An adaptive tightening system and operation method for a seat cushion robot

Abstract

The present invention relates to a seat cushion robot adaptive tightening system and an operation method; the system proposed by the present invention is composed of an integrated industrial computer, an AGV mobile platform, a collaborative robot, a tightening end effector, an industrial camera and its accessories; the collaborative robot is installed on the AGV mobile platform, and the tightening end effector and the industrial camera are installed at its end, and the entire system is controlled by the integrated industrial computer. Through the visual identification method and combined with the designed multi-layer screening method, the accurate position of the center of the bolt to be tightened can be obtained; at the same time, different feeding methods are set for different pre-tightening situations to achieve automatic cap searching and ensure that the tightening is in place; in addition, by adding a reaction force arm, the reaction force during the tightening process is offset to avoid damage to the robot. The tightening system and operation method proposed by the present invention have extremely high flexibility and can adapt to complex tightening environments, ensuring both the accuracy of the tightening work and improving the work efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic bolt tightening, and specifically relates to a seat ring gasket robot adaptive tightening system and an operation method thereof. Background Art

[0002] With the continuous development and maturity of robots and their related technologies, as well as the rising labor costs, robots are playing an increasingly important role in production. A large number of factories have started to invest in robots to cooperate with workers in production operations, which can improve work efficiency.

[0003] Bolt tightening is a very important part of mechanical assembly. For a long time, it has been manually operated. For some large equipment, there are often hundreds of bolts to be tightened, and the manual production efficiency will be very low. In order to improve production efficiency and reduce the labor intensity of workers, many production solutions using mechanical equipment to replace manual labor have emerged in recent years.

[0004] The patent "CN 119175678 A, a nut storage and supply device for automatic tightening" integrates nut storage, supply and automatic tightening. By storing nuts in a nut buffer and then feeding the nuts into the nut sleeve of the tightening shaft one by one from the nut buffer, the tightening shaft automatically takes the next nut directly after tightening one nut and then goes to the next position to tighten, so that nut tightening can be carried out automatically and continuously. However, the device itself cannot move, and other equipment is needed to transport the workpiece with nuts to be tightened to the lower part of the nut sleeve, which is not applicable to large equipment. The patent "CN 108608200 A, a tightening control management system and a tightening control method" provides a tightening control management system and a tightening control method. By using RFID radio frequency identification technology, local control of the tightening control management system is realized, so that the system can operate independently of the network, thereby improving the stability and reliability of the system. This method has high application value, but it needs to read all pre-set parameters and cannot be adjusted according to the actual situation.

[0005] Existing automatic tightening solutions are mostly aimed at specific production environments, with poor versatility. The tightening devices are fixed and cannot achieve flexible movement. The tightening system proposed by the present invention uses an AGV mobile platform and a collaborative robot as carriers, which can move widely in the production environment to achieve high-torque tightening in a narrow space. At the same time, the operation method designed for the system proposed by the present invention makes corresponding adjustments according to different pre-tightening conditions during the specific operation process, with better environmental adaptability and flexibility. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the present invention proposes a seat ring pad robot adaptive tightening system and an operation method, aiming to solve the problems of low manual production efficiency and high labor intensity of workers, and utilize the characteristics of collaborative robots to improve the flexibility and versatility of the tightening device.

[0007] To achieve the above technical objectives, the present invention proposes a seat ring pad robot adaptive tightening system, which specifically includes:

[0008] An AGV mobile platform, a collaborative robot, a tightening end effector, an industrial camera and its accessories, and an integrated industrial computer;

[0009] The AGV mobile platform is fixedly installed with a collaborative robot above it; the bottom surface of the collaborative robot is parallel to the horizontal ground, and its end is installed with a tightening end effector, an industrial camera and its accessories through a plate-shaped connecting piece; the tightening end effector is rotatably connected to the plate-shaped connecting piece through a bearing, and the industrial camera and its accessories are fixed to the plate-shaped connecting piece by screws; all components are connected to the integrated industrial computer;

[0010] The AGV mobile platform is used to drive the collaborative robot to move; the collaborative robot is used to drive the tightening end effector, the industrial camera and its accessories to reach the designated position and perform operations according to the planned route; the tightening end effector is used to perform tightening operations in a narrow space; the industrial camera and its accessories are used to collect image data and position data of the parts to be tightened; the integrated industrial computer is used to process data, plan paths, and control the movement and operations of each component.

[0011] Further, the tightening end effector includes:

[0012] A tightening gun, a sleeve, a cylinder, a reaction force arm, a small piece Z-shaped connecting piece, and a cube-shaped connecting piece;

[0013] The cube-shaped connecting piece is composed of a top plate, two side plates, and a bottom plate. The plates are connected by screws. The upper part of the top plate is used for connection with the bearing of the plate-shaped connecting piece through a circular structure. The two side plates are used to connect the bottom plate. The tightening gun extends in through the surface without a side plate and is fixed to the bottom plate by screws. The bottom plate has a circular hollow for the extension of the end of the tightening gun. The sleeve is fixed to the end of the tightening gun through a swivel joint and screws and rotates together with the end of the tightening gun; the reaction force arm is welded to the bottom plate;

[0014] The inner cavity of the sleeve is designed as a regular hexagon structure identical to the bolt head, and the inner cavity area is slightly larger than the bolt head; during the process of the bolt head being inserted into the sleeve for tightening, both rotate simultaneously without relative rotation; a spring is connected to the end of the sleeve, and it is axially self-adaptively compressed when subjected to an axial force, avoiding rigid collision between the sleeve and the bolt surface and the installation surface during axial feeding;

[0015] One end of the cylinder is hinged to the plate-shaped connecting piece, and the other end is hinged to the small Z-shaped connecting piece; the small Z-shaped connecting piece is fixedly connected to the top plate of the cube-shaped connecting piece by screws, and the small Z-shaped connecting piece converts the linear motion of the cylinder's expansion and contraction into the rotation of the cube-shaped connecting piece, thereby pushing the reaction force arm to extend and retract; the reaction force arm is used to balance the reaction force of the bolt cap on the end of the collaborative robot during the tightening operation.

[0016] Further, the industrial camera and its accessories include:

[0017] A camera, a light source, and a laser displacement sensor;

[0018] The camera and the laser displacement sensor are adjacently installed on the plate-shaped connecting piece, and the laser displacement sensor is installed horizontally with the camera to ensure the same height of the camera each time it takes a photo; the light source is installed around the lens of the camera in a circular ring shape; the camera, the light source, and the laser displacement sensor have a certain height difference from the sleeve during installation to avoid collision with the installation platform.

