Large-span double-layer steel truss suspension bridge appearance detection robot and working method thereof

Abstract

The invention discloses a large-span double-layer steel truss suspension bridge appearance detection robot and a working method thereof.The large-span double-layer steel truss suspension bridge appearance detection robot comprises a hinge transition module, a front vehicle body module, a rear vehicle body module, a front crawler belt module, a rear crawler belt module, a forward vision module and a backward vision module, and the hinge transition module is arranged between the front vehicle body module and the rear vehicle body module; the front track modules are assembled on the left side wall and the right side wall of the front vehicle body module respectively, the rear track modules are assembled on the left side wall and the right side wall of the rear vehicle body module respectively, the front visual module is fixedly installed on the top of the front vehicle body module, and the rear visual module is fixedly installed on the top of the rear vehicle body module. Relative rotation of the front vehicle body module and the rear vehicle body module is achieved through the hinged transition module, self-adaption to external corners and internal corners of bridge steel trusses is achieved, smooth transition of wall faces is completed, the forward vision module collects disease information images in the advancing direction, the backward vision module collects disease images in the lateral area, missing detection is avoided through cooperation of the forward vision module and the backward vision module, and comprehensive detection of the appearance of a bridge is achieved.

Description

Technical Field

[0001] This invention belongs to the field of bridge inspection technology, and more specifically, relates to a robot for the appearance inspection of a large-span double-layer steel truss suspension bridge and its working method. Background Technology

[0002] Long-span truss-type double-deck suspension bridges play a vital role in cross-sea transportation. They are characterized by high capacity, multiple structural layers, and a large number of widely distributed components. Constantly exposed to the salt spray, high humidity, strong winds, and alternating tides of the marine environment, their maintenance and inspection are significantly more challenging than those of land-based bridges. Under the combined effects of long-term heavy loads, high speeds, high flow rates, temperature and humidity cycles, and salt spray corrosion, protective coatings are prone to blistering, peeling, and failure; bolts become loose, missing, and corroded; and surface defects such as fatigue cracks and hole edge cracks appear in welded areas and heat-affected zones. These defects weaken the load-bearing cross-section and degrade stiffness, induce stress concentration, accelerate fatigue damage, increase structural risk, affect service safety and durability, and raise maintenance costs.

[0003] Current inspection methods primarily rely on manual close-range methods (suspended baskets, scaffolding, maintenance vehicles, rope work, etc.), vehicle-mounted or aerial work platform inspections, drone aerial photography, and fixed-point monitoring systems. However, these methods are limited by cross-sea winds and waves, weather conditions, traffic organization, and operational windows. Manual methods suffer from low efficiency, high operational risks, insufficient coverage of concealed areas, and poor data consistency and comparability. Drones face limitations in close-range imaging under strong winds, salt spray, and confined structural spaces, making it difficult to reliably acquire high-resolution images. Fixed-point monitoring struggles to achieve large-scale surface inspections of components. Furthermore, existing methods generally have blind spots in areas with dense bolt clusters, node plate angles, and welded areas, failing to meet the engineering requirements for rapid, comprehensive, and routine inspections of cross-sea bridges.

[0004] The development of wall-climbing robots provides a highly promising technical means for the accurate detection of surface defects in cross-sea bridges. However, due to the complex structure and marine environment, the safe and reliable implementation of this technology faces many severe challenges. First, adaptability to complex structural environments and stable adhesion performance are essential conditions for the robot's safe and reliable defect detection operations. Existing adhesion methods are mainly magnetic adsorption or negative pressure adsorption. Among them, the electromagnet solution is highly dependent on continuous power supply and heat dissipation; it loses adhesion upon power failure, limiting reliability and endurance. Negative pressure adsorption requires maintaining a sealed cavity and continuous air extraction, which is sensitive to surface flatness and sealing conditions. It is prone to air leakage in areas such as bolt groups, welds, and folds, affecting adsorption stability and resulting in higher energy consumption and maintenance burden. Meanwhile, the complex structure of the web members and chord members of the cross-sea bridge necessitates numerous obstacle-crossing requirements, including crossings at 90° positive angles and at least 75° negative angles, to achieve full-coverage defect detection. However, existing robots lack sufficient wall-changing capabilities, leading to pauses, slippage, or the need for manual intervention. In particular, the robot's crossing ability is severely inadequate when facing discontinuous surfaces such as bolt clusters with a height of approximately 25 mm and spliced ​​steps, affecting the continuity of operations. Turning at small-radius structures is also difficult, often accompanied by uneven adhesion distribution and slippage, resulting in insufficient turning stability. Furthermore, the close-range coverage of areas such as web members, chord members, and node plate angles is insufficient, creating blind spots and making it difficult to meet the overall detection coverage requirements. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a surface inspection robot for large-span double-layer steel truss suspension bridges and its working method. By employing a permanent magnet synchronous belt structure, the permanent magnets on the outer periphery of the synchronous belt slowly adhere to the steel surface to form a continuous attachment belt. This avoids the dependence of electromagnetic adsorption on continuous power supply and negative pressure adsorption on sealing conditions, thereby improving adhesion stability from the source and reducing the risk of falling. The permanent magnets are arranged with alternating N and S poles to form a continuous magnetic circuit. Simultaneously, the support plate makes the normal adhesion force of the synchronous belt contact belt tend to be uniform in the length direction, which can effectively reduce adsorption fluctuations caused by coating aging, moisture, or local curvature changes. The front and rear body modules adopt a dual-servo hinged transition structure, combined with the lifting function of the first and second electric push rods. The wall transformation is performed in the sequence of "lifting - relative rotation - re-adhesion". First, the push rods lift the body to release the contact constraint. Then, the two industrial servos synchronously drive the front and rear body to rotate in a controlled manner around the hinge axis, and finally complete the sequential adhesion and load transfer with the target wall. This collaborative structure can smoothly switch between the external corner (approximately 90°) and the internal corner (not less than 75°) of the wall, significantly reducing work stoppages and manual intervention, and improving the ability and efficiency of continuous cross-wall operations.

[0006] To achieve the above objectives, according to one aspect of the present invention, a robot for inspecting the appearance of a large-span double-deck steel truss suspension bridge is provided, comprising an articulated transition module, a front vehicle body module, a rear vehicle body module, a front track module, a rear track module, a forward vision module, and a rear vision module; wherein... The articulated transition module is located between the front body module and the rear body module, forming a movable connection mechanism between the two. Through this articulated transition module, the front body module and the rear body module can rotate relative to each other, enabling the robot to adapt to the shape of the positive and negative corners of adjacent walls in the bridge steel truss structure. By adjusting the relative posture of the front and rear bodies, a smooth transition between the walls can be completed, ensuring the robot's continuous movement capability on complex three-dimensional structures. The front track modules are respectively mounted on the left and right side walls of the front vehicle module, and the rear track modules are respectively mounted on the left and right side walls of the rear vehicle module. As the robot's mobile actuators, they jointly provide the robot with propulsion and support. The forward vision module is fixedly installed on the top of the front vehicle module and is used to continuously acquire images of the bridge surface area in the direction of travel during the robot's movement, thereby capturing in real time information on potential defects such as cracks, corrosion, and coating peeling in that direction. The rear vision module is fixedly installed on the top of the rear vehicle module and is used to continuously acquire images of the bridge's lateral surface area during robot operation. Together with the forward vision module, they form a collaborative detection system to avoid missed defects due to limited field of view, ultimately achieving comprehensive and blind-spot-free defect monitoring of the bridge surface.

[0007] Furthermore, the front body module includes a first frame, a first roof plate, a first floor plate, a first front plate, a first rear plate, a first side plate, and a first electric push rod; wherein, the first frame is a cuboid frame structure, the front and rear ends of the first frame are respectively fixedly mounted with the first front plate and the first rear plate, the left and right sides are fixedly mounted with the first side plate, the top and bottom are respectively fixedly mounted with the first roof plate and the first floor plate, the first front plate and the first rear plate are both U-shaped plate structures, the vertical plate of the first front plate is fixedly mounted to the front end face of the first frame, and its two horizontal plates are respectively fixed The first rear plate is installed on the bottom and top edges of the first frame. The vertical plate portion of the first rear plate is fixedly installed on the rear end face of the first frame, and its two horizontal plate portions are also fixedly installed on the bottom and top edges of the first frame, respectively. Two through holes are provided on the first base plate, which are symmetrically distributed along the central axis of the base plate. Two middle crossbeams are fixedly installed at the middle position of the top of the first frame. Two first electric push rods are fixedly installed at the bottom of the middle crossbeams. Their piston rods are arranged vertically and their ends point to the through holes on the first base plate. The piston rods can extend outward through the through holes. The front body module also includes multiple first lifting rings and a first handle. The multiple first lifting rings are fixed to the top of the first roof plate, and the first handle is fixed to the outer wall of the first front plate.

[0008] Furthermore, the rear vehicle module includes a second frame, a second top plate, a second bottom plate, a second front plate, a second rear plate, second side plates, and a second electric push rod; wherein, the second frame is a cuboid frame structure, the front and rear ends of the second frame are respectively fixedly mounted with the second front plate and the second rear plate, the left and right sides are fixedly mounted with the second side plates, the top and bottom are respectively fixedly mounted with the second top plate and the second bottom plate, the second front plate and the second rear plate are both U-shaped plate structures, the vertical plate of the second front plate is fixedly mounted on the front end face of the second frame, and its two horizontal plates are respectively fixed The second rear plate is installed at the bottom and top edges of the second frame; the vertical plate portion of the second rear plate is fixedly installed on the rear end face of the second frame, and its two horizontal plate portions are also fixedly installed on the bottom and top edges of the second frame respectively; two through holes are opened on the second base plate, which are symmetrically distributed along the central axis of the base plate; two middle crossbeams are fixedly installed at the middle position of the top of the second frame; two second electric push rods are fixedly installed at the bottom of the middle crossbeams, and their piston rods are arranged vertically with their ends pointing to the through holes on the second base plate; the piston rods can extend outward through the through holes. The rear body module also includes multiple second lifting rings and a second handle. The multiple second lifting rings are fixed to the top of the second top plate, and the second handle is fixed to the outer wall of the second rear plate.

