts the telephone line connection mode which adapts the system and researchs the mode thoroughly, and detailedly introduce the software design;Thirdly, it thoroughly analyses the method of realizing the ultrasonic frequency, <WP=6>and picks out the method that is fit for the system. It analyses the mode of measuring ultrasonic spreading time, discusses the problem of blink zone, and in accordance with the actual condition confirms the system’s blink zone. It measurs the surroundings temperature which mostly affect the ultrasonic wave speed, and in accordance with the actual condition adopts the temperature sensor chip which adapts the system. It describes in particular the MCU’s remote communication, analyses and offer the transforming circuit of RS232 voltage and TTL voltage, and transmits the ultrasonic transmission time and conditional temperature to the computer.Fouthly, the computer calculates the acknologied data,and according to calculated result,simply activitily displays,and conserves the data in order to analyse and adjust the deflection etc..At last, the paper thoroughly researchs the deflection of the ultrasonic wave measuring, and detailedly introduces the cause of the deflection, at the same time,, bings up some measurement to avoid the deflection. Additionally, the paper provide the experimental result and experimental data.更多还原