JPH0792377B2 - Thickness measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a continuous thickness measuring device utilizing, for example, ultrasonic waves or electromagnetic induction.

[Prior art]

As a device for measuring the thickness of an object to be measured, a device using various methods such as a method using ultrasonic waves, electromagnetic induction, or light, or a deviation measuring method using a mechanical contact means has been developed.

[Problems to be solved by the invention]

By the way, in the above-described measuring apparatus, a measurement error may occur due to a change in the relative positional relationship between the object to be measured and the sensor unit during measurement, or a noise signal generated from an electrical signal or the object to be measured itself. Therefore, in the inspection of the product, there is a problem that a normal product is determined to be a defective product and the reproducibility is deteriorated, so that the reliability of the entire measured value is also decreased. The present invention has been made in view of such circumstances, and when a large change in the measured value is detected during measurement, it is determined whether the measurement value is normal or abnormal based on the moving average value of the measured values. An object of the present invention is to provide a thickness measuring device that eliminates a measurement error.

[Means for solving problems]

A thickness measuring device according to the present invention calculates an average value of a plurality of measured values before a previous measured value in a thickness measuring device that relatively moves an object to be measured and measures its thickness in time series. A moving average calculation unit, a deviation amount calculation unit that obtains the difference between the latest measured value and the average value, and if the calculation result of the deviation amount calculation unit is greater than or equal to a predetermined value, the latest measured value is set to the previous one. And an abnormal value replacing unit that replaces and outputs the measured value of.

[Action]

When the latest measured value is measured, the moving average calculation unit calculates an average value of a plurality of measured values before the previous measured value, and the deviation amount calculation unit calculates the difference between this average value and the latest measured value. To calculate.

If the difference is less than the predetermined value, the abnormal value replacement unit outputs the latest measured value as it is, and if the difference is the predetermined value, the latest measured value is replaced with the previous measured value and output.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the drawings illustrating the embodiments. FIG. 1 is a block diagram showing a configuration of a thickness measuring device according to the present invention, in which a sensor section 1 using an ultrasonic oscillator is arranged so as to face a plate surface of a measured plate 6 and The plate thickness is scanned by conveying the plate in the arrow direction.

The sensor unit 1 is connected to the detection unit 2, which detects the plate thickness at regular time intervals and sends the measured value to the moving average calculation unit 3. The moving average calculation unit 3 calculates the moving average value M _N by totaling the measured values immediately before the sent measured value to the measured values m times before, and the average value is the deviation amount calculation unit 4
Sent to. The deviation amount calculation unit 4 is connected to the abnormal value replacement unit 5, and the difference between the latest measured value and the average value is calculated by these, and the measured value is determined and determined according to the magnitude relationship between the value and the predetermined value. .

FIG. 2 is a flow chart showing the control contents. First, when the measurement is started, the measurement value D _N is detected by the sensor unit 1 (step). Here, N represents the number of the detection point, and when the measured value D _N with N−m> 0 (m; the number of detection points for calculating the moving average value M _N ) is detected, D _N−1 An average value of the measured values up to D _Nm , that is, from the _immediately preceding measured value to the m-th previous measured value, that is, a moving average value M _N is calculated (step).

Next, D _N −M _N is calculated, and the absolute value of this is compared with the preset comparison reference value α (step). If the absolute value of D _N −M _N is smaller than α, that is, the current detection If the difference between the latest measured value D _N and the moving average value M _N is less than the comparison reference value α, then D _N is taken as the latest measured value (step), and conversely D _N
If the absolute value of -M _N is equal to or greater than α, the immediately preceding measured value D _N-1 is output as the latest measured value (step).

Similarly, every time the measured value D _N is read, the moving average value M _N is compared and the measured value is determined and output until the processing is completed in the same manner.

Note that the measurement value used for calculating the moving average value of the step returns from step to step, and the original measurement value is used instead of the value replaced by the step.

FIG. 3 is a graph for explaining the movement of the measured value obtained as described above, where the vertical axis represents the measured value and the horizontal axis represents the time. The measured value ● is a value determined by comparison with the moving average value ○, and when an abnormal value of the measured value is detected, the measured value immediately before is set as the corrected measured value ◎.

In this embodiment, the sensor section is of ultrasonic type, but instead of this, it may be of another method such as an electromagnetic induction type, and the object to be measured may be a shape other than a plate. Needless to say.

Further, in the present embodiment, if an abnormal value is detected continuously after the abnormal value is detected, it is replaced with the immediately preceding measured value in the abnormal value processing detected later, that is, the abnormal value detected earlier. However, this may be replaced with the correction value that has been replaced by the abnormal value process and output.

〔effect〕

In the thickness measuring device according to the present invention, the measured value detected by the sensor unit is compared with the moving average value up to that point, and if the difference is less than the comparison reference value, the measured value is output as it is. The fluctuation tendency is accurately measured,
If the difference is greater than or equal to the comparison reference value, it is processed as an abnormal value and the previous measured value is output as a new measured value. Therefore, a sudden fluctuation value caused by fluctuations in measurement conditions or abnormalities in the electrical signal system, etc. That is, since the abnormal value does not become the actual measured value, no measurement error is caused, and the reproducibility does not decrease, so that the reliability of the measured value does not decrease. Further, the apparatus of the present invention is also capable of measuring a shape having a discontinuous thickness, for example, a shape in which a step is formed. Further, the abnormal value processing of this can be changed to a measured value and replaced with an output value. Even in the case of being configured, the present invention has an excellent effect that the measurement interval can be dealt with even by setting the detection interval to be minute.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a thickness measuring device according to the present invention, FIG. 2 is a flow chart showing its control contents, and FIG. 3 is a graph showing the relationship between measured values and time. 1 ... Sensor part, 3 ... moving average value calculating part 4 ... deviation amount calculating part, 5 ... abnormal value replacing part 6 ... measured plate

Claims (1)

[Claims] 1. A thickness measuring device for relatively moving an object to be measured to measure its thickness in a time series, wherein a moving average calculation for calculating an average value of a plurality of measured values before the immediately preceding measured value. Part, a deviation amount calculation part for obtaining a difference between the latest measured value and the average value, and if the calculation result of the deviation amount calculation part is less than a preset comparison reference value, the latest measured value is output. And an abnormal value replacement unit that replaces the latest measured value with the previous measured value and outputs the result if the calculated result of the deviation amount calculation unit is equal to or greater than a preset comparison reference value. Thickness measuring device.