[0009] Furthermore, the articulated transition module includes a first servo motor, a first servo motor base, and a second servo motor base. The first servo motor base is a U-shaped plate structure. The outer wall of the bottom plate of the first servo motor base is fixedly connected to the first rear plate of the front body module. The two side plates of the first servo motor base are respectively fixedly connected to the output end of the first servo motor. The second servo base includes two U-shaped connecting plates and an I-shaped partition plate. The two U-shaped connecting plates are arranged in a counter-bracing manner, and the side plates of both are fixedly installed on the outer side walls of the two side flanges of the I-shaped partition plate. The two U-shaped connecting plates and the I-shaped partition plate together form a H-shaped frame. The bottom plates of the two U-shaped connecting plates are through which the first servo is fixedly installed. The H-shaped frame is fixedly connected to the front end side wall of the second front plate of the rear body module through the side plates of the two U-shaped connecting plates.

[0010] Further, the front track module includes a first fixed plate, a first synchronous belt, a first permanent magnet, a first support plate, a first drive motor, a first drive wheel, a first driven wheel, a first spindle, a first bearing, a second bearing, a first tension bolt, a first limit block, and a second tension bolt. The top and bottom of the first drive motor are both fixedly mounted with U-shaped first support plates. The outer side plate of the first support plate is fixedly connected to the first fixed plate, and its inner side plate is fixedly installed on the outer wall of the first side plate of the front vehicle module. The output shafts on both sides of the first drive motor are both fixedly mounted with first drive wheels. The ends of the output shafts are fixedly connected to the inner rings of the first bearings. The outer rings of the outer first bearings are fixedly connected to the front end of the first fixed plate, and the inner first bearings are respectively fixedly connected to the front ends of the first side plates of the front vehicle module. A rectangular adjustment hole is opened at the rear end of the first fixed plate, and a through hole is opened on the outer wall of the adjustment hole. One end of the first spindle has an external thread, and its end has a through threaded hole. The first tension bolt passes through the through hole and connects to the end of the first spindle. The first spindle is threaded and connected. Two second bearings are sleeved on the outer side of the first spindle. The inner second bearing is fixed to the first spindle by engaging with the external thread at one end of the first spindle through a lock nut. The outer second bearing is directly fixed to the first spindle. The outer rings of the two second bearings are fixedly connected to the first driven wheel. The two first driving wheels and one first driven wheel are connected by a first synchronous belt. Multiple first permanent magnets are fixedly installed on the outer circumference of the first synchronous belt. The first permanent magnets are arranged in an alternating N / S pattern along the track travel direction. A first limiting block is fixedly installed at the other end of the first spindle. The first limiting block has grooves on its upper and lower sides. A rectangular adjustment hole is opened at the rear end of the first fixing plate. The top and bottom of the rectangular adjustment hole have slot plates that engage with the grooves. The first limiting block has a threaded hole. The side wall of the rectangular adjustment hole on the first fixing plate has a through hole. A second tensioning bolt passes through the through hole and is threadedly connected to the threaded hole on the first limiting block.

[0011] Furthermore, the rear track module includes a second fixed plate, a second synchronous belt, a second permanent magnet, a second support plate, a second drive motor, a second driving wheel, a second driven wheel, a second spindle, a third bearing, a fourth bearing, a third tension bolt, a second limit block, and a fourth tension bolt. The top and bottom of the second drive motor are both fixedly mounted with U-shaped second support plates. The outer side plate of the second support plate is fixedly connected to the second fixed plate, and its inner side plate is fixedly installed on the outer wall of the second side plate of the rear vehicle module. The output shafts on both sides of the second drive motor are fixedly mounted with second driving wheels. The ends of the output shafts are fixedly connected to the inner rings of the third bearings. The outer rings of the outer third bearings are fixedly connected to the rear end of the second fixed plate, and the inner third bearings are respectively fixedly connected to the rear end of the second side plates of the rear vehicle module. A rectangular adjustment hole is opened at the front end of the second fixed plate, and a through hole is opened on the outer wall of the adjustment hole. One end of the second spindle has an external thread, and its end has a through threaded hole. The third tension bolt passes through the through hole and connects to the end of the second spindle. The second spindle is threaded and connected. Two fourth bearings are sleeved on the outer side of the second spindle. The inner fourth bearing is fixed to the second spindle by engaging with the external thread at one end of the second spindle through a lock nut. The outer fourth bearing is directly fixed to the second spindle. The outer rings of the two fourth bearings are fixedly connected to the second driven wheel. The two second driving wheels and one second driven wheel are connected by a second synchronous belt. Multiple second permanent magnets are fixedly installed on the outer circumference of the second synchronous belt. The second permanent magnets are arranged in an alternating N / S pattern along the track travel direction. A second limiting block is fixedly installed at the other end of the second spindle. The upper and lower sides of the second limiting block have grooves. The rear end of the second fixing plate has a rectangular adjustment hole. The top and bottom of the rectangular adjustment hole have slot plates that engage with the grooves. The second limiting block has a threaded hole. The side wall of the rectangular adjustment hole on the second fixing plate has a through hole. A fourth tensioning bolt passes through the through hole and is threadedly connected to the threaded hole on the second limiting block.

[0012] Furthermore, the forward vision module includes a first binocular camera, a first industrial camera, a first industrial camera lens, a binocular camera bracket, a second servo motor, an industrial camera base, and an industrial camera bracket. The binocular camera bracket is fixedly installed at the top center of the top horizontal plate of the first front panel. The first binocular camera is fixed to the top of the binocular camera bracket. The industrial camera bracket is fixedly installed at the top of the front end of the first top plate. The second servo motor is fixedly installed through the middle of the top of the industrial camera bracket. The industrial camera base is fixedly installed at the output end of the second servo motor. The first industrial camera is fixedly installed on the front side wall of the top of the industrial camera base. The first industrial camera lens is mounted on the first industrial camera.

[0013] Further, the rearward vision module includes a robotic arm base, a third servo motor, a robotic arm base, a fourth servo motor, a first joint link, a link support, a fifth servo motor, a fifth servo motor bracket, a second joint link, a sixth servo motor, a sixth servo motor bracket, a binocular camera mounting plate, a second binocular camera, a second industrial camera, a second industrial camera lens, and an industrial camera mounting plate. The robotic arm base is fixedly installed at the middle position of the top of the two crossbeams of the rear body module. The third servo motor is fixedly installed on the top of the robotic arm base, and its output end is fixedly connected to the robotic arm base. The fourth servo motor is fixedly installed on the top of the robotic arm base. The two sides of the output end of the fourth servo motor are fixedly connected to the first joint link, and the other end of the first joint link is fixedly connected to the fifth servo motor bracket. A fifth servo motor is fixedly installed on the outer wall of the fifth servo motor bracket. The output ends of the fifth servo motor are fixedly connected to the second joint connecting rods on both sides. Several connecting rods are spaced apart between the two first joint connecting rods and between the two second joint connecting rods. A sixth servo motor bracket is fixedly installed between the other ends of the second joint connecting rods. A sixth servo motor is fixedly installed on the outer wall of the sixth servo motor bracket. The output end of the sixth servo motor is fixedly connected to the industrial camera mounting plate. A second industrial camera is fixedly installed on the outer wall of the industrial camera mounting plate. The lens of the second industrial camera is mounted on the second industrial camera. A binocular camera mounting plate is fixedly installed at the bottom between the other ends of the second joint connecting rods. A second binocular camera is fixedly installed at the bottom of the binocular camera mounting plate.

[0014] According to a second aspect of the present invention, a method for operating a robot for the appearance inspection of a large-span double-layer steel truss suspension bridge is provided, which is implemented using the aforementioned robot for the appearance inspection of a large-span double-layer steel truss suspension bridge, and includes the following steps: S100: The inspection robot is transported to the surface of the target steel component. The robot's posture is adjusted by manual guidance so that the permanent magnets on the outer periphery of the track are evenly and slowly attached to the surface of the steel component, forming a continuous and stable magnetic adsorption attachment band. After the attachment status is confirmed to be correct, the robot is powered on. S200: After starting the robot, it first completes the electrical self-test of the drive motor, track drive, forward vision module and rear vision module. At the same time, it performs zero-position calibration on the forward vision module and the rear vision module. According to the detection requirements, the robot's travel path parameters are set in the control system. The first drive motor and the second drive motor are started, so that the front track module and the rear track module can move smoothly along the surface of the steel component. During the movement, the forward vision module synchronously collects the appearance image in the direction of movement. At the same time, by controlling the action of each level of servo motor of the rear vision module, it obtains close-range images of the side area of ​​the web members, chord members and node plates of the steel component. S300: When the robot travels to a discontinuous surface at a group of bolts or spliced ​​steps, it first reduces its travel speed. At the same time, it controls the first electric push rod of the front body module to extend, raising the height of the front of the front body module and maintaining a low speed. This allows the first permanent magnet on the front track module to smoothly cross the group of bolts or spliced ​​steps and be attracted to its exposed surface in sequence. After the front track module crosses the first row of bolts or spliced ​​steps and establishes a stable attachment, it slowly retracts the first electric push rod and continues to move forward, allowing the robot to sit smoothly on the surface of the bolt group and continue to pass through the obstacle area at a low speed. S400: When the inspection robot needs to switch from the first wall to the adjacent second wall, at the corner, firstly, the first electric push rod of the front body module is extended to lift the front body module until the front track module is completely separated from the first wall. Then, the two first servo motors of the articulated transition module are activated to drive the front and rear body modules to rotate relative to each other around the articulation axis until the posture of the front body module matches the second wall. Then, the first electric push rod is retracted to make the front track module adhere to the second wall and attach stably, keeping the posture of the front body module unchanged. Then, the second electric push rod of the rear body module is extended to lift the rear body module until the rear track module is separated from the first wall. At the same time, the two first servo motors are controlled to adjust the rear body module to a horizontal posture and align the track with the second wall. Finally, the second electric push rod is retracted to control the robot to move forward at a low speed, so that the track of the rear body module contacts the second wall in sequence and completely adheres to it, completing the wall switching. S500: If turning is required at a small radius structure, the front track module and the rear track module on the left and right sides of the front body module and the rear body module are used to achieve turning; S600: After completing the predetermined inspection path, stop the machine and power off in sequence. With manual assistance, separate the front track module and the rear track module from the surface of the steel component segment by segment, and finally transport the robot to the designated storage location.

