A device and method for online identification of defects in pipes and bars

Abstract

The present invention discloses an online marking device and method for defects in pipes and bars. For a two-dimensional or three-dimensional online surface quality inspection system for pipes and bars based on machine vision technology, the position of the defect is accurately calculated, and the marking device is controlled by a host computer to mark the defect, thereby providing a means for quality inspection personnel to quickly confirm the position of the defect, which is convenient for production personnel to repair the defect or sort the product. The present invention can be widely used in the field of online surface quality inspection of pipes and bars, and its application prospects are very broad.

Description

Technical Field

[0001] The invention relates to a tube and bar material defect identification technology, and in particular to an online tube and bar material defect identification device and method. Background Art

[0002] For the surface quality inspection of steel products, the technology based on machine vision has been widely used in recent years. At present, the production line speed of most steel products is relatively fast. If the defects detected by visual inspection technology, especially the defects of tube and rod products, cannot be marked online, it will be difficult for on-site quality inspectors to conduct subsequent review and evidence collection of defects. In the field of tube and rod production lines, defect identification is particularly important. On the one hand, on-site operators need to grind the defective positions of tubes and rods, and the identification of defects helps them quickly find the location of the defects; on the other hand, the identification of defects is also conducive to the automatic sorting of such products.

[0003] The patent with publication number CN01113036.9 discloses a method and device for monitoring defect marking in eddy current flaw detection of steel pipes. The device does not strictly consider the correspondence between the defect marking position and the actual position of the defect. The patent with application number 201910939301.3 discloses a non-destructive testing device for three-dimensional defect detection on the surface of seamless steel pipes. The patent uses three-dimensional defect detection technology to realize non-destructive detection of defects on the surface of steel pipes, and realizes the spraying action of defects by delaying time, but the reliability of this delay cannot be guaranteed, and there is no method for accurately locating the defect position. Summary of the invention

[0004] In order to solve the above problems in the prior art, the present invention provides an online marking device and method for defects in pipes and bars, which can realize online marking of defects by accurately calculating the positions of defects and controlling the marking device by a host computer.

[0005] In one aspect, the present invention provides an online defect identification device for tubes and bars, comprising:

[0006] The upper computer receives the production information on site, including the radius specifications of the tubes and bars. Under the determined pulse resolution setting value, it determines the frequency division coefficient of the signal processing box according to the specification information of the tubes and bars and the roller information, receives the pulse accumulation value of the signal processing box, and obtains the actual pulse accumulation value used to control the spraying according to the response time of the spraying equipment;

[0007] An imaging detection system is installed on the roller table to perform two-dimensional or three-dimensional imaging detection on the passing tubes and bars;

[0008] The encoder is installed on the conveying motor on the roller table to record the position of the tube and bar in the moving direction;

[0009] Photoelectric switches are located on the front and rear sides of the imaging detection system, and provide the start, stop and reset of pulse counting for the signal processing box through the detection tube rod;

[0010] The signal processing box converts the encoder pulse signal frequency according to the frequency division and multiplication coefficient, counts the pulses according to the start and stop signals provided by the photoelectric switch, and provides a trigger signal to the imaging detection system for imaging;

[0011] The marking equipment receives the control instruction of the actual pulse accumulation value from the upper computer and marks the detected defects of the tube and bar.

[0012] The roller is a V-shaped roller, and the roller information includes an angle α of the V-shaped roller and a rotation radius R1 of a V-shaped intersection.

[0013] The calculation formula of the frequency division coefficient λ is:

[0014]

[0015] In the formula,

[0016] R2 is the rotation radius of the point where the tube, bar and V-shaped roller are tangent to each other;

[0017] R is: the specification radius of the tube and bar;

[0018] N is: the number of pulses output by the encoder per week;

[0019] p is: the resolution of the encoder corresponding to the direction of movement of the tube and rod.