[0019] The present invention also provides a seat ring pad robot adaptive tightening system, which specifically includes the following steps:

[0020] S1. Build the seat ring pad robot adaptive tightening system; fix the tightening end effector, the industrial camera and its accessories to the end of the collaborative robot, and fix the collaborative robot to the AGV mobile platform, and its bottom surface is parallel to the horizontal ground;

[0021] The tightening end effector includes a tightening gun, a sleeve, a cylinder, and a reaction force arm; the industrial camera and its accessories include a camera, a light source, and a laser displacement sensor;

[0022] All components are connected to the integrated industrial computer and are uniformly controlled by it;

[0023] S2. Establish the coordinate systems of all parts of the system, including: the AGV mobile platform coordinate system, the robot base coordinate system, the robot end coordinate system, the camera coordinate system, the sleeve coordinate system, and the installed workpiece coordinate system, and determine the relative position relationships between the coordinate systems of all parts;

[0024] S3. Perform hand-eye calibration and tightening end effector calibration; determine the relative position relationship between the camera and the sleeve through hand-eye calibration to obtain the transformation matrix of the camera coordinate system relative to the robot end coordinate system, and obtain the transformation matrix of the sleeve coordinate system relative to the robot end coordinate system through tightening end effector calibration;

[0025] S4, teaching the photographing points and setting the photographing parameters; through manual teaching, ensure that the bolt to be tightened is located at the center of the camera's field of view, and after ensuring that a clear and identifiable image of the bolt to be tightened without ghosting or blurring can be taken, record the position information and photographing parameters of the end of the collaborative robot in the robot base coordinate system, and after obtaining the photographing point of a bolt to be tightened, calculate the photographing points of the remaining bolts to be tightened based on the product digital model information; setting the photographing parameters includes setting the exposure time and gain;

[0026] S5, perform path planning and offline programming; according to the photographing points of the bolts to be tightened obtained in step S4, the product digital model information, and the relative positions of the entire tightening system and the system to be tightened, plan the motion path of the collaborative robot to ensure the highest tightening efficiency, and use offline programming to ensure that the collaborative robot can run in an offline state to reach each photographing point, completing the entire path planning and offline programming workflow;

[0027] S6. Set the process parameters of the tightening gun according to the actual working conditions to meet the tightening requirements;

[0028] S7. Based on the different pre-tightening states of the bolts, each photographing point obtained in step S4 is corrected; the collaborative robot first moves according to the path preset by offline programming, and after reaching each photographing point, a laser displacement sensor is used to ensure that the height from the camera to the upper surface of each bolt cap remains unchanged, thereby correcting each photographing point;

[0029] S8, identifying the center position of the bolt to be tightened; after the end of the collaborative robot reaches the corrected photo-taking point, the camera is started to take a photo, and the image is transmitted to the integrated industrial computer. The obtained image is identified and processed using the preset algorithm program in the integrated industrial computer. By designing a multi-layer screening method, the precise position of the center of each bolt to be tightened in the robot base coordinate system is obtained;

[0030] S9, the end of the collaborative robot moves to the precise position obtained in step S8, runs the cap-finding program, controls the bolt cap to be inserted into the sleeve, the cylinder pushes the reaction force arm to extend, against the installation workpiece, the tightening gun starts tightening, and the bolt rotates with the sleeve until the tightening reaches the torque set by the processing task to complete the tightening;

[0031] S10. After the bolt is tightened, the cylinder works, the reaction force arm retracts, and the sleeve first rotates slightly in the opposite direction of tightening to create a gap between its inner cavity and the side surface of the bolt cap, and then the end moves in the vertical direction to separate the sleeve and the bolt;

[0032] S11, the integrated industrial computer makes a judgment, if there are still bolts to be tightened, then repeat steps S7-S10 until all tightening tasks are completed; if all tightening tasks have been completed, the system returns to the initial position.

[0033] Based on the above technical solutions, the present invention has at least the following beneficial effects:

[0034] 1) The present invention uses a collaborative robot as the carrier of the tightening device, which is small in size. Moreover, the collaborative robot is installed on an AGV mobile platform, with high flexibility, capable of moving over a large range and adapting to complex working environments.

[0035] 2) The present invention designs a lightweight and automated tightening end effector, which can be carried on a small collaborative robot and can perform tightening operations in narrow spaces. In addition, a reaction force arm is added to the tightening end effector to counteract the reaction force during the tightening process and avoid damage to the robot caused by the reaction force.

[0036] 3) The present invention adopts a visual recognition method, utilizes a laser displacement sensor, and combines a designed multi-layer screening method to achieve high-precision recognition of the center of the bolt nut to be tightened under different pre-tightening states, and then guides the end of the collaborative robot to accurately locate to the position to be tightened.

[0037] 4) The present invention designs a compressible sleeve, which improves the adaptability to the tightening requirements of bolts under different pre-tightening states, and designs corresponding tightening feed schemes for bolts under different pre-tightening states, enabling automatic and continuous tightening with high tightening efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic diagram of the overall structure of the system proposed by the present invention;

[0039] Figure 2 is a specific structural diagram of the tightening end effector, industrial camera and its accessories in the system proposed by the present invention;

[0040] Figure 3 is a flowchart of the operation method of the system proposed by the present invention;

[0041] Figure 4 is a flowchart of bolt center position recognition in the operation method proposed by the present invention;

[0042] Reference numerals: 1 - AGV mobile platform, 2 - collaborative robot, 3 - tightening end effector, 4 - industrial camera and its accessories; 301 - tightening gun, 302 - sleeve, 303 - cylinder, 304 - reaction force arm; 401 - industrial camera, 402 - light source, 403 - laser displacement sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] The following further elaborates the present invention in detail with reference to the drawings and specific embodiments.

[0044] To make the objectives, technical solutions and advantages of the present invention clearer, the following will be combined with the attachedFigures 1-4 A detailed description of the present invention will be given. It should be noted that these specific embodiments are only used to explain the present invention and do not limit its scope. In addition, the technical features involved in each of the embodiments described in the text can be combined with each other as long as they do not conflict with each other.

[0045] When describing the present invention, it should be specifically noted that unless otherwise clearly specified or limited, when referring to a component being "connected" to another component, it means that it can be directly connected or indirectly connected through an intermediate medium. Terms such as "installed" and "fixed" should be understood widely. For example, they can refer to fixed connection, detachable connection or integral connection, and can also be mechanical connection or electrical connection, directly connected or indirectly connected through a medium, and even include the communication relationship or interaction inside the two components. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0046] In addition, although the steps in the present invention are arranged with reference numerals, they are not used to limit the order of the steps. Unless the order of the steps is clearly stated or the execution of a certain step requires other steps as a basis, the relative order of the steps can be adjusted. It can be understood that the term "and / or" used herein covers any and all possible combinations of one or more of the associated listed items.