[0015] Further, in step S400, at the corner, the vehicle first decelerates and stops at a predetermined position, and slowly extends the first electric push rod of the front body module to lift the front body module until it is completely detached from the first wall. While ensuring that the rear body module is still stably attached to the first wall, the articulated transition module is activated, and the first servo is controlled at a low speed and in a segmented driving manner to make the front body module gradually rotate around the articulation axis toward the second wall. When the track of the front body module is detected to make initial contact with the edge of the second wall, the rotation of the servo is paused, and the first electric push rod of the front body module is slowly retracted to allow its track to form a continuous attachment strip on the second wall and achieve stable adhesion. Then, the second electric push rod of the rear body module is controlled to lift, so that the rear body module is detached from the first wall. After maintaining this posture and moving forward at a low speed to a suitable position, the second electric push rod of the rear body module is retracted, and then the two first servo motors are driven in segments at a low speed so that the track of the rear body module contacts the second wall in sequence and is completely attached, thus completing the wall transformation.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. The appearance inspection robot for large-span double-layer steel truss suspension bridges of the present invention adopts a permanent magnet synchronous belt structure. The permanent magnets on the outer periphery of the synchronous belt slowly adhere to the steel surface to form a continuous attachment belt, avoiding the dependence of electromagnetic adsorption on continuous power supply and negative pressure adsorption on sealing conditions. This improves the adhesion stability from the source and reduces the risk of falling. The permanent magnets are arranged with alternating N and S poles to form a continuous magnetic circuit. At the same time, the support plate makes the normal adhesion force of the synchronous belt contact belt tend to be uniform in the length direction, which can effectively reduce the adsorption fluctuation caused by coating aging, moisture or local curvature changes. Under the condition of vertical steel surface, the adhesion safety factor is ≥2.0.

[0017] 2. The appearance inspection robot for large-span double-layer steel truss suspension bridges of the present invention employs a dual-servo motor articulated transition structure for its front and rear vehicle modules. Combined with the lifting functions of the first and second electric push rods, it performs wall transformation according to the sequence of "lifting—relative rotation—re-fitting." First, the push rods lift the vehicle body to release contact constraints. Then, the two industrial servo motors synchronously drive the front and rear vehicle bodies to rotate in a controlled manner around the articulated axis, finally completing the sequential fitting and load transfer with the target wall. This collaborative structure can smoothly complete the wall switching at external angles (approximately 90°) and internal angles (not less than 75°), with a pass rate ≥90%, significantly reducing operation downtime and manual intervention, and improving the ability and efficiency of continuous operation across walls.

[0018] 3. The appearance inspection robot for large-span double-layer steel truss suspension bridges of the present invention, by reasonably setting the length of the permanent magnet, the diameter of the driving wheel and the driven wheel, the gap between the track and the bottom of the vehicle body, and the effective contact width between the track and the steel surface, allows the permanent magnet on the outer periphery of the synchronous belt to directly adhere to the exposed surface of the bolts and maintain a continuous attachment state when the track passes through bolt groups or spliced ​​steps. Thus, it can achieve uninterrupted continuous passage under the condition of equivalent step height ≤25mm, with a continuous crossing success rate ≥95%.

[0019] 4. The appearance inspection robot for large-span double-layer steel truss suspension bridges of the present invention adopts a differential drive structure of left and right side track modules. By controlling the inner track to decelerate / short-term reverse and the outer track module to move forward at low speed, a stable differential speed is formed, which can achieve smooth directional turning in a confined space. During the turning process, the contact strip of the track maintains stable contact and driving continuity. The minimum turning radius is ≤250mm, and there is no sudden drop in adhesion or obvious slippage. It effectively reduces repeated adjustments and retreats in place, significantly improves the accessibility of narrow areas such as web members, chord members and nodes, and improves the accessibility and continuity of the overall inspection path.

[0020] 5. The appearance inspection robot for large-span double-layer steel truss suspension bridges of the present invention uses a robotic arm end-effector camera equipped with a forward vision module and a backward vision module to collaboratively acquire images according to a preset posture and path. The forward vision module takes into account both large-scale defect recording and precise capture of small-scale defects in the direction of travel, while the backward vision module can adjust its posture through various servo motors to perform close-range imaging of lateral areas such as the outer side of the web members, the side of the chord members, and the angle of the node plates. This collaborative configuration takes into account both continuous recording in the direction of travel and supplementation of lateral details, with a detection coverage of ≥90%, reducing blind spots and improving the comprehensiveness and effectiveness of defect identification.

[0021] 6. The appearance inspection robot for large-span double-layer steel truss suspension bridges of the present invention achieves high-coverage close-range inspection while ensuring stable attachment and reliable wall transition. It can support efficient and routine inspection of large-span truss double-layer suspension bridges across the sea without affecting existing traffic organization, and provide reliable technical equipment support for the long-term safe operation and refined maintenance of large-span truss double-layer suspension bridges across the sea. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention; Figure 2 This is a bottom view of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention; Figure 3 This is a structural diagram of the articulated transition module of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention; Figure 4This is a structural diagram of the front body module of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention; Figure 5 This is a structural diagram of the rear vehicle module of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention; Figure 6 This is a structural diagram of the front and rear track modules of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention; Figure 7 This is an exploded view of the front and rear track modules of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention. Figure 8 This is a schematic diagram of the tensioning bolt installation structure of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the forward vision module of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention; Figure 10 This is a schematic diagram of the rear vision module of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention; Figure 11 This is a bottom view of the rear vision module of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention. Figure 12 This is a reference diagram showing the usage of the appearance inspection robot for a large-span double-layer steel truss suspension bridge when crossing a group of bolts, according to an embodiment of the present invention. Figure 13 This is a reference diagram showing the usage state of the appearance inspection robot for a large-span double-layer steel truss suspension bridge during corner wall transformation, as described in an embodiment of the present invention. Figure 14 This is a reference diagram showing the usage state of the appearance inspection robot for a large-span double-layer steel truss suspension bridge during the transformation of the inner corner wall, according to an embodiment of the present invention. Figure 15 This is a flowchart illustrating the working method of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to an embodiment of the present invention.

[0023] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-Articulated transition module, 101-First servo motor, 102-First servo motor base, 103-Second servo motor base, 1031-U-shaped connecting plate, 1032-I-shaped partition plate, 1033-Reinforcing plate, 2-Front body module, 201-First frame, 202-First roof plate, 203-First floor plate, 204-First front plate, 205-First rear plate, 206-First side plate, 207-First electric push rod, 208-First lifting ring, 209-First handle, 3-Rear body module, 301-Second Frame, 302-Second Top Plate, 303-Second Bottom Plate, 304-Second Front Plate, 305-Second Rear Plate, 306-Second Side Plate, 307-Second Electric Push Rod, 308-Second Lifting Ring, 309-Second Handlebar, 4-Front Track Module, 401-First Outer Side Plate, 402-First Synchronous Belt, 403-First Permanent Magnet, 404-First Support Plate, 405-First Drive Motor, 406-First Drive Wheel, 407-First Driven Wheel, 408-First Spindle, 409-First Bearing, 410-Second Bearing, 411-First Tensioning Bolt, 412-First Limiting Block, 4 13-Second tension bolt, 5-Rear track module, 501-Second outer side plate, 502-Second synchronous belt, 503-Second permanent magnet, 504-Second support plate, 505-Second drive motor, 506-Second drive wheel, 507-Second driven wheel, 508-Second spindle, 509-Third bearing, 510-Fourth bearing, 511-Third tension bolt, 512-Second limit block, 513-Fourth tension bolt, 6-Forward vision module, 601-First binocular camera, 602-First industrial camera, 603-First industrial camera lens, 604-Binocular camera bracket, 60 5-Second servo motor, 606-Industrial camera base, 607-Industrial camera bracket, 7-Rear vision module, 701-Robot arm base, 702-Third servo motor, 703-Robot arm base, 704-Fourth servo motor, 705-First joint link, 706-Link support, 707-Fifth servo motor, 708-Fifth servo motor bracket, 709-Second joint link, 710-Sixth servo motor, 711-Sixth servo motor bracket, 712-Binocular camera mounting plate, 713-Second binocular camera, 714-Second industrial camera, 715-Second industrial camera lens, 716-Industrial camera mounting plate. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0025] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0026] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0027] In this patent, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0028] Example 1 like Figure 1-14As shown, this embodiment of the invention provides a robot for the appearance inspection of a large-span double-layer steel truss suspension bridge, including an articulated transition module 1, a front vehicle module 2, a rear vehicle module 3, a front track module 4, a rear track module 5, a forward vision module 6, and a rear vision module 7. The articulated transition module 1 is disposed between the front vehicle module 2 and the rear vehicle module 3, forming a movable connection mechanism between them. Through this articulated transition module 1, the front vehicle module 2 and the rear vehicle module 3 can achieve relative rotation. Its core function is to enable the robot to adapt to the external and internal angles of adjacent walls in the bridge's steel truss structure, and to achieve a smooth transition between walls by adjusting the relative posture of the front and rear vehicles, ensuring the robot's continuous movement capability on complex three-dimensional structures. The front track module 4 is respectively mounted on the left and right side walls of the front vehicle module 2, and the rear track module 5 is respectively mounted on the left and right side walls of the rear vehicle module 3. Both serve as the robot's mobile execution mechanisms, jointly providing the robot with propulsion and support. By utilizing the contact and engagement between the tracks and the surface of the steel truss components, combined with the tracks' own adsorption structure, the robot ensures stable adhesion and reliable movement when traversing steel truss surfaces in various orientations, such as inclined and vertical. This prevents slippage or falls due to smooth surfaces or excessive angles, adapting to the multi-dimensional operating environment of bridge steel truss structures. The forward vision module 6 is fixedly mounted on the top of the front vehicle module 2 and continuously acquires images of the bridge's surface area in the direction of travel during robot movement. This allows for real-time capture of potential defects such as cracks, corrosion, and coating peeling in that direction. Its forward placement prioritizes coverage of the detection area along the robot's path, enabling a highly efficient "inspection while moving" operation. The rearward vision module 7 is fixedly mounted on the top of the rear vehicle module 3 and continuously acquires images of the bridge's lateral surface area during robot operation. This module supplements the detection range not covered by the forward vision module 6, forming a collaborative detection system with it. This avoids missed defects due to limited field of view, ultimately achieving comprehensive, blind-spot-free defect monitoring of the bridge's surface. This invention significantly improves the robot's ability to navigate complex corner structures of bridges through the attitude adaptive adjustment function of the articulated transition module 1; ensures reliable movement of the robot on various steel truss surfaces by leveraging the stable attachment and driving capabilities of the front and rear track modules; and achieves comprehensive detection of bridge surface defects through the collaborative acquisition of forward and backward vision modules, effectively improving detection efficiency and data integrity, and providing accurate surface defect data support for the safety assessment of large-span double-layer steel truss suspension bridges.

