Steel bridge deck crack image acquisition crawler robot and control method

Abstract

The application provides a steel bridge deck plate crack image acquisition crawler robot and a control method, which comprises the following steps: the mechanical main body is a cavity structure with a magnetic crawler; a power and transmission device drives the robot to complete advancing, retreating or crossing actions; a crack image acquisition device acquires crack image information and distance information; a brushless motor holder device adjusts the angle of the crack image acquisition device, and obtains a homography transformation matrix between a camera imaging plane and a physical plane where a fatigue crack is located based on the crack image information and the distance information; an environment sensing device acquires environment information in the robot movement process; and a main circuit board realizes the cooperative control and movement of the whole robot. In the application, the magnetic adsorption force is uniformly distributed on each crawler, so that the robot can realize crossing between any planes, complete omnidirectional, dead angle-free acquisition of fatigue cracks and accurate measurement of crack sizes, and the real-time wireless transmission to a remote terminal is realized through the brushless motor holder device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of steel structure fatigue crack detection device, in particular, to a steel bridge deck crack image acquisition crawler robot and a control method. BACKGROUND

[0002] China is a big country of bridges and a big country of steel. Because steel has excellent material properties such as light weight, high strength, good workability, etc., it is widely used in the construction of bridges. In the process of modern bridge construction, the recognition degree of steel structure bridge is getting higher and higher. According to statistics, in order to alleviate the traffic pressure of the original bridge, and also to vigorously develop economic construction, the construction speed of steel structure bridge with a span of more than 1,000 meters across the Yangtze River and the Yellow River is six per year, and the average steel consumption of each bridge is 10,000 tons. In recent years, China has built a large number of steel structure bridges, covering a wide range, including railway bridges, highway bridges, highway-railway combined bridges and pedestrian bridges.

[0003] Among them, the orthotropic steel bridge deck composed of longitudinal ribs, cross beams and cover plates welded together has become the first choice for large and medium span steel structure bridge deck panels due to its light structure weight, high overall efficiency, strong spanning capacity and good seismic performance. Today, there are thousands of orthotropic steel bridge deck bridges in the world. However, due to the direct bearing of the local action of the vehicle on the orthotropic steel bridge deck, the stress diffusion effect is small, and the vehicle driving will cause several stress cycles, plus the stress concentration of the welded joints and the inevitable welding defects, the steel bridge deck is prone to fatigue cracking, which seriously affects the safety and functional reliability of the bridge. In recent decades, different degrees of fatigue cracks have been found in a large number of steel bridge deck projects at home and abroad, and the influence of these cracks needs to be quantitatively evaluated and on this basis, maintenance and repair strategies are developed to ensure the safe and normal operation of the bridge. Steel bridge deck fatigue crack detection and monitoring is the most important basic work, whether the crack measurement data is comprehensive and accurate directly relates to the correctness of the evaluation results and the effectiveness of the maintenance and repair strategies.

[0004] At present, the fatigue crack detection of steel bridge deck is mainly manual detection. The detector holds the detection equipment, measures and records the position and length of the fatigue crack at close range. Due to the large amount of work and discontinuous detection time and space, there are disadvantages of low detection efficiency, high cost and easy missed detection of small cracks. The Chinese patent with publication number CN115772850A proposes a railway bridge surface crack automatic detection robot, but the single inspection range of the crack automatic detection robot is small, and manual installation is required in the crack area, which cannot realize large-scale detection of fatigue cracks. The Chinese patent with publication number CN115639209A proposes a steel box girder fatigue crack intelligent detection system, but the detection system must run on the flexible track laid in advance, and the robot cannot walk freely in all directions. The Chinese patent with publication number CN109613010A proposes a fatigue crack detection system for orthotropic steel bridge deck, but the detection system cannot realize omnidirectional and dead angle-free image acquisition. SUMMARY

[0005] In view of the defects in the prior art, the purpose of the present application is to provide a steel bridge deck crack image acquisition crawler robot and a control method thereof.

