Guo Yi-Xin, Lai Cong, Shao Zhi-Biao, Xu Kai-Liang, Li Ting
School of Electronic and Information Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an, Shaanxi 710049, China.
School of Automation and Information Engineering, Xi'an University of Technology, No. 5 South Jinhua Road, Xi'an, Shaanxi 710048, China.
Sensors (Basel). 2019 May 13;19(9):2210. doi: 10.3390/s19092210.
The inductive proximity sensor (IPS) is applicable to displacement measurements in the aviation field due to its non-mechanical contact, safety, and durability. IPS can increase reliability of position detection and decrease maintenance cost of the system effectively in aircraft applications. Nevertheless, the specialty in the aviation field proposes many restrictions and requirements on the application of IPS, including the temperature drift effect of the resistance component of the IPS sensing coil. Moreover, reliability requirements of aircrafts restrict the use of computational-intensive algorithms and avoid the use of process control components. Furthermore, the environment of airborne electronic equipment restricts measurements driven by large current and proposes strict requirements on emission tests of radio frequency (RF) energy. For these reasons, a differential structured IPS measurement method is proposed in this paper. This measurement method inherits the numerical separation of the resistance and inductance components of the IPS sensing coil to improve the temperature adaptation of the IPS. The computational complexity is decreased by combining the dimension-reduced look-up table method to prevent the use of process control components. The proposed differential structured IPS is equipped with a differential structure of distant and nearby sensing coils to increase the detection accuracy. The small electric current pulse excitation decreases the RF energy emission. Verification results demonstrate that the differential structured IPS realizes the numerical decoupling calculation of the vector impedance of the sensing coil by using 61 look-up table units. The measuring sensitivity increased from 135.5 least significant bits (LSB)/0.10 mm of a single-sensing-coil structured IPS to 1201.4 LSB/0.10 mm, and the linear approximation distance error decreased from 99.376 μm to -3.240 μm. The proposed differential structured IPS method has evident comparative advantages compared with similar measuring techniques.
电感式接近传感器（IPS）因其非机械接触、安全性和耐用性，适用于航空领域的位移测量。在飞机应用中，IPS可以有效提高位置检测的可靠性并降低系统维护成本。然而，航空领域的特殊性对IPS的应用提出了许多限制和要求，包括IPS传感线圈电阻元件的温度漂移效应。此外，飞机的可靠性要求限制了计算密集型算法的使用，并避免使用过程控制组件。此外，机载电子设备的环境限制了大电流驱动的测量，并对射频（RF）能量的发射测试提出了严格要求。基于这些原因，本文提出了一种差分结构的IPS测量方法。这种测量方法继承了IPS传感线圈电阻和电感分量的数值分离，以提高IPS的温度适应性。通过结合降维查找表方法降低计算复杂度，以避免使用过程控制组件。所提出的差分结构IPS配备了远近传感线圈的差分结构，以提高检测精度。小电流脉冲激励降低了RF能量发射。验证结果表明，差分结构IPS通过使用61个查找表单元实现了传感线圈矢量阻抗的数值解耦计算。测量灵敏度从单传感线圈结构IPS的135.5最低有效位（LSB）/0.10 mm提高到1201.4 LSB/0.10 mm，线性近似距离误差从99.376 μm降低到 -3.240 μm。与类似测量技术相比，所提出的差分结构IPS方法具有明显的比较优势。