[0029] Furthermore, the front body module 2 includes a first frame 201, a first top plate 202, a first bottom plate 203, a first front plate 204, a first rear plate 205, a first side plate 206, and a first electric push rod 207. The first frame 201 is made of aluminum profiles to form a cuboid frame structure, serving as the load-bearing base of the front body module 2, used to integrate and fix various components. Simultaneously, its lightweight design reduces overall weight to improve mobility. The first front plate 204 and the first rear plate 205 are fixedly mounted at the front and rear ends of the first frame 201, respectively. First side plates 206 are fixedly mounted on both its left and right sides, and the first top plate 202 and the first bottom plate 203 are fixedly mounted on its top and bottom, respectively. These plates together constitute... A closed protective structure is used to protect the internal components of the first frame 201; the first front plate 204 and the first rear plate 205 are both U-shaped plate structures. The vertical plate of the first front plate 204 is fixedly installed on the front end face of the first frame 201, and its two horizontal plates are fixedly installed on the bottom edge and top edge of the first frame 201, respectively; the vertical plate of the first rear plate 205 is fixedly installed on the rear end face of the first frame 201, and its two horizontal plates are also fixedly installed on the bottom edge and top edge of the first frame 201, respectively; two through holes are provided on the first bottom plate 203, which are symmetrically distributed along the central axis of the bottom plate. These through holes serve as the extension channel for the piston rod of the first electric push rod 207, ensuring that the movement path of the piston rod is not interfered with. Two central crossbeams are fixedly installed at the top transverse middle position of the first frame 201. The central crossbeams serve two purposes: firstly, to enhance the overall rigidity of the top structure of the first frame 201, and secondly, to serve as the mounting carrier for the first electric push rods 207. The two first electric push rods 207 are fixedly installed at the bottom of the central crossbeams. Their piston rods are arranged vertically with their ends pointing towards the through holes on the first base plate 203. The piston rods can extend outward through the through holes. When the robot travels to discontinuous surfaces such as bolt groups or spliced ​​steps, the piston rods extend to push the support surface to lift the robot body, preventing the bottom of the robot body from colliding and getting stuck with obstacles. At the same time, during the wall transformation process, it can coordinate with the dual servo motor hinged structure to achieve a smooth transition between adjacent walls by adjusting the robot body posture, thereby improving the robot's adaptability to complex steel truss structures.

[0030] Furthermore, the front body module 2 also includes multiple first lifting rings 208 and first handles 209. The multiple first lifting rings 208 are fixed to the top of the first top plate 202, and the first handles 209 are fixed to the outer wall of the first front plate 204. The first lifting rings 208 provide a reliable connection point for the overall lifting of the robot. During equipment transportation, on-site deployment, or maintenance operations, the first lifting rings 208 can be used in conjunction with external lifting equipment (such as cranes or lifting belts) to achieve stable lifting and transfer of the front body module 2 or the entire robot, avoiding damage to the module structure and internal components during manual handling. The first handles 209 provide a force application point for manual operation assistance. When the robot is deployed in a narrow space, undergoes fine-tuning of its posture, or experiences a sudden malfunction requiring manual intervention, the operator can apply force to the front body module 2 by holding the first handles 209 to precisely adjust the module's position or posture, improving operational convenience and emergency handling efficiency.

[0031] Furthermore, the rear body module 3 includes a second frame 301, a second top plate 302, a second bottom plate 303, a second front plate 304, a second rear plate 305, second side plates 306, and a second electric push rod 307. The second frame 301 is made of aluminum profiles to form a cuboid frame structure, serving as the load-bearing base of the rear body module 3, used to integrate and fix various components. Simultaneously, its lightweight design reduces overall weight to improve mobility. The second frame 301 has a second front plate 304 and a second rear plate 305 fixedly mounted at its front and rear ends, respectively. Second side plates 306 are fixedly mounted on its left and right sides, and a second top plate 302 and a second bottom plate 303 are fixedly mounted on its top and bottom, respectively. These plates together constitute... A closed protective structure is used to protect the internal components of the second frame 301; the second front plate 304 and the second rear plate 305 are both U-shaped plate structures. The vertical plate of the second front plate 304 is fixedly installed on the front end face of the second frame 301, and its two horizontal plates are fixedly installed on the bottom edge and top edge of the second frame 301, respectively; the vertical plate of the second rear plate 305 is fixedly installed on the rear end face of the second frame 301, and its two horizontal plates are also fixedly installed on the bottom edge and top edge of the second frame 301, respectively; the second bottom plate 303 has two through holes symmetrically distributed along the central axis of the bottom plate. These through holes serve as the extension channel for the piston rod of the second electric push rod 307, ensuring that the piston rod's movement path is not interfered with. Two crossbeams are fixedly installed at the top transverse middle position of the second frame 301. The crossbeams serve two purposes: firstly, to enhance the overall rigidity of the top structure of the second frame 301, and secondly, to act as mounting carriers for the second electric push rods 307. The two second electric push rods 307 are fixedly installed at the bottom of the crossbeams. Their piston rods are arranged vertically with their ends pointing towards the through holes on the second base plate 303. The piston rods can extend outward through these through holes. When the robot travels to discontinuous surfaces such as bolt groups or spliced ​​steps, the piston rods extend to push the support surface to lift the robot body, preventing the bottom of the robot body from colliding and getting stuck with obstacles. At the same time, during wall transformation, the robot can coordinate with the dual servo motor hinged structure to achieve a smooth transition between adjacent walls by adjusting the robot body's posture, thereby improving the robot's adaptability to complex steel truss structures.

[0032] Furthermore, the rear body module 3 also includes multiple second lifting rings 308 and a second handle 309. The multiple second lifting rings 308 are fixed to the top of the second top plate 302, and the second handle 309 is fixed to the outer wall of the second rear plate 305. The second lifting rings 308 provide a reliable connection point for the overall lifting of the robot. During equipment transportation, on-site deployment, or maintenance operations, the second lifting rings 308 can be used in conjunction with external lifting equipment (such as cranes or lifting belts) to achieve stable lifting and transfer of the rear body module 3 or the entire robot, avoiding damage to the module structure and internal components during manual handling. The second handle 309 provides a force application point for manual operation assistance. When the robot is deployed in a narrow space, undergoes fine-tuning of its posture, or experiences a sudden malfunction requiring manual intervention, the operator can apply force to the rear body module 3 by holding the second handle 309 to precisely adjust the module's position or posture, improving operational convenience and emergency handling efficiency.

[0033] Furthermore, the articulated transition module 1 includes a first servo motor 101, a first servo motor base 102, and a second servo motor base 103. The first servo motor base 102 has a U-shaped plate structure. The outer side wall of the bottom plate of the first servo motor base 102 is fixedly connected to the first rear plate 205 of the front body module 2 to ensure the connection stability between the base and the front body module 2. The two side plates of the first servo motor base 102 are respectively fixedly connected to the output end of the first servo motor 101, so that the power output of the first servo motor 101 can directly drive the front body module 2 to rotate to achieve attitude adjustment. The second servo motor base 103 includes two U-shaped connecting plates 1031 and an I-shaped partition plate 1032. The U-shaped connecting plates 1031 are arranged in a counter-bracing manner, and the side plates of both are fixedly installed on the outer walls of the two side flanges of the I-shaped partition plate 1032. Through the above assembly, the two U-shaped connecting plates 1031 and the I-shaped partition plate 1032 together form a H-shaped frame. This frame structure can increase the overall stability of the structure. The bottom plates of the two U-shaped connecting plates 1031 are both through and fixedly installed with the first servo motor 101, so that the first servo motor 101 can stably output power. The H-shaped frame is fixedly connected to the front side wall of the second front plate 304 of the rear body module 3 through the side plates of the two U-shaped connecting plates 1031, thereby establishing a reliable connection between the articulated transition module 1 and the rear body module 3.

[0034] Furthermore, a reinforcing plate 1033 is fixedly provided on the inner side wall of the U-shaped connecting plate 1031 to improve the connection rigidity and load-bearing capacity of the U-shaped connecting plate 1031 itself, prevent the connecting plate from deforming during the stress process, and ensure through structural positioning that the rotation axis of the hinge transition module 1 is precisely aligned with the installation reference of the front body module 2 and the rear body module 3, so as to prevent the robot's movement from getting stuck or its posture from deviating due to axis offset.

