Multi-wheel drive intelligent welding, spraying and detecting integrated device in pipeline and control method

Abstract

The invention discloses a multi-wheel drive intelligent welding, spraying and detecting integrated device in a pipeline and a control method.The device comprises a multifunctional cabin, driving wheels and a clamping mechanism are arranged on the surface of the multifunctional cabin, the front end of the multifunctional cabin is connected with a track auxiliary mounting mechanism, and a welding seam detecting device, a spraying device and a visual recognition device are arranged at the rear end of the multifunctional cabin; the rail auxiliary installation mechanism is connected with the flexible magnetic attraction welding rail through a hydraulic push rod, and the flexible magnetic attraction welding rail is matched with the welding trolley. A series of problems caused by manual welding are solved; the mechanical arm is used as a carrier, so that the automatic operation of welding seam detection and rust-proof spraying in the pipe is realized; and by means of the automatic weld joint detecting and spraying integrated device, the intelligent platform can conduct detection and rust-proof spraying on a previous weld joint while conducting welding, and the engineering efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of pipeline robot welding, and in particular to an integrated device and control method for multi-wheel drive intelligent welding, spraying and detection in a pipeline. Background Art

[0002] Pumped storage power stations use hydropower as a carrier to generate electricity. In low-peak electricity consumption areas, excess electricity can be used to pump water to the upper reservoir to store energy. In peak electricity consumption areas, the gates are opened to release water to achieve the conversion of water potential energy into electrical energy, thereby playing the role of "peak regulation and valley leveling". The upper and lower reservoirs have a large drop and frequent water level changes. The water body circulates back and forth between the upper and lower reservoirs, which puts high demands on pipelines. The pipelines used generally have a large diameter, wall thickness and high compressive strength grade. In order to facilitate the installation of pipelines in mountain culverts, pipelines are generally in the form of sections. The steel pipe factory produces multi-section steel pipes of appropriate lengths. After being transported to the site, they are installed through a cycle of segmented welding, pouring concrete, and installing new segmented pipelines. Among the above operations, welding is the most important step in pipeline installation due to its difficulty in operation and its great impact on project quality.

[0003] Due to the thickness and large diameter of the pipeline and the limited operating space in the culvert, manual welding currently requires a lot of time and manpower. The quality and efficiency of manual welding are mainly determined by the proficiency of the welder, which will lead to unstable project quality and even affect the construction period. In addition, due to the harsh working environment, welders work in a humid environment for a long time, and are also at risk of high temperature burns and poisoning, which also places high demands on construction safety. At the same time, it is becoming increasingly difficult to recruit skilled welders, which risks affecting the construction period.

[0004] With the rapid growth of clean energy demand such as oil and gas, pumped storage power stations, higher requirements are placed on the welding process of energy equipment; manual welding, semi-automatic welding and other welding methods are unable to meet the actual needs of pipeline on-site welding due to their large quality impact, low welding efficiency, low one-time welding pass rate, many welding defects and high labor intensity of workers; therefore, automatic welding devices in pipelines have emerged as the times require, becoming the main welding method for high-grade steel and large-diameter pipeline welding construction; however, the existing automatic welding devices in pipelines have the following defects: 1. The welding track cannot be installed automatically and can only be installed manually, which makes the installation accuracy low, resulting in low welding quality and greatly reduced efficiency, and the flexible magnetic welding track needs to be manually carried between pipeline sections, which consumes a lot of manpower; 2. Although the existing detection and spraying mechanisms have the ability to automatically identify and track weld operations, most of them need to be installed in fixed positions, such as on assembly lines, and lack carriers for operating in pipes. 3. Welding, weld inspection, and anti-rust spraying need to be carried out separately, which increases the complexity and time cost of the operation, resulting in reduced overall construction efficiency. It may also cause certain welding defects to not be discovered and repaired in time, increasing safety hazards. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a multi-wheel drive intelligent welding spray detection integrated device and control method in a pipeline to solve a series of problems caused by manual welding, realize the automated operation of weld detection and anti-rust spraying in the pipe, and at the same time as welding, the previous weld can be detected and anti-rust sprayed to improve engineering efficiency.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: an integrated multi-wheel drive intelligent welding spraying detection device in a pipeline, including a multi-functional cabin, a driving wheel and a clamping mechanism are provided on the surface of the multi-functional cabin, the front end of the multi-functional cabin is connected to the track auxiliary installation mechanism, and the rear end is provided with a weld detection device, a spraying device and a visual recognition device. The track auxiliary installation mechanism is connected to the flexible magnetic welding track through a hydraulic push rod, and the flexible magnetic welding track cooperates with the welding trolley.