[0006] According to one aspect of the present application, a steel bridge deck crack image acquisition crawler robot is provided, comprising:

[0007] A mechanical body in a cavity structure with a magnetic track;

[0008] A power and transmission device connected with the mechanical body to drive the robot to complete forward, backward or leapfrog actions;

[0009] A crack image acquisition device arranged outside the mechanical body to acquire crack image information and distance information;

[0010] A brushless motor gimbal device installed inside the mechanical body to adjust the angle of the crack image acquisition device, and to obtain a homography transformation matrix between the camera imaging plane and the physical plane where the fatigue crack is located based on the crack image information and distance information, and to extract the geometric features of the crack;

[0011] An environmental sensing device arranged outside the mechanical body to acquire environmental information during the movement of the robot;

[0012] A main circuit board arranged inside the mechanical body to communicate with the crack image acquisition device, the brushless motor gimbal device and the environmental sensing device to realize the cooperative control and movement of the whole robot.

[0013] Preferably, the mechanical body comprises:

[0014] The two bent sheet metal pieces are spliced to form a cavity, and the brushless motor holder is installed inside the cavity.

[0015] The aluminum profile is connected to the bottom of the sheet metal piece.

[0016] The two side plates are both equilateral triangles and are connected to the two sides of the bent sheet metal piece.

[0017] The track surrounds the outer periphery of the side plate and has a triangular structure as a whole.

[0018] The permanent magnets are evenly distributed on the track, allowing the track to be adsorbed on the U-rib, cross beam, and top plate, and enabling straight walking, turning around, or steering through the driving of the power and transmission device.

[0019] Preferably, the number of power and transmission devices is two, and each is installed on the two sides of the mechanical body. Each power and transmission device comprises:

[0020] The driving wheel is arranged at a corner of the side plate and engages with the track.

[0021] The brush DC motor is arranged inside the side plate and is connected to the driving wheel to provide a rotating torque.

[0022] The driven wheels are arranged at the remaining two corners of each side plate and engage with the track.

[0023] Preferably, the number of crack image acquisition devices is two, and each is installed on the two sides of the mechanical body. Each crack image acquisition device comprises:

[0024] The base is connected to the brushless motor holder.

[0025] The crack image acquisition camera is installed on the base to acquire crack image information.

[0026] The laser ranging modules are installed on the base to acquire distance information.

[0027] The at least one fill light is installed on the base to provide a shooting light source.

[0028] Preferably, based on the crack image information and distance information, a homography transformation matrix between the camera imaging plane and the physical plane where the fatigue crack is located is obtained, and the geometric features of the crack are extracted, including:

[0029] The crack image acquisition camera takes a crack picture to obtain crack image information;

[0030] The plurality of laser ranging modules work in sequence to measure crack distance information;

[0031] Based on the image information and the distance information, a homography transformation matrix is calculated;

[0032] The world coordinates of the crack profile are calculated using the homography transformation matrix, and the length and width of the crack are calculated.

[0033] Preferably, the brushless motor holder device comprises:

[0034] The holder bottom plate is fixed inside the mechanical main body;

[0035] The holder circuit board is the control panel of the entire brushless motor holder device, and is fixed to the holder bottom plate. The holder circuit board comprises a communication single-chip microcomputer, a flexible circuit board connector, and a connector connector. The flexible circuit board connector and the connector connector enable the communication single-chip microcomputer to have serial communication capability and communicate and coordinate with the main circuit board and the crack image acquisition device;

[0036] The brushless motor is fixed to the holder circuit board and provides power for adjusting the angle of the crack image acquisition device;

[0037] The crack image acquisition device fixing member is connected to the brushless motor and used for mounting the crack image acquisition device.

[0038] Preferably, the main circuit board comprises:

[0039] The power connector is used to mount a lithium battery to establish power supply;

[0040] The main control single-chip microcomputer is the main control chip of the main circuit board;

[0041] The display screen is used to display robot state information and function debugging;

[0042] The under-voltage protection chip is used to monitor the voltage of the lithium battery in real time;

[0043] The motor drive step-down chip is used to step down the voltage of the battery to drive the circuit of the brushed DC motor and the brushless motor;

[0044] The digital circuit step-down chip is used to step down the voltage of the battery to drive the digital circuit;

[0045] The brush DC motor driving chip is used for receiving information of the master control single chip and adjusting current to meet the demand of the brush DC motor on driving current.