[0035] Furthermore, triangular stiffening ribs are fixed between the flange and web of the I-shaped partition plate 1032, and between the bottom plate and side plate of the first servo base 102. Through the stability of the triangular structure, the structural strength of the corresponding connection parts is enhanced, effectively improving the load-bearing capacity and torsional stiffness of the I-shaped partition plate 1032 and the first servo base 102, ensuring that the articulated transition module 1 can withstand the weight and torque of the vehicle body without structural failure when the robot crosses obstacles and adjusts its posture.

[0036] Furthermore, the front track module 4 is located on both sides of the front vehicle body module 2, and includes a first fixing plate 401, a first synchronous belt 402, a first permanent magnet 403, a first support plate 404, a first drive motor 405, a first drive wheel 406, a first driven wheel 407, a first spindle 408, a first bearing 409, a second bearing 410, a first tension bolt 411, a first limiting block 412, and a second tension bolt 413; wherein, the first drive motor 405 is fixedly equipped with a U-shaped first support at both its top and bottom. The first support plate 404 has its outer side plate fixedly connected to the first fixed plate 401, and its inner side plate fixedly installed on the outer wall of the first side plate 206 of the front body module 2. This double support plate structure provides bidirectional stable support for the first drive motor 405, ensuring stable power output. The output shafts on both sides of the first drive motor 405 are fixedly equipped with first drive wheels 406. The ends of the output shafts are fixedly connected to the inner rings of first bearings 409. The outer rings of the outer first bearings 409 are fixedly connected to the front end of the first fixed plate 401, and the inner first bearings 409 are fixedly connected to the front ends of the first side plates 206 of the front body module 2. The bearings provide low-friction rotational support for the output shafts, reducing power loss. The rear end of the first fixed plate 401 has a rectangular adjustment hole with a through hole on its outer wall. One end of the first spindle 408 has an external thread, and its end has a through threaded hole. A first tensioning bolt 411 passes through the through hole and is threadedly connected to the threaded hole at the end of the first spindle 408, achieving... The first spindle 408 is fixedly connected to the first fixed plate 401. Two second bearings 410 are sleeved on the outer side of the first spindle 408. The inner second bearing 410 is fixed to the first spindle 408 by a locking nut engaging with the external thread at one end of the first spindle 408. The outer second bearing 410 is directly fixed to the first spindle 408. The outer rings of the two second bearings 410 are fixedly connected to the first driven wheel 407, and the first driven wheel 407 can rotate flexibly through the bearing structure. The two first driving wheels 406 and one first driven wheel 407 are connected by a first synchronous belt 402 to form a track transmission mechanism. Multiple first permanent magnets 403 are fixedly installed on the outer periphery of the first synchronous belt 402. The first permanent magnets 403 are arranged in an alternating N / S pattern along the track travel direction. The magnetic attraction between the permanent magnets and the steel truss structure forms a uniform adhesion band on the steel surface and provides reliable traction.By reasonably setting the length of the first permanent magnet 403, the diameter of the first drive wheel 406, the gap between the track and the bottom of the vehicle body, and the effective contact width with the steel surface, the first permanent magnet 403 on the outer periphery of the track can be directly attracted to the exposed surface of the bolts when the track passes through discontinuous surfaces such as bolt groups or spliced ​​steps, maintaining a continuous attachment state, thereby achieving stable passage through discontinuous surfaces; the other end of the first spindle 408 is fixedly equipped with a first limiting block 412, the upper and lower sides of the first limiting block 412 are provided with grooves, the rear end of the first fixing plate 401 is provided with a rectangular adjustment hole, the top and bottom of the rectangular adjustment hole are provided with a slot plate, the slot plate is engaged in the groove, forming an anti-rotation limiting structure, which is used to limit the circumferential rotation of the first spindle 408 and constrain its axial displacement. The first limiting block 412 has a threaded hole, and the rectangular adjustment hole on the first fixing plate 401 has a through hole on its side wall. The second tensioning bolt 413 passes through the through hole and is threadedly connected to the threaded hole on the first limiting block 412. By turning the first tensioning bolt 411 and the second tensioning bolt 413, the position of the first spindle 408 can be finely adjusted along the length of the rectangular hole, thereby achieving the tensioning or loosening of the first synchronous belt 402 and ensuring transmission reliability.

[0037] Furthermore, the rear track module 5 is located on both sides of the rear vehicle module 3, and includes a second fixing plate 501, a second synchronous belt 502, a second permanent magnet 503, a second support plate 504, a second drive motor 505, a second drive wheel 506, a second driven wheel 507, a second spindle 508, a third bearing 509, a fourth bearing 510, a third tension bolt 511, a second limiting block 512, and a fourth tension bolt 513; wherein, the second drive motor 505 is fixedly equipped with U-shaped second supports at both its top and bottom. Plate 504, the outer side plate of the second support plate 504 is fixedly connected to the second fixed plate 501, and its inner side plate is fixedly installed on the outer wall of the second side plate 306 of the rear body module 3. The double support plate structure provides bidirectional stable support for the second drive motor 505, ensuring the stability of power output. The output shafts on both sides of the second drive motor 505 are fixedly equipped with second drive wheels 506. The end of the output shaft is fixedly connected to the inner ring of the third bearing 509. The outer ring of the outer third bearing 509 is fixedly connected to the rear end of the second fixed plate 501, and the inner third bearing 509 is fixedly connected to the rear end of the second side plate 506 of the rear body module 3. The bearing cooperation realizes low friction rotation support of the output shaft and reduces power loss. The front end of the second fixed plate 501 has a rectangular adjustment hole, and the outer wall of the adjustment hole has a through hole. One end of the second spindle 508 has an external thread, and its end has a through threaded hole. The third tensioning bolt 511 passes through the through hole and is threadedly connected to the threaded hole at the end of the second spindle 508 to realize the second drive motor 505's power output. The second spindle 508 is fixedly connected to the second fixed plate 501. Two fourth bearings 510 are sleeved on the outer side of the second spindle 508. The inner fourth bearing 510 is fixed to the second spindle 508 by a locking nut engaging with the external thread at one end of the second spindle 508. The outer fourth bearing 510 is directly fixed to the second spindle 508. The outer rings of the two fourth bearings 510 are fixedly connected to the second driven wheel 507, and the flexible rotation of the second driven wheel 507 is achieved through the bearing structure. The two second driving wheels 506 and one second driven wheel 507 are connected by a second synchronous belt 502 to form a track transmission mechanism. Multiple second permanent magnets 503 are fixedly installed on the outer periphery of the second synchronous belt 502. The second permanent magnets 503 are arranged in an alternating N / S pattern along the track travel direction. The magnetic attraction between the permanent magnets and the steel truss structure forms a uniform adhesion band on the steel surface and provides reliable traction.By reasonably setting the length of the second permanent magnet 503, the diameter of the second drive wheel 506, the gap between the track and the bottom of the vehicle body, and the effective contact width with the steel surface, the second permanent magnet 503 on the outer periphery of the track can be directly attracted to the exposed surface of the bolts when the track passes through discontinuous surfaces such as bolt groups or spliced ​​steps, maintaining a continuous attachment state, thereby achieving stable passage through discontinuous surfaces; the other end of the second spindle 508 is fixedly equipped with a second limiting block 512, the upper and lower sides of the second limiting block 512 are provided with grooves, the rear end of the second fixing plate 501 is provided with a rectangular adjustment hole, the top and bottom of the rectangular adjustment hole are provided with a slot plate, the slot plate is engaged in the groove, forming an anti-rotation limiting structure, which is used to limit the circumferential rotation of the second spindle 508 and constrain its axial displacement. The second limiting block 512 has a threaded hole, and the rectangular adjustment hole on the second fixing plate 501 has a through hole on its side wall. The fourth tensioning bolt 513 passes through the through hole and is threadedly connected to the threaded hole on the second limiting block 512. By turning the third tensioning bolt 511 and the fourth tensioning bolt 513, the position of the second spindle 508 can be finely adjusted along the length of the rectangular hole, thereby achieving the tensioning or loosening of the second synchronous belt 502 and ensuring transmission reliability.

[0038] Furthermore, the forward vision module 6 includes a first binocular camera 601, a first industrial camera 602, a first industrial camera lens 603, a binocular camera bracket 604, a second servo motor 605, an industrial camera base 606, and an industrial camera bracket 607. The binocular camera bracket 604 is fixedly installed at the top center of the top horizontal plate of the first front panel 204. The first binocular camera 601 is fixed to the top of the binocular camera bracket 604 for acquiring large-scale disease images. The industrial camera bracket 607 is fixedly installed at the top of the front end of the first top plate 202. The second servo motor 605 is fixedly installed through the middle of the top of the industrial camera bracket 607. The industrial camera base 606 is fixedly installed at the output end of the second servo motor 605. The first industrial camera 602 is fixedly installed on the front sidewall of the top of the industrial camera base 606. The first industrial camera lens 603 is mounted on the first industrial camera 602. Together, they capture high-definition images of small-scale diseases in the direction of bridge travel through high-resolution imaging. Large-scale defect images are acquired by the first binocular camera 601, while high-resolution images of small-scale defects are captured by the first industrial camera 602 and its lens 603. This forms a dual-layer detection mode of "large-scale inspection + small-scale precision inspection," which covers the entire area along the bridge's direction of travel and accurately identifies minute defects, effectively avoiding missed detections due to incomplete detection range or insufficient accuracy. The second servo motor 605 drives the industrial camera base 606 to rotate the first industrial camera 602, flexibly adjusting the viewing angle for small-scale defect detection. This adapts to the detection needs of different angles and positions of the bridge's steel truss structure, solving the problem of fixed-view cameras being unable to cover blind spots in complex structures and improving the module's adaptability to the complex environment of bridges. The first binocular camera 601 ensures the integrity of images of large-scale areas, while the high-resolution imaging of the first industrial camera 602 and its lens ensures the clarity of images of small-scale defects (such as fine cracks and localized corrosion). The high-quality data output by both types of cameras provides a reliable basis for subsequent defect type identification, size measurement, and severity assessment, helping to achieve accurate diagnosis of bridge surface defects.

