Automatic installation method and equipment for pre-embedded bolt sleeves at the root of wind turbine blades

Abstract

This invention discloses an automated installation method for pre-embedded double-ended studs at the root of wind turbine blades. It is based on a mobile robot and control system. The mobile robot consists of a wheeled chassis, a six-degree-of-freedom industrial robotic arm mounted on the chassis, two automatic feeders, and a hydraulic system. A gripper is installed at the end of the robotic arm's wrist. The method includes the following steps: the equipment automatically moves forward and backward, left and right / swinging, and vertically for precise positioning; the control system controls the movement of the robotic arm, the gripper grasps the double-ended stud, and the control system moves the gripper to the center of the designated assembly hole on the flange of the wind turbine blade; the mobile robot uses the gripper to helically feed the double-ended stud to a designated extension distance; the gripper screws the double-ended stud into the bolt hole to be installed, and the screwing length of the double-ended stud is calculated; the above steps are repeated to screw multiple double-ended studs into the corresponding bolt holes one by one. This invention features automated control and high installation accuracy.

Description

Technical Field

[0001] This invention belongs to the technical field of auxiliary equipment for wind turbine blade manufacturing, and in particular relates to an automatic installation method and equipment for pre-embedded bolt sleeves with double-ended bolts at the root of wind turbine blades. Background Technology

[0002] Wind power generation is a clean energy generation technology. Its equipment generally includes wind turbine generators, wind turbine blades, towers supporting the generators, inverters, load unloaders, grid-connected controllers, and battery banks. Wind power equipment manufacturing is characterized by poor material precision, large dimensions, numerous models, and high dispersion. This decentralized and independent manufacturing model requires significant manpower and resources, resulting in high costs for enterprises and clearly failing to meet the demands of high-quality development. Wind turbine blades, as a major component of wind power equipment, are difficult to hoist and move. As large components manufactured discretely, their placement is not precisely fixed. Traditional robotic arms, typically bolted to the ground, have limited working space. Each blade replacement requires hoisting and repositioning adjustments, which struggle to meet the required positioning accuracy. This complex operation hinders efficiency, reduces versatility, and lowers safety, making it unsuitable for assembling such large, discrete components.

[0003] Currently, in the wind turbine blade manufacturing industry, the double-ended studs embedded in the root bolt sleeves of wind turbine blades are all installed manually, requiring multiple people to work together and climbing to heights. After the double-ended studs are screwed into the bolt sleeves, the extension length of each stud must be within ±1mm of the specified extension length from the end face of the root flange. Measurements are taken during installation to ensure consistency in the extension length. This facilitates the connection between the wind turbine blade and the wind turbine hub via high-altitude hoisting. Because a large number of double-ended studs are required—at least hundreds—the assembly efficiency is low, the time consumption is long, the labor costs are high, the risks are high, and the inconsistent extension length of the double-ended studs hinders the subsequent production progress of the wind turbine blades. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to provide an automatic installation method and equipment for pre-embedded bolt sleeves with double-ended bolts at the root of wind turbine blades.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] An automated installation method for pre-embedded double-headed bolts at the root of wind turbine blades is based on a mobile robot and a connected control system. The mobile robot consists of a wheeled chassis, a six-degree-of-freedom industrial robotic arm mounted on the chassis, two automatic feeders, and a hydraulic system. The two automatic feeders are located on the left and right sides of the robotic arm, respectively. A gripper is installed at the end of the robotic arm's wrist, and a positioning vision component is mounted on the gripper. The positioning vision component includes a set of vision cameras and a structured light emitter. The structured light emitter is used to acquire image information, calculate it into three-dimensional spatial position information, and then, through coordinate system transformation with the robotic arm, the control system enables rapid positioning of the mobile robot. The vision cameras are used to scan the outline of the bolt holes of the wind turbine blade located in front of the mobile robot, achieving center detection of all bolt holes on the wind turbine blade. Three lifting adjustment devices are connected to the chassis of the mobile robot to compensate for the angle between the end of the wind turbine blade and the ground, ensuring that the mobile robot and different wind turbine blades maintain consistent end-face positions after placement. The method includes the following steps:

[0007] S1. Coarse positioning of the equipment: First, hoist the wind turbine blade and fix it on the support for positioning. Then, the operator operates the remote control device to drive the mobile robot to move so that the front end of the wheeled chassis of the mobile robot is directly in front of the end of the wind turbine blade within 1.5 to 2 meters.

