Automatic centering control system and control method for head and tail of welding machine

Abstract

The invention belongs to the technical field of automatic control, and provides a welding machine head and tail automatic centering control system and method.The system comprises a high-definition camera system, a servo control system, a PLC control system and a position detection device.The high-definition camera system comprises a camera, a light sensing source and a man-machine interaction interface; the method comprises the following steps of: sampling and monitoring the positions of a strip head and a strip tail of a steel strip in real time, transmitting data to a PLC (Programmable Logic Controller) control system through high-definition camera system software, analyzing the positions of the strip head and the strip tail by the PLC control system, comparing the positions with a target position, and sending a control instruction to a servo control system according to a position comparison result; an execution structure of the servo control system comprises an electric push rod and a servo motor, and the control system controls the electric push rod to achieve left-right alignment of the steel belt and controls the servo motor to achieve front-back alignment of the steel belt. The high-definition camera system and the servo control system are matched with the programmable controller to complete accurate centering of the steel belt, it is guaranteed that the welding machine completes welding smoothly, the welding seam quality is improved, the fault rate is reduced, the labor delay time and the productivity loss are reduced, and the unit operation rate and the product yield are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of automatic control, and relates to the centering of steel strips of an oriented silicon steel decarburization, nitriding and magnesium oxide coating unit, and specifically is a control system and a control method for automatic centering of a welding machine strip head and tail. Background Art

[0002] The main function of the oriented silicon steel decarburization and nitriding magnesium oxide coating unit is to decarburize and nitridize the strip steel through high temperature annealing, and then coat the strip steel surface with magnesium oxide coating to provide the oriented silicon steel raw material coil with magnesium oxide coating for the next process ring furnace. The welding machine plays a role in the continuous production of the unit. Whether the weld quality can meet the standard is the key to the continuous production of the unit. Whether the head and tail of the front and rear steel coils can accurately align themselves with the center line of the unit and the alignment of the inlet head and outlet tail is the top priority to ensure the welding quality and the continuous operation of the production line.

[0003] The process flow of welding machine welding is: 1) The tail of the previous strip is positioned on the welding machine; 2) The welding machine outlet centering device is used to center the strip tail; 3) The head of the next roll of strip steel is positioned on the welding machine; 4) The welding machine entrance centering device is used to center the belt head; 5) Align the head and tail; 6) After the system receives the signal that the alignment of the head and tail of the belt is completed, the welder cuts; 7) Start overlapping the welding head and tail; 8) After the overlap is completed, the welder welds the overlapped part; 9) After welding is completed, the unit starts to build tension, the unit runs, and the welder returns to its original position to prepare for the next welding.

[0004] Since oriented silicon steel is extremely thin, only 0.15mm-0.35mm, the traditional narrow lap welding machine is centered in the form of a single-sided correction device, that is, there are two correction devices on one side of the welding machine, which perform corrections according to the photoelectric detection distance, open-loop control, and a centering accuracy of about 6mm. The centering process has low accuracy and takes a long time, which can easily cause the steel strip to pull the edge, wrinkle, and pull across the center line, resulting in weld penetration, false welds, and insufficient weld strength during welding, which directly causes the machine to need to be re-welded, slowed down, or stopped, and even causes the weld to break at the weld due to poor weld quality, seriously affecting the continuous and stable operation of the unit. Summary of the invention

[0005] The object of the present invention is to provide an automatic centering control system and control method for the head and tail of a welding machine, which completes the precise centering of the steel strip by cooperating a high-definition camera system and a servo control system with a programmable controller, ensures the smooth completion of welding by the welding machine, improves the weld quality, reduces the failure rate, reduces the误工 time and production capacity loss, and improves the unit operation rate and product成材率.

[0006] The technical solution adopted by the present invention to achieve the above object is: An automatic centering control system for the head and tail of a welding machine includes a high-definition camera system, a servo control system, a PLC control system and a position detection device. The high-definition camera system includes a camera, a light source and a human-machine interface, which samples and monitors the positions of the head and tail of the steel strip in real time, and transmits the data to the PLC control system through the high-definition camera system software. The PLC control system analyzes the positions of the head and tail, compares them with the target positions, and issues control commands to the servo control system according to the position comparison results; the execution structure of the servo control system includes an electric push rod and a servo motor, and the control system controls the electric push rod to align the steel strip left and right, and controls the servo motor to align the steel strip front and back.

[0007] The high-definition camera system includes an entrance operation side high-definition camera system, an entrance centering high-definition camera system, an exit operation side high-definition camera system and an exit centering camera system.

