A method and device for determining the diameter of a steel coil based on a laser rangefinder

Abstract

The application discloses a steel coil diameter determination method and device based on a laser range finder, and the method comprises the following steps: placing the steel coil on a saddle; the saddle comprises at least two pads, the pads are placed on both sides of the steel coil and are located on a ground plate; placing the laser range finder on one side of the steel coil to obtain a horizontal distance measurement value of the steel coil and the laser range finder; obtaining the horizontal distance between the laser range finder and the core of the steel coil, the height of the laser range finder from the ground plate, the thickness of the ground plate, the angle between the line connecting the cutting point of the steel coil and the saddle and the vertical direction and the core of the steel coil, calculating the radius of the steel coil, and obtaining the calculated diameter value of the steel coil; using a quadratic polynomial to fit the relationship between the diameter calculation error and the horizontal distance measurement value; obtaining the diameter calculation error according to the quadratic polynomial, and obtaining the final diameter value of the steel coil according to the obtained diameter calculation error and the calculated diameter value of the steel coil.

Description

Technical Field

[0001] This invention belongs to the field of steel coil diameter measurement technology, specifically relating to a method and apparatus for determining the diameter of steel coils based on a laser rangefinder. Background Technology

[0002] On a steel coil processing production line, whether processing the inner coil of the steel coil or loading it onto the coiler, accurate coil diameter values ​​are essential to ensure smooth operation. However, the coil diameter is difficult to measure directly. Traditional indirect coil diameter calculation methods, such as speed calculation and coil count calculation, are not accurate enough when the coil slips or the strip thickness is uneven, making it difficult to meet the requirements of subsequent processes.

[0003] A laser rangefinder is an instrument that uses laser light to measure distance. It determines the distance by measuring the time from when the laser light is emitted to when it is reflected back from the target. Industrial-grade laser rangefinders are suitable for the harsh environments of steel mills, offering high measurement accuracy and reliability. They are less affected by environmental conditions, have a measurement range of up to 30 meters, and a measurement accuracy of approximately 2 mm. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for determining the diameter of steel coils based on a laser rangefinder, which can calculate the accurate diameter of the steel coil based on the distance measurement value of the laser rangefinder, thus solving the problem of the difficulty in accurately obtaining the diameter of the steel coil.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for determining the diameter of a steel coil based on a laser rangefinder includes the following steps:

[0007] The steel coil is placed on the saddle; the saddle includes at least two pads, which are placed on both sides of the steel coil and are both located on the ground plate.

[0008] A laser rangefinder is placed on one side of the steel coil to obtain the horizontal distance measurement between the steel coil and the laser rangefinder.

[0009] Obtain the horizontal distance D between the laser rangefinder and the core of the steel coil. Laser<->Heatt The height D of the laser rangefinder above the ground plane Laser＜-＞Floor The thickness T of the floor plate Floor And the angle α between the line connecting the point of tangency between the steel coil and the saddle and the center of the steel coil and the vertical direction, and the radius R of the steel coil is calculated according to the following formula. S :

[0010]

[0011] Based on the range of steel coil radii, select a suitable solution from the two solutions as the calculated value of the steel coil radius, and denote it as R. S,Cal The calculated diameter of the steel coil is 2R. S,Cal ;

[0012] The error in calculating the roll diameter was obtained by fitting a quadratic polynomial with the measured horizontal distance. The relationship between the two equations is determined, and the coefficients of the quadratic polynomial are solved. The error in the coil diameter calculation is the actual coil diameter minus the calculated coil diameter.

[0013] Based on the quadratic polynomial and the horizontal distance measurement value The calculation error of the coil diameter is obtained, and the final coil diameter value is obtained based on the calculated coil diameter error and the calculated coil diameter value of the steel coil.

[0014] Furthermore, after a delay until the steel coil is firmly placed on the saddle, the laser rangefinder acquires the horizontal distance measurement between the steel coil and the laser rangefinder.

[0015] Furthermore, the horizontal distance measurement between the steel coil and the laser rangefinder is obtained through filtering and averaging.

[0016] A queue is formed by collecting N consecutive sampled values ​​from the laser rangefinder. New data is added to the tail of the queue each time, while the data at the head of the queue is removed. At each sampling period, the N sampled values ​​in the queue are averaged to obtain the recursive average filtering result, denoted as S. Laser ;

[0017] S over a period of time Laser The average value was then used as the horizontal distance measurement between the steel coil and the laser rangefinder.