[0008] S2. Automatic front and rear precise positioning of the equipment: After the mobile robot is started, three active structured light emitters with different ranging ranges are set on the gripper installed at the end of the robotic arm wrist to emit measurement laser signals. The robotic arm controls the laser beam on the gripper to be projected onto the inner wall of the wind turbine blade. The wheeled chassis is driven to move back and forth by the control system through the preset distance value to achieve distance adjustment and determine the working distance from the front end of the mobile robot to the front end face of the wind turbine blade.

[0009] S3. Automatic Left / Right / Swing Precise Positioning: The robotic arm moves, causing the structured light emitter of the positioning vision component to perform two horizontal scans of the outer diameter distance on the left and right sides and the front-to-back distance of the wind turbine blade flange. The first scan is a coarse scan, after which the wheeled chassis moves to adjust the left and right and the swing angle of the wheeled chassis plane to center the position of the mobile robot, directly facing the root end face of the wind turbine blade. The second scan is for compensation, scanning to confirm whether the position adjusted by the wheeled chassis is in the centered working position at the root of the wind turbine blade.

[0010] S4. Automatic and precise vertical positioning of the equipment: After the wheeled chassis has been adjusted in front-to-back / left-to-right / swing position, the structured light emitter of the positioning vision component scans the upper and lower outer diameter distances of the wind turbine blade flange twice within the working range of the robotic arm. The first scan is performed by driving the three lifting adjustment devices at the bottom of the wheeled chassis to lift and lower, thus moving the mobile robot up and down. After the hydraulic lifting and lowering actions of the three lifting adjustment devices stop, a plane is determined to make the front end face of the wheeled chassis as parallel as possible to the front end face of the wind turbine blade, with the angle error controlled within ±2°, to determine the position of the robotic arm's base coordinate system relative to the root of the wind turbine blade and to meet the conditions for the gripping action. The second scan is performed by determining the visual image and positioning information starting from the bottom bolt holes of the wind turbine blade flange, in preparation for the gripping and installation work.

[0011] S5. Based on the pre-set position data of the bolt holes on the root flange of the entire wind turbine blade in the robotic arm simulation software, the control system outputs signals to control the movement of the robotic arm. The gripper drives the elastic clamp to open at a certain angle. Under the action of the robotic arm and vision judgment and analysis, the motion coordinates are determined and the posture is adjusted to grasp the screw part of a stud in the material box, and then the gripper closes. Then, under the vision judgment and analysis, the positioning vision component identifies the position center of the bolt holes on the wind turbine blade, finds the center point, calculates the position values ​​of the bolt holes in the Y and Z directions, and sends them to the control system, causing the gripper to... The robot grasps a stud and moves it to the center of the designated assembly hole on the flange of the wind turbine blade, while giving the stud a certain amount of rotational feed. At the same time, the positioning vision component identifies the hole position, and the distance information transmitted back by the structured light emitter in the positioning vision component on the robotic arm identifies the distance value between the front face of the wind turbine blade and the current mobile robot, as well as the X value of the bolt hole end face, and sends it to the control system. The mobile robot accurately finds the position of the bolt hole to be installed based on the obtained X, Y, and Z values, and feeds the follower stud to the designated extension distance through the rotating hand. At the same time, the gripper opens a certain amount and brings a certain preload.

[0012] S6. Use the gripper to screw the stud into the bolt hole of the head bolt to be installed. The screwing depth is controlled by determining the relative positions of the tool coordinate system, workpiece coordinate system and base coordinate system based on the previous posture adjustment. The screwing length of the double-headed stud is calculated by calculating the distance value of the structure light emitter and the actual length of the double-headed bolt to be installed.

[0013] S7. Repeat steps S5 to S6, and screw the multiple double-ended bolts on the automatic feeder into the corresponding bolt holes to be installed.

