The Researches Of High-precision Inductance Sensor

Inductive displacement sensor is the sensor that built on the basis of electromagnetic induction, using changes of the coil self-inductance or mutual inductance to measure the displacement. The inductive displacement sensor system consists of data acquisition circuit and the inductance probe. inductance probe perceives small displacement and output a voltage that has a certain amount of relationship with the displacement; data acquisition board is charged with connecting sensor probe and the host computer's task, on the one hand it provides excitation signal for the sensor probe, then demodulates the output signal of the sensor probe and collects data, on the other hand it communicates with the host computer.This article requires the development of a high-precision inductive displacement sensor system, on the one hand, designs and improvements the data acquisition circuit board, improves temperature drift, stability, etc.; on the other hand, the electromagnetic field of the inductance coil within sensor probe is calculated and analyzed, to provide theoretical guidance for the design of inductor coil, on this basis, then designs an excellent inductance probe.First of all, in this article I gave a brief introduction of what the inductive sensor works on, then according to the characteristics of inductive sensors, I designed the data acquisition circuit and the mechanical probe of the inductive sensor from the overall.Secondly, in this article I focused on the electromagnetic field distribution of the coil inside the inductive probe, and the magnetic field distribution on the solenoid coil, inductance and sensitivity was analyzed; detailedly calculated the affects of the coil structure parameters to the electromagnetic field, and provided theoretical guidance for the design of the inductor coil probe; and the electromagnetic field of the actual designed differential solenoid coil of this subject was calculated.Once again, in order to develop a high-precision inductive sensor system, I designed matching inductive probe, analysed its mechanical structure, and calculated the mechanical motion error; and analysed the frequency of the vibration modal using mechanical simulation software.Finally, in this article I did experiments with two inductance probe who's coil structure parameters were different and analysed the results. Then we compared the non-linearity, voltage sensitivity and resolution. When the coil radius was decreased, the sensor non-linearity increased from 5.4% to 1.1%; when core length was shortened, the voltage sensitivity increased from 16mV/μm to 22mV/μm. The experimental results verified the correctness of the theory presented earlier.