[0047] As Figure 1 shown, the present invention provides an adaptive tightening system for a seat ring pad robot, which specifically includes:

[0048] An AGV mobile platform 1, a collaborative robot 2, a tightening end effector 3, an industrial camera and its accessories 4, and an integrated industrial computer;

[0049] The collaborative robot 2 is fixedly installed above the AGV mobile platform 1; the bottom surface of the collaborative robot 2 is parallel to the horizontal ground, and a tightening end effector 3 and an industrial camera and its accessories 4 are installed at its end through a plate-shaped connecting piece; the tightening end effector 3 is rotationally connected to the plate-shaped connecting piece through a bearing, and the industrial camera and its accessories 4 are fixed to the plate-shaped connecting piece by screws; all components are connected to the integrated industrial computer;

[0050] The AGV mobile platform 1 is used to drive the collaborative robot 2 to move; the collaborative robot 2 is used to drive the tightening end effector 3 and the industrial camera and its accessories 4 to reach the designated position and perform operations according to the planned route; the tightening end effector 3 is used to perform tightening operations in a narrow space; the industrial camera and its accessories 4 are used to collect image data and position data of the parts to be tightened; the integrated industrial computer is used to process data, plan paths, and control the movement and operations of each component.

[0051] In this embodiment, the tightening end effector 3, the industrial camera and its accessories 4 are collectively referred to as the robot end effector, which moves along with the end of the collaborative robot 2. The specific structures of these two components are as follows: Figure 2 shown as:

[0052] The tightening end effector 3 includes: a tightening gun 301, a sleeve 302, a cylinder 303, a reaction force arm 304, a small block Z-shaped connecting piece, and a cube-shaped connecting piece;

[0053] The cube-shaped connecting piece is composed of a top plate, two side plates, and a bottom plate. The plates are connected by screws. The upper part of the top plate is used to connect with the bearing of the plate-shaped connecting piece through a circular structure. The two side plates are used to connect the bottom plate. The tightening gun 301 extends in through the side-less surface and is fixed on the bottom plate by screws. The bottom plate has a circular hollow for the end of the tightening gun 301 to extend out. The sleeve 302 is fixed at the end of the tightening gun 301 through an adapter and screws and rotates together with the end of the tightening gun 301; the reaction force arm 304 is welded to the bottom plate;

[0054] The inner cavity of the sleeve 302 is designed as a regular hexagon structure identical to the bolt head, and the inner cavity area is slightly larger than the bolt head; during the process of the bolt head being inserted into the sleeve 302 for tightening, both rotate simultaneously without relative rotation; a spring is connected to the end of the sleeve 302, and it is adaptively compressed along the axial direction of the sleeve 302 when subjected to an axial force, avoiding rigid collision between the sleeve 302 and the bolt surface and the installation surface during axial feeding; in addition, it should be noted that the bolt head in this application refers to the regular hexagon head at the top of the bolt.

[0055] One end of the cylinder is hinged to the plate-shaped connecting piece, and the other end is hinged to the small block Z-shaped connecting piece; the small block Z-shaped connecting piece is fixedly connected to the top plate of the cube-shaped connecting piece by screws. The small block Z-shaped connecting piece converts the linear motion of the cylinder's telescoping into the rotation of the cube-shaped connecting piece, thereby driving the extension and retraction of the reaction force arm; the reaction force arm is used to balance the reaction force exerted on the end of the collaborative robot by the bolt head during the tightening operation.

[0056] The industrial camera and its accessories 4 include: a camera 401, a light source 402, and a laser displacement sensor 403;

[0057] The camera 401 and the laser displacement sensor 403 are adjacently installed on the plate-shaped connecting piece, and the laser displacement sensor 403 is installed horizontally with the camera 401 to ensure that the height of the camera 401 is the same each time it takes a photo; the light source 402 is installed around the lens of the camera 401 in a circular ring shape; the camera 401, the light source 402, and the laser displacement sensor 403 are installed with a certain height difference from the sleeve 302 to avoid collision with the installation platform.

[0058] As Figures 3-4As shown, a method for operating an adaptive tightening system of a seat cushion robot proposed by the present invention is shown, which specifically includes the following steps:

[0059] S1. Build an adaptive tightening system for the seat cushion robot; fix the tightening end effector 3, the industrial camera and its accessories 4 at the end of the collaborative robot 2, fix the collaborative robot 2 on the AGV mobile platform 1, and its bottom surface is parallel to the horizontal ground;

[0060] The tightening end effector 3 includes a tightening gun 301, a sleeve 302, a cylinder 303, and a reaction force arm 304; the industrial camera and its accessories include a camera 401, a light source 402, and a laser displacement sensor 403;

[0061] All components are connected to an integrated industrial computer and are uniformly controlled by it;

[0062] It should be noted that in this embodiment, the bolt to be tightened and the installation workpiece also form a system to be tightened.

[0063] S2. Establish the coordinate systems of each part of the system, including: the AGV mobile platform coordinate system, the robot base coordinate system, the robot end coordinate system, the camera coordinate system, the sleeve coordinate system, and the installation workpiece coordinate system, and determine the relative position relationships between the coordinate systems of each part;

[0064] S3. Perform hand-eye calibration and calibration of the tightening end effector; determine the relative position relationship between the camera 301 and the sleeve 302 through hand-eye calibration to obtain the transformation matrix of the camera coordinate system relative to the robot end coordinate system, and obtain the transformation matrix of the sleeve coordinate system relative to the robot end coordinate system through calibration of the tightening end effector; in this embodiment, steps S2 - S3 of establishing the coordinate system and performing calibration are all for accurately positioning the bolt to be tightened and accurately guiding the movement of the end of the collaborative robot 2

[0065] S4. Teach the photographing points and set the photographing parameters; through manual teaching, ensure that the bolt to be tightened is located at the center of the field of view of the camera 401. After determining that a clear, distinguishable, non - ghosted and non - blurred image of the bolt to be tightened can be captured, record the pose information of the end of the collaborative robot 2 in the robot base coordinate system and the photographing parameters. After obtaining a photographing point of a bolt to be tightened, calculate the photographing points of the remaining bolts to be tightened based on the product digital model information; setting the photographing parameters includes setting the exposure time and gain;

[0066] S5, perform path planning and offline programming; according to the photographing points of the bolts to be tightened obtained in step S4, the product digital model information, and the relative positions of the entire tightening system and the system to be tightened, plan the movement path of the collaborative robot 2 to ensure the highest tightening efficiency, and use offline programming to ensure that the collaborative robot 2 can run in an offline state to reach each photographing point, completing the entire path planning and offline programming workflow;

[0067] S6. Set the process parameters of the tightening gun 301 according to the actual working conditions to meet the tightening requirements. So far, steps S1-S6 have completed the preparation process of the tightening operation. Now start the tightening operation.