[0007] Preferably, there are two flexible magnetic welding tracks, which are electromagnetic adsorption flexible tracks with an arc-shaped structure. Each flexible magnetic welding track is provided with a welding trolley that slides with it, and the track auxiliary installation mechanism is connected to the flexible magnetic welding track through multiple hydraulic push rods.

[0008] Preferably, the welding carriage comprises a body, one side of the body is provided with a travel drive mechanism cooperating with a flexible magnetic welding track, and the other side is connected to a welding gun through a posture adjustment mechanism, and one side of the welding gun is provided with a wire feeding mechanism cooperating therewith.

[0009] Preferably, the surface of the multifunctional cabin is also provided with auxiliary wheels.

[0010] Preferably, the rear end of the multifunctional cabin is connected to the spraying device via a base.

[0011] Preferably, the spraying device includes a paint storage bottle arranged in the base, the paint storage bottle is connected to a spray gun installed on the outside of the base through a paint supply pipe, and a visual recognition device and a weld detection device are arranged near the spray gun.

[0012] More preferably, the spray gun is rotatably connected to the base via a mechanical arm, and a visual recognition device and a weld detection device are provided on the surface of the mechanical arm.

[0013] More preferably, a power supply and a control console are provided in the base, and the control console is connected to the control end of the robotic arm.

[0014] In addition, the present invention also discloses a method for controlling the traveling speed of a welding carriage in the above-mentioned multi-wheel drive intelligent welding spray detection integrated device in a pipeline, which comprises the following steps: S1. According to the different postures of the trolley, the welding process is divided into three stages: flat seam welding, vertical seam welding, and overhead seam welding; the three stages require the trolley to have different walking speeds, namely K1, K2, and K3. The speed distribution is as follows: (1); Where v is the traveling speed of the welding carriage, and ; The relationship between the speed of the car and the motor is: (2); In the formula, is the traveling speed of the welding carriage at different sampling times t, is the motor speed at different sampling times t, d is the walking pitch circle diameter, and i is the reduction ratio; S2. From (2), it can be seen that the motor speed is linearly related to the trolley speed, so the control of the trolley speed can be converted into the control of the motor speed. Similarly, the motor speed is also divided into three stages due to the different positions of the trolley. From (2), the speed of the trolley motor can be calculated. S3, PID controller is based on the given value With actual value The deviation between them is adjusted by performing three calculations: proportional P, integral I and differential D to adjust the output control signal u. Fuzzy PID is introduced to adjust the parameters in real time through the fuzzy controller. The membership function of the fuzzy controller selects the triangular membership function: ; In the formula, represents a function, is a variable, , is a constant; If it is too low, the triangle vertex angle will be small, and the system output value will be large; the fuzzy subsets are set in the order of negative large, negative medium, negative small, zero, positive small, positive medium, and positive large, abbreviated as {NB, NM, NS, Z, PS, PM, PB}; the fuzzy control rules are expressed by fuzzy conditional reasoning statements: ; The input is the difference between the ideal speed and the actual speed of the motor, e, and the rate of change of e, ec; the output is the proportional gain. , differential coefficient , integral coefficient ; That is, the parameters required for PID control are output by the fuzzy controller to ensure the stable driving of the welding trolley at different speed ranges; S4. Since the control system is not an ideal continuous system, the PID controller must be discretized. The discretized PID regulator becomes a digital PID regulator. moment, T is the sampling period, k is a constant, kT means the sampling time is the kth sampling period, and the actual control law of the digital PID regulator is: (3); In the formula is the output variable, e(k) is the deviation between the given value and the feedback value at the kth sampling period, e(k-1) is the deviation between the given value and the feedback value at the k-1th sampling period, is the proportional gain, is the differential coefficient, is the integration coefficient, To control the constant; In the process of the control system controlling the actuator, the change value of the control quantity is used instead of its absolute value; based on this principle, the specific expression of PID incremental control is derived as follows: (4); In the formula, A, B, and C are coefficients, among which: ; e(k-2) is the deviation between the given quantity and the feedback quantity at the sampling time of the k-2th sampling cycle.

