【作者】 路勇；

【导师】 权龙；

【作者基本信息】 太原理工大学 ， 机械电子工程， 2003， 硕士

【摘要】 超声波测距属于非接触检测的范畴，它在许多场合有接触测量不可比拟的优越性，同时与激光、红外、无线电等其它非接触性检测相比，超声检测在一定距离范围内不受光线影响、结构简单、成本低等特点。超声测距是一种比较新的检测方法，本课题就是围绕超声测距而研究的。文中对超声波在空气中、液压油中的衰减情况进行了分析，并对在空气中、液压缸中的影响测量精度的几个因素进行了分析。在空气和液压缸中影响测距精度的主要因素包括：超声波的频率、环境温度、超声换能器本身的系统误差(即探头固定误差)、硬件时间延迟、工作现场的电噪声和声噪声、市电的过压、介压噪声以及市电的尖峰和浪涌噪声，在本系统中采取了以下几种误差的补偿方案： ·对于超声波的频率对测量精度的影响，只能根据测距的距离选择合适的超声频率。在论文第四章对超声波在液压缸中衰减的分析中提出了选择合适超声频率的一种方法。 ·由于温度对超声速度有较大的影响，因而，温度的变化是影响超声测距精度的一大因素。本论文第三章中提出了两种温度补偿方案。通过温度的补偿可以较好的解决这个问题。 ·对探头本身的系统误差提出了修正方案。 ·对硬件的时间延迟也提出了解决的方法。一太原理工大学硕士论文 。对工作现场的电噪声可以通过金属外壳屏蔽和设计正确的接地的方法解决，在本文第五章中给出了接地的设计。对于声噪声，我们采用算术平均值来代替其真值的方法来提高回波的信噪比，从而对声噪声进行抑制。 。对于市电的介压、过压噪声，我们采用交流稳压器来去除。对于市电的尖峰和浪涌噪声，由于其属于高频成份，在本文第五章，我们设计了低通滤波器来滤波，消除其影响。 。论文在第四章中给出了在测量液压缸位移时的三种安装方案，并分析了其优劣性。给出一种新的计时方法。同时我们还讨论了利用超声测量钢坯磨床中砂轮直径的可能性。 在本文中，还给出了完整的电路设计方案，包括:发射接收电路、温度测量电路、显示电路、稳压电源电路、A/D转换电路等。并对部分电路在Protel 99 se下进行了仿真。更多还原

【Abstract】 Ultrasonic distance measurement belongs to the category of uncontact measurement.In the condition it has advantage which contact measure doesn’t has contrasting with uncontact measurement. Ultrasonic measure is not influenced by rays of light in the range ,and has simple struture,and cost cheaply cotrasting to other uncontract measurement such as laser measurement, rared ray easurement ,radio measurement. Ultrasonic distance measurement is the new distance measurement. This thesis studies the ultrasonic distance measurement,and reasearchs ultrasonic attenuation in the atmosphere and hydraulic oil,analyses the factors which inflence measurement precision. The factors include ultrasonic wave frequence ,condition temperature, ultrasonic converter instrinisic system error, hareware extended time, electricity noise and sonic noise in the spot,city power defmcient pressure and exceeded pressure,city power peak and pour. We adopt the following compensation schemes of error in the system.About ultrasonic wave frequence’s effect to measurement precision ,we can choose appropriate frequence according to the measured distance. The third chapter in the paper presents a method that we can select suitable ultrasonic frequence in the analysis of the ultrasonic attenuation.Owing to temperature having great effect ,the variation of temperature is a important factor that affects the measurementprecision. The third chart in the paper presents two compensation methods. We can satisfactorily solve the question.A method is presented in order to compensate ultrasonic converter instrinisic system error.Hareware extended time is compensated .Electricity noise in the spot can be solved by metal cover and right ground connection. The ground connection method is given in the fourth chart. Sonic noise can be solved through using arithmetic mean in place of the real numerical value to increase signal and noise ratio.We use alternating voltage regulator to remove city powe defincient pressure and exceeded pressure. Owing to high frequence ,city power peak and pou can be removed by low band-pass filter that we design in the fourth chart.We give three installing schemes in the measuring hydraulic cylinder in the fourth chart and analyse thire merits and shortcomings.We discuss the possibility of measuring grinding wheel diameter by ultrasonic waveWe give the full electric circuit schemes,including emitting and receiving circuit,measuring temperature circuit,displaying circuit,regulated power supply, A/D converter circuit and so on . We emulate some of the circuit in the Protel 99 se.更多还原