[0068] S7, based on the different pre-tightening states of each bolt, each photographing point obtained in step S4 is corrected; the collaborative robot 2 first moves according to the path preset by offline programming, and after reaching each photographing point, the laser displacement sensor 403 is used to ensure that the height from the camera 401 to the upper surface of each bolt cap remains unchanged, so as to realize the correction of each photographing point;

[0069] As a preferred embodiment, in step S7, the laser displacement sensor 403 is used to ensure that the height from the camera 401 to the upper surface of each bolt cap remains unchanged, and the correction of each photographing point is realized specifically as follows:

[0070] The preset height from the camera 401 to the upper surface of the bolt cap is set to h0, and the default height at which the end moves to each photographing point for photographing is H. The actual height h from the camera 401 to the upper surface of the bolt cap varies due to the different pre-tightening states of each bolt to be tightened. In order to facilitate subsequent image processing, in this embodiment, the laser displacement sensor 403 is used to measure the value of the actual height h, and each photographing point is corrected according to the difference between the actual height h and h0; the formula is expressed as:

[0071]

[0072] Wherein, H' represents the corrected height at which the end point moves to each photographing point for taking photos.

[0073] S8, identifying the center position of the bolt to be tightened; after the end of the collaborative robot 2 reaches the corrected photographing point, the camera 401 is started to take a photo, and the image is transmitted to the integrated industrial computer. The obtained image is identified and processed using the algorithm program preset in the integrated industrial computer. By designing a multi-layer screening method, the precise position of the center of each bolt to be tightened in the robot base coordinate system is obtained;

[0074] As a preferred embodiment, Figure 4 As shown, step S8 specifically includes:

[0075] S81. The bolt to be tightened has a hexagonal head, and its top view consists of a regular hexagon and the inscribed circle of the hexagon. First, process the image obtained at the current photographing position in the image coordinate system. Since the distances between several bolts to be tightened are relatively close, the obtained image may include the top views of multiple bolts. Therefore, it is necessary to identify the inscribed circle of the bolt to be tightened at the current photographing position through multi-layer screening to obtain the center data. In this embodiment, the image coordinate system refers to a plane coordinate system with the upper left corner of the photographed image as the coordinate origin, the x-axis parallel to the image plane and horizontally to the right, and the y-axis parallel to the image plane and perpendicular to the x-axis and downward.

[0076] More specifically, step S81 specifically includes:

[0077] S811. First, obtain the fitted ellipses of all bolts in the image. Since all bolt images are taken at a fixed height, the perimeters and areas of the inscribed circles of each bolt are similar. Therefore, first perform the first-layer screening on the fitted ellipses based on their perimeters and areas according to the following formula:

[0078]

[0079] where S and C are respectively the area and perimeter of the fitted ellipse participating in the first-layer screening, and S MIN , S MAX , C MIN , C MAX respectively represent the minimum value, maximum value of the area of the fitted ellipse that meets the conditions, and the minimum value, maximum value of the perimeter of the fitted ellipse. Considering that the ambient light will change and the surface conditions of each bolt are different, in actual selection, the ranges of area and perimeter should not be taken too small.

[0080] After the first-layer screening is completed, most of the ellipses that do not meet the conditions are screened out. At this time, perform the second-layer screening. Select two fitted ellipses from the remaining fitted ellipses after the first-layer screening in turn to calculate the center distance between the two fitted ellipses to avoid having two ellipses with overly close centers. Only retain one of the two fitted ellipses with too close center distances. That is:

[0081] First, calculate the center distance L between the two fitted ellipses, and the formula is expressed as:

[0082]

[0083] where (x m , y m ), (x n , y n ) represent the coordinates of the centers of the two fitted ellipses participating in the calculation in the image coordinate system.

[0084] Compare it with the maximum value L0 of the center distance of the two fitted ellipses set, and decide whether to screen out one of the fitted ellipses. The formula is expressed as:

[0085]

[0086] The remaining fitted ellipses after the second-layer screening, that is, those that meet the perimeter and area requirements and have no other fitted ellipse centers near their centers;

[0087] S813. Conduct the third-layer screening, and conduct roundness screening on the remaining fitted ellipses after the second-layer screening. The formula is expressed as:

[0088]

[0089] Among them, a represents the length of the semi-major axis of the fitted ellipse, b represents the length of the semi-minor axis of the fitted ellipse, and R0 is the set roundness requirement, and its value range is 0 to 1; in order to ensure that the remaining fitted ellipse is close to the inscribed circle, in this embodiment, R0 takes a value close to 1. At the same time, due to the existence of the second-layer screening, there is finally only one fitted ellipse that meets the roundness requirement (the ellipse centers of the ellipses with similar roundness are also close and are discarded); the finally remaining fitted ellipse is used as the inscribed circle of the bolt;

[0090] S814. After the above three-layer screening, the inscribed circles of all bolts in the image are screened out, and then the one with the closest distance from the inscribed circle center to the image center is selected as the inscribed circle of the bolt to be tightened at the current photographing position; specifically:

[0091] First calculate the coordinates (x0, y0) of the image center. The formula is expressed as:

[0092]

[0093] Among them, W represents the width of the image, and H represents the height of the image;

[0094] Then calculate the distance from the center of each inscribed circle to the image center, and find the shortest distance. The formula is expressed as:

[0095]

[0096] L Cmin =min{L Ci |i∈[1,2,...,n]};

[0097] Among them, L Ci represents the distance from the center of the i-th inscribed circle to the image center, and L Cmin represents the shortest distance from the image center. The coordinates of the center corresponding to this distance are the coordinates of the center of the inscribed circle of the bolt to be tightened at the current photographing position in the image coordinate system, denoted as (xc0 , y c0 ).