[0015] The present invention also discloses a method for controlling the welding gun position of a welding carriage in the above-mentioned multi-wheel drive intelligent welding spray detection integrated device in a pipeline, which comprises the following steps: The pipes welded by the device adopt a V-shaped groove design. For this type of groove structure, the welding gun is driven by the lateral and circumferential motors to swing along a sinusoidal trajectory. Therefore, at any time point t, the position offset y of the welding gun tip relative to its swing center can be defined as: (5); Where A is the swing amplitude of the welding gun; v is the welding speed; d is the distance the welding gun moves forward in one swing cycle; If the distance between the welding gun swing center and the weld center is e, the welding current when the welding gun is at the weld center is , the angle between the V-shaped groove and the horizontal direction is β, then the welding current at time t is: (6); Where a and b are constants, is the wire feeding speed; According to the welding current in formula (6), the deviation of the welding gun is extracted by calculating the integral difference of the welding current in the left and right swing intervals of the welding gun. The deviation is divided into two cases: the welding gun deviates to the left and the right. The deviation extraction algorithm of the integral difference between the left and right intervals is derived. When the deviation e>0, the integral difference of the welding current in the left and right areas is: (7); When the deviation e<0, the integral difference of the welding current in the left and right areas is: (8); (7) and (8) can be expressed as: (9); Where K is a constant, As a nonlinear term, the above equation is plotted, with the ordinate being the left and right integral difference of the welding current, and the abscissa being the deviation between the welding gun swing center and the weld center; when the deviation is less than the welding gun swing amplitude, there is a roughly linear correlation between the optimal integral difference of the welding current and the welding gun position deviation, which can be approximately obtained Linear relationship with e: (10); After data collection, it is transmitted to the main controller module in real time. The main controller controls the travel motor driver through the PID algorithm to ensure the stability of the travel speed of the welding trolley. The main controller calculates the deviation at this time through the collected data, controls the swing motor and high and low motor movements, and accurately controls the position of the welding gun to ensure qualified welds.

[0016] Beneficial effects of the present invention: 1. The present invention solves a series of problems caused by manual welding; through the use of a robotic arm as a carrier, the automated operation of weld detection and anti-rust spraying in the pipe is realized; and through the integrated device for automatic weld detection and spraying, the intelligent platform can detect and spray the previous weld for anti-rusting at the same time as welding, greatly improving engineering efficiency.

[0017] 2. The present invention realizes the simultaneous welding, weld detection and anti-rust spraying by installing an automatic welding system at one end and an automatic detection and spraying device at the other end, which greatly improves the efficiency of pipeline welding in pumped-storage power stations and improves many defects caused by current manual operations; by adopting a flexible magnetic track and a track auxiliary installation mechanism, the automatic paving of the track is realized, solving the problems of low precision and low efficiency of current manual installation; the welding trolley carried can track the weld along the track for welding, and the robotic arm equipped with a weld detection device and an anti-rust spraying device can also accurately track the weld through visual recognition, so the present invention realizes the comprehensive automation of pipeline welding in pumped-storage power stations.

[0018] 3. The present invention adopts fuzzy PID control to effectively ensure that the speed of the welding carriage during the operation meets the characteristics of various welding methods, and reduce the weld deviation problem caused by vehicle vibration, thereby maintaining the overall quality of the pipeline.

[0019] 4. When the welding gun deviates from the ideal path, the welding gun position correction control of the present invention can estimate the actual deviation degree according to the change of the welding current on both sides, so as to adjust the welding gun positioning in time and effectively control the weld quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a multi-wheel drive intelligent welding spray detection integrated device in a pipeline; Figure 2 It is a structural schematic diagram of a spraying device; Figure 3 It is a schematic diagram of the main structure of a multi-wheel drive intelligent welding spray detection integrated device working in a pipeline; Figure 4 for Figure 3 An enlarged structural diagram of the welding carriage in the circled area performing inner annular seam welding; Figure 5 is the fuzzy control membership function diagram; Figure 6 It is a schematic diagram of fuzzy rules; Figure 7 This is the control flow chart of the welding carriage; Figure 8 It is the flow chart of position-based visual servo control; Fig. 9Schematic diagram of weld visual tracking process. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0022] Example 1: Figure 1-4 As shown, a multi-wheel drive intelligent welding spraying detection integrated device in a pipeline includes a multi-functional cabin 12, and a driving wheel 8 and a clamping mechanism 5 are provided on the surface of the multi-functional cabin 12. The front end of the multi-functional cabin 12 is connected to a track auxiliary installation mechanism 2, and the rear end is provided with a weld detection device 9, a spraying device 10 and a visual recognition device 11. The track auxiliary installation mechanism 2 is connected to a flexible magnetic welding track 1 through a hydraulic push rod 3, and the flexible magnetic welding track 1 cooperates with a welding trolley 4.

[0023] Preferably, there are two flexible magnetic welding rails 1, which are electromagnetically adsorbed flexible rails with an arc-shaped structure. Each flexible magnetic welding rail 1 is provided with a welding trolley 4 that slides with it, and the rail auxiliary installation mechanism 2 is connected to the flexible magnetic welding rail 1 through multiple hydraulic push rods 3.

[0024] Preferably, the welding carriage 4 comprises a body, one side of which is provided with a travel drive mechanism 4.1 cooperating with the flexible magnetic welding track 1, and the other side is connected to a welding gun 4.3 through a posture adjustment mechanism 4.2, and one side of the welding gun 4.3 is provided with a wire feeding mechanism 4.4 cooperating therewith.

