Accuracy improvement method of eddy current sensor

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Accuracy improvement method of
eddy current sensor
Qiaoyun Liu1,2, Enming Miao1,2#, Xin Wang1,2, Xianrui Ji1,2
1School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei Anhui,230009,China 2State Key Laboratory for Manufacturing Systems Engineering(Xi’an Jiaotong University), Shanxi,710049,China #Corresponding Author :, TEL: +86-14705511579

KEYWORDS:Eddy Current Sensor; Error Correction; Least Squares

Eddy current sensor is widely used in industry,because of its non-contact measurement, and strong anti-interference, etc,. However, its accuracy is difficult to reach the micron-level. This paper uses the accuracy analysis theory and the software error correcting technology to calibrate measurements. Besides, it gives an effective principle, which uses “minimum interval” and “maximum ranges segment” to determine the optimum operating ranges of eddy current sensor, to improve the sensor’s measurement accuracy. This method is used in commercial eddy current sensor, resulting from the improvement of precision.


Home and abroad, researchers in enhancing the sensor
precision theoretical and technical aspects do a large

Eddy current sensor uses eddy current principle

number of studies [2-8],such as associated with

[1], through measuring the relative position of metal

optimal sensor parameter method [3],the differential

caused by different sensor coil inductance,impedance

form of sensor method [4],Using thermal devices or

changes,to achieve displacement measurement.With

temperature characteristics of electronic components,



for the temperature compensation method [5],look-up

ability,high accuracy, good dynamic response,eddy

table compensation method [6],and other methods to

current sensor is widely used in the production line of




"minimum interval" and "maximum ranges segment,"


the principles of interval selection section, selects the

measurements. However, he temperature changing of

eddy current sensor to meet the accuracy requirements

eddy current probe,current volatility and complexity

of the best working range of methods to improve

of the electromagnetic field, leading to sensor

measurement accuracy. This approach,with high

measurement accuracy more difficult to achieve

stability, reliability, good practical significance and

micron level.The current commercial eddy current

practical engineering value, is a useful complement to

sensor accuracy is usually 10 m,to reach 4m

sensor measurement theory.










accuracy of the above,the cost significantly increases.






2. Test Device

eddy current sensor (0.80 ~ 2.80 mm) is divided into
80 equally spaced points, preheat half an hour after

In this article,we use OD-900803-03-04-20-00

startup. Measurement process: rotating micro platform

models of eddy current sensor, production index as

1, every 25 m, read out the the voltage values of

follows: range for 0.8-2.80mm , standard sensitivity of

eddy current 3 and the displacement values of

2V/mm, resolution of 0.5m, measurement accuracy

inductance displacement sensor 4, and record data.

of 10m, work voltage of 24V. Calibration of

Inductive sensor 3 outputs displacement value through

measuring instruments is the use of sub-micron

display 7,eddy current transducer 3 processes feeling

Inductance Sensor (TESA ERONIC TT 80).Choose

of displacement after the front-end device 5 (voltage



of front-end device 5 is provided by the voltage

frequency 500Hz; use steel as the measurement object,

converter 6), it is converted into the corresponding

and two instruments measure...
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