[0020] The calculation formula of the pulse cumulative value n is:

[0021]

[0022] In the formula,

[0023] D is: the current position of the defect detected by the imaging detection system;

[0024] l2 is the distance between the imaging detection system and the photoelectric switch behind it;

[0025] l3 is the distance between the photoelectric switch on the rear side and the marking equipment.

[0026] The calculation formula of the actual pulse cumulative value is:

[0027] n'=n-vt / p

[0028] v is: the speed of the tube and rod;

[0029] t is: the response time of the marking equipment.

[0030] On the other hand, the marking method of the online marking device for pipe and bar defects comprises the following steps:

[0031] a. Receive on-site production information through the host computer, including the radius specifications of the tube and bar, and use the encoder to record the position of the tube and bar in the moving direction;

[0032] b. Determine the frequency division coefficient of the signal processing box according to the specification information of the tube and bar and the roller information;

[0033] c. The signal processing box transforms the encoder pulse signal frequency according to the frequency division and multiplication coefficient, counts the pulses according to the start and stop signals provided by the photoelectric switch, and provides a trigger signal to the imaging detection system for two-dimensional or three-dimensional imaging detection;

[0034] d. When the imaging detection system detects defects, a control instruction of the actual pulse accumulation value is issued according to the pulse accumulation value and the response time of the marking equipment to control the marking equipment to mark the detected defects of the tube and bar.

[0035] The roller is a V-shaped roller, and the roller information includes an angle α of the V-shaped roller and a rotation radius R1 of a V-shaped intersection.

[0036] The calculation formula of the frequency division coefficient λ is:

[0037]

[0038] In the formula,

[0039] R2 is the rotation radius of the point where the tube, bar and V-shaped roller are tangent to each other;

[0040] R is: the specification radius of the tube and bar;

[0041] N is: the number of pulses output by the encoder per week;

[0042] P is: the resolution of the encoder corresponding to the moving direction of the tube and rod.

[0043] The calculation formula of the pulse cumulative value n is:

[0044]

[0045] In the formula,

[0046] D is: the current position of the defect detected by the imaging detection system;

[0047] l2 is the distance between the imaging detection system and the photoelectric switch behind it;

[0048] l3 is the distance between the photoelectric switch on the rear side and the marking equipment.

[0049] The calculation formula of the actual pulse cumulative value is:

[0050] n'=n-vt / p

[0051] v is: the speed of the tube and rod;

[0052] t is: the response time of the marking equipment.

[0053] By using the device and method for online marking defects of pipes and bars of the present invention, the position of the defects is accurately calculated, and the marking device is controlled by the host computer to mark the defects, thereby providing a means for quality inspection personnel to quickly confirm the position of the defects, and facilitating production personnel to repair the defects or sort the products. The present invention can be widely used in the field of online detection of the surface quality of pipes and bars, and its application prospects are very broad. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a principle block diagram of the identification device of the present invention;

[0055] Figure 2 A schematic diagram of defect location calculation of the present invention;

[0056] Figure 3 It is the principle diagram of the V-shaped roller table of the present invention;

[0057] Figure 4 A three-dimensional diagram of an embodiment of a marking device of the present invention;

[0058] Figure 5 for Figure 4 A top view of the identification device in FIG. DETAILED DESCRIPTION

[0059] The following is a further description of an online tube and bar defect identification device and method of the present invention in conjunction with the accompanying drawings and embodiments.

[0060] See also Figure 1 As shown, the online marking device for defects of pipes and bars of the present invention mainly includes a host computer, an imaging detection system, an encoder, a photoelectric switch, a signal processing box, and a marking device, wherein:

[0061] The host computer receives the production information on site, mainly including the radius specifications and length of the tubes and bars. Under the determined pulse resolution setting value, the frequency division coefficient of the signal processing box is determined according to the specifications of the tubes and bars and the roller information, so as to facilitate the imaging detection system to record the position of the detected object;

[0062] The signal processing box transforms the encoder pulse signal frequency according to the frequency division coefficient, counts the pulses according to the start and stop signals provided by the photoelectric switch, and provides a trigger signal to the imaging detection system for the imaging detection system to perform online two-dimensional or three-dimensional imaging detection of defects. When the imaging detection system detects a defect, the corresponding position information is transmitted to the host computer, which controls the action of the marking equipment according to the defect position and response time.