[0098] S82. Then, with this center as the center, define the ROI region (region of interest). The ROI region excludes other irrelevant parts in the image and only leaves the bolts to be tightened near the current photographing position. Then, perform the screening of the six sides of the regular hexagon. After screening out the six sides, find the six intersection points of the six sides as the six corner points of the regular hexagon. Take the average value of the coordinates of the six points as the exact position of the center of the bolt to be tightened under the current photographing position in the image coordinate system. Through the positional relationship between the coordinate systems, transform to obtain the exact position of the center of the bolt to be tightened under the current photographing position in the robot base coordinate system;

[0099] Step S82 specifically includes:

[0100] S821. Take the inscribed circle center of the bolt to be tightened under the current photographing position as the center and the rectangular region of the entire hexagon containing the projection of the bolt head as the ROI region; and screen out all the line segments within the ROI region from the image. The formula is expressed as:

[0101]

[0102] where, W R and H R represent the width and height of the ROI region, (x A , y A ) and (x B , y B ) respectively represent the two endpoints of the line segment;

[0103] S822. After screening out all the line segments within the ROI region, screen out the line segments judged to be repeated according to the cosine value and midpoint distance between the line segments and divide them into six groups; specifically:

[0104] First, calculate the cosine value between two line segments When the cosine value satisfies , the two line segments are parallel, and it is considered that these two line segments are repeated and grouped into the same group;

[0105] where, P represents the minimum cosine value for determining the parallelism of two lines, A and B represent the vectors corresponding to the two line segments; |A| and |B| are the moduli of these two vectors;

[0106] Then, screen out the cases where they are parallel due to being opposite sides of the hexagon through the midpoint distance; the formula is expressed as:

[0107]

[0108] where, (x 1a , y 1a ), (x1b , y 1b ), (x 1c , y 1c ), (x 2a , y 2a ), (x 2b , y 2b ), (x 2c , y 2c ), (x c0 represent the coordinates of the two endpoints and the midpoint of line segment 1 respectively, and (x c0 ), (x

[0109] After the cosine value and midpoint distance judgment, six groups of line segments are obtained, and the line segments within each group are judged to be repeated;

[0110] S823. According to the distance from the midpoint of the line segment to the center of the inscribed circle, select the line segment representing each side of the regular hexagon from each group. The formula is expressed as:

[0111]

[0112] where l 1c , l 2c represent the distances from the centers of line segment 1 and line segment 2 in a group to the center of the inscribed circle respectively; each time, the line segment with a farther distance from the center of the inscribed circle is retained. After traversing all the line segments in the group, the finally retained line segment represents one side of the regular hexagon. After all six groups are screened, six line segments representing the six sides of the regular hexagon are obtained;

[0113] S824. According to the straight-line equations of the six line segments obtained in step S823, find the intersection points of the six straight lines pairwise. The formula is expressed as:

[0114] The general form equations of the straight lines where the six line segments are located: A i x + B i y + C i = 0 (i = 1, 2,..., 6);

[0115] Intersection point calculation formula: i, j = 1, 2,..., 6, i ≠ j;

[0116] where A i , B i , C i are the coefficients of the general form equation of straight line i, and A j , B j , C j are the coefficients of the general form equation of straight line j, (xij ,y ij ) is the intersection point of lines i and j

[0117] Then, based on the fact that the distance from the intersection of non-adjacent straight lines to the center of the inscribed circle is greater than the distance from the intersection of adjacent straight lines to the center of the inscribed circle, non-adjacent straight line intersections are screened out. The formula is:

[0118]

[0119] Among them, L c1 is the set distance threshold, exceeding the distance threshold L c1 The intersection points are considered as non-adjacent straight line intersection points and are discarded; the six intersection points retained after final screening are the six corner points of the regular hexagon, and the six corner points are recorded as x n ,n=1,2,...,6;

[0120] S825, calculate the coordinates (x c ,y c ):

[0121]

[0122] Convert the image coordinate system to the robot base coordinate system according to (x c ,y c ) calculates the precise position of the center of the bolt to be tightened at the current photographing point in the robot base coordinate system, and then guides the end of the collaborative robot 2 to move to the exact position for tightening.

[0123] S83, traverse each corrected photographing point, repeat steps S81-S82, and obtain the precise position of the center of each bolt to be tightened in the base coordinate system.

[0124] S9, the end of the collaborative robot 2 moves to the precise position obtained in step S8, runs the cap-finding program, controls the bolt cap to be inserted into the sleeve 302, and the cylinder 303 pushes the reaction force arm 304 to extend and resist the installation workpiece, and the tightening gun 301 starts tightening, and the bolt rotates with the sleeve 302 until the tightening reaches the torque set by the processing task to complete the tightening;

[0125] As a preferred implementation, step S9 specifically includes:

[0126] S91. According to the precise position obtained in step S8, the end of the collaborative robot 2 first moves in the horizontal direction until the axis of the bolt is in line with the axis of the sleeve 302, and then the end is fed axially as a whole, and the sleeve 302 approaches the surface of the bolt. Different feeding and tightening methods are required according to the different pre-tightening states of each bolt to be tightened; the formula is expressed as:

[0127]

[0128] Wherein, h is the height of the camera 401 relative to the upper surface of the bolt cap obtained by the laser displacement sensor 403 before the photographing height adjustment, and h0 is the photographing height;

[0129] S92, when h≥h0, the bolt has been pre-tightened in place and one-time feeding is adopted; specifically:

[0130] First, the cap is searched, and the end of collaborative robot 2 feeds h0-h along the axial direction. t +h l , where h t represents the axial distance difference between the lower surface of the sleeve 302 and the camera 401, h l Indicates the thickness of the bolt cap;

[0131] After the feeding is completed, if the bolt is not inserted into the sleeve 302, but the lower surface of the sleeve 302 contacts the upper surface of the bolt, the feeding cannot continue. At this time, the spring is compressed by force, and the compression amount is h l , the sleeve 302 is controlled by the tightening gun 301 to move at a lower angular velocity w l After slowly rotating for one circle, when the inner cavity of the sleeve 302 and the shape of the bolt cap completely coincide, the bolt cap is inserted into the sleeve 302 under the elastic force of the spring, and the bolt cap is found as the sleeve 302 rotates;

[0132] After the cap search is completed, the reaction arm 304 is pushed out by the cylinder 303 to press against the edge of the installation workpiece, and the tightening gun 301 controls the sleeve 302 to move at a higher angular velocity w h Rotate to tighten the bolts; when the tightening torque reaches the task requirement, the tightening is completed;

[0133] S93, when h<h0, the bolt is not pre-tightened in place, and the distance between the upper surface of the bolt and the installation workpiece is h0+h l -h, when tightening, the total axial feed of the end of collaborative robot 2 increases by h0-h compared with the case of one-time feeding. In this case, multiple feeding is adopted, specifically:

[0134] First, the end of collaborative robot 2 still feeds h0-h along the axial direction t +h l , and perform the same cap-finding operation as the tightening process of one feed; after the cap-finding is completed, the lower surface of the sleeve 302 is h0-h away from the installation workpiece, then the end of the collaborative robot 2 is controlled to feed downward again h0-h, the bolt is inserted into the inner cavity of the sleeve 302, and the lower surface of the sleeve 302 fits the installation workpiece; then, the cylinder 303 pushes the reaction force arm 304 to extend and press against the edge of the installation workpiece, and the tightening gun 301 controls the sleeve to move at a higher angular velocity w hRotate to tighten the bolt, and when the tightening torque reaches the task requirement, the tightening is completed.