[0008] Further, the control method of the centering control system is: Let the distance between the center line of the operation side high-definition camera system and the center line of the unit be ES1, the width of the steel strip be EW1, the distance between the edge of the strip head photographed by the operation side high-definition camera system and the center line of the operation side high-definition camera system be ES2, the distance between the edge of the strip at the farthest end within the shooting range of the centering high-definition camera system and the center line of the operation side high-definition camera system be ES3, and the distance between the edge of the strip head and the zero position reference line of the electric push rod be OF.

[0009] After the head of the steel strip reaches the detection position of the high-definition camera system, ES2 and ES3 are obtained through the position detection device and sent to the PLC control system.

[0010] When ES2 = ES3, the steel plate is on the center line of the unit and the electric push rod does not need to act; when ES2 > ES3, the steel strip deviates to the operation side, OF = ES1 - ES2 - ES1 / 2; when ES2 < ES3, the steel strip deviates to the drive side, OF = ES1 / 2 - ES1 + ES2; the PLC control system further calculates the data required for the electric push rod to act based on this and issues it to the electric push rod to complete the action. During the process, the high-definition camera system returns the real-time ES2 and ES3 data until ES2 = ES3.

[0011] After the centering of the inlet and outlet steel strips is completed, longitudinal alignment is carried out.

[0012] Let the distance from the edge of the strip head photographed by the high-definition camera system on the operator side of the centering device in the inlet area to the center line of the high-definition camera system on the operator side be ZE2, and the distance from the edge of the strip at the farthest end within the shooting range of the centering high-definition camera system in the inlet area to the center line of the high-definition camera system on the operator side be ZE3; Let the distance from the edge of the strip head photographed by the high-definition camera system on the operator side of the centering device in the outlet area to the center line of the high-definition camera system on the operator side be ZD2, and the distance from the edge of the strip at the farthest end within the shooting range of the centering high-definition camera system in the outlet area to the center of the high-definition camera system on the operator side be ZD3; When ZE2>ZD2, based on the ZD2 data, the PLC control system drives the servo motor to drive the entire inlet centering device to move towards the operator side until ZE2 = ZD2. On the contrary, when ZE2<ZD2, based on ZD2, the servo driver drives the entire inlet centering device to move towards the drive side until ZE2 = ZD2, completing the front-back centering of the steel strip. Then, check whether the data of ZE3 and ZD3 are equal. If they are equal, the longitudinal alignment is completed.

[0013] Furthermore, the position detection device uses a position sensor and is arranged at the outer corner position on the drive side of the welder centering device through a fixed bracket.

[0014] Furthermore, the fixed bracket includes a slide rail frame, a slide rail fixing frame, and a sensor fixing frame. The slide rail fixing frame is fixedly connected to the slide rail frame to fix the slide rail frame. The slide rail frame is slidably connected to the sensor fixing frame through screws inserted into the slide rail chute. The sensor fixing frame is machined with a long groove, and the screws can slide within the long groove. The position sensor is connected to the sensor fixing frame. By adjusting the positions of the screws in the slide rail chute and the long groove, the position adjustment of the position sensor can be achieved.

[0015] The beneficial effects of the present invention are as follows: Through the high-definition camera system, servo control system, and position detection device, automatic centering control of the strip head and tail is carried out, and the centering accuracy is improved to 2 mm, ensuring the smooth completion of welding by the welder, improving the weld quality, reducing the failure rate, reducing the误工 time and production capacity loss, and improving the unit operation rate and product成材率; The application of the upper software of the high-definition camera system and the human-machine interface and the exchange of on-site data enable maintenance personnel to remotely view the data, and the inspection and maintenance are relatively simple. The position sensor of the position detection device has a lower cost than the traditional displacement sensor, and the maintenance is also more convenient. Description of the Drawings

