Intelligent sensor techniques for fluctuating-temperature measurement (Self-diagnosis and adaptive compensation of sensor response)

研究结果总结如下：(1)本研究的目的是提高通用温度传感器（市售热敏电阻）在波动温度测量中的精度，扩大其适用性。首先，提出了反映板型和球形热敏电阻内部结构的传热模型，获得了温度波动时的理论频率响应。其次，提取了控制热敏电阻响应特性的参数，并证明了热敏电阻响应可以用一阶系统近似。最后，构建了热敏电阻的柔性响应补偿技术，由于热敏电阻周围流体的流速和物理性质对热时间常数的影响很大，因此该技术的开发非常困难。该技术采用了由Tagawa等人提出的双热电偶探针法——合理识别热参量和对响应延迟进行数字补偿。仪器学报，69,3370(1998)]，极大地提高了热敏电阻波动温度测量的精度。虽然改进的程度取决于被测流体类型和温度信号的信噪比，但目前的响应补偿技术是成功的。结果，补偿的热敏电阻的速度是未补偿的热敏电阻的五到五十倍。(2)提出了一种在频域估计温度传感器原位热时间常数值和补偿传感器输出响应延迟的新技术。所开发的方案是对先前由Tagawa等人报道的时域响应补偿方案的补充。乐器。69,3370(1998)]。该方案基于快速傅里叶变换（FFT）算法提供了快速、简单、灵活的数据处理，可用于各种物理和化学传感器的响应补偿。(3)对细丝热电偶和冷丝等细丝温度传感器的频率响应进行了理论分析，并通过严格处理感温部件与其相邻支架之间热传递的边界条件，导出了响应的严格解。得到的解是高度通用的，可以用一个方程表示温度传感器（如热电偶和冷丝）的频率响应，这些温度传感器在配置和响应特性上非常不同。实验验证了理论解的有效性，并在此基础上开发了一种适用于细丝温度传感器的响应补偿技术。例如，识别冷丝传感器的复杂响应特性及其响应补偿，这一直被认为是一个很大的挑战，已经成为可能。在这个过程中，不需要任何特殊的仪器来校准动态响应。目前的响应补偿技术可以使3.1μm钨冷丝的测量效果与0.63 μm铂冷丝的测量效果相当，被认为是市面上最快的温度传感器之一。少

The research results are summarized as follows:(1) The purpose of this study is to improve the accuracy of general-purpose temperature sensors (commercially available thermistors) in fluctuating temperature measurement and to extend their applicability. First, heat transfer models reflecting the internal structures of plate-type and spherical thermistors were proposed to obtain theoretical frequency response to temperature fluctuations. Secondly, parameters dominating the response characteristics of the thermistor were extracted, and it was shown that the thermistor response can be approximated by a first-order system. Finally, a flexible response compensation technique for the thermistor was constructed, the development of which has been very difficult because the thermal time constant varies greatly depending on the flow velocity and physical properties of the fluid surrounding the thermistor. The technique utilized a two-thermocouple probe method --rational identification of thermal … More time constants and digital compensation for response delay-proposed by Tagawa et al. [Rev. Sci. Instrum. 69, 3370(1998)], and greatly improved the accuracy of fluctuating temperature measurement by the thermistor. Although the level of the improvement depends on the fluid type measured and the signal-to-noise ratio of temperature signals, the present response compensation technique worked successfully. As a result, the compensated thermistor became five to fifty times as fast as the uncompensated (original) one.(2) A novel technique for estimating in situ thermal time-constant values of temperature sensors in the frequency domain and for compensating the sensor outputs for the response delays is proposed. The scheme developed is complementary to the time-domain response-compensation ones previously reported by Tagawa et al. [Rev. Sci. Instrum. 69, 3370(1998)]. The scheme provides fast, simple and flexible data professing based on the fast Fourier transform (FFT) algorithm, and is potentially applicabale to the response compensation of various physical and chemical sensors.(3) Theoretical analysis of frequency response of fine-wire temperature sensors, e.g. fine-wire thermocouple and cold-wire, was performed, and the strict solution of the response was derived by treating rigorously the boundary condition of heat transport between the temperature sensing part and its adjoining support. The solution obtained is highly universal and can represent frequency response of temperature sensors such as a thermocouple and a cold-wire--these are very different in configuration and response characteristics--with a single equation. The validity of the theoretical solution was examined experimentally, and a widely applicable response compensation technique for fine-wire temperature sensors was developed based on the theoretical results. For example, identification of the complex response characteristics of cold-wire sensors and their response compensation, which have been considered to be quite a challenge, have became possible. In this procedure, any special apparatus for calibrating the dynamic response is unnecessary. The present response compensation technique can make 3.1μm tungsten cold-wire measurement well comparable to 0.63 μm platinum cold-wire, which is regarded as one of the fasted temperature sensors commercially available. Less