[0063] See also Figure 2 As shown, the tube and bar 1 is transported to the right on the conveyor roller, and an encoder 7 is installed on the front roller 8 to record the position of the tube and bar in the moving direction. The imaging detection system 3 is arranged behind the front roller 8, and a photoelectric switch 2a, 2b is respectively arranged on the front and rear sides of the imaging detection system 3. The marking device 5 is installed at a certain position in the exit direction to mark the surface defects 6 of the tube and bar.

[0064] Whether the roller 8 is an inclined roller, a flat roller or other types of rollers, it is first necessary to calculate the pulse resolution of the encoder 7 installed on the roller in the direction of motion. In order to facilitate position calculation, the pulse resolution in the direction of motion of pipes and bars of different specifications is uniformly set to p, thereby determining the frequency division coefficient λ for the signal processing box.

[0065] by Figure 3 Take the most common V-shaped roller in actual production as an example to calculate the frequency division coefficient λ. Assume that the radius specification of the tube and rod is R, and the position tangent to the V-shaped roller during transportation is C and D. The angle of the V-shaped roller is α, and the rotation radius of the V-shaped intersection B is R1. Then the rotation radius R2 of the tangent point between the tube and rod and the V-shaped roller is:

[0066] Assume that the number of pulses output per week of the encoder of the V-shaped roller is N, and the required pulse resolution of the motion direction is p, then p = 2πR2 / λN, where λ is the frequency division coefficient of the signal processing box, For inclined rollers and flat rollers, the rotation radius of the tangent point between the similar tubes, rods and rollers can also be used to divide the frequency coefficient.

[0067] Assume that the distance between the front photoelectric switch 2a and the imaging detection system 3 is l1, the distance between the imaging detection system 3 and the rear photoelectric switch 2b is l2, and the distance between the rear photoelectric switch 2b and the marking device 5 is l3. When the imaging detection system finds that the current position of the defect is D (including the distance of the head of the tube and bar material photographed in advance, that is, the distance between the front photoelectric switch 2a and the imaging detection system 3 is l1, and the actual position of the defect on the tube and bar material from the head is d, d = D-l1), the cumulative distance counted from the front photoelectric switch 2a is D, and then the distance l2+l3 reaches the marking device position. Therefore, in theory, the cumulative distance value controlled by the front photoelectric switch 2a is D+l2+l3, and when this position is reached, the marking device is controlled to operate.

[0068] When the defect at position D needs to be marked by printing, the pulse accumulation value returned to the host computer by the signal processing box is When the marking equipment is controlled.

[0069] However, in actual application, the response time of the marking equipment must also be considered. Therefore, the actual pulse accumulation value must also subtract the distance the pipe wire is transported during the response time.

[0070] Therefore, the marking method of the online marking device for pipe and bar defects of the present invention comprises the following steps:

[0071] a. Receive on-site production information through the host computer, including the radius specifications of the tube and bar, and use the encoder to record the position of the tube and bar in the moving direction;

[0072] b. Determine the frequency division coefficient of the signal processing box according to the specification information of the tube and rod and the roller information. If the roller is a V-shaped roller, the calculation formula of the frequency division coefficient λ is:

[0073]

[0074] In the formula,

[0075] α is: the angle of the V-shaped roller;

[0076] R1 is the rotation radius of the V-shaped intersection;

[0077] R is: the specification radius of the tube and bar;

[0078] N is: the number of pulses output by the encoder per week;

[0079] P is: the resolution of the encoder corresponding to the moving direction of the tube and rod;

[0080] c. The signal processing box transforms the encoder pulse signal frequency according to the frequency division and multiplication coefficient, counts the pulses according to the start and stop signals provided by the photoelectric switch, and provides a trigger signal to the imaging detection system for two-dimensional or three-dimensional imaging detection;

[0081] d. When the imaging detection system detects defects, it issues a control instruction of the actual pulse accumulation value according to the pulse accumulation value and the response time of the marking equipment, and controls the marking equipment to mark the detected defects of the tube and bar.