[0025] Preferably, auxiliary wheels 6 are also provided on the surface of the multifunctional cabin 12 .

[0026] Preferably, the rear end of the multifunctional cabin 12 is connected to the spraying device 10 via the base 7 .

[0027] Preferably, the spraying device 10 includes a paint storage bottle 10.1 disposed in the base 7, the paint storage bottle 10.1 is connected to a spray gun 10.3 installed on the outside of the base 7 through a paint supply pipe 10.2, and a visual recognition device 11 and a weld detection device 9 are arranged near the spray gun 10.3.

[0028] More preferably, the spray gun 10.3 is rotatably connected to the base 7 via a mechanical arm 10.4, and a visual recognition device 11 and a weld detection device 9 are arranged on the surface of the mechanical arm 10.4.

[0029] More preferably, a power supply and a control console 10.5 are provided in the base 7, and the control console 10.5 is connected to the control end of the mechanical arm 10.4.

[0030] The working principle of this embodiment is as follows: The track auxiliary installation mechanism used in this embodiment is connected to 20 hydraulic push rods and is installed in a ring shape at one end of the multi-functional cabin by welding. When not welded, a flexible magnetic welding track can be placed on the device. After the welding operation starts, a flexible magnetic welding track can be pushed to the specified position on the inner wall of the pipe by 10 hydraulic push rods. After confirming that the installation position of the flexible magnetic welding track is correct, power is turned on to generate magnetic force, so that the track is firmly adsorbed to the inner wall of the pipe. After the magnetic track is installed, the welding trolley starts and starts working. The travel drive mechanism on the welding trolley drives the welding trolley to move on the flexible magnetic welding track, allowing the welding trolley to rotate 180° along the flexible magnetic welding track. Figure 4 As shown, the core parts of the welding carriage include a welding gun, a travel drive mechanism, a wire feeding mechanism and a posture adjustment mechanism, which are powered by a distribution cabinet installed on the multi-functional cabin. The travel drive mechanism is composed of a motor and a gear transmission mechanism to ensure that the motor can be accurately aligned and has good speed stability; the wire feeding mechanism is responsible for ensuring that the wire feeding speed is accurate and stable, and can supply the welding gun with an appropriate amount of welding wire in time; the posture adjustment mechanism is responsible for a series of operations such as the left and right swing, high and low posture, and end point stop of the welding gun, and the welding gun is equipped with a 360° rotating welding head to adapt to flat welding, vertical welding, and overhead welding at different angles and positions, ensuring that the welding head can accurately align with the weld to achieve precise welding; the welding trolley can move along the flexible magnetic welding track, and the welding gun and wire feeding mechanism are installed on the welding trolley, and a retractable cylinder is installed on the trolley; when the cylinder piston rod is extended, the welding gun bracket moves upward and the welding gun extends into the weld groove. If the welding gun position does not reach the ideal position, it can be adjusted through the posture adjustment mechanism and the 360° rotating welding head; after welding is completed, the welding gun bracket is retracted by the cylinder piston, and the cylinder rotates a certain angle around the mounting rotary axis so that the front end of the welding gun does not exceed the highest point of the trolley to prevent the welding gun from being damaged. The magnetic track is powered off and demagnetized, the hydraulic push rod releases the pressure, and the flexible magnetic welding track's own gravity causes it to slowly return to its original position. After returning to its original position, a "welding completed" message is sent to the central control platform.

[0031] After welding is completed, the weld needs to be inspected to ensure the welding quality is qualified. After the inspection is qualified, anti-rust paint is sprayed to reduce the risk of weld corrosion. The spray gun and weld inspection device are installed at the rear end of the multi-functional cabin through the mechanical arm and the base. The control, power supply and feeding parts of the integrated inspection and spraying device are installed as follows: Figure 2As shown. The base is fixed on the device and is responsible for providing a stable working environment for the robot arm. The robot arm can rotate on the base to achieve accurate tracking of the pipe annular weld. The robot arm automatically detects and identifies the center of the weld and tracks it through a visual recognition device, such as a visual sensor, so that the weld detection device and the spray gun can work around the pipe 360° through the movement of the robot arm to ensure the accuracy of weld detection and spraying. The weld detection device uses an ultrasonic probe to scan the weld and detects the quality of the weld by measuring the propagation speed and reflection intensity of the ultrasonic wave in the material. Defects or bad areas in the weld will cause changes in the propagation speed and reflection intensity of the ultrasonic wave, so that the quality of the weld can be judged by analyzing the ultrasonic signal; if the welding quality test fails, an alarm is sent to the central control platform and the welding system at the other end is stopped. At this time, staff should be dispatched in time to conduct a secondary inspection of the unqualified weld and troubleshoot the welding system. If the quality of the weld is guaranteed to meet the standards, the spraying operation will begin. The robot arm will adjust its posture to aim the spray gun at the weld. The spray gun can rotate 360° around the weld for 2 circles in the pipeline under the movement of the robot arm, so that the weld is completely covered with paint. The paint is evenly mixed by the stirring mechanism and then transported to the paint storage bottle for pressurization. The pressurized paint is sprayed out of the spray gun in atomization after the spray gun solenoid valve is opened and coated on the pipe surface. High-pressure airless spraying technology is used to improve the utilization rate of paint and reduce VOCs emissions.