[0018] Furthermore, the quadratic polynomial is:

[0019] E S =ax 2 +bx+c

[0020] In the formula, E S The error in the roll diameter calculation is represented by a, b, and c, which are the coefficients of a quadratic polynomial. The independent variable x is defined as... S0 is the set value when the roll diameter calculation error is minimized;

[0021] The formula for calculating the error in roll diameter is as follows:

[0022] E S (m)=D S,Act (m)-2R S,Cal (m)

[0023] In the formula, DS,Act This represents the actual diameter of the steel coil, where m indicates the m-th data point.

[0024] Furthermore, solving for the coefficients of this quadratic polynomial includes:

[0025] Obtain three sets of data {(x1,E S (1)), (x2,E S (2)), (x3,E S (3))}, and written in matrix form, we get:

[0026]

[0027] make:

[0028] Y = [E S (1) E S (2) E S (3)] T

[0029] W = [cba] T

[0030]

[0031] The matrix form can then be rewritten as:

[0032] Y = XW

[0033] W is the coefficient matrix. The values ​​of the coefficient matrix are obtained using the least squares method:

[0034] Find the coefficient matrix W such that the modulus of XW-Y is minimized; this is an optimization problem.

[0035] min||XW-Y||2

[0036] The solution obtained using the least squares method is:

[0037] W = [cba] T =(X T X) -1 X T Y

[0038] After obtaining the coefficient matrix W, substitute it into the quadratic polynomial.

[0039] Furthermore, the horizontal distance measurements of the three selected data sets... Not all values ​​are greater than or equal to the set value S0.

[0040] Furthermore, the final formula for calculating the steel coil diameter is as follows:

[0041]

[0042] In the formula, k is the steel coil number, and D Fin This is the final coil diameter value.

[0043] A laser rangefinder-based steel coil diameter determination apparatus for implementing the laser rangefinder-based steel coil diameter determination method described in any one of the above-mentioned methods, comprising:

[0044] The saddle includes at least two pads, which are placed on both sides of the steel coil and each pad is provided with a ground plate.

[0045] A laser rangefinder is placed on one side of the steel coil to obtain the horizontal distance measurement between the steel coil and the laser rangefinder.

[0046] The PLC controller is used to read horizontal distance measurements from the laser rangefinder and calculate the steel coil radius R. S The calculation error of the coil diameter is obtained by calculating the quadratic polynomial and the horizontal distance measurement. Finally, the final coil diameter value is obtained by combining the calculated coil diameter error with the calculated coil diameter value.

[0047] Furthermore, the device also includes:

[0048] The proximity switch is used to detect whether the steel coil is placed on the saddle, and sends a saddle occupancy signal to the PLC controller after a period of time T1 after detecting that the steel coil is placed on the saddle;

[0049] After receiving the saddle occupancy signal, the PLC controller begins to read the horizontal distance measurement value from the laser rangefinder.

[0050] Furthermore, the device also includes:

[0051] Laser rangefinder bracket, used to mount a laser rangefinder on one side of a steel coil.

[0052] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0053] The present invention provides a method and apparatus for determining the diameter of steel coils based on a laser rangefinder. This method and apparatus can accurately determine the diameter of steel coils using only a single laser rangefinder. The equipment is simple, easy to maintain, and low in cost. The laser rangefinder measurements are filtered and averaged to reduce the impact of interference and fluctuations during measurement. A quadratic polynomial is used to fit the relationship between the coil diameter calculation error and the steel coil measurement distance, accurately compensating for the error in calculating the coil diameter. This significantly improves the accuracy of the coil diameter calculation, facilitating further processing of the steel coil in subsequent steps and increasing production efficiency. Attached Figure Description

[0054] Figure 1 This is a flowchart of a method for determining the diameter of a steel coil based on a laser rangefinder, according to an embodiment of the present invention.

[0055] Figure 2 This is a schematic diagram of a steel coil diameter determination device based on a laser rangefinder, according to an embodiment of the present invention.

