JP3606496B2 - Method for measuring the length of a conveyed object - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring the length of a conveyed object such as a steel material or a steel pipe in a moving state.
[0002]
[Prior art]
For example, when a long object such as a steel material or a steel pipe is automatically cut into a predetermined dimension using a roller table, it is necessary to measure the length of the target long object in advance. At this time, considering the productivity, it is required to measure the length during the transfer. Here, a conventional method for measuring the length of a long object in a moving state will be described with reference to FIG.
[0003]
In FIG. 2, reference numeral 1 denotes a steel material to be measured, 2 denotes a movement amount measuring device capable of measuring the movement amount of the steel material 1, A denotes a tip detector that detects passage of the tip of the steel material 1, and B denotes a back of the steel material 1. It is a rear end detector for detecting the end. Ca and Cb are storage units, and 3 is a calculation unit.
[0004]
In the length measurement, first, the movement amount measuring device 2 starts measuring the movement amount of the steel material 1 from the time when the tip of the steel material 1 passes through the movement amount measuring device 2, and the measurement signals are stored in the storage units Ca and Cb. Output. And if the front-end | tip detector A detects the front-end | pass passage of the steel material 1, the memory | storage part Ca will stop the input of the measured value from the movement amount measuring device 2 at that time, and will memorize | store the value. Further, when the rear end of the steel material 1 is detected by the rear end detector B, the storage unit Cb stops the input of the measured value from the movement amount measuring device 2 at that time and stores the value.
[0005]
When the rear end detection signal is input to the rear end detector B, the arithmetic unit 3 inputs the stored measurement values to the storage units Ca and Cb and calculates the difference between them. Further, the length L of the steel material 1 is obtained from the difference x and the sum (x + b) of the distance b between the front end detector A and the rear end detector B set in advance.
[0006]
In order to accurately measure the length of the steel sheet, it is necessary to improve the measurement accuracy of the difference x, and several techniques have been disclosed. For example, in Japanese Utility Model Laid-Open No. 58-167406, a second rear end detector C is provided at a position z apart from the rear end detector B by a certain length, and the steel material obtained as described above by the rear end detector B is used. The length (x + b) of 1 is compared with the length (xb + z) of the steel material 1 obtained by the same method using the second rear end detector C, and the deviation exceeds a preset allowable value. Disclosed is a method for issuing an abnormal alarm.
[0007]
[Problems to be solved by the invention]
However, the above method simply outputs an abnormality alarm, and it cannot be determined which of the two rear end detectors B and C has issued an abnormality alarm due to a malfunction or failure. In addition, the detection timing varies depending on the transport speed due to the response characteristics of the detector, so that there are problems that require operational restrictions such as a constant transport speed in order to guarantee measurement accuracy. It was.
[0008]
The present invention automatically determines which detector has output an abnormal output without having the above-mentioned problem, and obtains good measurement accuracy even when the speed is different during conveyance of a long object. This is a problem.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides (1) a rear end detector and a front end detector are sequentially installed at predetermined intervals along the transport direction of the transport object, and the amount of movement of the transport object between the two detectors. A measuring device that measures the amount of movement from the time when the conveyed object passes through the moving amount measuring device to the time when it passes through the tip detector, and the conveyed object moves to the moving amount measuring device. The amount of movement from the time when the tip of the transported object passes through the rear end detector is measured by the movement amount measuring device, and the difference between the two measured values and the preset values of the rear end detector and the front end detector are measured. In the method of measuring the length of a transported object based on the sum of installation distances, three or more tip detectors are installed along the transport direction at a predetermined interval between the tip detector and the movement amount measuring device. The most downstream tip detector (A1) detects passing of the tip of the object The amount of movement measured by the moving amount measuring device between the point of time detected by the tip detector (A2) immediately upstream thereof and the point of the most downstream tip detector (A1) and tip detector (A1) immediately upstream ( If the difference in the installation distance of A2) is found and the difference is within the preset allowable value, the most downstream side tip detector (A1) is the tip detector to be measured, and if the difference is outside the tolerance value The difference between the measured movement amount of the movement amount measuring device and the distance between the two detectors between the most downstream side tip detector (A1) and the next upstream side tip detector (A3) between the tip passage detection time points, If this difference is within a preset allowable value, the most downstream side tip detector is the detector to be measured, and if the difference is outside the tolerance value, the upstream side tip detector (A2) is again upstream of that difference. Using the tip detector (A3), the same comparison is sequentially performed to detect the tip of the measurement target. It is a method for determining the.
[0010]
Further, (2) a moving speed measuring device for measuring the moving speed of the conveyed object is provided between the leading edge detector and the trailing edge detector, and the leading edge of the conveying object is detected by the leading edge detector and the trailing edge detector to be measured. Alternatively, a method of measuring the moving speed of the conveyed object at the time of detection of the rear end and subtracting a value obtained by multiplying the measured value by a time corresponding to the response delay time of the detector from the measured value of the moving amount at the detection time of the detector It is.
