Automatic pipe fitting welding equipment and welding method

Abstract

The invention relates to the technical field of pipe fitting welding, in particular to automatic pipe fitting welding equipment and method.The automatic pipe fitting welding equipment comprises a rack, and the rack is provided with a positioning assembly used for supporting metal pipe fittings and positioning the metal pipe fittings and a laser welding head used for welding the two metal pipe fittings; the positioning assembly comprises a main positioning plate capable of moving left and right and allowing the end face of one end of the first metal pipe fitting to abut against. A main positioning block and a positioning guide shaft rod are arranged on the main positioning plate, the main positioning block can be used for inserting and positioning an end opening part of one end of a first metal pipe fitting, the positioning guide shaft rod is arranged at the axis position of the main positioning block in a penetrating mode and can penetrate through the interiors of the two metal pipe fittings at the same time, and the positioning guide shaft rod can move left and right relative to the main positioning plate in the welding process; the far end, close to the main positioning block, of the positioning guide shaft rod is detachably connected with a pressing plate capable of abutting against the end face of the far end, close to the main positioning block, of the second metal pipe fitting, and the welding quality is higher.

Description

Technical Field

[0001] This invention relates to the field of pipe welding technology, and in particular to an automatic pipe welding equipment and welding method. Background Technology

[0002] Circular pipe fittings are used in various facilities such as industrial production, construction, and transportation. Considering factors such as economy, flexibility, maintainability, and technical feasibility in engineering practice, these circular pipe fittings are generally assembled by welding.

[0003] Existing technologies for welding processes and equipment are relatively mature. For example, Chinese Patent Application No. 201110316004.7 discloses an automatic welding method for circumferential welds on round pipe fittings. In this method, the round pipe fitting rotates relative to the welding torch during the welding process, and the welding position and angle of the welding torch in three dimensions can be automatically adjusted to achieve automatic welding of the circumferential weld. Using the welding method of this invention, during the welding process, the round pipe fitting rotates relative to the welding torch, and the welding position and angle of the welding torch in three dimensions can be automatically adjusted. This allows for more flexible and precise adjustment of the welding position and angle, enabling automatic multi-layer, multi-pass welding to form a circumferential weld with good mechanical properties.

[0004] For example, Chinese Patent Application No. 201921661754.6 discloses a pipe welding machine, including a support platform. Its features are: a fixed block is fixedly connected to one side of the upper part of one side of the support platform, a cylinder fixing block is bolted to the other side of the fixing block, a cylinder is fixedly connected to the cylinder, the lower end of the piston rod of the cylinder is fixedly connected to the upper side of the first pipe clamp, the ends of the two sides of the first pipe clamp are respectively threaded to the second pipe clamp by two bolts, and a connecting block is provided in the pipe hole formed by the first pipe clamp and the second pipe clamp.

[0005] However, existing equipment and processes are not yet mature enough in terms of weld penetration and internal treatment of pipe fittings. During welding, defects such as inconsistent weld uniformity, poor connection strength, and persistent oxidation and nitriding on the inner surface frequently occur. These technical deficiencies urgently need improvement to meet increasingly stringent pipe fitting quality requirements.

[0006] In particular, the fine control of the pipe fitting welding process is still insufficient. For example, the control of clamping force and the control of shielding gas during the welding process are not yet fully addressed in the existing technology. This application will provide a more systematic optimization of the entire welding process and corresponding equipment components to improve the quality of the welded parts. Summary of the Invention

[0007] The purpose of this invention is to provide an automatic welding equipment and welding method for pipe fittings with high welding quality.

[0008] The above-mentioned objective of the present invention is achieved through the following technical solution: an automatic pipe welding device, comprising a frame, wherein a positioning component for supporting and positioning metal pipes and a laser welding head for welding two metal pipes are provided on the frame, the positioning component comprising a main positioning plate that can move left and right and is abutted against by one end face of the first metal pipe, a main positioning block provided on the main positioning plate for inserting and positioning one end port portion of the first metal pipe, and a positioning guide shaft passing through the axial center of the main positioning block and capable of passing through the interior of both metal pipes simultaneously, the positioning guide shaft being able to move left and right relative to the main positioning plate during the welding process, and a clamping plate that abuts against the far end face of the second metal pipe near the main positioning block is detachably connected to the positioning guide shaft near the far end of the main positioning block.

[0009] As a preferred embodiment of the present invention, the positioning guide shaft is a hollow tube with inert gas introduced inside, and an exhaust hole for the inert gas to be discharged is provided on the positioning guide shaft.