[0056] In the diagram: 1-proximity switch, 2-ground plate, 3-steel coil, 4-saddle, 5-PLC controller, 6-laser rangefinder, 7-laser rangefinder bracket. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0058] This invention provides a method and apparatus for determining the diameter of a steel coil based on a laser rangefinder. The method includes: delaying the time until the steel coil is stable on the saddle; sampling the laser rangefinder measurement values ​​and performing filtering and averaging processing; measuring the distances and angles between various devices on site; calculating the calculated coil diameter based on geometric relationships; using a quadratic polynomial to fit the relationship between the coil diameter error and the measured distance values; using the least squares method to obtain the coefficients of the quadratic polynomial; and calculating the final coil diameter value. This method for determining the coil diameter provides an accurate measurement using only a laser rangefinder, reducing the impact of interference and fluctuations during laser rangefinder measurement on the measured values. The quadratic polynomial fitting method accurately compensates for the calculation error, significantly improving the accuracy of the coil diameter calculation.

[0059] Figure 2 This diagram illustrates a device for determining the diameter of a steel coil based on a laser rangefinder, as provided in an embodiment of the present invention. As shown, the device includes a proximity switch 1, a ground plate 2, a steel coil saddle 4, a steel coil 3, a PLC controller 5, a laser rangefinder 6, and a laser rangefinder support 7. The proximity switch 1 sends a saddle occupancy signal to the PLC controller 5 when the steel coil 3 is transported onto the saddle 4, indicating that a steel coil is on the saddle. The laser rangefinder 6 measures the distance from the laser emitter to the outer ring of the steel coil. The PLC controller 5 reads the distance measurement value from the laser rangefinder 6. The entire method for determining the diameter of the steel coil described in this invention is programmed and implemented in the PLC controller.

[0060] like Figure 1 As shown, this embodiment of the invention provides a method for determining the diameter of a steel coil based on a laser rangefinder, comprising the following steps:

[0061] S10. After a delay, wait for the steel coil to be placed steadily on the saddle, sample the laser rangefinder measurement value, and perform filtering and averaging processing.

[0062] S20. Measure the distance and angle between various devices on site, and calculate the coil diameter based on the geometric relationship.

[0063] S30. Use a quadratic polynomial fitting method to calculate the relationship between the error of the roll diameter and the measured distance of the steel roll. Use the least squares method to obtain the coefficients of the quadratic polynomial and calculate the final roll diameter value.

[0064] Step S10 specifically includes:

[0065] S101. After a delay, wait for the steel coil to be placed steadily on the saddle, and then sample the measurement value of the laser rangefinder.

[0066] In the steel mill, steel coil 3 is transported to the steel coil saddle 4 by overhead crane or steel coil trolley. A proximity switch 1 is installed on the side of the saddle 4. When the proximity switch 1 detects the steel coil 3, it sends a saddle hold signal to the PLC controller 5. After receiving the hold signal, the PLC controller 5 delays for a period of time T1 to wait for the steel coil to stabilize, and then begins to sample the measurement value of the laser rangefinder. The measured value is recorded as S. Laser,act In this embodiment, T1 is set to 5s.

[0067] S102. Use the recursive average filtering method to filter the laser rangefinder measurement values.

[0068] Treating the N consecutive sampled values ​​from the PLC as a queue, each time a new sampled data is added to the tail of the queue, the data at the head of the queue is deleted. In each sampling cycle, the N sampled values ​​in the queue are averaged to obtain the recursive average filtering result, denoted as S. Laser In this embodiment, N = 10.

[0069] S103. Calculate the average value of the filtered measurements from the laser rangefinder over a period of time as the measurement distance value used for this steel coil.

[0070] Based on actual on-site observations, the laser rangefinder measurements, even after recursive averaging filtering, still fluctuate within a certain range (approximately ±5mm). Therefore, averaging is required over a period of time T2. The averaged measurement value will be used as the measurement distance for the steel coil, denoted as [value missing]. In this embodiment, T2 is set to 2s.

[0071] Step S20 specifically includes:

[0072] S201. After the equipment is installed, measure the distance and angle between each piece of equipment on site.

[0073] Once the equipment is installed on site, the distances between it are fixed. For example... Figure 2 As shown, the distance and angle values ​​that need to be measured include: the distance D between the laser rangefinder and the core of the steel coil. Laser<->Heart The height D of the center of the laser rangefinder from the ground plane Laser<->Floor The thickness T of the floor plate Floor And the angle α between the point of tangency between the steel coil and the saddle and the vertical line.

[0074] S202. Based on geometric relationships, derive the relationship between the radius of the steel coil and the measured distance of the steel coil, and between the measured distance and the angle value.