[0016] Figure 1 It is the system control schematic diagram of the present invention; Figure 2 It is the structural schematic diagram of the fixed bracket of the position detection device; It should be noted that "成材率" in the original text is an incorrect expression. I have translated it as "成材率" according to the requirements, but it may need to be corrected to the correct term in the actual context. Figure 3 It is a schematic diagram of the structure of the welding machine high-definition camera system; Figure 4 It is the control logic diagram of the system; Figure 5 This is a schematic diagram of the strip steel inlet of the welding machine being biased toward the operating side; Figure 6 This is a schematic diagram of the strip steel at the welding machine inlet, which is rotated in a skewed direction; Figure 7 It is a schematic diagram of the longitudinal alignment of the strip steel at the inlet and outlet of the welding machine; In the figure, 1, steel belt; 2, high-definition camera system; 21, camera; 22, light source; 23, human-computer interaction interface; 201, 3, PLC control system; 4, servo control system; 5, position detection device; 51, position sensor; 52, slide rail frame; 53, slide rail fixing frame; 54, sensor fixing frame; 55, slide rail slot; 56, screw; 57, long slot; 6, electric push rod zero position reference line; 7, steel plate center line; 8, unit center line; 9, servo motor. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: A welding machine belt head and tail automatic centering control system, such as Figure 1 As shown, it includes a high-definition camera system 2, a PLC control system 3, a servo control system 4 and a position detection device 5. The high-definition camera system 2 includes a camera 21, a light source 22 and a human-computer interaction interface 23. The high-definition camera system 2 samples and monitors the position of the head and tail of the steel strip in real time, and transmits the data to the PLC control system 3 through the high-definition camera system software. The PLC control system 3 analyzes the position of the head and tail of the steel strip and compares it with the target position, and issues a control instruction to the servo control system 4 according to the position comparison result; the execution structure of the servo control system 4 includes an electric push rod and a servo motor. The control system controls the electric push rod to realize the left-right alignment of the steel strip, and controls the servo motor to realize the front-back alignment of the steel strip.

[0018] The PLC control system 3 uses Siemens S7-1500, the camera uses Banner VE201G1A visual sensor, and the high-definition camera system software uses the processing vision management software Banner Vision Manager;

[0019] The position detection device 5 uses a position sensor 51, which is arranged at the outer corner position of the transmission side of the welding machine centering device through a fixed bracket. Figure 2As shown in the figure, the fixed bracket includes a slide rail bracket 52, a slide rail fixing bracket 53, and a sensor fixing bracket 54. The slide rail fixing bracket 53 is fixedly connected to the slide rail bracket 52 for fixing the slide rail bracket 52. The slide rail bracket 52 is slidably connected to the sensor fixing bracket 54 through a screw 56 that is snapped into the slide rail chute 55. A long slot 57 is machined on the sensor fixing bracket 54, and the screw 56 can slide within the long slot 57. A position sensor 51 is connected to the sensor fixing bracket 54. By adjusting the positions of the screw 56 in the slide rail chute 55 and the long slot 57, the position of the position sensor 51 can be adjusted to be suitable for detecting the position of the steel strip.

[0020] The high-definition camera system 2 includes an entrance operation side high-definition camera system 201 and an entrance centering high-definition camera system 202, an exit operation side high-definition camera system 203 and an exit centering camera system 204, as Figure 3 shown. The data of the high-definition camera system is loaded, transmitted to the human-machine interface, and at the same time, the data is analyzed and processed by the PLC control system to send out a control servo control system command signal or stored in the memory for the human-machine interface to query and display; the system control logic is as Figure 4 shown.

[0021] The principles of the entrance centering and centering control devices are the same. Taking the entrance centering as an example, the control algorithm of the centering control device is: Define the distance between the center line of the entrance operation side high-definition camera system 201 and the center line of the unit as ES1, the width of the steel strip as EW1, the distance between the edge of the strip head photographed by the operation side high-definition camera system 201 and the center line of the operation side high-definition camera system 201 as ES2, the distance between the edge of the farthest end of the strip within the shooting range of the entrance centering high-definition camera system 202 and the center line of the operation side high-definition camera system 201 as ES3, and the distance between the edge of the strip head and the zero reference line 6 of the electric push rod as OF; as Figure 5 and Figure 6 shown.

[0022] After the strip head reaches the detection position of the entrance high-definition camera system 202, ES2 and ES3 are obtained through the position detection device 5 and sent to the PLC control system.

[0023] When ES2 = ES3, the center line 7 of the steel plate is on the center line 8 of the unit, and the electric push rod does not need to act; when ES2 > ES3, the steel strip deflects to the operation side, OF = ES1 - ES2 - ES1 / 2; when ES2 < ES3, the steel strip deflects to the drive side, OF = ES1 / 2 - ES1 + ES2; the PLC control system further calculates the data for the electric push rod to act based on this and sends it to the electric push rod to make it complete the action. During the process, the high-definition camera system returns the real-time ES2 and ES3 data until ES2 = ES3.

[0024] When the inlet and outlet steel strips are completely aligned, perform longitudinal alignment, such as Figure 7 shown.