[0011]
In the present invention, three or more steel edge detectors are provided, and an optimum measurement value is always supplied by comparing and verifying each measurement value. This makes it possible to perform automatic operation in the case of malfunction. Furthermore, by measuring the moving speed together with the moving amount and correcting the length measurement result, the length measuring error due to the response delay of the steel end detector is eliminated.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG.
[0013]
In FIG. 1, reference numeral 1 denotes a steel material as a measurement object, and 2 denotes a movement amount measuring device capable of measuring the movement amount of the steel material 1. 4 is a moving speed measuring device for measuring the moving speed of the steel material 1. A1 to An are front end detectors for detecting the passage of the steel material front end, and are provided on the downstream side in the moving direction of the steel material 1 with respect to the movement amount measuring device 2, and are sequentially arranged so that A1 is at the most downstream side. B is a rear end detector that detects the passage of the rear end of the steel material, and is installed upstream of the moving amount measuring device 2 in the moving direction of the steel material 1. C1 to Cn store the movement amount measured by the movement amount measuring device 2 from the time when the tip of the steel material 1 reaches the movement amount measuring device 2 until the tip detectors A1 to An detect the tip of the steel material 1. It is a storage unit. Cb stores the movement amount measured by the movement amount measuring device 2 from the time when the front end of the steel material 1 reaches the movement amount measuring device 2 until the rear end detector B detects the rear end of the steel material 1. Part. D1 to Dn and Db are storage units for storing the moving speed of the steel material 1 measured by the moving speed measuring device 4, and 3 is a calculation unit.
[0014]
Hereinafter, a method for measuring the length of the steel material 1 will be described.
[0015]
First, measurement of the moving amount of the steel material 1 is started by the moving amount measuring device 2 from the time when the tip of the steel material 1 passes over the moving amount measuring device 2, and the measurement signal is output to the storage units C1 to Cn and Cb. To do. Similarly, when the tip of the steel material 1 passes through the moving speed measuring device 4, the moving speed measuring device 4 measures the moving speed of the steel material 1, and outputs the measured values to the storage units D1 to Dn and Db. Then, when the tip detector An detects the passage of the tip of the steel material 1, the storage unit Cn stops the input of the measurement value from the movement amount measuring device 2 at that time and stores the value, and the storage unit Dn then stores the value. The measurement speed of the steel material 1 is stored. Thereafter, similarly, when each of the tip detectors An-1 to A1 detects the passage of the tip of the steel material 1, the storage units Cn-1 to C1 respectively stop inputting the measured values from the movement amount measuring device 2 at that time. A value is stored, and a measured value from the moving speed measuring device 4 at the time of detection is stored. Further, when the rear end of the steel material 1 is detected by the rear end detector B, the storage unit Cb stops the input of the measured value from the moving speed measuring device 4 at that time, stores the value, and the moving speed at that time. The measured value of the measuring device 4 is stored.
[0016]
Next, the calculation unit 3 determines tip detectors A1 to An used for length measurement and calculates the length of the steel material 1. This method will be described below.
[0017]
In order to examine whether or not to adopt the measurement value of the tip detector A1, the differences ΔX1 and Δ2 between the values X1 and X2 stored in the storage units C1 and C2 are obtained, and the difference ΔX1 and the preset tip are obtained. The installation distances b1 and b2 between the detector A1 and the tip detector A2 immediately before the detector A1 are substituted into the following equation (1).
[0018]
| ΔX1,2-b1,2 | ≦ k1,2 (1)
Here, k1 and k2 are preset allowable values, and are set to values that allow measurement errors due to the movement amount measuring device 2, the tip detector A1, and the tip detector A2.
[0019]
If the above equation (1) is satisfied, it is determined that the tip detector A1 is operating correctly, and the tip detector A1 is employed as the tip detector.
[0020]
However, in the case of | ΔX1,2-b1,2 |> k1, it is determined that either the tip detector A1 or the tip detector A2 is malfunctioning, and then the tip detector A1 and the tip detector The installation distance b1, 3 between A3 and the difference ΔX1, 3 between the values X1, X3 stored in the storage units C1, C3 are substituted into the following equation (2).
[0021]
| ΔX1,3-b1,3 | ≦ k1,3 (2)
Here, k1 and k3 are preset allowable values, and are set to values that allow measurement error by the movement amount measuring device 2, the tip detector A1, and the tip detector A3.
[0022]
When the above expression (2) is satisfied, it is determined that the tip detector A2 has malfunctioned and the tip detector A1 is operating correctly, and the tip detector A1 is employed as the tip detector. However, if | ΔX1,3-b1,3 |> k1,3, it is determined that the tip detector A1 is malfunctioning, the adoption of the tip detector A1 is abandoned, and then the tip detector A2 and the tip detector The adoption of the detector A3 is examined in the same manner as described above. If the tip detector A2 cannot be adopted, the tip detectors A3, A4,..., An-1 are sequentially examined for adoption and a detector that satisfies the conditions is adopted. However, when the applicability of the tip detector An-1 is examined, the distances bn-1, n between the tip detector An-1 and the tip detector An and the values stored in the storage units Cn-1 and Cn The difference ΔXn−1, n is compared, and if | ΔXn−1, n−bn−1, n |> kn−1, n, there is no further detector that can be compared, so the measurement is considered as abnormal. Discontinue.