[0082] The calculation formula of the pulse cumulative value n is:

[0083]

[0084] In the formula,

[0085] D is: the current location of the defect in the imaging detection system;

[0086] l2 is the distance between the imaging detection system and the photoelectric switch behind it;

[0087] l3 is the distance between the photoelectric switch on the rear side and the marking equipment.

[0088] The calculation formula of the actual pulse cumulative value is:

[0089] n'=n-vt / p

[0090] v is: the speed of the tube and rod;

[0091] t is: the response time of the marking equipment.

[0092] Example

[0093] like Figure 4-53 in the figure is a three-dimensional imaging detection system applied to a steel pipe production line. It is equipped with a photoelectric switch 2a and 2b at the front and rear, respectively. The photoelectric switch is installed near the conveying motor 4a and 4b. The encoder 7 is installed on the output shaft of the conveying motor 12. The encoder signal is transformed by the signal processing box to provide an external trigger signal for the three-dimensional sensor of the imaging detection system 3, so as to detect the steel pipe 9. The detected defects are marked by the spray marking device 5. Assuming that the longitudinal resolution of the imaging detection system is 1mm / pluse, the sub-multiple frequency coefficient of the signal processing box can be calculated. For a steel pipe with an outer diameter of φ, it is known that the angle α of the V-shaped roller is 149.7 degrees, and the intersection rotation radius R1 = 271.1 / 2, then R2 = 0.034755R + 135.55. Assuming that the number of pulses output per cycle of the encoder corresponding to the conveyor roller is 1024, and the required resolution of the movement direction is pmm / pluse, then p = πφ / λN, where λ is the frequency division coefficient, λ = πφ / pN = 2π(0.034755R+135.55) / pN, when the longitudinal resolution is 1mm / pluse, λ = 2π(0.034755R+135.55) / 1024 = (0.034755πφ+851.37089) / 1024.

[0094] Table 1 below lists the signal processing box frequency division coefficients λ corresponding to several different outer diameter specifications:

[0095] Table 1

[0096]

[0097] In actual application, the response time of the marking equipment needs to be considered. When the defect at the detection position D needs to be marked by printing, the pulse accumulation value returned to the host computer by the signal processing box is , advance the unit response time to control the marking equipment action. For steel pipe applications, the host computer transmits the command to the PLC (network delay time is not counted), the PLC scan cycle is 20ms, the PLC controls the solenoid valve action, the solenoid valve response time is 10ms, the spray gun spray action is about 20ms, and the entire response time is about 50ms. The speed of the steel pipe is about 2.8 meters per second (different pipe diameters have small differences, calculated as the average value), then the distance the steel pipe moves within the unit response time is 140mm. According to the actual installation of the on-site equipment, l1 = 500mm, l2 = 1000mm, l3 = 2500mm, p = 1mm / pluse, for the distance D (i.e. the defect at the distance d from the head of the steel pipe) needs to be printed, when the actual pulse accumulation value is n' = D + 3500-140 = D + 3360, the host computer sends a command to the PLC to perform the spray action.

