电容式位移传感器在气阀测试中的应用

APPLICATION OF CAPCITY-TYPE SHIFT TRANSDUCER AT GAS VALVE TESTING

电容式传感器具有结构简单、灵敏度高,动态特性好、对辐射和强烈振动等恶劣条件适应性强、价格便宜等一系列优点。但是,电容式传感器输出信号受干扰和温度影响较大、输出特性存在非线性等问题制约了电容式传感器的生产及应用。简述了自行研制的一种变距离电容位移传感器,以其在活塞式压缩机气阀运动规律测试中的应用为例,介绍了变距离电容位移传感器的设计原理和结构。同时采用单片机实现了输出信号的温度和非线性的软件补偿,并提出一种用正交多项式法来处理温度及非线性拟合曲线的数学方法,避免了采用最小二乘法解联立方程的繁琐过程,并可以任意增加逼近多项式的次数。在测量过程中实现了信号处理智能化。

Capacity-type transducer is characterized by its simple structure, high sensitivity, good dynamic characteristics, low price, good flexibility for bad radiation and strong vibration condition and so on. But the problems that output signals of capacity-type transducer are seriously affected by interference and temperature and nonlinear output characteristic restrain its production and application. A variable distance capacity-type shift transducer which had been developed by ourselves was described. Taking the movement law of piston compressor gas valve for example, the design philosophy and structure was introduced. At the same time, single-chip computer achieves software compensation of temperature and nonlinear for output signal. A mathematical method of orthogonal polynomial for processing temperature and nonlinear curve was put forward which avoids using the trivial procedure of the least square solution simultaneous equation and can add approximating multinomial arbitrarily.Intelligence of signal processing is achieved in this measurement.