[0023]
Here, kn−1, n is a preset allowable value, and is set to a value that allows measurement error due to the movement amount measuring device 2, the tip detector An-1, and the tip detector An. In addition, what is necessary is just to arrange | position suitably the number and space | interval of the front-end | tip detector An from the front-end | tip detector A1 according to the length of the steel material 1 used as object.
[0024]
When the tip detector (for example, A2) used for length measurement is determined in this way, the calculation unit 3 calculates the movement amount X2 of the steel material 1 stored in the storage unit C2 corresponding to the tip detector A2. select.
[0025]
However, since the front end detector A1-An and the rear end detector B actually have a response delay time from when the front and rear ends of the steel material 1 pass through until the passage is recognized, the storage units C1 to Cn , Cb contains the error component due to this response delay.
[0026]
For this reason, the response delay times t2 and tb of the front end detector A2 and the rear end detector B are examined in advance, and the movement amount measurement values X2 and Xb and the storage units D2 and Db stored in the storage units C2 and Cb are stored in the storage units C2 and Cb. From the stored speed measurement values V2 and Vb, the movement amounts Xa2 and Xab at the moment when the front and rear ends of the steel material 1 actually pass the front end detector A2 and the rear end detector B are obtained by the following equations (3) and (4).
[0027]
Xa2 = X2-V2 * t2 (3)
Xab = Xb−Vb * tb (4)
Thereby, the length L of the steel material 1 is calculated | required by following (5) Formula using the distance b2, b between the calculated | required Xa2, Xab and the front-end | tip detector A2 and the rear end detector B set beforehand.
[0028]
L = (Xab−Xa2) + b2, b (5)
In this example, the moving amount measuring device 2 and the moving speed measuring device 4 are shown separately, but for example, the moving speed and the moving amount are measured by the speed measuring device and the integral calculation circuit, or the moving amount measuring device Similar results may be obtained by measuring the moving speed and the moving amount with a differential operation circuit.
[0029]
【The invention's effect】
According to the present invention, it is determined which detector is malfunctioning, and the length measurement is performed by another normally operating detector except for the malfunctioning detector. The length of the steel material 1 can be measured. Further, by correcting the error due to the response delay of the detector, it is possible to measure with high accuracy without affecting the movement speed of the object to be measured.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steel material 2 to be measured 2 Movement amount measuring device 3 Calculation part 4 Movement speed measuring device A1, A2, ..., An tip detector B Rear end detector C1, C2, ..., Cn Memory | storage part Ca, Cb storage unit

Claims (2)

A rear end detector and a front end detector are sequentially installed at predetermined intervals along the transport direction of the transport object, and a measuring device for measuring the travel amount of the transport object is provided between the two detectors, and the transport object is moved. The amount of movement from the time when it passes through the measuring device to the time when it passes through the front end detector is measured by a moving amount measuring device, and the front end of the transported object from the time when the transported object passes through the moving amount measuring device A method for measuring the length of a transported object by measuring the amount of movement until it passes through a moving amount measuring device, and the sum of the difference between the two measured values and a preset installation distance between the rear end detector and the front end detector. In
Three or more tip detectors are installed along the transport direction at a predetermined interval between the tip detector and the movement amount measuring device. First, the tip detector (A1) on the most downstream side passes the tip of the transport object. The movement amount measured by the movement amount measuring device between the time point of detection and the time point detected by the tip detector (A2) immediately upstream thereof, the most downstream tip detector (A1) and the tip detector immediately upstream. If the difference in the installation distance of (A2) is found and the difference is within the preset tolerance, the most downstream tip detector (A1) is the tip detector to be measured, and the difference is outside the tolerance. For example, the difference between the measured movement amount of the movement amount measuring device and the distance between the two detectors between the time point of detecting the passage of the tip at the most downstream tip detector (A1) and the next upstream tip detector (A3) is obtained. If this difference is within the preset tolerance, the most downstream tip detector is the detector to be measured. If the difference is outside the permissible value, a similar comparison is sequentially performed from the immediately upstream tip detector (A2) using the upstream tip detector (A3), and the tip detector to be measured is changed. A method for measuring a length of a transported object characterized by determining the length. A moving speed measuring device for measuring the moving speed of the conveyed object is provided between the leading edge detector and the trailing edge detector, and the leading edge detector and the trailing edge detector of the measurement object at the time of detecting the leading edge or the trailing edge of the conveyed object. The moving speed of the transported object is measured, and a value obtained by multiplying the measured value by a time corresponding to the response delay time of the detector is subtracted from the measured moving amount at the detection time of the detector. 2. A method for measuring a length of a conveyed object according to 1.

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