[0032] This embodiment is driven by a driving wheel, which contains 4 driving wheels and 2 auxiliary wheels, and each driving wheel is powered by a hub motor. When working in a horizontal pipeline, the driving wheel at the bottom provides power, and the hydraulic push rod on the auxiliary wheel on the side will adjust the pressure between the auxiliary wheel and the inner wall of the pipeline to ensure that the pipeline robot can be centered; when welding, testing, and spraying, the clamping mechanism includes multiple connecting rods, which are driven by the cylinder piston to achieve clamping action to prevent the position of the device from changing during work. When working in an inclined pipeline, the traction mechanism outside the pipeline pulls the device to move along the axial direction of the pipeline. At this time, the driving wheel acts as an auxiliary driving device and can fine-tune the device during the positioning process to ensure positioning accuracy; when welding, testing, and spraying, the traction mechanism will be locked to ensure that the position of the device does not change along the axial direction of the pipeline, and the clamping mechanism is driven by the cylinder piston to achieve clamping action to prevent the device from rotating or having slight axial changes.

[0033] This embodiment includes a multifunctional cabin equipped with a control panel and a display screen, through which the operator can remotely control the movement and operation of the pipeline robot and monitor the working status of the robot in real time. The multifunctional cabin can also store tanks and various materials required for welding and spraying.

[0034] As a key component of the welding system, the welding trolley needs to move at different speeds in the fully automated welding process of the inner annular seam, because some angles have the characteristics of vertical seam welding and need to be welded quickly, while some angles have the characteristics of upward seam welding and need to be welded slowly. To this end, the present invention discloses a method for controlling the walking speed of a welding trolley in a multi-wheel drive intelligent welding spray detection integrated device in a pipeline (Example 2) to enhance the running stability of the welding trolley, so that the trolley can maintain different walking speeds in different areas to ensure stable welding quality. At the same time, a method for controlling the welding gun position of a welding trolley in a multi-wheel drive intelligent welding spray detection integrated device in a pipeline (Example 3) is also disclosed to realize welding gun position correction.

[0035] Embodiment 2: This embodiment discloses a method for controlling the traveling speed of a welding carriage in a multi-wheel drive intelligent welding spray detection integrated device in a pipeline, which comprises the following steps: S1. According to the different postures of the trolley, the welding process is divided into three stages: flat seam welding, vertical seam welding, and overhead seam welding; the three stages require the trolley to have different walking speeds, namely K1, K2, and K3. The speed distribution is as follows: (1); Where v is the traveling speed of the welding carriage, and ; The relationship between the speed of the car and the motor is: (2); In the formula, is the traveling speed of the welding carriage at different sampling times t, is the motor speed at different sampling times t, d is the walking pitch circle diameter, and i is the reduction ratio; S2. From (2), it can be seen that the motor speed is linearly related to the trolley speed, so the control of the trolley speed can be converted into the control of the motor speed. Similarly, the motor speed is also divided into three stages due to the different positions of the trolley. From (2), the speed of the trolley motor can be calculated. S3, PID controller is based on the given value With actual value The output control signal u is adjusted by performing three calculations: proportional P, integral I and differential D. However, PID control is sensitive to parameter changes of the controlled object. It has high control accuracy but poor adaptability. For the three-stage speed stability adjustment required by the present invention, a single PID controller is not effective. Therefore, fuzzy PID is introduced to adjust parameters in real time through the fuzzy controller, so that the control system has good stability. The membership function of the fuzzy controller is as follows: Figure 5 As shown, the rules are as follows Figure 6As shown, the fuzzy controller membership function selects the triangular membership function: ; In the formula, represents a function, is a variable, , is a constant; If it is too low, the triangle vertex angle will be small, and the system output value will be large; the fuzzy subsets are set in the order of negative large, negative medium, negative small, zero, positive small, positive medium, and positive large, abbreviated as {NB, NM, NS, Z, PS, PM, PB}; the fuzzy control rules are expressed by fuzzy conditional reasoning statements: ; The input is the difference between the ideal speed and the actual speed of the motor, e, and the rate of change of e, ec; the output is the proportional gain. , differential coefficient , integral coefficient ; That is, the parameters required for PID control are output by the fuzzy controller to ensure the stable driving of the welding trolley at different speed ranges; S4. Since the control system is not an ideal continuous system, the PID controller must be discretized. The discretized PID regulator becomes a digital PID regulator. moment, T is the sampling period, k is a constant, kT means the sampling time is the kth sampling period, and the actual control law of the digital PID regulator is: (3); In the formula is the output variable, e(k) is the deviation between the given value and the feedback value at the kth sampling period, e(k-1) is the deviation between the given value and the feedback value at the k-1th sampling period, is the proportional gain, is the differential coefficient, is the integration coefficient, To control the constant; In the process of the control system controlling the actuator, the change value of the control quantity is used instead of its absolute value; based on this principle, the specific expression of PID incremental control is derived as follows: (4); In the formula, ; e(k-2) is the deviation between the given quantity and the feedback quantity at the sampling time of the k-2th sampling cycle.