[0046] Preferably, the environment sensing device comprises:

[0047] The linear tracking camera is used for capturing a picture of the advancing direction in real time and transmitting to the master control single chip for image processing.

[0048] The laser ranging modules are installed in front of and on both sides of the mechanical body and are used for sensing the environment around the robot.

[0049] According to the second aspect of the present application, a control method of a track-type robot based on steel bridge deck crack image acquisition is provided, comprising:

[0050] The robot is adsorbed on the cross beam, U rib or top plate;

[0051] The power and transmission device is controlled to drive the robot to move, so that the robot runs to the crack area;

[0052] The brushless motor holder device is controlled to rotate, so that the elevation angle of the crack image acquisition device is adjusted, and the crack image acquisition device is directed to the crack;

[0053] The crack image acquisition device is controlled to acquire crack image and distance information;

[0054] The communication single chip installed in the brushless motor holder device calculates a homography transformation matrix between the imaging plane of the crack image acquisition camera and the plane where the fatigue crack is located, and extracts the geometric features of the crack.

[0055] Preferably, when the robot is running, the linear tracking camera captures a picture of the advancing direction in real time and transmits to the master control single chip;

[0056] The laser ranging modules measure the distance between the robot and the U ribs on both sides in real time and transmit to the master control single chip;

[0057] The main control single-chip receives the picture captured by the linear tracking camera, the distance value measured by the laser ranging module, completes path planning, determines the advancing direction, and finally outputs signals for driving two brush DC motors.

[0058] Compared with the prior art, the embodiment of the present application has at least one of the following beneficial effects:

[0059] The steel bridge deck crack image acquisition crawler robot in the embodiment of the present application does not need to be specially designed for a driving structure, the magnetic attraction force is uniformly distributed on each track, and only needs to be redistributed to the target wall surface through rotation of the track, thereby achieving smooth movement on the steel bridge deck, enabling the robot to realize crossing between any planes, completing all-around and dead-angle-free crack image acquisition and accurate crack size measurement, and transmitting the crack image to a remote terminal in real time through the brushless motor holder device.

[0060] The steel bridge deck crack image acquisition crawler robot in the embodiment of the present application realizes mutual crossing between main bodies of the steel bridge deck structure by controlling the brush DC motor to rotate, and adopting the permanent magnetic attraction track to walk on the top plate, the cross beam and the U rib of the steel bridge deck.

[0061] The steel bridge deck crack image acquisition crawler robot in the embodiment of the present application can adjust the free rotation of the crack image acquisition device by controlling the brushless motor holder to rotate, realizes all-around and dead-angle-free crack image acquisition and accurate crack size measurement of the steel bridge deck, meets the fatigue crack detection requirement of the in-service orthotropic steel bridge deck in the actual engineering, and can be applied to the actual engineering. BRIEF DESCRIPTION OF DRAWINGS

[0062] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0063] Figure 1 It is a robot overall design drawing of an embodiment of the present application;

[0064] Figure 2 It is a crack image acquisition device drawing of a preferred embodiment of the present application;

[0065] Figure 3 It is a brushless motor holder device drawing of a preferred embodiment of the present application;

[0066] Figure 4 It is a robot main circuit board drawing of a preferred embodiment of the present application;

[0067] Figure 5 It is a steel bridge deck cross beam crack acquisition drawing of a preferred embodiment of the present application;

[0068] Figure 6A steel bridge deck U rib crack collection diagram of a preferred embodiment of the present application;

[0069] Figure 7 A steel bridge deck top plate crack collection diagram of a preferred embodiment of the present application.

