A Thermal Drift Compensation Method for Precision Sensors Considering Historical Temperature State

Abstract

This article proposes a compensation method for precision sensors considering historical temperature states, which can significantly reduce the thermal drift of the sensors during rapid temperature change process. A typical differential eddy current sensor (ECS) measuring displacement is used as an example to explain the principle. By analyzing the source of thermal drift of the ECS, it is proved that time history of temperature change will also affect the output of the ECS. In this article, the temperature response characteristics of the sensing head of the ECS are obtained by the lumped capacitance method, and the output of the ECS is compensated by convolution operation. Experimental results show that the temperature coefficient of the ECS during a temperature change process is depressed from 34.62 to 1.64 nm/°C with this method, and it is also less than 1/4 of 7.70 nm/°C which is obtained with direct compensation using current temperature value. Furthermore, this method is expected to function efficiently for any precision sensor in complex and harsh temperature environments.