[0036] By adopting fuzzy PID control, the speed of the welding carriage during operation can be effectively ensured to meet the characteristics of various welding methods, and the weld deviation problem caused by vehicle vibration can be reduced, thereby maintaining the overall quality of the pipeline.

[0037] Embodiment 3: A method for controlling the welding gun position of a welding carriage in a multi-wheel drive intelligent welding spray detection integrated device in a pipeline, comprising the following steps: The pipes welded by the device adopt a V-shaped groove design. For this type of groove structure, the welding gun is driven by the lateral and circumferential motors to swing along a sinusoidal trajectory. Therefore, at any time point t, the position offset y of the welding gun tip relative to its swing center can be defined as: (5); Where A is the swing amplitude of the welding gun; v is the welding speed; d is the distance the welding gun moves forward in one swing cycle; If the distance between the welding gun swing center and the weld center is e, the welding current when the welding gun is at the weld center is , the angle between the V-shaped groove and the horizontal direction is β, then the welding current at time t is: (6); Where a and b are constants, is the wire feeding speed; The core challenge of arc sensing technology in weld tracking applications is how to accurately extract deviation information. The quality of the deviation extraction algorithm will directly affect the reliability and accuracy of arc sensing. According to the welding current in formula (6), the deviation of the welding gun is extracted by calculating the integral difference of the welding current in the left and right swing intervals. It is divided into two cases: the welding gun deviates to the left and the right, and the deviation extraction algorithm of the integral difference between the left and right intervals is derived; When the deviation e>0, the integral difference of the welding current in the left and right areas is: (7); When the deviation e<0, the integral difference of the welding current in the left and right areas is: (8); (7) and (8) can be expressed as: (9); In the formula, K is a constant. Plot the above formula, as shown in Figure 5 As shown in the figure, the vertical axis is the left and right integral difference of welding current, and the horizontal axis is the deviation between the welding gun swing center and the weld center; from the chart, it can be seen that when the deviation is less than the welding gun swing amplitude, the optimal integral difference of welding current and the welding gun position deviation show a roughly linear correlation, and due to the nonlinear term The calculation is complex and the deviation information is less reflected, so this item is ignored in the actual control program; therefore, it can be approximately obtained Linear relationship with e: (10); The overall control scheme of the welding carriage is as follows: Figure 7 As shown, after the data is collected, it is transmitted to the main controller module in real time. The main controller controls the travel motor driver through the PID algorithm to ensure the stability of the travel speed of the welding trolley. The main controller calculates the deviation at this time through the collected data, controls the swing motor and the high and low motor movements, and accurately controls the position of the welding gun to ensure qualified welds.

[0038] In the above technical solution, when the welding gun deviates from the ideal path, the welding gun position correction control can estimate the actual degree of deviation according to the change in welding current on both sides, so as to adjust the welding gun positioning in time and effectively control the weld quality.

[0039] Embodiment 4: This embodiment integrates the welding system with the weld inspection and spraying system. While the welding operation is in progress, the completed weld can be inspected instantly through the platform. The center point of the weld is determined by scanning of the visual recognition device and processing of the acquired image by the host computer, and the robot arm is controlled to move along the preset path to track the weld. This embodiment uses the method of obtaining the measurement point while moving to control the robot arm to achieve autonomous movement, which can achieve the purpose of automatic tracking without the need for fixtures and offline programming.

[0040] This embodiment uses a position-based visual servoing method as a control method. Position-based visual servoing takes the desired end effector posture as input, calculates the robot Jacobian matrix at the current moment, extracts the coordinates of the features in the image at the output posture after the control action, estimates the error between the changed posture and the desired posture, and then makes adjustments to eliminate the error and achieve the desired posture. The control flow diagram is shown in the figure below. Figure 8 shown.