[0070] In the figure: 1 - bending sheet metal parts; 2 - side plate; 3 - aluminum profile; 4 - driving wheel; 5 - driven wheel; 6 - bearing; 7 - track; 8 - permanent magnet; 9 - light supplement lamp; 10 - straight line tracking camera; 11 - laser ranging module; 12 - brushless motor holder device; 13 - robot main circuit board; 14 - crack image acquisition device; 15 - brush DC motor; 16 - holder bottom plate; 17 - fixed column; 18 - communication single-chip microcomputer; 19 - flexible circuit board connector; 20 - connector connector; 21 - brushless motor; 22 - crack image acquisition device fixing part; 23 - crack image acquisition camera; 24 - master control single-chip microcomputer; 25 - motor drive step-down chip; 26 - brush DC motor drive chip; 27 - power connector; 28 - digital circuit step-down chip; 29 - under-voltage protection chip; 30 - display screen; 31 - crossbeam; 32 - U rib; 33 - top plate. DETAILED DESCRIPTION

[0071] The present application will be described in detail below with specific embodiments. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made. These all belong to the protection scope of the present application.

[0072] In an embodiment of the present application, a steel bridge deck crack image acquisition crawler robot is provided, as shown in the figure, comprising: Figure 1 The mechanical body is a cavity structure with a magnetic track;

[0073] The power and transmission device is connected with the mechanical body, and drives the robot to complete the forward, backward or leapfrog action;

[0074] The crack image acquisition device is arranged outside the mechanical body, and acquires crack image information and distance information. The distance information refers to the distance between the camera imaging plane and the crack plane.

[0075]

[0076] ​The brushless motor holder device is installed inside the mechanical body, adjusts the angle of the crack image acquisition device, and obtains the homographic transformation matrix between the camera imaging plane and the physical plane where the fatigue crack is located based on the crack image information and the distance information. The homographic transformation matrix describes the transformation relationship between the object point in the world coordinate system and the image point in the pixel coordinate system. For a certain point in the crack image, the world coordinate can be obtained by multiplying the pixel coordinate by the homographic transformation matrix.

[0077] The environment sensing device is arranged outside the mechanical body and acquires the environment information in the movement process of the robot.

[0078] The main circuit board is arranged inside the mechanical body and communicates with the crack image acquisition device, the brushless motor holder device and the environment sensing device to realize the cooperative control and movement of the whole robot.

[0079] In an embodiment of the present application, the preferred structure of the mechanical body is provided. Specifically, the mechanical body includes a bent sheet metal part 1, a side plate 2, an aluminum profile 3, a track 7 and a permanent magnet 8.

[0080] The bent sheet metal part 1 is bolted to the aluminum profile 3, and the aluminum profile 3 is bolted to the side plates 2 on both sides. The track 7 surrounds the outer periphery of the side plate 2, and the permanent magnets 8 are evenly distributed on the track 7, so that the track 7 can be adsorbed on the U-rib, beam and top plate, and the linear walking, turning around or steering can be realized through the driving of the power and transmission device.

[0081] In some specific embodiments, the bent sheet metal part 1 is a part formed by cutting, folding and bending a metal plate. Here, the bent sheet metal part 1 is combined together to form a containing cavity for placing the brushless motor holder device. The bent sheet metal part 1 is specifically bent into an inverted V-shaped structure and bolted to the aluminum profile 3 at the end of the V-shaped structure. The side plate 2 is designed as a regular triangular structure. The three (the bent sheet metal part 1, the aluminum profile 3 and the side plate 2) are assembled together to form a cavity structure with a triangular cross section. The track 7 surrounds the outer periphery of the side plate 2 and also presents a triangular structure. In addition, two rings of permanent magnets 8 are embedded on the track 7, which enables the track to be adsorbed on the U-rib 32, beam 31 and top plate 33. Through the differential driving of the motor, the structure can realize the functions of linear walking, turning around and steering.

[0082] In the above embodiment, the robot is carefully designed as a triangular body, which is unique in that all three sides have the ability to be adsorbed on the steel plate. No matter which side is chosen as the adsorption surface, the robot can stably walk and cross, which gives the robot high flexibility, especially suitable for operation in narrow spaces, significantly improving its applicability and practicality.

[0083] In the above embodiment, the mechanical body part adopts a full-coverage track design. When the mechanical body is inside the robot, the robot can ensure that its three sides can be firmly adsorbed on the steel plate. In addition, the full-coverage track design not only ensures the stability of the robot, but also provides effective protection for the internal devices of the robot during the climbing process.