[0039] Furthermore, such as Figure 2-3As shown, the rearward vision module 7 includes a robotic arm base 701, a third servo motor 702, a robotic arm base 703, a fourth servo motor 704, a first joint link 705, a link support 706, a fifth servo motor 707, a fifth servo motor bracket 708, a second joint link 709, a sixth servo motor 710, a sixth servo motor bracket 711, a binocular camera mounting plate 712, a second binocular camera 713, a second industrial camera 714, a second industrial camera lens 715, and an industrial camera mounting plate 716; wherein, the robotic arm... The arm base 701 is fixedly installed at the middle position of the top of the two crossbeams of the rear body module 3, serving as the overall mounting base of the rear vision module 7. It is used to support the various components of the module and achieve a rigid connection with the rear body module 3. The third servo motor 702 is fixedly installed on the top of the robotic arm base 6701, and its output end is fixedly connected to the robotic arm base 703. The rotation drive of the third servo motor 702 can drive the robotic arm base 703 and subsequent connecting components to rotate around the vertical axis, thereby realizing the horizontal adjustment of the overall detection angle of the module. A fourth servo motor 704 is fixedly installed on the top of the robotic arm base 703. The output ends of the fourth servo motor 704 are fixedly connected to the first joint link 705 on both sides. Driven by the fourth servo motor 704, the first joint link 705 can be rotated around the horizontal axis to adjust the pitch angle of the first joint of the robotic arm. The other end of the first joint link 705 is fixedly connected to the fifth servo motor bracket 708. A fifth servo motor 707 is fixedly installed on the outer wall of the fifth servo motor bracket 708. The output ends of the fifth servo motor 707 are fixedly connected to the second joint link 709 on both sides. Driven by the fifth servo motor 707, the second joint link 709 can be rotated around the horizontal axis to adjust the pitch angle of the second joint of the robotic arm. Several link supports 706 are spaced apart between the two first joint links 705 and between the two second joint links 709. Their function is to enhance the overall rigidity of the link structure and prevent the links from bending or deforming under stress or during movement. A sixth servo motor bracket 711 is fixedly installed between the other ends of the second joint links 709. A sixth servo motor 710 is fixedly installed on the outer wall of the sixth servo motor bracket 711. The output end of the sixth servo motor 710 is fixedly connected to the industrial camera mounting plate 716. A second industrial camera 714 is fixedly installed on the outer wall of the industrial camera mounting plate 716. The second industrial camera lens 715 is mounted on the second industrial camera 714. The two constitute a small-scale defect detection unit. Driven by the sixth servo motor 710, the second industrial camera 714 and the second industrial camera lens 715 can be rotated around the horizontal axis to achieve fine-tuning of attitude. A binocular camera mounting plate 712 is fixedly installed at the bottom of the other end of the second joint link 709, and a second binocular camera 713 is fixedly installed at the bottom of the binocular camera mounting plate 712, forming a large-scale area detection unit.Through the multi-axis coordinated drive of the third to sixth servo motors, combined with the linkage of the first and second joints, the second binocular camera 713 and the second industrial camera 714 can achieve multi-degree-of-freedom attitude adjustment, ensuring that they can flexibly align with the parts to be inspected in the lateral area of ​​the bridge, and meet the needs of multi-angle and wide-range defect image acquisition under complex steel truss structures.

[0040] Furthermore, a controller is provided inside the rectangular frame of the rear body module 3. The controller is electrically connected to the drive control terminals of the first drive motor 207 and the second drive motor 307, as well as the first servo motor 101, the second servo motor 605, the third servo motor 702, the fourth servo motor 704, the fifth servo motor 707, and the sixth servo motor 710, and is used to output commands to control the motor speed, direction, and servo motor rotation angle. The controller is also electrically connected to the first binocular camera 601, the first industrial camera 602, the second binocular camera 713, and the second industrial camera 714, and receives and processes the defect images collected by each camera. At the same time, the controller integrates a power management module, and after connecting to an external power source, it manages the power-on / power-off of all the above-mentioned electrical components.

[0041] Example 2 Combination Figure 1-14 ,like Figure 15 As shown, this invention provides a working method for a robot used for the appearance inspection of large-span double-layer steel truss suspension bridges. The method utilizes the aforementioned robot and the specific steps are as follows: S100: The inspection robot is transported to the surface of the target steel component. The robot's posture is adjusted by manual guidance so that the permanent magnets on the outer periphery of the track are evenly and slowly attached to the surface of the steel component, forming a continuous and stable magnetic adsorption attachment band. After the attachment status is confirmed to be correct, the robot is powered on. Before the operation begins, the robot is hoisted and positioned on the surface of the target steel component using the first handle 209 and the second handle 309 or the first lifting ring 208 and the second lifting ring 308. The robot is manually guided to make the permanent magnet 403 on the outer periphery of the track evenly and slowly adhere to the steel surface. After confirming that there is continuous contact along the length of the track and no local lifting, the whole machine is powered on.

[0042] S200: After starting the robot, it first completes the electrical self-test of the drive motor, track drive, forward vision module 6 and rear vision module 7, and performs zero-position calibration on the forward vision module 6 and forward vision module 7. According to the detection requirements, the robot's travel path parameters are set in the control system, and the first drive motor 405 and the second drive motor 505 are started, so that the front track module 4 and the rear track module 5 can move smoothly along the surface of the steel component. During the movement, the forward vision module 6 synchronously collects the appearance image in the direction of movement. At the same time, by controlling the actions of each level of the servo motor of the rear vision module 7, it obtains close-range images of the side area of ​​the web members, chord members and node plates of the steel component. The first binocular camera 601 acquires image information of large-scale defect areas, while the first industrial camera 602, driven by the second servo motor 605, adjusts its horizontal angle around the industrial camera base 606 to achieve precise image acquisition of small-scale defects. Simultaneously, the servo motors of the rear vision module 7 coordinate their movements to align the end-effector second binocular camera 713 and the second industrial camera 714 with the lateral detection area (covering key areas such as the outer side of the web members, the side of the chord members, and the angle of the node plates), performing close-range imaging to ensure comprehensive coverage of bridge surface defects of different scales and orientations.

[0043] S300: When the robot travels to a group of bolts or a series of steps, it first reduces its travel speed. At the same time, it controls the first electric push rod 207 of the front body module 2 to extend, raising the height of the front of the front body module 2 and maintaining a low speed. This allows the first permanent magnet 403 on the front track module 4 to smoothly cross the group of bolts or the series of steps and attach to their exposed surfaces in sequence. After the front track module crosses the first row of bolts or the series of steps and establishes a stable attachment, it slowly retracts the first electric push rod 207 and continues to move forward, allowing the robot to sit smoothly on the surface of the group of bolts and continue to pass through the obstacle area at a low speed.

[0044] S400: When the inspection robot needs to switch from the first wall to the adjacent second wall, for the external angle (about 90°), first control the first electric push rod 207 of the front body module 2 to extend, lift the front body module 2 until the front track module 4 is completely separated from the first wall. Then, start the two first servo motors 101 of the articulated transition module 1 to drive the front and rear body modules to rotate relative to each other around the articulation axis until the posture of the front body module 2 matches the second wall. Then, retract the first electric push rod 207 to make the front track module 4 adhere to the second wall and attach stably, keeping the posture of the front body module 2 unchanged. Then extend the second electric push rod 307 of the rear body module 3 to lift the rear body module 3 until the rear track module 5 is separated from the first wall. At the same time, control the two first servo motors 101 to adjust the rear body module 3 to a horizontal posture and align the track with the second wall. Finally, retract the second electric push rod 307 and control the robot to move forward at a low speed, so that the track of the rear body module 3 contacts the second wall in sequence and completely adheres to it, completing the wall switching. S500: If turning is required at a small radius structure, the front track module 4 and the rear track module 5 on the left and right sides of the front body module 2 and the rear body module 3 are used to achieve the turning. First, reduce the travel speed to a low speed. Control the inner front track module 4 and rear track module 5 on the front vehicle module 2 and rear vehicle module 3 to decelerate to a low speed or briefly reverse. The outer front track module 4 and rear track module 5 maintain a low speed. Achieve directional turning through stable differential speed. During the turning process, slightly adjust the differential ratio to suppress lateral slippage and adhesion fluctuations. When the vehicle's heading approaches the target angle, synchronously converge the speeds of the two track modules until symmetrical drive is restored and the turning angular velocity is eliminated to complete the directional passage. If there is a momentary drop in adhesion or trajectory deviation during the turning process, immediately reduce the differential ratio and briefly stop to correct. After correction, travel in a straight line along the predetermined path and resume normal image acquisition.

[0045] S600: After completing the predetermined inspection path, stop the machine and power off in sequence. With manual assistance, separate the front track module 4 and the rear track module from the surface of the steel component segment by segment, and finally transport the robot to the designated storage location.

[0046] Specifically, after completing the predetermined testing tasks, the system is shut down in a predetermined sequence, stopping the operation of the first drive motor 405 and the second drive motor 505, bringing the front track module 4 and the rear track module 5 to a standstill, and controlling the rearward vision module 7 to retract to its storage posture; all cameras stop image acquisition and are powered off; the two industrial servo motors 101 of the drive articulated transition module 1 are returned to their zero positions; it is confirmed that the first electric push rod 207 and the second electric push rod 307 are fully retracted and the stroke feedback is normal. After the above power-off sequence is completed, the robot is manually disengaged by holding the first handle 209, the second handle 309, or connecting the first lifting ring 208 and the second lifting ring 308, slowly and evenly raising the robot body, so that the first permanent magnet 403 and the second permanent magnet 503 on the front track module 4 and the rear track module 5 are separated from the steel surface segment by segment along the length direction, avoiding impact caused by instantaneous prying. After the tracks on both sides are completely separated from the steel surface and it is confirmed that there is no residual adsorption, the robot is smoothly moved away from the component surface and transported to a safe location, completing this operation cycle.