[0135] In this embodiment, the working principle of the reaction force arm 304 provided in the present invention is also given: when further tightening the bolt after pre-tightening, the sleeve 302 will be subjected to a large torque T1 opposite to the tightening direction, and the sleeve 302 is installed at the end of the collaborative robot 2. The torque will eventually act on the collaborative robot 2 body, increasing the load on each axis of the robot. When the torque is too large, it will trigger the collaborative robot 2 to stop urgently. When working continuously, it will be under a high load for a long time, which will affect the service life of the robot. Therefore, the reaction force arm is designed to balance the torque. During the tightening process, the cylinder pushes the reaction force arm to extend and press against the side of the mounting table. The mounting table provides a support force F2 for the force arm, forming a balanced torque opposite to T1, reducing the load on the robot body and ensuring the stability of the operation.

[0136] S10, after the bolt is tightened, the cylinder 303 works, the reaction force arm 304 retracts, and the sleeve 302 first rotates slightly in the opposite direction of tightening to create a gap between its inner cavity and the side surface of the bolt cap, and then the end moves in the vertical direction to separate the sleeve 302 from the bolt;

[0137] S11, the integrated industrial computer makes a judgment, if there are still bolts to be tightened, then repeat steps S7-S10 until all tightening tasks are completed; if all tightening tasks have been completed, the system returns to the initial position.

[0138] So far, the tightening system proposed by the present invention has completed the entire tightening operation according to the above operation method. In summary, the seat ring pad robot adaptive tightening system and operation method proposed by the present invention have extremely high flexibility and can adapt to complex tightening environments, which not only ensures the accuracy of the tightening work, but also improves the work efficiency.

[0139] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0140] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment contains only an independent technical solution. This narrative style of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A running method of an adaptive tightening system for a toilet seat cushion robot, characterized in that, Specifically, it includes the following steps: S1. Build a self - adaptive tightening system for the toilet seat cushion robot; fix the tightening end - effector (3), industrial camera and its accessories (4) at the end of the collaborative robot (2), and fix the collaborative robot (2) on the AGV mobile platform (1), and its bottom surface is parallel to the horizontal ground; The tightening end - effector (3) includes a tightening gun (301), a sleeve (302), a cylinder (303), and a reaction force arm (304); the industrial camera and its accessories include a camera (401), a light source (402), and a laser displacement sensor (403); All components are connected to an integrated industrial computer and are uniformly controlled by it; S2. Establish the coordinate systems of all parts of the system, including: AGV mobile platform coordinate system, robot base coordinate system, robot end - effector coordinate system, camera coordinate system, sleeve coordinate system, and installed workpiece coordinate system, and determine the relative position relationships between the coordinate systems of all parts; S3. Perform hand - eye calibration and tightening end - effector calibration; determine the relative position relationship between the camera (401) and the sleeve (302) through hand - eye calibration to obtain the transformation matrix of the camera coordinate system relative to the robot end - effector coordinate system, and obtain the transformation matrix of the sleeve coordinate system relative to the robot end - effector coordinate system through tightening end - effector calibration; S4. Teach the photo - taking points and set the photo - taking parameters; through manual teaching, ensure that the bolt to be tightened is at the center of the field of view of the camera (401). After determining that a clear, distinguishable, non - ghosting and non - blurry image of the bolt to be tightened can be captured, record the pose information of the end of the collaborative robot (2) in the robot base coordinate system and the photo - taking parameters. After obtaining a photo - taking point of a bolt to be tightened, calculate the photo - taking points of the remaining bolts to be tightened based on the product digital model information; setting the photo - taking parameters includes setting the exposure time and gain; S5. Perform path planning and offline programming; according to the photo - taking points of the bolts to be tightened obtained in step S4, the product digital model information, and the relative positions of the entire tightening system and the system to be tightened, plan the motion path of the collaborative robot (2) to ensure the highest tightening efficiency, and use offline programming to ensure that the collaborative robot (2) can operate offline to reach each photo - taking point, completing the entire path planning and offline programming work process; S6. Set the process parameters of the tightening gun (301) according to the actual working conditions to meet the processing and tightening requirements; S7. Based on the different pre - tightening states of each bolt, perform correction work on each photo - taking point obtained in step S4; the collaborative robot (2) first moves according to the path preset by offline programming. After reaching each photo - taking point, use the laser displacement sensor (403) to ensure that the height from the camera (401) to the upper surface of each bolt cap remains unchanged, realizing the correction of each photo - taking point; S8, identifying the center position of the bolt to be tightened; after the end of the collaborative robot (2) reaches the corrected photographing point, the camera (401) is started to take a photo, and the image is transmitted to the integrated industrial computer. The obtained image is identified and processed using a preset algorithm program in the integrated industrial computer, and the precise position of the center of each bolt to be tightened in the robot base coordinate system is obtained by designing a multi-layer screening method; specifically including: S81. The bolt to be tightened is a hexagonal head, and its top view consists of a regular hexagon and an inscribed circle of the hexagon. First, the image obtained at the current shooting point is processed in the image coordinate system, and the inscribed circle is first identified through multi-layer screening to obtain the position data of the center of the circle; S82, delineating an ROI region with the center of the circle as the center, screening the six sides of the regular hexagon, and after screening the six sides, obtaining the six intersection points of the six sides as the six corner points of the regular hexagon; taking the average of the coordinates of the six points as the precise position of the center of the bolt to be tightened at the current photographing point in the image coordinate system, and then transforming the precise position of the center of the bolt to be tightened at the current photographing point in the robot base coordinate system through the positional relationship between the coordinate systems; S83, traverse each corrected photographing point, repeat steps S81-S82, and obtain the precise position of the center of each bolt to be tightened in the base coordinate system; S9, the end of the collaborative robot (2) moves to the precise position obtained in step S8, runs the cap-finding program, controls the bolt cap to be inserted into the sleeve (302), the cylinder (303) pushes the reaction force arm (304) to extend, against the installation workpiece, the tightening gun (301) starts tightening, and the bolt rotates with the sleeve (302) until the tightening reaches the torque set by the processing task to complete the tightening; S10, after the bolt is tightened, the cylinder (303) works, the reaction force arm (304) retracts, and the sleeve (302) first rotates slightly in the opposite direction of tightening to create a gap between its inner cavity and the side surface of the bolt cap, and then the end moves in the vertical direction to separate the sleeve (302) and the bolt; S11, the integrated industrial computer makes a judgment, if there are still bolts to be tightened, then repeat steps S7-S10 until all tightening tasks are completed; if all tightening tasks have been completed, the system returns to the initial position.