[0010] As a preferred embodiment of the present invention, the clamping plate is connected to an auxiliary positioning block for the second metal pipe fitting to be inserted and positioned near the far end of the main positioning block.

[0011] As a preferred embodiment of the present invention, an external thread is formed on the outer wall of the positioning guide shaft.

[0012] As a preferred embodiment of the present invention, the axial portion of the clamping plate is through which the positioning guide shaft passes and is threadedly connected to the positioning guide shaft via an external thread.

[0013] As a preferred embodiment of the present invention, the outer wall of the positioning guide shaft is threaded with a plurality of pre-support positioning sleeves that are spaced apart on the left and right and are used for pre-supporting metal pipe fittings. The inner ring of the pre-support positioning sleeve forms a threaded hole that fits with the external thread. The pre-support positioning sleeve is annular, and the outer ring diameter of the main positioning block is greater than or equal to the outer ring diameter of the pre-support positioning sleeve.

[0014] As a preferred embodiment of the present invention, the pre-support positioning sleeve is integrally connected to a tapered guide sleeve on the side opposite to the main positioning block, which is used to pre-guide the metal pipe to move towards the main positioning block. The outer ring of the tapered guide sleeve is tapered and the inner ring is threadedly connected to the external thread.

[0015] As a preferred embodiment of the present invention, a first moving drive mechanism for moving the main positioning plate is connected to the lower side of the main positioning plate, a second moving drive mechanism for moving the positioning guide shaft is connected to one end of the main positioning plate, and a pressure sensor is installed on the main positioning plate.

[0016] As a preferred embodiment of the present invention, the positioning guide shaft passes through the main positioning plate and is connected to the motor shaft of the rotary motor at one end of the main positioning plate opposite to the main positioning block. The rotary motor is mounted on the second moving drive mechanism, and the main positioning plate can rotate and is mounted on the first moving drive mechanism through a rotating mechanism.

[0017] A welding method for an automatic pipe welding device includes the following steps: Step 1, passing a first metal pipe through a positioning guide shaft and inserting it into a main positioning block to abut against a main positioning plate; Step 2, passing a second metal pipe through the positioning guide shaft to abut against the end of the first metal pipe, and installing a clamping plate on the positioning guide shaft to press down the other end of the second metal pipe; Step 3, aligning the laser welding head with the mating position of the first and second metal pipes for welding, while simultaneously rotating and moving the positioning guide shaft left and right to adjust the clamping force; Step 4, after welding, removing the clamping plate and moving the welded final pipe out of the positioning guide shaft.

[0018] The beneficial effects of this invention are: the clamping force between the pipes can always be kept in a stable state during welding, the control of the molten pool and the depth of the weld is optimized, and the uniformity of the weld and the connection strength are guaranteed.

[0019] The alignment stability is also reliable, making it less likely for unevenness to occur in the welded pipe fittings caused by misalignment at the welding position.

[0020] The internal oxidation and nitriding problems have been well resolved;

[0021] It offers greater controllability and allows for more precise welding processes, resulting in the production of higher-quality welded pipe fittings.

[0022] This application solves many problems existing in the prior art, and the beneficial effects are significant: the entire concept revolves around dynamically adjusting the clamping force between pipe fittings during the welding process, and through a design centered on a positioning guide shaft, it solves multiple problems and achieves corresponding technical effects.

[0023] The entire organic solution revolves around the positioning and guiding shaft:

[0024] It achieved the guiding and positioning of the pipe fittings;

[0025] The inert gas is used inside the pipe fitting to effectively resist oxidation, nitriding, and welding spatter, thus ensuring the welding quality inside the pipe fitting.

[0026] It enables rotation during the welding process, ensuring a stable welding flow;

[0027] It can also adjust the position to ensure the stability of the clamping force between pipe fittings during the welding process, thereby achieving high reliability and uniformity of welding and improving the effect of welding connection;

[0028] It can also be programmed with a controller to automate welding processes, making it more controllable;

[0029] The overall design is quite practical, highly suitable for the requirements of high-quality welded pipe fitting production, and also has good economic value. Attached Figure Description

[0030] Figure 1 This is a three-dimensional structural schematic diagram of the welding equipment in Example 1;

[0031] Figure 2 yes Figure 1 A schematic diagram of the three-dimensional structure from another perspective;

[0032] Figure 3 yes Figure 1 A three-dimensional structural diagram of the equipment during the welding of two metal pipe fittings;

[0033] Figure 4 yes Figure 3 A three-dimensional structural diagram of the alignment and assembly process of the middle structure before welding;

[0034] Figure 5 yes Figure 1 A schematic diagram of the three-dimensional structure after further optimization of the central structure;

[0035] Figure 6 yes Figure 3 A schematic diagram of the three-dimensional structure after further optimization of the central structure;

[0036] Figure 7 yes Figure 1 A schematic diagram of the optimized three-dimensional structure of the tapered guide section in the middle;

[0037] Figure 8 yes Figure 7 A schematic diagram of the three-dimensional structure from another perspective. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the accompanying drawings.

