基于非线性拟合的电容传感器测量  

Measurement of capacitance sensor based on nonlinear fitting

作　　者：秦娟[1] 王将宇 李琨[1] 姜道连[1] 吕联荣[1] QIN Juan;WANG Jiangyu;LI Kun;JIANG Daolian;L Lianrong(School of Integrated Circuit Science and Engineering,Tianjin University of Technology,Tianjin 300384,China)

机构地区：[1]天津理工大学集成电路科学与工程学院,天津300384

出　　处：《实验室科学》2022年第1期51-54,57,共5页Laboratory Science

基　　金：2019年教育部产学合作协同育人项目(项目编号:201902094003);天津理工大学重点教学改革项目(项目编号:ZD19-09)。

摘　　要：针对电容传感器的非线性严重影响工程中的测量,进行非线性校正。采用拉格朗日插值算法,对电容值进行拟合,对以往的单点校准改进为分段三点校准,改善了测量精度。设计的方案采用STM32为微控制器,以两片平行板电容器作为纸张厚度信息采集设备,使用CD4046将采集的电容值转换为不同频率的方波信号,使用拉格朗日插值算法得到纸张的数目和不同频率方波信号的非线性关系。实验证明了拉格朗日插值算法在非线性的电容测量中的合理性和有效性。In view of the fact that the nonlinearity of capacitance sensor seriously affects the measurement in engineering,nonlinear correction is carried out.In this paper,the nonlinear fitting algorithm,Lagrange interpolation,is adopted to fit the capacitance value.It improves the measurement accuracy that the previous single-point calibration is improved to three-point subsection calibration.The design selects STM32 as microcontroller,two parallel plate capacitors as paper thickness information acquisition equipment,and CD4046 to convert the collected capacitance values into square waves signals of different frequencies.In this scheme,Lagrange interpolation algorithm is used to get the nonlinear relationship between the number of paper and square wave signals of different frequencies.Experiments show that Lagrange interpolation algorithm is reasonable and effective in nonlinear capacitance measurement.

关 键 词：非线性拟合 电容式位移传感器 三次拉格朗日插值 

分 类 号：TP212.9[自动化与计算机技术—检测技术与自动化装置]