2. The operating method of an adaptive tightening system for a toilet seat cushion robot according to claim 1, characterized in that, In step S7, the laser displacement sensor (403) is used to ensure that the height from the camera (401) to the upper surface of each bolt cap remains unchanged, and the correction of each photographing point is achieved specifically as follows: The preset height from the camera (401) to the upper surface of the bolt cap is set as h0, and the default height at which the end moves to each photographing point for photographing is H. The actual height h from the camera (401) to the upper surface of the bolt cap varies due to the different pre-tightening states of each bolt to be tightened. The value of the actual height h is measured by the laser displacement sensor (403), and correction is performed at each photographing point according to the difference between the actual height h and h0. The formula is expressed as follows: Wherein, H' represents the corrected height at which the end point moves to each photographing point for taking photos.

3. The operating method of an adaptive tightening system for a toilet seat cushion robot according to claim 1, characterized in that Step S81 specifically includes: S811. First, obtain the fitted ellipses of all bolts in the image. Based on the perimeter and area of the fitted ellipses, perform the first - layer screening according to the following formula: Among them, S and C are the area and perimeter of the ellipse currently involved in the first-level screening and fitting, respectively. MIN , S MAX , C MIN , C MAX They respectively represent the minimum and maximum values ​​of the area of ​​the fitted ellipse and the minimum and maximum values ​​of the perimeter of the fitted ellipse that meet the set conditions; S812. Perform the second - layer screening. Select two fitted ellipses from the remaining fitted ellipses after the first - layer screening in sequence and calculate the center distance between the two fitted ellipses. Only retain one of the two fitted ellipses with an overly close center distance; that is: First, calculate the center distance L between the two fitted ellipses, which is expressed by the formula: Among them, (x m , y m ), (x n , y n ) represent the coordinates of the centers of two fitted ellipses participating in the calculation in the image coordinate system; Then, compare it with the maximum value L0 of the center distance between the two fitted ellipses set to determine whether to screen out one of the fitted ellipses. The formula is expressed as: The remaining fitted ellipses after the second - layer screening are those that meet the perimeter and area requirements and have no other fitted ellipse centers near their centers; S813. Perform the third - layer screening. Screen the remaining fitted ellipses after the second - layer screening for circularity, and the formula is expressed as: Among them, a represents the length of the semi - major axis of the fitted ellipse, b represents the length of the semi - minor axis of the fitted ellipse, and R0 is the set circularity requirement; the finally retained fitted ellipse is used as the inscribed circle of the bolt; S814. After the above three - layer screening, the inscribed circles of all bolts in the image are screened out. Then, select the one with the closest distance from the center of the inscribed circle to the center of the image as the inscribed circle of the bolt to be tightened at the current photographing position; specifically: First, calculate the coordinates (x0, y0) of the center of the image, and the formula is expressed as: Among them, W represents the width of the image, and H represents the height of the image; Then, calculate the distance from the center of each inscribed circle to the center of the image and find the shortest distance. The formula is expressed as: L Cmin = min{L Ci | i ∈ [1, 2,..., n]}; Among them, L Ci represents the distance from the center of the i-th inscribed circle to the center of the image, and L Cmin represents the shortest distance from the center of the image. The center coordinates corresponding to this distance are the coordinates of the center of the inscribed circle of the bolt to be tightened under the current photographing position in the image coordinate system, denoted as (x c0 , y c0 ).

4. The operating method of an adaptive tightening system for a toilet seat cushion robot according to claim 3, characterized in that, Step S82 specifically includes: S821. Take the rectangle area of the entire hexagon containing the projection of the bolt head with the center of the inscribed circle of the bolt to be tightened at the current photographing position as the ROI area; and screen out all the line segments within the ROI area from the image, and the formula is expressed as: Among them, W R and H R represent the width and height of the ROI region, and (x A , y A ) and (x B , y B ) represent the two endpoints of the line segment respectively; S822. After screening out all the line segments within the ROI area, screen out the line segments judged to be duplicates according to the cosine value and mid - point distance between the line segments and divide them into six groups; specifically: First, calculate the cosine value between two line segments When the cosine value satisfies the two line segments are parallel, and it is considered that these two line segments are duplicates and grouped into the same group; Among them, P represents the minimum cosine value for determining the parallelism of two straight lines, and A, B represent the vectors corresponding to the two line segments; |A|, |B| are the moduli of these two vectors; Then, screen out the cases of parallelism due to being opposite sides of the hexagon through the mid - point distance; the formula is expressed as: Among them, (x 1a , y 1a ), (x 1b , y 1b ), (x 1c , y 1c ) represent the coordinates of the two endpoints and the midpoint of line segment 1 respectively, and (x 2a , y 2a ), (x 2b , y 2b ), (x 2c , y 2c ) represent the coordinates of the two endpoints and the midpoint of line segment 2 respectively. Line segment 1 and line segment 2 are judged to be parallel; L c0 represents the maximum value of the distance between the midpoints of the two set line segments. When the distance between the midpoints of the two line segments does not exceed L c0 , the judgment that these two line segments are duplicates is retained; After judgment by the cosine value and mid - point distance, six groups of line segments are obtained, and the line segments within each group are judged to be duplicates; S823. According to the distance from the mid - point of the line segment to the center of the inscribed circle, screen out the line segments representing each side of the regular hexagon from each group, and the formula is expressed as: where l 1c and l 2c respectively represent the distances from the centers of line segment 1 and line segment 2 in a group to the in-circle center; each comparison retains the line segment with the greater distance to the in-circle center. After traversing all the line segments in the group, the last remaining line segment represents one side of the regular hexagon. After all six groups have completed the screening, six line segments representing the six sides of the regular hexagon are obtained. S824. According to the straight - line equations of the six line segments obtained in step S823, find the intersection points of the six straight lines intersecting pairwise, and the formula is expressed as: The general equation of the straight line where each of the six line segments lies: A i x + B i y + C i = 0 (i = 1, 2,..., 6); Intersection point calculation formula: Among them, A i , B i , C i are the coefficients of the general form equation of line i, A j , B j , C j are the coefficients of the general form equation of line j, (x ij , y ij ) is the intersection point of lines i and j; Then, according to the fact that the distance from the intersection point of non - adjacent straight lines to the center of the inscribed circle is greater than the distance from the intersection point of adjacent straight lines to the center of the inscribed circle, screen out the intersection points of non - adjacent straight lines. The formula is expressed as: Among them, L c1 is a set distance threshold. The intersection points beyond the distance threshold L c1 are judged as non-adjacent straight-line intersection points and discarded; the six intersection points retained after the final screening are the six corner points of the regular hexagon. Denote the six corner points as x n , n = 1, 2,..., 6; S825. Calculate the coordinates (x c , y c ) of the center of the bolt to be tightened in the image coordinate system based on the obtained six corner points: Convert the image coordinate system to the robot base coordinate system, and calculate the exact position of the center of the bolt to be tightened at the current photo-taking point in the robot base coordinate system according to (x c , y c ), so as to guide the end of the collaborative robot (2) to move to the accurate position for tightening work.