[0047] Further, in step S400, when the detection robot needs to switch from the first wall to the adjacent second wall, for the inside corner (not less than 75°), it first decelerates and stops at a predetermined position, controls the first electric push rod 207 of the front body module 2 to slowly extend, raising the front body module 2 until it is completely detached from the first wall. While ensuring that the rear body module 3 remains stably attached to the first wall, the articulated transition module 1 is activated, controlling the first servo motor 101 with a small angular velocity and segmented drive, causing the front body module 2 to gradually rotate around the articulation axis towards the second wall. When the front body module 2 is detected... When the track makes initial contact with the edge of the second wall, the servo motor rotation is paused, and the first electric push rod 207 of the front body module 2 is slowly retracted, allowing its track to form a continuous attachment strip on the second wall and achieve stable adhesion. Then, the second electric push rod 307 of the rear body module 3 is controlled to lift, causing the rear body module 3 to detach from the first wall. After maintaining this posture and moving forward at a low speed to a suitable position, the second electric push rod 307 of the rear body module 3 is retracted, and then the two first servo motors 101 are driven in segments at a small angular velocity, so that the track of the rear body module 3 contacts the second wall in sequence and fully adheres to it, completing the wall change.

[0048] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A robot for inspecting the appearance of a large-span, double-layer steel truss suspension bridge, characterized in that, It includes an articulated transition module (1), a front body module (2), a rear body module (3), a front track module (4), a rear track module (5), a forward vision module (6), and a rear vision module (7); among which, The articulated transition module (1) is located between the front body module (2) and the rear body module (3) to form a movable connection mechanism between the two. Through the articulated transition module (1), the front body module (2) and the rear body module (3) can rotate relative to each other, enabling the robot to adapt to the shape of the positive and negative corners of the adjacent walls in the bridge steel truss structure. By adjusting the relative posture of the front and rear bodies, the robot can complete the smooth transition between the walls and ensure the robot's continuous movement capability on complex three-dimensional structures. The front track module (4) is respectively mounted on the left and right side walls of the front body module (2), and the rear track module (5) is respectively mounted on the left and right side walls of the rear body module (3). The two serve as the robot's mobile execution mechanism and together provide the robot with propulsion power and support. The forward vision module (6) is fixedly installed on the top of the front body module (2) and is used to continuously acquire images of the bridge surface area in the direction of travel during the robot's movement, thereby capturing in real time information on defects such as cracks, corrosion, and coating peeling that may exist in that direction. The rear vision module (7) is fixedly installed on the top of the rear body module (3) and is used to continuously acquire images of the bridge lateral area during the robot's operation, forming a collaborative detection system with the forward vision module (6) to avoid missing defects due to limited viewing angle, and ultimately achieve comprehensive and blind-angle defect monitoring of the bridge surface.

2. The appearance inspection robot for a large-span double-layer steel truss suspension bridge according to claim 1, characterized in that, The front body module (2) includes a first frame (201), a first top plate (202), a first bottom plate (203), a first front plate (204), a first rear plate (205), a first side plate (206), and a first electric push rod (207); wherein, the first frame (201) is a cuboid frame structure, the front end and rear end of the first frame (201) are respectively fixedly mounted with the first front plate (204) and the first rear plate (205), the left and right sides are fixedly mounted with the first side plate (206), the top and bottom are respectively fixedly mounted with the first top plate (202) and the first bottom plate (203), the first front plate (204) and the first rear plate (205) are both U-shaped plate structures, and the vertical plate of the first front plate (204) is fixedly mounted on the first electric push rod (207). The front end face of the first frame (201) has two horizontal plates fixedly installed on the bottom edge and top edge of the first frame (201) respectively. The vertical plate of the first rear plate (205) is fixedly installed on the rear end face of the first frame (201), and its two horizontal plates are also fixedly installed on the bottom edge and top edge of the first frame (201) respectively. The first base plate (203) has two through holes symmetrically distributed along the central axis of the base plate. Two middle crossbeams are fixedly installed at the middle position of the top of the first frame (201). Two first electric push rods (207) are fixedly installed at the bottom of the middle crossbeams. Their piston rods are arranged vertically and their ends point to the through holes on the first base plate (203). The piston rods can extend outward through the through holes. The front body module (2) also includes a plurality of first lifting rings (208) and a first handle (209). The plurality of first lifting rings (208) are fixed to the top of the first top plate (202), and the first handle (209) is fixed to the outer side wall of the first front plate (204).

3. The appearance inspection robot for a large-span double-layer steel truss suspension bridge according to claim 1, characterized in that, The rear vehicle module (3) includes a second frame (301), a second top plate (302), a second bottom plate (303), a second front plate (304), a second rear plate (305), a second side plate (306), and a second electric push rod (307); wherein, the second frame (301) is a cuboid frame structure, the front end and rear end of the second frame (301) are respectively fixedly mounted with the second front plate (304) and the second rear plate (305), the left and right sides are fixedly mounted with the second side plate (306), the top and bottom are respectively fixedly mounted with the second top plate (302) and the second bottom plate (303), the second front plate (304) and the second rear plate (305) are both U-shaped plate structures, and the vertical plate of the second front plate (304) is fixedly mounted on the second electric push rod (307). The front end face of the second frame (301) has two horizontal plates fixedly installed on the bottom edge and top edge of the second frame (301) respectively; the vertical plate of the second rear plate (305) is fixedly installed on the rear end face of the second frame (301), and its two horizontal plates are also fixedly installed on the bottom edge and top edge of the second frame (301) respectively; two through holes are opened on the second base plate (303) symmetrically distributed along the central axis of the base plate; two middle crossbeams are fixedly installed at the middle position of the top of the second frame (301); two second electric push rods (307) are fixedly installed at the bottom of the middle crossbeams, and their piston rods are arranged vertically and their ends point to the through holes on the second base plate (303); the piston rods can extend outward through the through holes. The rear body module (3) also includes a plurality of second lifting rings (308) and a second handle (309). The plurality of second lifting rings (308) are fixedly mounted on the top of the second top plate (302), and the second handle (309) is fixedly mounted on the outer side wall of the second rear plate (305).

4. The appearance inspection robot for a large-span double-layer steel truss suspension bridge according to claim 1, characterized in that, The articulated transition module (1) includes a first servo motor (101), a first servo motor base (102), and a second servo motor base (103). The first servo motor base (102) is a U-shaped plate structure. The outer side wall of the bottom plate of the first servo motor base (102) is fixedly connected to the first rear plate (205) of the front body module (2). The two side plates of the first servo motor base (102) are fixedly connected to the output end of the first servo motor (101) respectively. The second servo base (103) includes two U-shaped connecting plates (1031) and an I-shaped partition plate (1032). The two U-shaped connecting plates (1031) are arranged in a counter-bracing manner, and their side plates are fixedly installed on the outer side walls of the two side flanges of the I-shaped partition plate (1032). The two U-shaped connecting plates (1031) and the I-shaped partition plate (1032) together form a H-shaped frame. The bottom plates of the two U-shaped connecting plates (1031) are both through which the first servo (101) is fixedly installed. The H-shaped frame is fixedly connected to the front side wall of the second front plate (304) of the rear body module (3) through the side plates of the two U-shaped connecting plates (1031).

5. The appearance inspection robot for a large-span double-layer steel truss suspension bridge according to claim 1, characterized in that, The front track module (4) includes a first fixed plate (401), a first synchronous belt (402), a first permanent magnet (403), a first support plate (404), a first drive motor (405), a first drive wheel (406), a first driven wheel (407), a first spindle (408), a first bearing (409), a second bearing (410), a first tension bolt (411), a first limit block (412), and a second tension bolt (413). The first drive motor (405) is fixedly mounted with a U-shaped first support plate (404) at both the top and bottom. The outer side plate of the first support plate (404) is fixedly connected to the first fixed plate (401), and the inner side plate is fixedly installed on the front vehicle body. The outer wall of the first side plate (206) of module (2) has the first drive wheel (406) fixedly mounted on the output shafts on both sides of the first drive motor (405). The end of the output shaft is fixedly connected to the inner ring of the first bearing (409). The outer ring of the outer first bearing (409) is fixedly connected to the front end of the first fixed plate (401). The inner first bearing (409) is fixedly connected to the front end of the first side plate (206) of the front body module (2). The rear end of the first fixed plate (401) has a rectangular adjustment hole. The outer wall of the adjustment hole has a through hole. One end of the first spindle (408) has an external thread, and its end has a through threaded hole. The first tensioning bolt (411) passes through the spindle. The through hole is threadedly connected to the threaded hole at the end of the first spindle (408). Two second bearings (410) are sleeved on the outer side of the first spindle (408). The inner second bearing (410) is fixed to the first spindle (408) by a lock nut engaging with the external thread at one end of the first spindle (408). The outer second bearing (410) is directly fixed to the first spindle (408). The outer rings of the two second bearings (410) are fixedly connected to the first driven wheel (407). The two first driving wheels (406) and one first driven wheel (407) are connected by a first synchronous belt (402). Multiple [unclear] are fixedly installed on the outer circumference of the first synchronous belt (402). A first permanent magnet (403) is arranged in an alternating N / S pattern along the track travel direction. A first limiting block (412) is fixed at the other end of the first spindle (408). Grooves are provided on the upper and lower sides of the first limiting block (412). A rectangular adjustment hole is provided at the rear end of the first fixing plate (401). The top and bottom of the rectangular adjustment hole are provided with a slot plate, which is engaged in the groove. A threaded hole is provided on the first limiting block (413). A through hole is provided on the side wall of the rectangular adjustment hole on the first fixing plate (401). A second tensioning bolt (413) passes through the through hole and is threadedly connected to the threaded hole on the first limiting block (412).