[0039] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0040] Example 1, such as Figure 1-8As shown, an automatic pipe welding device includes a frame 1, which can adopt an existing frame structure or support platform. The frame 1 is equipped with a positioning component for supporting and positioning the metal pipe g, and a laser welding head j for welding two metal pipes. The laser welding head j can be an existing laser welding product and can be installed and connected to the frame in an existing manner. It is preferable to use an existing mobile installation structure because the laser welding head j often needs to be adjusted in angle and position according to specific conditions, and may even need to be rotated. The most important component in this application is the positioning assembly. Specifically, the positioning assembly includes a main positioning plate 2 that can move left and right and allows one end face of the first metal pipe to abut against it; a main positioning block 22 on the main positioning plate 2 that allows one end port of the first metal pipe to be inserted and positioned; and a positioning guide shaft 21 that passes through the axial center of the main positioning block 22 and can pass through the interior of both metal pipes simultaneously. The main positioning plate 2, the main positioning block 22, and the positioning guide shaft 21 are the most important design concepts of this application, especially the positioning guide shaft 21. The positioning guide shaft 21 passes through the axial center area of ​​the main positioning plate 2 and the main positioning block 22. The main positioning plate 2 and the main positioning block 22 have corresponding axial holes for the positioning guide shaft 21 to pass through and maintain a gap. Because the positioning guide shaft 21 needs to move left and right during the welding process, if it is in contact, a smooth surface must be maintained, so a gap fit is better. The positioning guide shaft 21 can be made of metal steel and is a cylindrical rod. Both the main positioning plate 2 and the main positioning block 22 can be cylindrical. The outer diameter of the main positioning plate 2 is larger than that of the main positioning block 22, and their axial directions should be consistent, both in the left-right direction. The outer diameter of the main positioning block 22 needs to be consistent with the inner diameter of the metal pipe fitting, although a certain degree of error is permissible. If the main positioning block 22 is made of plastic, it can be slightly larger because of its plastic deformation capability, which allows for a tighter compression fit. However, in this case, it is best to have a pre-guided tapered structure on the main positioning block 22 for transition. If the main positioning block 22 is made of steel, it is necessary to ensure the consistency of dimensions as much as possible, with as few gaps as possible.

[0041] The main positioning plate 2 and the main positioning block 22 can be fixed by existing methods that facilitate easy disassembly and assembly, such as connecting them by bolts running through the left and right sides. This makes it easy to replace the main positioning block 22 of different sizes to suit metal pipe fittings of different sizes.

[0042] Furthermore, the positioning guide shaft 21 can move left and right relative to the main positioning plate 2 during the welding process. The positioning guide shaft 21 is detachably connected to a clamping plate 23 near the far end of the main positioning block 22, which can abut against the far end face of the second metal pipe near the main positioning block 22. This allows the two metal pipes to be pressed between the main positioning plate 2 and the clamping plate 23, so that the mating parts between the two are close together, which can be welded better. In laser welding, the assembly gap between pipes is required to be extremely strict. The ideal state is to fit tightly, with zero gap or a very small gap. If a large gap is left, it will lead to welding failure or a serious deterioration of weld quality.

[0043] The specific reason lies in the fact that the core advantage of laser welding is focusing energy onto a very small point, with a spot diameter typically ranging from 0.1mm to 1mm. The spot size itself is very small. If there is a gap between the components that exceeds or is close to the spot diameter, the laser beam will pass directly through the gap and irradiate the air or fixture below, instead of acting on the edges of the workpieces on both sides. The result is that the edges of the base materials on both sides cannot be melted, an effective connection cannot be formed, and the molten pool cannot bridge the gap, leading to incomplete fusion or burn-through. Laser welding also produces a molten pool, but its size is much smaller than that of arc welding, and its existence is very brief. The surface tension and rapid cooling and solidification characteristics of the molten metal limit its ability to bridge gaps. Even if a small amount of molten metal flows into the gap, the cold base materials on both sides need a very small or nonexistent gap to form a good metallurgical bond, thus preventing defects such as dents and undercuts. The laser welding process itself has relatively high requirements for the assembly precision of the workpieces, such as the gaps between components and misalignment. Therefore, the requirements for the gap between the pipe fittings are high. This application uses the aforementioned design to allow the two metal pipe fittings to fit more tightly together.