5. The operating method of an adaptive tightening system for a toilet seat cushion robot according to claim 1, characterized in that, Step S9 specifically includes: S91. According to the accurate position obtained in step S8, the end of the collaborative robot (2) first moves horizontally until the axis of the bolt is collinear with the axis of the sleeve (302), and then the whole end feeds axially, and the sleeve (302) approaches the surface of the bolt. Different feeding and tightening methods need to be adopted according to the pre-tightening states of the bolts to be tightened; the formula is expressed as: where h is the height of the camera (401) relative to the upper surface of the bolt head obtained by the laser displacement sensor (403) before the adjustment of the photographing height, and h0 is the photographing height; S92. When h≥h0, the bolt has been pre-tightened in place, and one-time feeding is adopted; specifically: First, perform cap searching. The end of the collaborative robot (2) feeds axially by h0 - h t + h l , where h t represents the axial distance difference between the lower surface of the sleeve (302) and the camera (401), and h l represents the thickness of the bolt cap; After the feeding is completed, if the bolt is not sleeved into the sleeve (302), but the lower surface of the sleeve (302) contacts the upper surface of the bolt and further feeding is impossible, the spring is compressed by force, and the compression amount is h l , then the tightening gun (301) is used to control the sleeve (302) to rotate slowly at a lower angular velocity w l for one full turn. When the shape of the inner cavity of the sleeve (302) completely coincides with that of the bolt head, under the elastic force of the spring, the bolt head is sleeved into the sleeve (302) and rotates with the sleeve (302) to complete cap searching; After the cap search is completed, the reaction force arm (304) is pushed out by the cylinder (303) to abut against the edge of the mounting workpiece, and the tightening gun (301) controls the sleeve (302) to rotate at a higher angular velocity w h to tighten the bolt; when the tightening torque reaches the task requirement, the tightening is completed; S93. When h < h0, the bolt is not pre-tightened in place, and the distance between the upper surface of the bolt and the mounting workpiece is h0 + h l -h. When tightening, the total axial feed of the end of the collaborative robot (2) increases by h0 - h compared with the case of one-time feed. At this time, multiple feeds are adopted, specifically: First, the end of the collaborative robot (2) still feeds h0-h along the axial direction t +h l , and performs the same cap-finding operation as the tightening process of one feed; after the cap-finding is completed, the lower surface of the sleeve (302) is h0-h away from the installation workpiece, and the end of the collaborative robot (2) is controlled to feed downward again h0-h, the bolt is inserted into the inner cavity of the sleeve (302), and the lower surface of the sleeve (302) fits with the installation workpiece; then, the cylinder (303) pushes the reaction force arm (304) to extend and press against the edge of the installation workpiece, and the tightening gun (301) controls the sleeve to move at a higher angular velocity w h Rotate to tighten the bolt, and when the tightening torque reaches the task requirement, the tightening is completed.

6. An application system for the operation method according to any one of claims 1 to 5, characterized in that Specifically included: AGV mobile platform (1), collaborative robot (2), tightening end effector (3), industrial camera and its accessories (4), and integrated industrial computer; The collaborative robot (2) is fixedly installed above the AGV mobile platform (1); the bottom surface of the collaborative robot (2) is parallel to the horizontal ground, and its end is equipped with a tightening end effector (3) and industrial camera and accessories (4) through a plate-shaped connecting piece; the tightening end effector (3) is rotationally connected to the plate-shaped connecting piece through a bearing, and the industrial camera and accessories (4) are fixed on the plate-shaped connecting piece by screws; all components are connected to the integrated industrial computer; The AGV mobile platform (1) is used to drive the collaborative robot (2) to move; the collaborative robot (2) is used to drive the tightening end effector (3) and industrial camera and accessories (4) to reach the specified position and perform operations according to the planned route; the tightening end effector (3) is used to perform tightening operations in a narrow space; the industrial camera and accessories (4) are used to collect image data and position data of the parts to be tightened; the integrated industrial computer is used to process data, plan paths, and control the movement and operations of each component.

7. The application system according to claim 6, characterized in that, The tightening end effector (3) includes: Tightening gun (301), sleeve (302), cylinder (303), reaction force arm (304), small block Z-shaped connecting piece, and cube-shaped connecting piece; The cube-shaped connecting piece is composed of a top plate, two side plates, and a bottom plate. The plates are connected by screws. The upper part of the top plate is used to connect to the bearing of the plate-shaped connecting piece through a circular structure. The two side plates are used to connect the bottom plate. The tightening gun (301) extends in through the surface without a side plate and is fixed on the bottom plate by screws. The bottom plate has a circular hollow for the end of the tightening gun (301) to extend out. The sleeve (302) is fixed to the end of the tightening gun (301) through a swivel joint and screws and rotates together with the end of the tightening gun (301); the reaction force arm (304) is welded to the bottom plate; The inner cavity of the sleeve (302) is designed as a regular hexagon structure identical to the bolt head, and the inner cavity area is slightly larger than the bolt head; during the process of the bolt head being inserted into the sleeve (302) for tightening, both rotate simultaneously without relative rotation; a spring is connected to the end of the sleeve (302), and it is adaptively compressed along the axial direction of the sleeve (302) when subjected to an axial force, avoiding rigid collision between the sleeve (302) and the bolt surface and the installation surface during axial feeding; One end of the cylinder (303) is hinged to a plate-shaped connecting piece, and the other end is hinged to a small Z-shaped connecting piece; the small Z-shaped connecting piece is fixedly connected to the top plate of the cubic connecting piece by screws. The small Z-shaped connecting piece converts the linear motion of the telescopic cylinder (303) into the rotation of the cubic connecting piece, thereby driving the extension and retraction of the reaction force arm (304); the reaction force arm (304) is used to balance the reaction force exerted on the end of the collaborative robot (2) by the bolt cap during the tightening operation.

8. The application system according to claim 7, wherein the industrial camera and accessories (4) comprise: a camera (401), a light source (402), and a laser displacement sensor (403); The camera (401) and the laser displacement sensor (403) are adjacently mounted on a plate-shaped connecting piece, and the laser displacement sensor (403) is mounted horizontally with the camera (401) to ensure that the height of the camera (401) is the same each time it takes a photo; the light source (402) is mounted around the lens of the camera (401) in a circular ring shape; the camera (401), the light source (402), and the laser displacement sensor (403) are mounted at a certain height difference from the sleeve (302) to avoid collision with the installation platform.

Images