[0014] An automated installation device for pre-embedded double-headed bolts at the root of wind turbine blades includes a mobile robot and a control system connected to it. The mobile robot consists of a wheeled chassis, a six-degree-of-freedom industrial robotic arm mounted on the wheeled chassis, two automatic feeders, and a hydraulic system. The two automatic feeders are located on the left and right sides of the robotic arm, respectively. A gripper is installed at the wrist of the robotic arm, and a positioning vision component is installed on the gripper. The positioning vision component includes a set of vision cameras and a structured light emitter. The structured light emitter is used to collect image information, calculate it into three-dimensional spatial position information, and then, through coordinate system transformation with the robotic arm, the control system enables the mobile robot to quickly position itself. The vision cameras are used to scan the outline of the bolt holes of the wind turbine blades located in front of the mobile robot to achieve center detection of all bolt holes of the wind turbine blades. Three lifting and adjusting devices are installed under the chassis of the mobile robot and connected to it to compensate for the adjustment of the angle between the end of the wind turbine blade and the ground, ensuring that the mobile robot and different wind turbine blades maintain the same end face position after placement.

[0015] Furthermore, the aforementioned gripper includes a base, a clamping part for holding the double-ended bolts of the wind turbine blade, and a driving part for driving the movement of the double-ended bolts of the wind turbine blade. The top surface of the base is fixedly connected to the wrist end of the robotic arm. A vision camera of the positioning vision component is fixedly mounted on one end of the top surface of the base via a mounting bracket, and a crossbeam perpendicular to it is provided on the bottom surface. The clamping part includes a linear slide rail and finger cylinders. The linear slide rail is fixedly mounted on the front side of the bottom of the crossbeam. Two sliders are slidably connected on the linear slide rail. A connecting plate is fixedly connected to the bottom of the two sliders. Two finger cylinders are fixedly mounted on the connecting plate. The output ends of the two finger cylinders face downwards, and the ends are equipped with chucks for holding the double-ended bolts of the wind turbine blade. The driving part includes a slide cylinder, a servo motor, a planetary reducer, and an elastic head. The slide cylinder is fixedly mounted on the rear side of the bottom of the crossbeam via a mounting base. The bottom of the slide cylinder is connected to the planetary reducer via a slide. The input end of the planetary reducer is connected to the servo motor, and the output end is connected to the elastic head, which faces the clamping part.

[0016] Furthermore, the gripper described above also includes a buffer cylinder in its clamping part. The buffer cylinder is located behind the clamping part, and its output end is connected to the slider.

[0017] Furthermore, the aforementioned gripper is also equipped with multiple sensors for real-time measurement of the installation of the double-headed bolts on the wind turbine blades. The first sensor is installed on the front end of the slide cylinder and is used in conjunction with the structured light emitter to emit rays to determine the sliding distance of the slide. The second and third sensors are installed on the crossbeam of the gripper and are at a certain relative distance from each other. The sliding distance of the buffer cylinder is determined by the second and third sensors in conjunction with the photoelectric sensor embedded in the buffer cylinder.

[0018] Furthermore, the aforementioned elastic head consists of a compression spring, a universal joint, and a limiting sleeve. The universal joint is installed inside the limiting sleeve and is installed by a baffle at its end in cooperation with the limiting sleeve. The compression spring is set on the universal joint. One end of the universal joint is connected to the output end of the servo motor through a connecting shaft, and the other end is connected to a hexagonal wrench head.

[0019] The aforementioned gripper, when used for installing the double-ended bolts on wind turbine blades, includes the following steps:

[0020] Step 1: Initial state - Two finger cylinders open the chuck, the output end of the buffer cylinder extends, the slide cylinder is in the retracted state, and the servo motor does not rotate; the vision camera and structured light emitter are positioned in the positioning bolt holes.

[0021] Step 2: The mobile robot moves the gripper to the bolt gripping position, the two finger cylinders close, and the double-ended bolt is clamped by the chuck. The slide cylinder extends the elastic head to fit into the internal hexagonal hole at the tail of the double-ended bolt. Through the operation of the mobile robot, the double-ended bolt is inserted into the bolt hole of the flange of the wind turbine blade, and the buffer cylinder is passively compressed. When the second sensor triggers the photoelectric sensor, the two finger cylinders release, the buffer cylinder releases air and retracts, and at this time the slide cylinder presses the double-ended bolt onto the threaded hole through the elastic head.