[0044] In this embodiment, the welding process is briefly described as follows: First, the first metal pipe is passed through the positioning guide shaft 21 and then inserted into the main positioning block 22, with one end abutting against the main positioning plate 2. Then, the second metal pipe is also passed through the positioning guide shaft 21 and connected to the other end of the first metal pipe. Next, a fixing plate 23 is installed at the far end of the positioning guide shaft 21 on the main positioning plate 2, with the fixing plate 23 pressing against the other end of the second metal pipe. The positioning guide shaft 21 can be moved left and right to adjust the clamping degree. The two metal pipes are positioned between the main positioning plate 2 and the fixing plate 23, and welding can be performed when there is no gap or a very small gap in the clamped state. Then, the laser welding head j begins welding. The laser welding head j can be movable, allowing it to rotate for welding. Because the clamping force is maintained during the welding process, the positioning guide shaft 21 will move further, maintaining the clamping state during movement. The welding area where the two metal pipes meet will shift, and the laser welding head j will move left and right accordingly. Alternatively, the position and clamping degree can be adjusted by moving the main positioning plate 2. After welding is completed, remove the clamping plate 23 and move the welded metal pipe fitting away for reuse. The pipe fitting can be moved using a robotic arm gripper or manually, and the choice of method is crucial, including the initial alignment.

[0045] Furthermore, the positioning guide shaft 21 is a hollow tube with an inert gas introduced inside. An exhaust port 210 for the inert gas is provided on the positioning guide shaft 21, communicating with the internal cavity. The inert gas is argon, helium, nitrogen, or a mixture thereof, preventing the molten metal from reacting with oxygen and nitrogen in the air, avoiding oxidation and nitriding, improving weld quality, and blowing away plasma generated during welding (generally formed by the ionization of metal vapor under a high-energy laser), preventing plasma from shielding laser energy and affecting the weld penetration. This treatment is performed inside the metal tube, which is an advantage of this application. Of course, inert gas also needs to be blown into the weld area outside the metal tube during welding; this can be achieved using existing external inert gas catalytic structures.

[0046] Preferably, the clamping plate 23 is connected to an auxiliary positioning block 24 for the second metal fitting to be inserted and positioned near the distal end of the main positioning block 22. Both the clamping plate 23 and the auxiliary positioning block 24 can be cylindrical. The auxiliary positioning block 24 is fixed to the clamping plate 23 using existing methods, and the clamping plate 23 needs to be fixed to the positioning guide shaft 21 for effective clamping. The dimensions of the auxiliary positioning block 24 can be referenced to those of the main positioning block 22. The axial directions of the auxiliary positioning block 24, the clamping plate 23, the main positioning block 22, and the main positioning plate 2 are all in the left-right direction.

[0047] Furthermore, an external thread 200 is formed on the outer wall of the positioning guide shaft 21 to enable a detachable installation method. The axial portion of the clamping plate 23 allows the positioning guide shaft 21 to pass through and is threadedly connected to the positioning guide shaft 21 via the external thread 200. A threaded hole is formed in the axial portion of the clamping plate 23 to facilitate assembly and disassembly with the external thread 200. In this method, the positioning guide shaft 21 also passes through the auxiliary positioning block 24. The axial portion of the auxiliary positioning block 24 also has a hole for the positioning guide shaft 21 to pass through, which can also be a threaded hole for assembly with the external thread 200. Of course, other structural designs that facilitate assembly and disassembly can be selected, allowing the clamping plate 23 and the auxiliary positioning block 24 to be detachably and fixedly connected to the positioning guide shaft 21.

[0048] Preferably, the outer wall of the positioning guide shaft 21 is threaded with a plurality of left-right spaced pre-support positioning sleeves 3 for pre-supporting metal pipe fittings via external threaded portions 200. The inner ring of each pre-support positioning sleeve 3 forms a threaded hole that mates with the external threaded portion 200. The pre-support positioning sleeve 3 is annular, but its overall shape is cylindrical, except that the axial part, i.e., the inner ring, becomes a threaded hole, hence the annular shape. The outer diameter of the main positioning block 22 is greater than or equal to the outer diameter of the pre-support positioning sleeve 3. The metal pipe fitting is fitted around the pre-support positioning sleeve 3 for pre-support and guiding positioning. Given the pre-support and guiding positioning, the outer diameter of the pre-support positioning sleeve 3 is designed to be less than or equal to the inner diameter of the metal pipe, ideally within half the wall thickness of the metal pipe. This ensures a larger contact area at the left and right ends when the pipe fittings are pre-connected. The pre-support positioning sleeve 3 can be made of metal or plastic.