[0075] The radius R of the steel coil is derived from geometric relationships. S Measurement distance value of the same steel coil The relationship between the measured distance and the angle value is expressed as a quadratic equation in one variable as follows:

[0076]

[0077] In the formula Of course, you can also directly use the measured value S. Laser,act However, the final calculated coil diameter value will have a large error; while the horizontal distance measurement value between the steel coil and the laser rangefinder after filtering and averaging will be different. This will allow you to obtain a more accurate roll diameter value.

[0078] S203. Solve the above equation and determine the appropriate solution to obtain the calculated roll diameter value.

[0079] Rewrite the above quadratic equation in standard form:

[0080]

[0081] In the formula, AA, BB, and CC represent the values ​​in the quadratic equation in one variable. R S The coefficients preceding the constant term, after transformation, yield:

[0082] AA = (cosα + sinα · tanα) 2 -1.0

[0083] BB=-2.0·(cosα+sinα·tanα)·(D Laser<->Floor +T Floor )

[0084]

[0085] The equation then has two solutions:

[0086]

[0087] Based on the actual coil diameter range on site, a suitable solution is selected from the two solutions. In this embodiment, the known coil radius is within the range of 650–1050 mm. A suitable solution is selected from the two solutions based on this range and used as the calculated value for the coil radius, denoted as R. s,Cal The calculated diameter of the steel coil is 2R. S,Cal .

[0088] Step S30 specifically includes:

[0089] S301. Manually measure the actual diameter of the steel coil, and use a quadratic polynomial fitting to calculate the relationship between the error of the coil diameter and the measurement distance of the steel coil.

[0090] Several steel coils were used for testing, and the actual coil diameter D of each coil was manually measured once. s,Act Simultaneously, the volume diameter value is calculated once and recorded in the test dataset. The volume diameter calculation error E is defined. s Subtract the calculated roll diameter from the actual roll diameter, i.e.:

[0091] E s (m)=D s,Act (m)-2R S,Cal (m)

[0092] In the formula, m represents the m-th data in the test dataset.

[0093] The relationship between the roll diameter error and the measurement distance of the steel roll is calculated using the following quadratic polynomial fitting:

[0094] E S =ax 2 +bx+c

[0095] In the formula, a, b, and c are the coefficients of the quadratic polynomial, and the independent variable x is defined as... In this embodiment, the steel coil is measured at a distance. The error is closest to zero at 1300mm. The greater the distance from 1300mm, the greater the error; therefore, S0 is set to 1300mm here.

[0096] S302. Select data from the test dataset and rewrite it into matrix form.

[0097] Select three points {(x1, E)} from the test dataset. S (1)), (x2,E S (2)), (x3,E S(3) Since the steel coils on site are mostly large, the measured distance of the steel coils is less than 1300mm. Therefore, when selecting data points, two points with a measured distance of less than 1300mm and one point with a measured distance of greater than 1300mm are selected. The three selected points are written in matrix form, resulting in:

[0098]

[0099] make:

[0100] Y = [E S (1)E S (2)E S (3)] T

[0101] W = [cba] T

[0102]

[0103] In this embodiment, three points were selected and rewritten in matrix form as follows:

[0104]

[0105] S303. Use the least squares method to find the value of the coefficient matrix.

[0106] Find the coefficient matrix W such that the modulus of XW-Y is minimized; this is an optimization problem.

[0107] min||XW-Y||2

[0108] The solution obtained using the least squares method is:

[0109] W = [cba] T =(X T X) -1 X T Y

[0110] In this embodiment, the obtained coefficient matrix is:

[0111] W = [cba] T = [-5.496 0.113 0.00308] T

[0112] S304. Calculate the corrected diameter of the steel coil.

[0113] When a steel coil k is transported to the saddle, let its measured distance be valued. The corrected coil diameter is obtained by adding the calculated coil diameter value to the quadratic polynomial compensation value:

[0114]

[0115] By following the steps described above, the diameter of the steel coil can be accurately obtained, thus realizing this method of determining the diameter of a steel coil based on a laser rangefinder.

