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挤压气体内部温度的精确测量对确定贮箱内推进剂剩余量和提高氧化剂和燃烧剂的混合比控制精度有重要意义.提出了一种基于热敏电阻的矢量测温方法,通过测量气瓶壁面温度推算气体内部真实温度,分析温度电阻非线性特性、温度—电压处理电路、A/D采样非线性等因素导致的温度测量误差,最终获得系统自身的温度采集误差,在此基础上分析了影响此误差的主要因素.最后分析了外界干扰引起的测量噪声对温度测量的影响,并采用小波降噪的方法对此进行降噪处理,使温度测量精度得到较大改善,并最终确定了内部气体温度的测量误差.
Accurate measurement of the internal temperature of extrusion gas is of great significance to determine the residual amount of propellant in the tank and to improve the control accuracy of the mixture ratio of oxidant and combustion agent.This paper presents a vector thermometric method based on thermistor, The temperature inside the gas is calculated by calculating the real temperature inside the gas, the temperature measurement error caused by the non-linearity of the temperature resistance, the temperature-voltage processing circuit and the A / D sampling nonlinearity are analyzed. Finally, the temperature acquisition error of the system is obtained, The main factor that affects this error is analyzed.Finally, the influence of measurement noise caused by external disturbance on temperature measurement is analyzed and the noise reduction processing is carried out by using the method of wavelet denoising to improve the temperature measurement accuracy greatly and finally determine the internal Measurement error of gas temperature.