[0022] Step 3: Start the servo motor to rotate. The first sensor and the first laser rangefinder detect the screwing depth of the double-ended bolt in real time. The second laser rangefinder measures the distance from the gripper to the end face of the threaded hole in real time. The two measurements are used to detect the reserved length at the tail of the double-ended bolt in real time. When the reserved length target value is reached, the servo motor stops rotating, the slide cylinder retracts, and the next bolt tightening cycle begins.

[0023] Furthermore, the aforementioned lifting and adjusting device includes a first hydraulic cylinder, a second hydraulic cylinder, and a third hydraulic cylinder located on one side of the mobile robot, and the support points of the three hydraulic cylinders can be adapted to a plane that matches the end of the wind turbine blade when it is at an angle to the ground.

[0024] Due to the adoption of the technical solution described above, the present invention has the following advantages:

[0025] This invention relates to an automatic installation method for pre-embedded bolts with double-ended bolts at the root of wind turbine blades. It utilizes a mobile robot and a connected control system to install the bolts at the root of the wind turbine blades. The automated control ensures high installation accuracy, greatly improves work efficiency, effectively shortens bolt installation time, saves manpower, and reduces costs.

[0026] Because the threaded sleeves corresponding to the double-ended bolts on wind turbine blades are pre-cast and embedded in the blades, deformation during the casting process can cause irregular tilting of the threaded sleeves. Furthermore, the large bolt pitch poses a significant challenge to the automatic assembly of the bolts while maintaining precision. This invention, an automatic installation device for pre-embedded double-ended bolts at the root of wind turbine blades, employs a gripper structure that effectively solves these problems. Its novel and reasonable structural design provides high installation accuracy and ease of operation, making it highly valuable for widespread application. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a mobile robot that implements the automatic installation method for wind turbine blade root bolts of the present invention;

[0028] Figure 2 yes Figure 1 A schematic diagram illustrating the usage status of the mobile robot in the diagram;

[0029] Figure 3 yes Figure 1 A schematic diagram of the gripper structure of a mobile robot;

[0030] Figure 4 yes Figure 1 A schematic diagram of the working state of the gripper of the mobile robot in the image;

[0031] Figure 5 yes Figure 4 A schematic diagram of the main structure of the elastic head in the middle;

[0032] Figure 6 yes Figure 5 A schematic diagram of the A-A cross-sectional structure;

[0033] Figure 7 yes Figure 6 A schematic diagram of the structure of the universal joint in China;

[0034] In the diagram: 1 - Robotic arm; 2 - Gripper; 3 - Double-ended bolt; 4 - Automatic feeder; 5 - Wheeled chassis; 6 - Crossbeam; 7 - Base; 8 - Second sensor; 9 - Third sensor; 10 - Mounting bracket; 11 - Linear slide rail; 12 - Finger cylinder; 13 - Chuck; 14 - Buffer cylinder; 15 - Planetary reducer; 16 - Servo motor; 17 - Slide cylinder; 18 - Vision camera; 19 - Second laser rangefinder; 20 - Elastic head; 21 - First sensor; 22 - Third laser rangefinder; 23 - First laser rangefinder; 24 - Hex wrench head; 25 - Connecting shaft; 26 - Limit sleeve; 27 - Universal joint; 28 - Compression spring; 29 - Stop plate. Detailed Implementation

[0035] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0036] like Figures 1-7 As shown, an automatic installation method for pre-embedded bolts with double-ended bolts at the root of wind turbine blades is based on a mobile robot and a connected control system. The mobile robot consists of a wheeled chassis 5, a six-degree-of-freedom industrial robotic arm 1 mounted on the wheeled chassis, two automatic feeders 4, and a hydraulic system. The two automatic feeders are located on the left and right sides of the robotic arm, respectively. A gripper 2 is installed at the wrist of the robotic arm, and a positioning vision component is installed on the gripper. The positioning vision component includes a set of vision cameras 18 and a structured light emitter. The structured light emitter includes a first laser rangefinder 23, a second laser rangefinder 19, and a third laser rangefinder 10. Sensor 22, the structured light emitter is used to collect image information, calculate it into three-dimensional spatial position information, and then, through coordinate system transformation with the robotic arm, achieve rapid positioning of the mobile robot; the vision camera is used to scan the outline of the bolt holes of the wind turbine blades located in front of the mobile robot, realizing the center detection of all bolt holes of the wind turbine blades; three lifting adjustment devices are set under the chassis of the mobile robot to compensate for the adjustment between the end of the wind turbine blade and the ground, ensuring that the end face position of the mobile robot and different wind turbine blades remains consistent after placement; the automatic installation method includes the following steps:

[0037] S1. Coarse positioning of the equipment: First, hoist the wind turbine blade and fix it on the support for positioning. Then, the operator operates the remote control device to drive the mobile robot to move so that the front end of the wheeled chassis of the mobile robot is directly in front of the end of the wind turbine blade within 1.5 to 2 meters.

[0038] S2. Automatic front and rear precise positioning of the equipment: After the mobile robot is started, three active structured light emitters (laser range sensors) with different ranging ranges are set on the gripper installed at the end of the robotic arm wrist to emit measuring laser signals. The robotic arm controls the laser beam on the gripper to be projected onto the inner wall of the wind turbine blade. The wheeled chassis is driven to move back and forth by the control system to achieve distance adjustment and determine the working distance from the front end of the mobile robot to the front end face of the wind turbine blade.

[0039] S3. Automatic Left / Right / Swing Precise Positioning: The robotic arm moves, causing the structured light emitter of the positioning vision component, i.e., the first laser rangefinder 23, to perform two horizontal scans of the left and right outer diameter distances and front-to-back distances of the wind turbine blade flange. The first scan is a coarse scan, after which the wheeled chassis moves to adjust the left and right and the wheeled chassis plane swing angles to center the position of the mobile robot, directly facing the root end face of the wind turbine blade. The second scan is for compensation, confirming whether the wheeled chassis movement adjustment position is in the centered working position directly facing the root of the wind turbine blade.

[0040] S4. Automatic and precise vertical positioning of the equipment: After the wheeled chassis has been adjusted in front-to-back / left-to-right / swing position, the structured light emitter of the positioning vision component scans the upper and lower outer diameter distances of the wind turbine blade flange twice within the working range of the robotic arm. The first scan is performed by driving the three lifting adjustment devices at the bottom of the wheeled chassis to lift and lower, thus moving the mobile robot up and down. After the hydraulic lifting and lowering actions of the three lifting adjustment devices stop, a plane is determined to make the front end face of the wheeled chassis as parallel as possible to the front end face of the wind turbine blade, with the angle error controlled within ±2°, to determine the position of the robotic arm's base coordinate system relative to the root of the wind turbine blade and to meet the conditions for the gripping action. The second scan is performed by determining the visual image and positioning information starting from the bottom bolt holes of the wind turbine blade flange, in preparation for the gripping and installation work.

[0041] S5. Based on the pre-set program data of the bolt hole positions on the root flange of the entire wind turbine blade in the robotic arm simulation software, the control system outputs a signal to control the movement of the robotic arm. The parallel opening and closing finger cylinder 12 of the gripper 2 drives the elastic clamp 13 to open at a certain angle. Under the action of the robotic arm and vision judgment and analysis, the motion coordinates are determined and the posture is adjusted to grab the screw part of a double-ended stud in the material box, and then the gripper closes. Then, under the vision judgment and analysis, the positioning vision component identifies the position center of the bolt hole on the wind turbine blade, finds the center point, calculates the position value of the bolt hole in the Y and Z directions, and sends it to the control system. The finger cylinder of the gripper grabs a double-ended stud and moves to the designated flange of the wind turbine blade. The center of the hole to be assembled is reached, and the screw is fed a certain amount of rotation through the slide cylinder 17. While the positioning vision component identifies the hole position, the distance information transmitted back by the structured light emitter in the positioning vision component on the robotic arm identifies the distance value between the front face of the wind turbine blade and the current mobile robot, as well as the X value of the bolt hole end face, and sends it to the control system. The mobile robot accurately finds the position of the bolt hole to be installed based on the obtained X, Y, and Z values. Under the driving force of the slide cylinder, the follower stud is spirally fed to the specified extension distance, while the gripper opens a certain amount and brings a certain preload. If there is a deformation problem with the bolt sleeve, the stud is not installed in place, and the problem bolt hole is automatically skipped, and the next stud is installed.