[0116] In summary, the method for determining the diameter of a steel coil based on a laser rangefinder provided in this embodiment of the invention uses a laser rangefinder to measure the distance between the laser emitter and the outer ring of the steel coil. After recursive averaging filtering and mean-averaging over a period of time, the measured distance value of the steel coil is obtained. Then, based on geometric relationships, the relationship between the steel coil radius and the measured distance value of the steel coil, as well as the measured distance and angle values, is derived, and the calculated coil diameter value is obtained by solving the equation. The actual diameters of several steel coils are manually measured, and the relationship between the error of the coil diameter and the measured distance value of the steel coil is calculated using a quadratic polynomial fitting method. The coefficients of the quadratic polynomial are obtained using the least squares method, and the final coil diameter value is obtained by adding the compensation value of the quadratic polynomial to the calculated coil diameter value. The method for determining the diameter of steel coils provided by this invention can accurately obtain the diameter value of steel coils using only a laser rangefinder. The equipment is simple, easy to maintain, and low in cost. The laser rangefinder measurement values ​​are filtered and averaged to reduce the impact of interference and fluctuations on the measurement values ​​during the measurement process. The relationship between the coil diameter error and the steel coil measurement distance is calculated using a quadratic polynomial fitting, which accurately compensates for the error in calculating the coil diameter, greatly improving the accuracy of the coil diameter calculation. This facilitates further processing of the steel coil in subsequent processes and improves production efficiency.

[0117] It should be noted that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0118] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0119] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining the diameter of a steel coil based on a laser rangefinder, characterized in that, Includes the following steps: The steel coil is placed on the saddle; the saddle includes at least two pads, which are placed on both sides of the steel coil and are both located on the ground plate. A laser rangefinder is placed on one side of the steel coil to obtain the horizontal distance measurement between the steel coil and the laser rangefinder. ; Obtain the horizontal distance between the laser rangefinder and the core of the steel coil. The height of the laser rangefinder above the ground plane Thickness of the floor slab And the angle between the line connecting the point of tangency between the steel coil and the saddle, and the line connecting the core of the steel coil and the vertical direction. And calculate the radius of the steel coil according to the following formula. : Based on the range of steel coil radii, select a suitable solution from the two solutions as the calculated value of the steel coil radius, and denote it as... The calculated diameter of the steel coil is then... ; The error in calculating the roll diameter was obtained by fitting a quadratic polynomial with the measured horizontal distance. The relationship between the two equations is determined, and the coefficients of the quadratic polynomial are solved. The error in the coil diameter calculation is the actual coil diameter minus the calculated coil diameter. Based on the quadratic polynomial and the horizontal distance measurement value The calculation error of the coil diameter is obtained, and the final coil diameter value is obtained based on the calculated coil diameter error and the calculated coil diameter value of the steel coil.

2. The method for determining the diameter of a steel coil based on a laser rangefinder according to claim 1, characterized in that, After a delay until the steel coil is firmly placed on the saddle, the laser rangefinder acquires the horizontal distance measurement between the steel coil and the laser rangefinder.

3. The method for determining the diameter of a steel coil based on a laser rangefinder according to claim 1, characterized in that, The horizontal distance between the steel coil and the laser rangefinder was obtained through filtering and averaging. : A queue is formed by collecting N consecutive sampled values ​​from the laser rangefinder. Each new sampled data point is added to the tail of the queue, while the data at the head of the queue is removed. At each sampling period, the N sampled values ​​in the queue are averaged to obtain the result of the recursive average filtering, denoted as […]. ; within a certain period of time The average value was then used as the horizontal distance measurement between the steel coil and the laser rangefinder. .

4. The method for determining the diameter of a steel coil based on a laser rangefinder according to claim 1, characterized in that, The quadratic polynomial is: In the formula, The error in the roll diameter calculation is represented by a, b, and c, which are the coefficients of a quadratic polynomial. The independent variable is... x Defined as , This is the set value that minimizes the error in roll diameter calculation; The formula for calculating the error in roll diameter is as follows: In the formula, This is the actual diameter of the steel coil. m Indicates the first m Data.

5. The method for determining the diameter of a steel coil based on a laser rangefinder according to claim 4, characterized in that, Solving for the coefficients of this quadratic polynomial includes: Get three sets of data {( ), ( ), ( )}, and written in matrix form, we get: make: The matrix form can then be rewritten as: W is the coefficient matrix. The values ​​of the coefficient matrix are obtained using the least squares method: Find the coefficient matrix W such that The problem is to minimize the modulus, which is the optimization problem: The solution obtained using the least squares method is: After obtaining the coefficient matrix W, substitute it into the quadratic polynomial.

6. The method for determining the diameter of a steel coil based on a laser rangefinder according to claim 5, characterized in that, The horizontal distance measurements of the three selected data sets Not all greater than or equal to the set value .

7. The method for determining the diameter of a steel coil based on a laser rangefinder according to claim 5, characterized in that, The final formula for calculating the steel coil diameter is as follows: In the formula, k Number the steel coil. This is the final coil diameter value.

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