[0084] In a preferred embodiment of the present application, a preferred structure of the power and transmission device is provided. The power and transmission device is a set, which is respectively installed on both sides of the mechanical body. Specifically, each power and transmission device includes a driving wheel 4, a driven wheel 5, a bearing 6 and a brush DC motor 15. The driving wheel 4 is arranged at a corner of the side plate 2 and engages with the track 7; the brush DC motor 15 is installed inside each side plate 2, and the brush DC motor 15 is connected with the driving wheel 4 and provides a rotating torque for the driving wheel 4; the driven wheel 5 is arranged at the remaining two corners of the side plate through the bearing 6 and also engages with the track 7.

[0085] The power and transmission device of the above embodiment can effectively redistribute the magnetic force to the target wall surface by only providing a rotating torque through the brush DC motor to drive the track to rotate, thereby achieving smooth movement on the steel bridge plate.

[0086] In a preferred embodiment of the present application, a preferred structure of the crack image acquisition device is provided. Specifically, as shown in Figure 2 the crack image acquisition device includes a base, a laser ranging module 11, a crack image acquisition camera 23 and a fill light 9. The base is connected with the brushless motor holder device; a plurality of laser ranging modules 11 and fill lights 9 are welded on the surface of the base; and the crack image acquisition camera 23 is glued to the center of the base. Among them, the laser ranging module 11 collects distance information, thereby obtaining the extrinsic parameters of each crack image, and then extracting the geometric features of the crack; and the crack image acquisition camera 23 collects crack image information.

[0087] In a preferred embodiment, the process of obtaining geometric features is as follows: the crack image acquisition camera shoots a crack picture to obtain crack image information; a plurality of laser ranging modules work in turn to measure crack distance information; based on the image information and the distance information, a homography transformation matrix is calculated; and the world coordinates of the crack contour are calculated by using the homography transformation matrix, and the length and width of the crack are calculated.

[0088] In a preferred embodiment of the present application, a preferred structure of the brushless motor holder device is provided. Specifically, as shown in Figure 3 the brushless motor holder device includes a holder bottom plate 16, a holder circuit board, a brushless motor 21 and a crack image acquisition device fixing part 22.

[0089] The gimbal base plate 16 is the integrated basis of the entire brushless motor gimbal device, which is fixed in the mechanical body, such as bolted to the aluminum profile 3, so that the entire brushless motor gimbal device is installed in the mechanical body. The gimbal circuit board is the control panel of the entire brushless motor gimbal device, which is fixed to the gimbal base plate. The brushless motor 21 is fixed to the gimbal circuit board, which provides power for adjusting the angle of the crack image acquisition device; the crack image acquisition device fixing member 22 is connected to the brushless motor for mounting the crack image acquisition device.

[0090] In some embodiments, the gimbal circuit board is installed on the gimbal base plate 16 through the fixing column 17, and the brushless motor is installed on the gimbal circuit board through the fixing column 17. The crack image acquisition device fixing member 22 is bolted to the brushless motor.

[0091] In some embodiments, the gimbal circuit board includes a communication single-chip microcomputer 18, a flexible circuit board connector 19 and a connector 20; so that the communication single-chip microcomputer 18 has serial communication capability and can communicate and coordinate with the robot main circuit board 13 and the crack image acquisition device 14.

[0092] In some embodiments, the crack image acquisition device fixing member 22 includes a disc base and a connecting rod extending to both sides, the connecting rod extends to the outside of the side plate and is connected with the base of the crack image acquisition device. The crack image acquisition device 14 is installed on the crack image acquisition device fixing member 22 through 4 M3 screws, and the crack image acquisition device fixing member 22 is installed on the brushless motor 21 through 4 M2.5 screws. See the attached Figure 3 The brushless motor 21 drives the crack image acquisition device fixing member to rotate synchronously, thereby changing the pitch angle of the crack image acquisition device.

[0093] Because the actual working environment of the robot is complex, there may be obstacles on the forward route, so the robot needs to collect environmental information and then plan the forward route. In a preferred embodiment of the present application, a preferred structure of the environment sensing device is provided. Specifically, the environment sensing device includes a straight line tracking camera 10 and a laser ranging module 11. Both are installed on the bent sheet metal part 1. During the entire robot movement, the straight line tracking camera has the following functions:

[0094] A high-definition camera is installed in front of the robot to capture real-time images in the forward direction to prevent the robot from deviating from the predetermined route; the main control single-chip microcomputer needs to process the images captured by the tracking camera in real time and perform complex calculations to determine the deviation angle of the travel path; based on the deflection angle, the power percentage that the two motors should output is calculated to accurately control the forward route of the robot.