[0042] S6. Using the bolt tightening machine installed on the gripper, the double-ended stud is screwed into the bolt hole of the bolt to be installed. The screwing depth is controlled by determining the relative positions of the tool coordinate system, workpiece coordinate system, and base coordinate system based on the previous posture adjustment. The screwing length of the double-ended stud is calculated by calculating the distance measured by the laser range sensor and the actual length of the double-ended stud to be installed. Since the flatness of the flange end face of the wind turbine blade has tolerance, in order to ensure the consistency of the protrusion length of the double-ended stud after each screwing, the protrusion length must be within ±1mm error.

[0043] S7. Repeat steps S5 to S6, and screw the multiple double-ended bolts on the automatic feeder into the corresponding bolt holes to be installed.

[0044] An automated installation device for pre-embedded double-headed bolts at the root of wind turbine blades includes a mobile robot and a control system connected to it. The mobile robot consists of a wheeled chassis 5, a six-degree-of-freedom industrial robotic arm 4 mounted on the wheeled chassis, two automatic feeders 4, and a hydraulic system. The two automatic feeders are located on the left and right sides of the robotic arm, respectively. A gripper 2 is installed at the wrist of the robotic arm, and a positioning vision component is installed on the gripper. The positioning vision component includes a set of vision cameras and a structured light emitter. The structured light emitter is used to collect image information, calculate it into three-dimensional spatial position information, and then, through coordinate system transformation with the robotic arm, the control system enables the mobile robot to quickly position itself. The vision cameras are used to scan the outline of the bolt holes of the wind turbine blade located in front of the mobile robot to achieve center detection of all bolt holes of the wind turbine blade. Three lifting and adjusting devices are installed under the chassis of the mobile robot and connected to it to compensate for the adjustment of the angle between the end of the wind turbine blade and the ground, ensuring that the mobile robot and different wind turbine blades maintain the same end face position after placement.

[0045] The aforementioned gripper 2 includes a base 7, a clamping part for holding the double-ended bolts 3 of the wind turbine blades, and a driving part for driving the movement of the double-ended bolts of the wind turbine blades (i.e., the aforementioned bolt tightening machine). The top surface of the base 7 is fixedly connected to the wrist end of the robotic arm 1. A vision camera 18 with a positioning vision component is fixedly mounted on one end of the top surface of the base via a mounting bracket 10. A crossbeam 6 perpendicular to the base is provided on the bottom surface. The clamping part includes a linear slide rail 11 and a finger cylinder 12. The linear slide rail 11 is fixedly mounted on the front side of the bottom of the crossbeam 6. Two sliders are slidably connected on the linear slide rail. A connecting plate is fixedly attached to the bottom of each slider. Two finger cylinders 12 are fixedly installed on the connecting plate. The output ends of the two finger cylinders face downwards and are equipped with chucks 13 for clamping the double-headed bolts of the wind turbine blades. The drive unit includes a slide cylinder 17, a servo motor 16, a planetary reducer 15, and an elastic head 20. The slide cylinder 17 is fixedly installed on the rear side of the bottom of the crossbeam 6 through a mounting base. The bottom of the slide cylinder is connected to the planetary reducer 15 through the slide. The input end of the planetary reducer is connected to the servo motor 16, and the output end is connected to the elastic head. The elastic head faces the clamping part.

[0046] The gripper 2 mentioned above also includes a buffer cylinder 14 in its clamping part. The buffer cylinder is located behind the clamping part, and the output end of the buffer cylinder is connected to the slider. This structure ensures that the elastic head can smoothly connect to the double-ended bolt from the gripper, and prevents the gripper from being damaged by collision if the double-ended bolt is not inserted into the threaded hole.

[0047] The aforementioned gripper is also equipped with multiple sensor plates for real-time measurement of the installation of double-headed bolts on wind turbine blades. The first sensor plate 21 is installed on the front end face of the slide cylinder 17 and is used in conjunction with the structured light emitter, namely the third laser rangefinder 22, to emit rays to provide feedback and determine the sliding distance of the slide. The second sensor plate 8 and the third sensor plate 9 are installed on the crossbeam 6 of the gripper and are at a certain relative distance from each other. The sliding distance of the buffer cylinder is determined by the second and third sensor plates in conjunction with the photoelectric sensor embedded in the buffer cylinder 14.