[0049] Furthermore, the pre-support positioning sleeve 3, facing away from the main positioning block 22, is integrally connected to a tapered guide sleeve 31 for pre-guiding the movement of the metal pipe towards the main positioning block 22. The outer ring of the tapered guide sleeve 31 is tapered, and its inner ring is threaded to the external threaded portion 200. The outer ring diameter of the tapered guide sleeve 31 decreases in the direction facing away from the main positioning block 22. The inner ring of the tapered guide sleeve 31 is also a threaded hole for the positioning guide shaft 21 to pass through and be installed and connected. The maximum diameter of the outer ring of the tapered guide sleeve 31 is less than or equal to the outer ring diameter of the pre-support positioning sleeve 3. This design allows for left and right position adjustment by screwing the sleeve body, and also allows for the replacement of different sizes of the pre-support positioning sleeve 3 and tapered guide sleeve 31. This design provides better guidance, stability, and support when the metal pipe is fitted.

[0050] Based on the above design, a tapered first pre-insertion guide block 201 is integrally connected to the side of the main positioning block 22 opposite to the main positioning plate 2. The first pre-insertion guide block 201 and the positioning guide shaft 21 are preferably in clearance fit. A hole is opened at the axis of the first pre-insertion guide block 201 for the positioning guide shaft 21 to pass through while maintaining the clearance. The outer ring of the first pre-insertion guide block 201 is tapered and forms a tapered surface, and the direction in which the tapering decreases is consistent with the tapered guide sleeve 31. Furthermore, the maximum diameter of the outer ring of the first pre-insertion guide block 201 is less than or equal to the outer ring diameter of the main positioning block 22. Similarly, the auxiliary positioning block 24 is integrally connected to the tapered second pre-insertion guide block 202 on the side opposite to the clamping plate 23. However, the tapered direction is opposite to that of the first pre-insertion guide block 201. The axis of the second pre-insertion guide block 202 is also for the positioning guide shaft 21 to pass through. However, it is better if the axis forms a threaded hole and is threaded to the external thread 200 of the positioning guide shaft 21. Of course, clearance fit is also acceptable. The main purpose is that after the two metal pipes are joined together, the auxiliary positioning block 24 is inserted into the port of the second metal pipe at the far end, so that it can be positioned at the end of the second metal pipe and the clamping plate can be pressed against the port of the second metal pipe.

[0051] Furthermore, the pre-support positioning sleeve 3 and the conical guide sleeve 31 are provided with gas flow holes 331 that extend through the left and right sides. The pre-support positioning sleeve 3 also has a blind accumulation hole 332 extending from its opposite side towards the conical guide sleeve 31. The gas flow holes 331 facilitate the lateral flow of inert gas, preventing excessive internal pressure. The blind accumulation hole 332 provides space to store solid particles of fumes and spatter generated during the welding process, allowing for periodic cleaning or replacement. This ensures smooth flow of inert gas and stable internal pressure, while also providing better internal handling of debris, both of which contribute to improving the welding process.

[0052] Preferably, the lower side of the main positioning plate 2 is connected to a first moving drive mechanism 51 for moving it. The first moving drive mechanism 51 can be an existing lead screw mechanism or a stepper motor or other translation mechanism. The main positioning plate 2 needs to be installed and connected to the moving part of this translation structure, such as a movable slider. Of course, the translation mechanism can be equipped with equipment of different precision as needed.

[0053] The positioning guide shaft 21 is connected to a second moving drive mechanism 52 at one end near the main positioning plate 2. The second moving drive mechanism 52 can also be an existing lead screw mechanism or a stepper motor translation mechanism, mainly to enable left and right translation. A pressure sensor is installed on the main positioning plate 2. Of course, the entire welding equipment will also be equipped with a controller, which can be an existing automatic controller. Based on the data from the pressure sensor, the pressure is kept stable, and the aforementioned drive mechanism is controlled to make corresponding movements.