[0095] The function of the laser ranging module is as follows:

[0096] Laser ranging modules are installed at the front and sides of the robot to sense obstacles in front of and to the sides. The front laser ranging module continuously measures whether there are obstacles in front of the robot. If there are obstacles, the robot will stop crawling automatically. The side laser ranging modules continuously measure the distance between the robot and the U-ribs on both sides to determine whether the robot is running correctly on the predetermined route. If the robot deviates from the predetermined route, the main control microcontroller will perform route correction based on the data measured by the laser ranging modules.

[0097] The environmental sensing device in the above embodiments helps the robot collect environmental information, thereby planning its route and enabling automatic crawling between the U-ribs.

[0098] In a preferred embodiment of the present invention, a preferred structure for the main circuit board 3 is provided. Specifically, as shown... Figure 4 As shown, the robot's main circuit board 13 is bolted to the bent sheet metal part 1. It mainly includes a main control microcontroller 24, a motor drive step-down chip 25, a brushed DC motor drive chip 26, a power connector 27, a digital circuit step-down chip 28, an undervoltage protection chip 29, and a display screen 30.

[0099] like Figure 4 As shown, in the main circuit structure of the robot, the lithium battery provides power to the robot through the power connector; the connector 20 enables the robot's main circuit board 13 to communicate with the brushless motor gimbal device 12 and the crack image acquisition device 14 via the serial port protocol; the motor drive step-down chip 25 stabilizes the battery voltage to 12V for driving the brushed DC motor 15 and the brushless motor 21; the digital circuit step-down chip 28 stabilizes the battery voltage to 5V for driving the digital circuit; the brushed DC motor drive chip 26 receives the pulse width modulation signal from the main control microcontroller and drives the brushed DC motor 5 to work at different speeds; the undervoltage protection chip 29 compares the battery voltage with the reference voltage to prevent the battery from being over-discharged; the main control microcontroller 24 is the robot's central system, responsible for driving the robot to complete various maneuvers, receiving remote control signals, calculating the tracking route, and controlling the operation of the subsequent circuits; the display screen 30 can display the robot's status information and can also be used for function debugging.

[0100] Based on the same inventive concept, in other embodiments of the present invention, a control method for a tracked robot for acquiring images of cracks in steel bridge decks is provided, the specific steps of which are as follows:

[0101] S100, the robot attaches to the beam, U-rib or top plate;

[0102] S200, the power and transmission device drives the robot to move to the crack area;

[0103] S300, control the brushless motor holder device to rotate, adjust the elevation angle of the crack image acquisition device, so that the crack image acquisition device is directly opposite the crack;

[0104] S400, control the crack image acquisition device to collect crack image and distance information;

[0105] S500, the brushless motor holder device calculates the homography transformation matrix between the imaging plane of the crack image acquisition camera and the plane where the fatigue crack is located, and obtains the geometric information of the crack.

[0106] Further, in a specific embodiment, as shown in Figure 5 , the robot first detects the crack on the cross beam 31, controls and drives the caterpillar tracks 7 on both sides of the robot to move, so that the robot runs to the crack area; control the brushless motor holder device 12 to rotate, adjust the elevation angle of the crack image acquisition device 14, so that the image acquisition device 14 is directly opposite the crack on the cross beam 31; control the crack image acquisition camera 23 to collect crack pictures and save them to the internal storage card of the robot; control the laser ranging module 11 to collect laser ranging values, and the communication single-chip microcomputer 18 will operate the laser ranging values, calculate the homography transformation matrix between the imaging plane of the crack image acquisition camera 23 and the plane where the fatigue crack is located, and save the parameters on the internal storage card of the robot.