6. The appearance inspection robot for a large-span double-layer steel truss suspension bridge according to claim 1, characterized in that, The rear track module (5) includes a second fixed plate (501), a second synchronous belt (502), a second permanent magnet (503), a second support plate (504), a second drive motor (505), a second drive wheel (506), a second driven wheel (507), a second spindle (508), a third bearing (509), a fourth bearing (510), a third tension bolt (511), a second limit block (512), and a fourth tension bolt (513). The second drive motor (505) has a U-shaped second support plate (504) fixedly mounted on its top and bottom. The outer side plate of the second support plate (504) is fixedly connected to the second fixed plate (501), and the inner side plate is fixedly installed on the rear vehicle body module. The outer wall of the second side plate (306) of block (3), the output shafts on both sides of the second drive motor (505) are fixedly mounted with the second drive wheel (506), the end of the output shaft is fixedly connected to the inner ring of the third bearing (509), the outer ring of the outer third bearing (509) is fixedly connected to the rear end of the second fixed plate (501), the inner third bearing (509) is fixedly connected to the rear end of the second side plate (506) of the rear body module (3), the front end of the second fixed plate (501) is provided with a rectangular adjustment hole, the outer wall of the adjustment hole is provided with a through hole, one end of the second spindle (508) is provided with an external thread, and the end of the spindle is provided with a through threaded hole, through which the third tensioning bolt (511) passes. The hole is threadedly connected to the threaded hole at the end of the second spindle (508). Two fourth bearings (510) are sleeved on the outer side of the second spindle (508). The inner fourth bearing (510) is fixed to the second spindle (508) by engaging with the external thread at one end of the second spindle (508) through a lock nut. The outer fourth bearing (510) is directly fixed to the second spindle (508). The outer rings of the two fourth bearings (510) are fixedly connected to the second driven wheel (507). The two second driving wheels (506) and one second driven wheel (507) are connected by a second synchronous belt (502). Multiple... A second permanent magnet (503) is arranged in an alternating N / S pattern along the track travel direction. A second limiting block (512) is fixed at the other end of the second spindle (508). The upper and lower sides of the second limiting block (512) are provided with grooves. A rectangular adjustment hole is provided at the rear end of the second fixing plate (501). The top and bottom of the rectangular adjustment hole are provided with slot plates. The slot plates are engaged in the grooves. The second limiting block (512) is provided with threaded holes. The side wall of the rectangular adjustment hole on the second fixing plate (501) is provided with through holes. A fourth tensioning bolt (513) passes through the through holes and is threadedly connected to the threaded hole on the second limiting block (512).

7. The appearance inspection robot for a large-span double-layer steel truss suspension bridge according to claim 1, characterized in that, The forward vision module (6) includes a first binocular camera (601), a first industrial camera (602), a first industrial camera lens (603), a binocular camera bracket (604), a second servo motor (605), an industrial camera base (606), and an industrial camera bracket (607). The binocular camera bracket (604) is fixedly installed at the top middle position of the top horizontal plate of the first front plate (204). The first binocular camera (601) is fixed at the top of the binocular camera bracket (604). The industrial camera bracket (607) is fixedly installed at the top front end of the first top plate (202). The second servo motor (605) is fixedly installed through the middle position of the top of the industrial camera bracket (607). The industrial camera base (606) is fixedly installed at the output end of the second servo motor (605). The first industrial camera (602) is fixedly installed on the front side wall of the top of the industrial camera base (606). The first industrial camera lens (603) is mounted on the first industrial camera (602).

8. The appearance inspection robot for a large-span double-layer steel truss suspension bridge according to claim 1, characterized in that, The rearward vision module (7) includes a robotic arm base (701), a third servo motor (702), a robotic arm base (703), a fourth servo motor (704), a first joint link (705), a link support (706), a fifth servo motor (707), a fifth servo motor bracket (708), a second joint link (709), a sixth servo motor (710), a sixth servo motor bracket (711), a binocular camera mounting plate (712), a second binocular camera (713), a second industrial camera (714), a second industrial camera lens (715), and an industrial... The camera mounting plate (716) is fixedly mounted on the top of the two middle crossbeams of the rear body module (3). The third servo motor (702) is fixedly mounted on the top of the mechanical arm base (701), and its output end is fixedly connected to the mechanical arm base (703). The top of the mechanical arm base (703) is fixedly mounted on the fourth servo motor (704). The output ends of the fourth servo motor (704) are fixedly connected to the first joint link (705) on both sides. The other end of the first joint link (705) is connected to the fifth servo motor. A bracket (708) is fixedly connected, and a fifth servo (707) is fixedly installed on the outer wall of the fifth servo bracket (708). The output ends of the fifth servo (707) are fixedly connected to the second joint connecting rods (709) on both sides respectively. Several connecting rod supports (706) are provided at intervals between the two first joint connecting rods (705) and between the two second joint connecting rods (709). A sixth servo bracket (711) is fixedly installed between the other ends of the second joint connecting rods (709). The outer wall of the sixth servo bracket (711) is fixedly connected to the bracket (708). A sixth servo motor (710) is fixedly installed. The output end of the sixth servo motor (710) is fixedly connected to an industrial camera mounting plate (716). A second industrial camera (714) is fixedly installed on the outer wall of the industrial camera mounting plate (716). The lens (715) of the second industrial camera is mounted on the second industrial camera (714). A binocular camera mounting plate (712) is fixedly installed at the bottom between the other ends of the second joint connecting rod (709). A second binocular camera (713) is fixedly installed at the bottom of the binocular camera mounting plate (712).

9. A working method for a robot for appearance inspection of a large-span double-layer steel truss suspension bridge, characterized in that, The appearance inspection robot for a large-span double-layer steel truss suspension bridge, as described in any one of claims 1-7, is characterized by comprising the following steps: S100: The inspection robot is transported to the surface of the target steel component. The robot's posture is adjusted by manual guidance so that the permanent magnets on the outer periphery of the track are evenly and slowly attached to the surface of the steel component, forming a continuous and stable magnetic adsorption attachment band. After the attachment status is confirmed to be correct, the robot is powered on. S200: After starting the robot, first complete the electrical self-test of the drive motor, track drive, forward vision module (6) and rear vision module (7), and at the same time perform zero-position calibration on the forward vision module (6) and forward vision module (7). According to the detection requirements, set the robot's travel path parameters in the control system, start the first drive motor (405) and the second drive motor (505), so that the front track module (4) and the rear track module (5) can travel smoothly along the surface of the steel component. During the travel, the forward vision module (6) synchronously collects the appearance image of the travel direction. At the same time, by controlling the actions of each level of the servo motor of the rear vision module (7), obtain close-range images of the side area of ​​the web members, chord members and node plates of the steel component. S300: When the robot travels to the discontinuous surface of the bolt group or splicing steps, it first reduces its travel speed. At the same time, it controls the first electric push rod (207) of the front body module (2) to extend, raise the height of the front of the front body module (2), and maintain low speed. This allows the first permanent magnet (403) on the front track module (4) to smoothly cross the bolt group or splicing steps and be attracted to its exposed surface in sequence. After the front track module crosses the first row of bolts or splicing steps and establishes a stable attachment, it slowly retracts the first electric push rod (207) and continues to move forward, so that the robot body sits smoothly on the surface of the bolt group and continues to pass through the obstacle area at a low speed. S400: When the inspection robot needs to switch from the first wall to the adjacent second wall, at the corner, first control the first electric push rod (207) of the front body module (2) to extend, lift the front body module (2) until the front track module (4) is completely separated from the first wall, then start the two first servo motors (101) of the articulated transition module (1) to drive the front and rear body modules to rotate relative to each other around the articulation axis until the posture of the front body module (2) matches the second wall, then retract the first electric push rod (207) so that the front track module (4) The robot attaches to the second wall and remains stable, keeping the front body module (2) in the same position. Then, the second electric push rod (307) of the rear body module (3) is extended to lift the rear body module (3) until the rear track module (5) separates from the first wall. At the same time, the two first servo motors (101) are controlled to adjust the rear body module (3) to a horizontal position and align the track with the second wall. Finally, the second electric push rod (307) is retracted to control the robot to move forward at a low speed, so that the track of the rear body module (3) contacts the second wall in sequence and fits completely, thus completing the wall switching. S500: If turning is required at a small radius structure, the front track module (4) and rear track module (5) on the left and right sides of the front body module (2) and the rear body module (3) are used to achieve the differential turning; S600: After completing the predetermined detection path, stop the machine and power off in sequence. With manual assistance, separate the front track module (4) and the rear track module from the surface of the steel component segment by segment, and finally transport the robot to the designated storage location.

10. The working method of the appearance inspection robot for a large-span double-layer steel truss suspension bridge according to claim 9, characterized in that, In step S400, at the inner corner, the vehicle first decelerates and stops at a predetermined position, and controls the first electric push rod (207) of the front body module (2) to slowly extend, raising the front body module (2) until it is completely detached from the first wall. On the premise of ensuring that the rear body module (3) is still stably attached to the first wall, the articulated transition module (1) is activated, and the first servo motor (101) is operated at a lower speed and in a segmented driving manner, so that the front body module (2) gradually rotates around the articulation axis toward the second wall. When the track of the front body module (2) is detected to have initial contact with the edge of the second wall, Pause the servo rotation and slowly retract the first electric push rod (207) of the front body module (2) so that its track forms a continuous attachment strip on the second wall and achieves stable contact. Then control the second electric push rod (307) of the rear body module (3) to lift it up, so that the rear body module (3) is separated from the first wall. Maintain this posture and move forward at low speed to a suitable position. Then retract the second electric push rod (307) of the rear body module (3) and drive the two first servo motors (101) in segments at a low speed so that the track of the rear body module (3) contacts the second wall in sequence and is completely attached, thus completing the wall change.

Images