[0054] Furthermore, the positioning guide shaft 21 passes through the main positioning plate 2 and is connected to the motor shaft 40 of the rotary motor 4 at one end of the main positioning plate 2 opposite to the main positioning block 22. The motor shaft and the positioning guide shaft 21 are both axially in the left-right direction. The rotary motor 4 is mounted on the second moving drive mechanism 52, so one end of the positioning guide shaft 21 is fixedly connected to the motor shaft 40 of the rotary motor 4. The motor body of the rotary motor 4 can be directly fixed to the moving part of the drive mechanism. Therefore, the positioning guide shaft 21 is mounted on the second moving drive mechanism 52 through the rotary motor 4. Of course, for the stability of the pipe support operation, the frame can be equipped with several lifting support rollers z. The support rollers z can be arranged in a front-to-back design. That is, after the metal pipe is positioned on the positioning guide shaft 21, it rises to support the lower side of the metal pipe and facilitates the rotation of the pipe. Because some pipes are heavy, even if the positioning guide shaft 21 is made of metal, it may deform after long-term use. Of course, when the load is small when the shaft is empty, there is not much of a problem. Of course, if the positioning guide shaft 21 is strong enough, it is not a big deal if an auxiliary support structure is not needed.

[0055] Furthermore, the main positioning plate 2 is rotatable and is mounted on the first moving drive mechanism 51 via a rotating mechanism. The rotating mechanism can employ an existing structure, using a large-sized support bearing. The main positioning plate 2 is embedded in the inner ring of the support bearing, and the outer ring of the support bearing is fixed to the moving part of the first moving drive mechanism 51. Thus, the rotation of the rotary motor 4 drives the positioning guide shaft 21 to rotate, thereby rotating the metal pipe for welding. This method prevents the welding head from rotating, resulting in higher stability. Here, a passive, existing rotating mechanism is sufficient, as the positioning guide shaft 21 itself rotates actively. Alternatively, an active rotating mechanism can be used, such as a gear ring structure. The main positioning plate 2 is fixed inside the gear ring, which is equipped with a gear pair. This gear pair is then mounted on an active rotating device. In this case, the positioning guide shaft 21 does not need to be connected to the motor shaft 40 of the rotary motor 4; it can be connected via a passive rotating structure and then mounted on the second moving drive mechanism 52. These are all for the convenience of rotation.

[0056] In this embodiment, a welding clamping force control system is configured on the controller side. This system is designed to ensure that the clamping force between the pipes remains stable during the welding process.

[0057] Below is a Python-based simulation program for a pipe fitting welding clamping force control system. The system monitors the clamping force in real time using sensors and uses a PID controller to adjust the positions of the first and second moving drive mechanisms, ensuring optimal clamping force between the pipe fittings during welding. The program uses a PID controller to implement closed-loop control, ensuring the clamping force remains stable near the target value. The specific program is as follows:

[0058] import time

[0059] class PIDController:

[0060] PID Controller Class

[0061] def __init__(self, kp, ki, kd, min_output, max_output):

[0062] self.kp = kp # Scale factor

[0063] self.ki = ki # Integral coefficient

[0064] self.kd = kd # Differential coefficients

[0065] self.min_output = min_output # Output the minimum value

[0066] self.max_output = max_output # Maximum output value

[0067] self.prev_error = 0 # Previous error

[0068] self.integral = 0 # Accumulate points

[0069] def compute(self, setpoint, measured_value):

[0070] Calculate PID output.

[0071] error = setpoint - measured_value

[0072] # Proportion Item

[0073] proportional = self.kp * error

[0074] # Integral terms with anti-saturation

[0075] self.integral += error

[0076] integral = self.ki * self.integral

[0077] # Differential Term

[0078] derivative = self.kd * (error - self.prev_error)

[0079] self.prev_error = error

[0080] # Calculate total output

[0081] output = proportional + integral + derivative

[0082] # Limit output range

[0083] output = max(self.min_output, min(self.max_output, output))

[0084] return output

[0085] class DriveSystem:

[0086] """Mobile Drive System Control Class"""

[0087] def __init__(self, pid_params):

[0088] self.pid_x1 = PIDController(*pid_params) # First drive mechanism PID

[0089] self.pid_x2 = PIDController(*pid_params) # Second drive mechanism PID

[0090] self.target_force = 0 # Target clamping force

[0091] self.x1_position = 0 # Current position driven by the first driver

[0092] self.x2_position = 0 # Current position of the second driver

[0093] def set_target_force(self, target):

[0094] """Set the target clamping force"""

[0095] self.target_force = target

[0096] def read_force_sensor(self):

[0097] """Read the clamping force sensor simulation function"""