[0048] The aforementioned elastic head 20 consists of a compression spring 28, a universal joint 27, and a limiting sleeve 26. The universal joint 27 is installed inside the limiting sleeve 26 and is fitted with the limiting sleeve through a baffle 29 at its end. The compression spring 28 is mounted on the universal joint. One end of the universal joint is connected to the output end of the servo motor 15 via a connecting shaft 25, and the other end is connected to a hexagonal wrench head 24. The axis of the elastic head 20 is coaxial with the axis of the double-ended bolt 3. The elastic head can swing in all directions and returns to the axial position when suspended. When the bolt is screwed in, rotation and appropriate thrust are required. Therefore, the spiral elastic head is pushed forward by the slide cylinder.

[0049] The aforementioned gripper, when used for installing the double-ended bolts on wind turbine blades, includes the following steps:

[0050] Step 1: In the initial state, the two finger cylinders 12 work to open the chuck 13, the output end of the buffer cylinder 14 extends, the slide cylinder 17 is in the retracted state, and the servo motor 16 does not rotate; the vision camera 18 and the laser range sensor cooperate to position the bolt hole.

[0051] Step 2: The mobile robot moves the gripper 2 to the bolt gripping position, the two finger cylinders 12 close, and the double-ended bolt is clamped by the chuck 13. The slide cylinder 17 extends the elastic head 20 to fit into the internal hexagonal hole at the tail of the double-ended bolt 3. Through the operation of the mobile robot, the double-ended bolt is inserted into the bolt hole of the flange of the wind turbine blade, and the buffer cylinder is passively compressed. When the second sensor 8 triggers the photoelectric sensor (the second sensor 8 and the third sensor 9 work together with the photoelectric sensor to detect the extension and retraction position of the buffer cylinder 14), the two finger cylinders are released, the buffer cylinder is depressurized and retracted, and at this time the slide cylinder presses the double-ended bolt onto the threaded hole through the elastic head.

[0052] Step 3: Start the servo motor 16 to rotate. The first sensor 21 and the third laser range sensor 22 detect the screwing depth of the double-ended bolt in real time. The second laser range sensor 19 measures the distance from the gripper to the end face of the threaded hole in real time. The two measurements are used to detect the reserved length at the tail of the double-ended bolt in real time. When the reserved length target value is reached, the servo motor stops rotating, the slide cylinder retracts, and the next bolt tightening cycle begins.

[0053] In the above installation process, each double-ended bolt requires a laser rangefinder and induction plate for real-time measurement and calculation.

[0054] The aforementioned lifting and adjusting device includes a first hydraulic cylinder, a second hydraulic cylinder, and a third hydraulic cylinder located on one side of the mobile robot, and the support points of the three hydraulic cylinders can be adapted to a plane that matches the end of the wind turbine blade when it is at an angle to the ground.

[0055] The above description is only a preferred embodiment of the present invention and not a limitation thereof. Any equivalent changes and modifications made in accordance with the scope of the present invention without departing from the spirit and scope of the present invention shall be within the scope of patent protection of the present invention.

