基于粒子群算法的超声测温系统研究

发布时间：2018-08-14 14:40

【摘要】：能源问题已经成为世界各国的核心议题,应用新技术对以化工和冶金为代表的高耗能行业进行重大技术改造迫在眉睫,使用微波加热替代传统加热可以极大提高能源的利用率,达到节能减排的目的。而微波能在大规模工业应用中还存在着急待解决的技术瓶颈问题:难以真正实现大功率微波源的高效、安全和可靠的应用。上述问题的存在,归根于缺乏微波与时变媒质相互作用过程中的信息获取、处理和控制的有效手段,而媒质内部温度场的感知是决定控制有效性的关键。考虑到工业加工环境的特殊性,传统的测温方式难以实现测温需求,选用超声波测温技术突破了普通测温方式的局限。作为一种非接触式测温方法,超声波测温技术具有测量范围宽、对被测温度场干扰小、传感器布置简易等特点,并且能够实时地监测温度场的瞬态变化,具备能够在强腐蚀、强振动以及强电磁干扰等特殊环境下完成温度测量的优势,广泛应用于工业锅炉燃烧、海洋热液、仓库储粮以及等离子体室、核反应堆、汽轮进气、惰性气体、温度标准等领域的温度场测量。超声波测温技术是利用超声波在介质中的传播速度会随着介质温度而变化这一特点,通过测得介质中不同温度下的超声波飞渡时间后,可间接地求得介质温度。因此超声波飞渡时间的精确测量是影响超声测温精确度的关键因素,而针对超声波飞渡时间难确定的问题,本文提出了一种基于粒子群优化算法的超声波飞渡时间的测量方法。首先给予发射换能器一组双激励发射信号,然后用希尔伯特变换法对接收到的两次回波信号分别求取包络,选用混合指数模型对包络信号进行上升沿拟合,构建最小二乘法优化目标函数,最后使用粒子群优化算法进行参数估计,得到两次包络信号上升沿的分离点,从而获得超声波飞渡时间,继而求得飞渡路径上的温度值。本文分别从软硬件方面详细介绍了超声测温系统的设计与搭建,并在二维三路径的实物平台上对本文所提方法进行了实验验证,通过对实验数据和结果的统计和分析,证明本文所提方法结合所设计的超声测温系统能够实现较高的测温精度。
[Abstract]:The energy problem has become the core issue in the world. It is urgent to use new technology to transform the energy-consuming industry, which is represented by chemical industry and metallurgy. Microwave heating instead of traditional heating can greatly improve the efficiency of energy utilization. To achieve the purpose of energy saving and emission reduction. However, there are still some technical bottlenecks in large-scale industrial application: it is difficult to realize the high-efficient, safe and reliable application of high-power microwave source. The existence of these problems is rooted in the lack of effective means of information acquisition, processing and control in the process of interaction between microwave and time-varying medium, and the perception of temperature field in the medium is the key to the effectiveness of the control. Considering the particularity of the industrial processing environment, it is difficult to realize the requirement of temperature measurement by traditional temperature measurement method. The ultrasonic temperature measurement technology has broken through the limitation of ordinary temperature measurement method. As a non-contact temperature measurement method, ultrasonic temperature measurement technology has the characteristics of wide measurement range, small interference to the measured temperature field, simple sensor arrangement, and can monitor the transient change of temperature field in real time. The advantages of temperature measurement in special environment, such as strong vibration and strong electromagnetic interference, are widely used in industrial boiler combustion, marine hydrothermal, storage of grain in warehouse and plasma chamber, nuclear reactor, steam turbine intake, inert gas, Temperature field measurement in the field of temperature standards. Ultrasonic temperature measurement is based on the fact that the velocity of ultrasonic wave propagates in the medium varies with the temperature of the medium. The temperature of the medium can be obtained indirectly by measuring the flight time of the ultrasonic wave at different temperatures in the medium. Therefore, the accurate measurement of ultrasonic flyover time is the key factor that affects the accuracy of ultrasonic temperature measurement. Aiming at the difficulty of determining ultrasonic flyover time, a method of ultrasonic flyover time measurement based on particle swarm optimization (PSO) algorithm is proposed in this paper. First, a set of double excitation transmitting signals are given to the transmitter, then the envelope of the received two echo signals is obtained by Hilbert transform method, and the rising edge of the envelope signal is fitted by the mixed exponential model. The objective function is optimized by the least square method, and the parameters are estimated by using particle swarm optimization algorithm. The separation point of the rising edge of the twice envelope signal is obtained, and the ultrasonic flying time is obtained, and then the temperature value on the flight path is obtained. In this paper, the design and construction of ultrasonic temperature measurement system are introduced in detail from the aspects of hardware and software, and the proposed method is verified experimentally on the two-dimensional and three-path physical platform, and the statistics and analysis of experimental data and results are carried out. It is proved that the proposed method combined with the designed ultrasonic temperature measurement system can achieve high temperature measurement accuracy.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP18;TB559

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