[0098] # Replace with real sensor reading code in actual projects

[0099] # Return Example: Simulate sensor reading of current clamping force

[0100] return 0.0 # Need to be replaced with the actual sensor interface

[0101] def move_drive(self, drive_id, displacement):

[0102] """Simulation function for controlling the movement of the drive mechanism"""

[0103] # Replace with real driver control code in actual projects

[0104] if drive_id == 1:

[0105] self.x1_position += displacement

[0106] print(f"Driver 1 has moved to: {self.x1_position:.2f} mm")

[0107] elif drive_id == 2:

[0108] self.x2_position += displacement

[0109] print(f"Driver 2 has moved to: {self.x2_position:.2f} mm")

[0110] def adjust_positions(self):

[0111] "Adjust the position of the drive mechanism according to the clamping force."

[0112] current_force = self.read_force_sensor()

[0113] # Calculate the adjustment amount of the two drive mechanisms

[0114] adj1 = self.pid_x1.compute(self.target_force, current_force)

[0115] adj2 = self.pid_x2.compute(self.target_force, current_force)

[0116] # Execution location adjustment

[0117] self.move_drive(1, adj1)

[0118] self.move_drive(2, adj2)

[0119] return current_force

[0120] # Parameter Configuration

[0121] PID_PARAMS = {

[0122] 'kp': 0.5, # The scaling factor needs to be adjusted according to system characteristics.

[0123] 'ki': 0.01, # Integral coefficient

[0124] 'kd': 0.1, # Differential coefficient

[0125] 'min_output': -5, # Minimum adjustment amount (mm)

[0126] 'max_output': 5 ​​# Maximum adjustment amount (mm)

[0127] }

[0128] # Initialize the driver system

[0129] system = DriveSystem(PID_PARAMS)

[0130] system.set_target_force(100.0) # Set the target clamping force to 100N

[0131] # Main control loop

[0132] try:

[0133] while True:

[0134] current_force = system.adjust_positions()

[0135] print(f"Current clamping force: {current_force:.2f}N, Target: {system.target_force}N")

[0136] time.sleep(0.1) # Control period 100ms

[0137] except KeyboardInterrupt:

[0138] print("The program has been manually terminated").

[0139] Key Function Descriptions:

[0140] PID controller:

[0141] Implement a closed-loop control algorithm to calculate the adjustment amount based on the clamping force error;

[0142] Includes an anti-saturation mechanism to prevent integral saturation;

[0143] Adjustable parameters: Kp (proportional), Ki (integral), Kd (derivative).

[0144] Drive system core logic:

[0145] adjust_positions(): The core control function, completes the following:

[0146] Read the current clamping force;

[0147] Calculate the adjustment amount of the two drive mechanisms;

[0148] Execution location adjustment;

[0149] Supports independent adjustment of the two drive mechanisms;

[0150] The simulated interface needs to be replaced with the actual hardware interface.

[0151] read_force_sensor(): Reads the pressure sensor;

[0152] move_drive(): Controls the movement of the drive mechanism.

[0153] Parameter adjustment suggestions:

[0154] PID parameters:

[0155] Initial values ​​need to be adjusted according to the actual system:

[0156] kp: 0.2-0.8 response speed;

[0157] ki: 0.001-0.05 to eliminate steady-state error;

[0158] kd: 0.05-0.3 suppresses oscillations.

[0159] Debugging method:

[0160] First, set ki=0 and kd=0, then adjust kp until the system responds but does not oscillate.

[0161] Increasing ki eliminates residual error;

[0162] Finally, add kd to suppress overshoot.

[0163] Security restrictions:

[0164] min_output / max_output: Set according to the machine's allowable range;

[0165] In practical applications, position limit protection should be added.

[0166] Important considerations for actual deployment:

[0167] Replace the simulated functions with real hardware interfaces;

[0168] Added handling for abnormal situations such as sensor failures and drive over-limits;

[0169] Add position calibration function for zero point setting;

[0170] Consider the mutual influence between the two drive mechanisms due to mechanical coupling effects;

[0171] The system needs to perform initial position calibration upon startup;

[0172] This program provides the core control framework, but in practical applications it needs to be adjusted and optimized according to the specific mechanical system and sensor characteristics.

[0173] Example 2: An automatic pipe welding method using the welding equipment in Example 1, specifically including the following steps: Step 1: Passing the first metal pipe through the positioning guide shaft and inserting it into the main positioning block, then pressing it against the main positioning plate. The passage process is relatively smooth due to the pre-guided structure. Step 2: Passing the second metal pipe through the positioning guide shaft and pressing it against the end of the first metal pipe. A clamping plate is installed on the positioning guide shaft to press down the other end of the second metal pipe. Step 3: The laser welding head is aligned with the mating position of the first and second metal pipes and welded. At the same time, the positioning guide shaft rotates and moves left and right to adjust the clamping force, so that the two pipes can maintain a stable clamping force during rotation. Step 4: After welding, the clamping plate is removed, and the welded final pipe is moved out of the positioning guide shaft.