[0107] As shown in Figure 6 , Figure 7 , the robot secondly detects the crack on the U rib 32 or the top plate 33, controls the robot to move to the junction of the cross beam 31 and the top plate 33, so that the advancing direction of the robot is perpendicular to the U rib 32 or the top plate 33, continues to drive the robot to advance, the robot will shift and adsorb on the surface of the U rib 32 or the top plate 33, and continue to drive the robot to advance to the crack area; control the brushless motor holder device 12 to rotate, adjust the elevation angle of the crack image acquisition device 14, ensure that the image acquisition device 14 can be directly opposite the crack on the U rib 32 or the top plate 33; control the crack image acquisition camera 23 to collect crack pictures and save these pictures to the internal storage card of the robot; control the laser ranging module 11 to collect laser ranging values. The communication single-chip microcomputer 18 will operate these laser ranging values, calculate the homography transformation matrix between the imaging plane of the crack image acquisition camera 23 and the plane where the fatigue crack is located, and save the matrix to the internal storage card of the robot.

[0108] The communication single-chip microcomputer accurately calculates the homography transformation matrix, which is based on the detailed information of the image pixel points and can accurately map the coordinate position of the crack in the real world, and then extract the key geometric information such as the length and width of the crack.

[0109] In the overall operation process of the robot, the components between each other show high synergy and precise control. Specifically:

[0110] For the adjustment of the elevation angle, precise rotation signals are sent to the brushless motor by the main circuit board.

[0111] At the same time, when the robot is running, the environment sensing device will continuously and real-time collect environmental data. For example, the straight line tracking camera can capture the picture of the forward direction in real time, and transmit these picture data to the main control single-chip microcomputer. The laser ranging module continuously measures the distance between the robot and the two side U ribs, and sends these distance data to the main control single-chip microcomputer in real time. After receiving the picture captured by the straight line tracking camera and the distance value measured by the laser ranging module, the main control single-chip microcomputer will make accurate path planning, determine the best travel direction, and finally output the control signal to drive the two brush DC motors to run according to the planned path.

[0112] The specific embodiments of the application are described above. It should be understood that the application is not limited to the specific implementation described above, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the application. The above preferred features can be used in combination as long as they do not conflict with each other.

Claims

1. A tracked robot for acquiring images of cracks in steel bridge decks, characterized in that, include: The mechanical body is a hollow structure with magnetic tracks; A power and transmission device, which is connected to the main mechanical body, drives the robot to perform forward, backward, or vaulting actions; A crack image acquisition device is disposed outside the mechanical body to acquire crack image information and distance information; A brushless motor gimbal device is installed inside the mechanical body to adjust the angle of the crack image acquisition device, and based on the crack image information and distance information, obtain the homography transformation matrix between the camera imaging plane and the physical plane where the fatigue crack is located, and extract the geometric features of the crack. An environmental sensing device is installed outside the mechanical body to collect environmental information during the robot's movement. The main circuit board is located inside the mechanical body and communicates with the crack image acquisition device, the brushless motor gimbal device and the environmental sensing device to realize the overall coordinated control and movement of the robot. The number of crack image acquisition devices is two, respectively installed on both sides of the mechanical body. Each crack image acquisition device includes: The base is connected to the brushless motor gimbal device; A crack image acquisition camera is mounted on the base to acquire crack image information; A laser ranging module, wherein multiple laser ranging modules are mounted on the base, for collecting distance information; At least one of the fill lights is mounted on the base to provide a light source for shooting. Based on the crack image information and distance information, the homography transformation matrix between the camera imaging plane and the physical plane where the fatigue crack is located is obtained, and the geometric features of the crack are extracted, including: A crack image acquisition camera captures a crack image to obtain crack image information; Multiple laser ranging modules operate sequentially to measure crack distance information; Based on the image information and the distance information, calculate the homography transformation matrix; The world coordinates of the crack profile are calculated using the homography transformation matrix, and the length and width of the crack are calculated. The environmental sensing device includes: A linear tracking camera captures images of the forward direction in real time and transmits them to the main control microcontroller for image processing. The image processing includes calculating the offset angle of the forward path to obtain the percentage of power output by the brushed DC motor, and precisely controlling the robot's forward path. The brushed DC motor is used to provide rotational torque to the drive wheel of the track. Multiple laser ranging modules are installed at the front and sides of the mechanical body to sense the robot's surrounding environment. The laser ranging module at the front continuously measures whether there are obstacles in front of it, and when an obstacle is present... The robot stops moving forward; the laser ranging modules located on both sides will continuously measure the distance between the robot and the U-ribs on both sides to determine whether the robot is running correctly on the predetermined route. If the robot deviates from the predetermined route, the main control microcontroller will perform route correction based on the data measured by the laser ranging modules.