[0041] Since noise is unavoidable in the construction environment, in order to effectively reduce the impact of noise on image processing, the grayscale image collected by the camera is usually first subjected to median filtering. This method can better maintain the edge information in the image while suppressing noise. After that, the image with reduced noise and retained useful information is binarized. The role of binarization is to set the grayscale value above the set threshold to the maximum grayscale value, and the grayscale value below the set threshold to the minimum grayscale value. In this way, the modulated structured light stripes can be effectively separated from the background, which is convenient for subsequent work.

[0042] In order to obtain the coordinates of the center point of the weld, this embodiment takes a skeleton for the light strip area when extracting feature points. In the light strip extracted after processing the weld, the center point is at the center of the short horizontal area in the lower part of the image. The skeleton can be regarded as the medial axis of a shape area, that is, the axis equidistant from the shape boundary. The medial axis transformation can determine the skeleton composed of all the center trajectories of the largest disk set in the area. According to the actual light strip image shape of the weld, a targeted weld center extraction method is proposed: first, the light strip is divided into three connected domains, and the area with the smallest area is selected. The skeleton of the selected area is taken, and the skeleton is the weld.

[0043] After determining the exact position of the weld center point in the image, we can transform it into the robot reference coordinate system through a series of coordinate transformations. Then, we use the inverse kinematics algorithm to calculate the angle values ​​of each joint of the robot arm corresponding to this point, so as to guide the robot's action execution. The specific visual tracking control process is as follows Fig. 9 shown.

[0044] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. An integrated multi-wheel drive intelligent welding spray detection device in a pipeline, comprising a multifunctional cabin (12), a driving wheel (8) and a clamping mechanism (5) being provided on the surface of the multifunctional cabin (12), characterized in that: The front end of the multifunctional cabin (12) is connected to a track auxiliary installation mechanism (2), and the rear end is provided with a weld detection device (9), a spraying device (10) and a visual recognition device (11); the track auxiliary installation mechanism (2) is connected to a flexible magnetic welding track (1) via a hydraulic push rod (3); and the flexible magnetic welding track (1) cooperates with a welding trolley (4).

2. The multi-wheel drive intelligent welding spraying detection integrated device in a pipeline according to claim 1 is characterized in that: The number of the flexible magnetic welding rails (1) is two, and they are electromagnetically adsorbed flexible rails with an arc-shaped structure. Each flexible magnetic welding rail (1) is provided with a welding trolley (4) that slidably cooperates with the rail, and the rail auxiliary installation mechanism (2) is connected to the flexible magnetic welding rail (1) via a plurality of hydraulic push rods (3).

3. The multi-wheel drive intelligent welding spray detection integrated device in a pipeline according to claim 1 is characterized in that: The welding carriage (4) comprises a carriage body, one side of which is provided with a travel drive mechanism (4.1) cooperating with a flexible magnetic welding track (1), and the other side of which is connected to a welding gun (4.3) via a posture adjustment mechanism (4.2), and one side of the welding gun (4.3) is provided with a wire feeding mechanism (4.4) cooperating therewith.

4. The multi-wheel drive intelligent welding spray detection integrated device in a pipeline according to claim 1 is characterized in that: Auxiliary wheels (6) are also provided on the surface of the multifunctional cabin (12).

5. The multi-wheel drive intelligent welding spray detection integrated device in a pipeline according to claim 1 is characterized in that: The rear end of the multifunctional cabin (12) is connected to the spraying device (10) via a base (7).

6. The multi-wheel drive intelligent welding spraying detection integrated device in a pipeline according to claim 5 is characterized in that: The spraying device (10) comprises a paint storage bottle (10.1) arranged in a base (7); the paint storage bottle (10.1) is connected to a spray gun (10.3) installed outside the base (7) via a paint delivery pipe (10.2); a visual recognition device (11) and a weld detection device (9) are arranged near the spray gun (10.3).

7. The multi-wheel drive intelligent welding spray detection integrated device in a pipeline according to claim 6 is characterized in that: The spray gun (10.3) is rotatably connected to the base (7) via a mechanical arm (10.4), and a visual recognition device (11) and a weld detection device (9) are arranged on the surface of the mechanical arm (10.4).

8. The multi-wheel drive intelligent welding spray detection integrated device in a pipeline according to claim 7 is characterized in that: A power source and a control console (10.5) are provided in the base (7), and the control console (10.5) is connected to a control end of the mechanical arm (10.4).