[0174] The above-described method of dynamic welding significantly improves the welding effect.

[0175] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An automatic pipe fitting welding device, characterized in that, The device includes a frame (1), on which a positioning assembly for supporting and positioning metal pipes and a laser welding head (j) for welding two metal pipes are provided. The positioning assembly includes a main positioning plate (2) that can move left and right and allows one end face of the first metal pipe to abut against it. The main positioning plate (2) is provided with a main positioning block (22) that allows one end port of the first metal pipe to be inserted and positioned. A positioning guide shaft (21) that can pass through the axial position of the main positioning block (22) and can pass through the interior of both metal pipes at the same time is provided. The positioning guide shaft (21) can move left and right relative to the main positioning plate (2) during the welding process. The positioning guide shaft (21) is detachably connected to a clamping plate (23) that can abut against the far end face of the second metal pipe near the main positioning block (22) near the main positioning block (22).

2. The automatic pipe welding equipment according to claim 1, characterized in that, The positioning guide shaft (21) is a hollow tube and inert gas is introduced into it. An exhaust hole (210) is provided on the positioning guide shaft (21) for the inert gas to be discharged.

3. The automatic pipe welding equipment according to claim 1, characterized in that, The clamping plate (23) is connected to an auxiliary positioning block (24) for the second metal pipe fitting to be inserted and positioned near the far end of the main positioning block (22).

4. The automatic pipe welding equipment according to claim 3, characterized in that, An external thread (200) is formed on the outer wall of the positioning guide shaft (21).

5. The automatic pipe welding equipment according to claim 4, characterized in that, The axial portion of the clamping plate (23) is through which the positioning guide shaft (21) passes and is threadedly connected to the positioning guide shaft (21) via the external thread (200).

6. The automatic pipe welding equipment according to claim 4, characterized in that, The outer wall of the positioning guide shaft (21) is threaded with a plurality of pre-support positioning sleeves (3) that are spaced apart on the left and right and are used for pre-supporting metal pipe fittings. The inner ring of the pre-support positioning sleeve (3) forms a threaded hole that fits with the external thread (200). The pre-support positioning sleeve (3) is annular. The outer ring diameter of the main positioning block (22) is greater than or equal to the outer ring diameter of the pre-support positioning sleeve (3).

7. The automatic pipe welding equipment according to claim 6, characterized in that, The pre-support positioning sleeve (3) is integrally connected to a conical guide sleeve (31) on the side opposite to the main positioning block (22) for pre-guiding the movement of the metal pipe in the direction of the main positioning block (22). The outer ring of the conical guide sleeve (31) is conical and the inner ring is threadedly connected to the external thread (200).

8. The automatic pipe welding equipment according to claim 2, characterized in that, The lower side of the main positioning plate (2) is connected to a first moving drive mechanism (51) for moving thereto, and the positioning guide shaft (21) is connected to a second moving drive mechanism (52) for moving thereto at one end near the main positioning plate (2). A pressure sensor is installed on the main positioning plate (2).

9. An automatic pipe fitting welding device according to claim 3, characterized in that, The positioning guide shaft (21) passes through the main positioning plate (2) and is connected to the motor shaft (40) of the rotary motor (4) at one end of the main positioning plate (2) opposite to the main positioning block (22). The rotary motor (4) is mounted on the second moving drive mechanism (52). The main positioning plate (2) can rotate and is mounted on the first moving drive mechanism (51) through the rotating mechanism.

10. A welding method for an automatic pipe fitting welding equipment according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Pass the first metal pipe through the positioning guide shaft (21) and insert it into the main positioning block (22) to abut against the main positioning plate (2); Step 2: Pass the second metal pipe through the positioning guide shaft (21) to abut against the end of the first metal pipe, and install a clamping plate (23) on the positioning guide shaft (21) to press against the other end of the second metal pipe; Step 3: Align the laser welding head (j) with the mating position where the first and second metal pipes abut against each other and weld them. At the same time, rotate the positioning guide shaft (21) and move it left and right to adjust the clamping force; Step 4: After welding, remove the clamping plate (23) and move the welded final pipe out of the positioning guide shaft (21).

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