2. The tracked robot for acquiring images of steel bridge deck cracks according to claim 1, characterized in that, The mechanical body includes: A bent sheet metal part, two of which are joined together to form a cavity; the brushless motor gimbal device is installed inside the cavity. An aluminum profile, which is connected to the bottom of the sheet metal part; Side plates, both of which are equilateral triangles, are respectively connected to both sides of the bent sheet metal part; The track, which wraps around the outer periphery of the side plate, has an overall triangular structure; Permanent magnets are evenly distributed on the track, enabling the track to adhere to the U-ribs, crossbeams, and top plate, and to achieve straight-line movement, turning, or steering through a power and transmission device.

3. The tracked robot for acquiring images of steel bridge deck cracks according to claim 2, characterized in that, There are two power and transmission devices, respectively installed on both sides of the mechanical body; each power and transmission device includes: A drive wheel is located at one corner of the side plate and engages with the track. A brushed DC motor is disposed inside the side plate, and is connected to the drive wheel to provide rotational torque. Driven wheels are located at the remaining two corners of each of the side plates and engage with the tracks.

4. The tracked robot for acquiring images of steel bridge deck cracks according to claim 1, characterized in that, The brushless motor gimbal device includes: A gimbal base plate, which is fixed inside the mechanical body; The gimbal circuit board is the control panel of the entire brushless motor gimbal device and is fixed to the gimbal base plate. The gimbal circuit board includes a communication microcontroller, a flexible circuit board connector, and a plug connector. The flexible circuit board connector and the plug connector enable the communication microcontroller to have serial communication capability and communicate and coordinate with the main circuit board and the crack image acquisition device. A brushless motor, fixed to the gimbal circuit board, provides power for the crack image acquisition device to adjust its angle. A crack image acquisition device mounting bracket is provided, which is connected to the brushless motor and is used to mount the crack image acquisition device.

5. The tracked robot for acquiring images of cracks in steel bridge decks according to claim 1, characterized in that, The main circuit board includes: A power connector for mounting a lithium battery to establish power supply; The main control microcontroller is the main control chip of the main circuit board. A display screen is used to display robot status information and perform function debugging. An undervoltage protection chip is used to monitor the lithium battery voltage in real time. A motor drive step-down chip, which is used in circuits to step down the battery voltage to drive brushed DC motors and brushless motors; A digital circuit step-down chip, wherein the digital circuit step-down chip is used to step down the battery voltage to drive digital circuits; The brushed DC motor driver chip is used to receive information from the main control microcontroller and adjust the current to meet the drive current requirements of the brushed DC motor.

6. A control method for a tracked robot for acquiring images of steel bridge deck cracks according to any one of claims 1-5, characterized in that, The robot is attached to a beam, U-rib, or top plate. The control power and transmission device drives the robot to move and move the robot to the crack area; Control the rotation of the brushless motor gimbal device to adjust the elevation angle of the crack image acquisition device so that the crack image acquisition device is directly facing the crack; The crack image acquisition device is controlled to acquire crack images and distance information; The communication microcontroller installed on the brushless motor gimbal device calculates the homography transformation matrix between the imaging plane of the crack image acquisition camera and the plane where the fatigue crack is located, and extracts the geometric features of the crack.

7. The control method for a tracked robot for acquiring images of cracks in steel bridge decks according to claim 6, characterized in that, During robot operation, the linear tracking camera captures images of the forward direction in real time and transmits them to the main control microcontroller; The laser ranging module will measure the distance between the robot and the two U-ribs in real time and transmit it to the main control microcontroller; The main control microcontroller receives the images captured by the linear tracking camera and the distance values ​​measured by the laser ranging module, completes path planning, determines the direction of travel, and finally outputs signals to drive the two brushed DC motors.

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