9. A method for controlling the traveling speed of a welding carriage in a multi-wheel drive intelligent welding spraying detection integrated device in a pipeline as claimed in any one of claims 1 to 8, characterized in that: It includes the following steps: S1. According to the different postures of the trolley, the welding process is divided into three stages: flat seam welding, vertical seam welding, and overhead seam welding; the three stages require the trolley to have different walking speeds, namely K1, K2, and K3. The speed distribution is as follows: （1）； Where v is the traveling speed of the welding carriage, and ; The relationship between the speed of the car and the motor is: （2）； In the formula, is the traveling speed of the welding carriage at different sampling times t, is the motor speed at different sampling times t, d is the walking pitch circle diameter, and i is the reduction ratio; S2. From (2), it can be seen that the motor speed is linearly related to the trolley speed, so the control of the trolley speed can be converted into the control of the motor speed. Similarly, the motor speed is also divided into three stages due to the different positions of the trolley. From (2), the speed of the trolley motor can be calculated. S3, PID controller is based on the given value With actual value The deviation between them is adjusted by performing three calculations: proportional P, integral I and differential D to adjust the output control signal u. Fuzzy PID is introduced to adjust the parameters in real time through the fuzzy controller. The membership function of the fuzzy controller selects the triangular membership function: ； In the formula, represents a function, is a variable, , is a constant; If it is too low, the triangle vertex angle will be small, and the system output value will be large; the fuzzy subsets are set in the order of negative large, negative medium, negative small, zero, positive small, positive medium, and positive large, abbreviated as {NB, NM, NS, Z, PS, PM, PB}; the fuzzy control rules are expressed by fuzzy conditional reasoning statements: ； The input is the difference between the ideal speed and the actual speed of the motor, e, and the rate of change of e, ec; the output is the proportional gain , differential coefficient , integral coefficient ; That is, the parameters required for PID control are output by the fuzzy controller to ensure the stable driving of the welding trolley at different speed ranges; S4. Since the control system is not an ideal continuous system, the PID controller must be discretized. The discretized PID regulator becomes a digital PID regulator. moment, T is the sampling period, k is a constant, kT means the sampling time is the kth sampling period, and the actual control law of the digital PID regulator is: （3）； In the formula is the output variable, e(k) is the deviation between the given value and the feedback value at the kth sampling period, e(k-1) is the deviation between the given value and the feedback value at the k-1th sampling period, is the proportional gain, is the differential coefficient, is the integration coefficient, To control the constant; In the process of the control system controlling the actuator, the change value of the control quantity is used instead of its absolute value; based on this principle, the specific expression of PID incremental control is derived as follows: （4）； In the formula, A, B, and C are coefficients, among which: ; e(k-2) is the deviation between the given quantity and the feedback quantity at the sampling time of the k-2th sampling cycle.

10. A method for controlling the welding gun position of a welding carriage in a multi-wheel drive intelligent welding spraying and detection integrated device in a pipeline as claimed in any one of claims 1 to 8, characterized in that: It includes the following steps: The pipes welded by the device adopt a V-shaped groove design. For this type of groove structure, the welding gun is driven by the lateral and circumferential motors to swing along a sinusoidal trajectory. Therefore, at any time point t, the position offset y of the welding gun tip relative to its swing center can be defined as: (5)； Where A is the swing amplitude of the welding gun; v is the welding speed; d is the distance the welding gun moves forward in one swing cycle; If the distance between the welding gun swing center and the weld center is e, the welding current when the welding gun is at the weld center is , the angle between the V-shaped groove and the horizontal direction is β, then the welding current at time t is: （6）； Where a and b are constants, is the wire feeding speed; According to the welding current in formula (6), the deviation of the welding gun is extracted by calculating the integral difference of the welding current in the left and right swing intervals of the welding gun. The deviation is divided into two cases: the welding gun deviates to the left and the right. The deviation extraction algorithm of the integral difference between the left and right intervals is derived. When the deviation e>0, the integral difference of the welding current in the left and right areas is: （7）； When the deviation e<0, the integral difference of the welding current in the left and right areas is: （8）； (7) and (8) can be expressed as: （9）； Where K is a constant, As a nonlinear term, the above equation is plotted, with the ordinate being the left and right integral difference of the welding current, and the abscissa being the deviation between the welding gun swing center and the weld center; When the deviation is smaller than the welding gun swing, the optimal integral difference of welding current and the welding gun position deviation show a roughly linear correlation, which can be approximately obtained as Linear relationship with e: （10）； After data collection, it is transmitted to the main controller module in real time. The main controller controls the travel motor driver through the PID algorithm to ensure the stability of the travel speed of the welding trolley. The main controller calculates the deviation at this time through the collected data, controls the swing motor and high and low motor movements, and accurately controls the position of the welding gun to ensure qualified welds.

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