Claims

1. An automatic installation method for pre-embedded bolt sleeves with double-ended bolts at the root of wind turbine blades, characterized in that: It is based on a mobile robot and a connected control system. The mobile robot consists of a wheeled chassis, a six-degree-of-freedom industrial robotic arm mounted on the chassis, two automatic feeders, and a hydraulic system. The two automatic feeders are located on the left and right sides of the robotic arm, respectively. A gripper is installed at the end of the robotic arm's wrist, and a positioning vision component is installed on the gripper. The positioning vision component includes a set of vision cameras and a structured light emitter. The structured light emitter is used to collect image information, calculate it into three-dimensional spatial position information, and then, through coordinate system transformation with the robotic arm, the control system achieves rapid positioning of the mobile robot. The vision cameras are used to scan the outline of the bolt holes of the wind turbine blades located in front of the mobile robot, realizing the center detection of all bolt holes of the wind turbine blades. Three lifting adjustment devices are installed under the chassis of the mobile robot and connected to it to compensate for the adjustment of the angle between the end of the wind turbine blade and the ground, ensuring that the mobile robot and different wind turbine blades maintain the same end face position after placement. The automatic installation method includes the following steps: S1. Coarse positioning of the equipment: First, hoist the wind turbine blade and fix it on the support for positioning. Then, the operator operates the remote control device to drive the mobile robot to move so that the front end of the wheeled chassis of the mobile robot is directly in front of the end of the wind turbine blade within 1.5 to 2 meters. S2. Automatic front and rear precise positioning of the equipment: After the mobile robot is started, three active structured light emitters with different ranging ranges are set on the gripper installed at the end of the robotic arm wrist to emit measurement laser signals. The robotic arm controls the laser beam on the gripper to be projected onto the inner wall of the wind turbine blade. The wheeled chassis is driven to move back and forth by the control system through the preset distance value to achieve distance adjustment and determine the working distance from the front end of the mobile robot to the front end face of the wind turbine blade. S3. Automatic Left / Right / Swing Precise Positioning: The robotic arm moves, causing the structured light emitter of the positioning vision component to perform two horizontal scans of the outer diameter distance on the left and right sides and the front-to-back distance of the wind turbine blade flange. The first scan is a coarse scan, after which the wheeled chassis moves to adjust the left and right and the swing angle of the wheeled chassis plane to center the position of the mobile robot, directly facing the root end face of the wind turbine blade. The second scan is for compensation, scanning to confirm whether the position adjusted by the wheeled chassis is in the centered working position at the root of the wind turbine blade. S4. Automatic and precise vertical positioning of the equipment: After the wheeled chassis has been adjusted in front-to-back / left-to-right / swing position, the structured light emitter of the positioning vision component scans the upper and lower outer diameter distances of the wind turbine blade flange twice within the working range of the robotic arm. The first scan is performed by driving the three lifting adjustment devices at the bottom of the wheeled chassis to lift and lower, thus moving the mobile robot up and down. After the hydraulic lifting and lowering actions of the three lifting adjustment devices stop, a plane is determined to make the front end of the wheeled chassis as parallel as possible to the front end of the wind turbine blade, so as to determine the position of the robotic arm's base coordinate system relative to the root of the wind turbine blade and to meet the conditions for the grasping action. The second scan is performed by determining the visual image and positioning information starting from the bottom bolt holes of the wind turbine blade flange, in preparation for the grasping and installation work. S5. Based on the pre-set program data of the bolt hole positions on the root flange of the entire wind turbine blade in the robotic arm simulation software, the control system outputs a signal to control the movement of the robotic arm. The gripper drives the elastic clamp to open at a certain angle. Under the action of the robotic arm and vision judgment and analysis, the motion coordinates are determined and the posture is adjusted to grasp the screw part of a double-ended bolt in the material box, after which the gripper closes. Then, under the vision judgment and analysis, the positioning vision component identifies the position center of the bolt hole on the wind turbine blade, finds the center point, calculates the position value of the bolt hole in the Y and Z directions, and sends it to the control system, so that the gripper can grasp the bolt hole. A double-ended bolt is moved to the center of the designated assembly hole on the flange of the wind turbine blade, and a certain amount of rotational feed is applied to the screw. While the positioning vision component identifies the hole position, the distance information transmitted back by the structured light emitter in the positioning vision component on the robotic arm identifies the distance value between the front face of the wind turbine blade and the current mobile robot, as well as the X value of the bolt hole end face, and sends it to the control system. The mobile robot accurately finds the position of the bolt hole to be installed based on the obtained X, Y, and Z values, and feeds the follower double-ended bolt to the designated extension distance through the gripper. At the same time, the gripper opens a certain amount and applies a certain preload. S6. Use the gripper to screw the double-ended bolt into the bolt hole of the double-ended bolt to be installed. The screwing depth is controlled by determining the relative positions of the tool coordinate system, workpiece coordinate system and base coordinate system based on the previous posture adjustment. The screwing length of the double-ended bolt is calculated by calculating the distance value of the structure light emitter and the actual length of the double-ended bolt to be installed. S7. Repeat steps S5 to S6, and screw the multiple double-ended bolts on the automatic feeder into the corresponding bolt holes to be installed.

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