[0098] However, those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. An online defect identification device for tubes and bars, characterized in that: include: The upper computer receives the production information on site, including the radius specifications of the tubes and bars. Under the determined pulse resolution setting value, it determines the frequency division coefficient of the signal processing box according to the specification information of the tubes and bars and the roller information, receives the pulse accumulation value of the signal processing box, and obtains the actual pulse accumulation value used to control the spraying according to the response time of the spraying equipment; An imaging detection system is installed on the roller table to perform two-dimensional or three-dimensional imaging detection on the passing tubes and bars; The encoder is installed on the conveying motor on the roller table to record the position of the tube and bar in the moving direction; Photoelectric switches are located on the front and rear sides of the imaging detection system, and provide the start, stop and reset of pulse counting for the signal processing box through the detection tube rod; The signal processing box converts the encoder pulse signal frequency according to the frequency division and multiplication coefficient, counts the pulses according to the start and stop signals provided by the photoelectric switch, and provides a trigger signal to the imaging detection system for imaging; The marking equipment receives the control instruction of the actual pulse accumulation value from the upper computer, and marks the detected defects of the tube and bar; the roller is a V-shaped roller, and the roller information includes the angle α of the V-shaped roller and the rotation radius R1 of the V-shaped intersection; the calculation formula of the sub-frequency coefficient λ is: In the formula, R1 is the rotation radius of the intersection of the V-shaped roller center; R is: the specification radius of the tube and bar; N is: the number of pulses output by the encoder per week; p is: the resolution of the encoder pulse signal in the direction of movement of the tube and bar after frequency division and multiplication; α is the angle of the V-shaped roller.

2. The device for online marking defects of pipes and bars according to claim 1, characterized in that: The calculation formula of the pulse cumulative value n is: In the formula, D is: the current position of the defect detected by the imaging detection system; l2 is the distance between the imaging detection system and the photoelectric switch behind it; l3 is the distance between the photoelectric switch on the rear side and the marking equipment.

3. The device for online marking defects of pipes and bars according to claim 2, characterized in that: The calculation formula of the actual pulse cumulative value is: n'=n-vt / p v is: the speed of the tube and rod; t is: the response time of the marking equipment.

4. A method for online identification of defects in pipes and bars, characterized in that: The device for online marking defects of pipes and bars according to any one of claims 1 to 3 comprises the following steps: a. Receive on-site production information through the host computer, including the radius specifications of the tube and bar, and use the encoder to record the position of the tube and bar in the moving direction; b. Determine the frequency division coefficient of the signal processing box according to the specification information of the tube and bar and the roller information; c. The signal processing box transforms the encoder pulse signal frequency according to the frequency division and multiplication coefficient (relationship with pulse count?), counts pulses according to the start and stop signals provided by the photoelectric switch, and provides a trigger signal to the imaging detection system for two-dimensional or three-dimensional imaging detection; d. When the imaging detection system detects defects, it issues a spray control instruction based on the pulse accumulation value and the response time of the spray equipment to control the spray equipment to mark the detected defects of the tube and bar.

5. The method for online marking of defects of pipes and bars according to claim 4, characterized in that: The roller is a V-shaped roller, and the roller information includes an angle α of the V-shaped roller and a rotation radius R1 of a V-shaped intersection.

6. The marking method according to claim 5, characterized in that: The calculation formula of the frequency division coefficient λ is: In the formula, R1 is the rotation radius of the intersection of the V-shaped roller center; R is: the specification radius of the tube and bar; N is: the number of pulses output by the encoder per week; P is: the resolution of the encoder pulse signal in the direction of movement of the tube and bar after frequency division and multiplication; α is the angle of the V-shaped roller.

7. The marking method according to claim 6, characterized in that: The calculation formula of the pulse cumulative value n is: In the formula, D is: the current position of the defect detected by the imaging detection system; l2 is the distance between the imaging detection system and the photoelectric switch behind it; l3 is the distance between the photoelectric switch on the rear side and the marking equipment.

8. The marking method according to claim 7, characterized in that: The calculation formula of the actual pulse cumulative value is: n'=n-vt / p v is: the speed of the tube and rod; t is: the response time of the marking equipment.

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