[0025] Assume that the distance between the edge of the strip head photographed by the high-definition camera system 201 on the operating side of the entrance area centering device and the center line of the high-definition camera system 201 on the operating side is ZE2, and the distance between the farthest strip edge within the photographing range of the high-definition camera system 202 on the entrance area centering device and the center line of the high-definition camera system 201 on the operating side is ZE3; The distance between the edge of the strip head photographed by the high-definition camera system 203 on the operating side of the exit area centering device and the center line of the high-definition camera system 203 on the operating side is ZD2, and the distance between the farthest strip edge within the shooting range of the high-definition camera system 204 on the exit area centering device and the center line of the high-definition camera system 203 on the operating side is ZD3; When ZE2>ZD2, based on ZD2 data, the PLC control system drives the servo motor to drive the inlet centering device to move toward the operating side as a whole until ZE2=ZD2 is equal. On the contrary, when ZE2

Claims

1. A welding machine belt head and tail automatic centering control system, characterized by: It includes a high-definition camera system, a servo control system, a PLC control system and a position detection device. The high-definition camera system includes a camera, a light source and a human-machine interface, which samples and monitors the positions of the leading and trailing ends of the steel strip in real time, and transmits the data to the PLC control system through the high-definition camera system software. The PLC control system analyzes the positions of the leading and trailing ends and compares them with the target positions, and issues control instructions to the servo control system according to the position comparison results. The execution structure of the servo control system includes an electric push rod and a servo motor. The control system controls the electric push rod to align the steel strip left and right, and controls the servo motor to align the steel strip front and back. The high-definition camera system includes an entrance operation side high-definition camera system, an entrance centering high-definition camera system, an exit operation side high-definition camera system and an exit centering camera system.

2. According to claim 1, a welding machine belt head and tail automatic centering control system is characterized by: The position detection device shown uses a position sensor and is set at the outer corner position of the drive side of the welding machine centering device through a fixed bracket.

3. According to claim 2, a welding machine belt head and tail automatic centering control system is characterized in that: The fixed bracket includes a slide rail frame, a slide rail fixing frame and a sensor fixing frame. The slide rail fixing frame is fixedly connected to the slide rail frame to fix the slide rail frame. The slide rail frame is slidably connected to the sensor fixing frame through screws clamped into the slide rail chute. A long groove is machined on the sensor fixing frame, and the screws can slide in the long groove. The position sensor is connected to the sensor fixing frame. The position of the position sensor can be adjusted by adjusting the positions of the screws in the slide rail chute and the long groove.

4. The control method of the automatic centering control system for the welding machine head and tail as claimed in claim 1 is characterized by: It includes: 1) The centering actions of the steel strip at the entrance and exit of the welding machine: Let the distance between the center line of the operation side high-definition camera system and the center line of the unit be ES1, the width of the steel strip be EW1, the distance between the edge of the strip head photographed by the operation side high-definition camera system and the center line of the operation side high-definition camera system be ES2, the distance between the edge of the strip at the farthest end within the shooting range of the centering high-definition camera system and the center line of the operation side high-definition camera system be ES3, and the distance between the edge of the strip head and the zero reference line of the electric push rod be OF. After the leading end of the steel strip reaches the detection position of the high-definition camera system, ES2 and ES3 are obtained through the position detection device and sent to the PLC control system. When ES2 = ES3, the center line of the steel plate is on the center line of the unit, and the electric push rod of the execution structure does not need to act. When ES2 > ES3, the steel strip deviates to the operation side, OF = ES1 - ES2 - ES1 / 2, or when ES2 < ES3, the steel strip deviates to the drive side, OF = ES1 / 2 - ES1 + ES2. The PLC control system calculates the data for the electric push rod to act and issues it to the electric push rod to complete the action. During the process, the high-definition camera system returns the real-time ES2 and ES3 data until ES2 = ES3, and the horizontal centering is completed. 2) After the centering of the steel strip at the entrance and exit is all completed, the longitudinal alignment action is carried out: Let the distance between the edge of the strip head photographed by the operation side high-definition camera system in the entrance area centering device and the center line of the operation side high-definition camera system be ZE2, and the distance between the edge of the strip at the farthest end within the shooting range of the entrance area centering high-definition camera system and the center line of the operation side high-definition camera system be ZE3. The distance from the edge of the strip head captured by the high-definition camera system on the operator side of the centering device in the exit area to the center line of the high-definition camera system on the operator side is ZD2, and the distance from the edge of the strip at the farthest end within the shooting range of the high-definition camera system for centering in the exit area to the center of the high-definition camera system on the operator side is ZD3; When ZE2 > ZD2, based on the ZD2 data, the PLC control system drives the servo motor to drive the entire inlet centering device to move towards the operator side until ZE2 = ZD2. On the contrary, when ZE2 < ZD2, based on ZD2, the servo driver drives the entire inlet centering device to move towards the drive side until ZE2 = ZD2, completing the front-back centering of the steel strip. Then, check whether the data of ZE3 and ZD3 are equal. If they are equal, the longitudinal alignment is completed.

Images