Crack detection robot for box girder and detection method

Abstract

The invention relates to a box girder crack detection robot and a detection method, and belongs to the technical field of robot visual inspection, the box girder crack detection robot comprises a remote control car, magnetic suction devices are arranged at the front end and the rear end of a car chassis, the first magnetic suction device is located at the front end of the car chassis, and the second magnetic suction device is located at the rear end of the car chassis; the magnetic attraction device comprises a base, a movable shaft, a driven gear, a connecting rod, a magnetic attraction plate, a control motor and a driving gear; a first angle measuring device and a second angle measuring device are arranged on the remote control car, and the control terminal can control the control motors of the first magnetic attraction device and the second magnetic attraction device to rotate according to the angles monitored by the first angle measuring device and the second angle measuring device; a visual recognition device used for shooting surface images of the inner cavity of the box girder is fixedly installed on the upper surface of the chassis. According to the robot and the detection method, cracks on the surface of the inner cavity of the box girder can be detected, the angle of the magnetic suction plate can be changed, and the magnetic suction force with the surface of the cavity of the box girder is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of robot vision detection, and in particular relates to a crack detection robot and a detection method for a box girder. Background Art

[0002] Box girder is a commonly used structural form in bridge engineering. Common box girder types include prestressed reinforced concrete box girder and steel box girder.

[0003] The steel box girder is mainly composed of a top plate, two web plates and a bottom plate. The top plate, two web plates and the bottom plate form a box girder cavity. In general, the surface of the box girder cavity is regarded as the inner surface of the box girder, and the surface outside the box girder cavity is regarded as the outer surface of the box girder.

[0004] For steel box girders, a full surface inspection is required before they are put into use to check for cracks, damage and corrosion.

[0005] The meaning of full surface inspection is to inspect both the inner and outer surfaces of the box girder. The meaning of surface inspection is to observe whether there are cracks on the surface of the steel box girder by human eyes.

[0006] Since the outer space of the box girder is large and can be convenient for inspectors to stand, it is more convenient for inspectors to conduct surface inspection on the outer surface of the box girder, and the inspectors will not be constrained by space. However, the cavity size of the box girder is generally small. For steel box girders with a span of less than 40m, the height of the box girder cavity is less than 1.8m, which makes it difficult for inspectors to stand upright and enter the box girder cavity; for steel box girders with a span of less than 30m, the height of the box girder cavity is even less than 1.2m, which makes it impossible for inspectors to enter the box girder cavity. Therefore, it is not convenient to inspect the cavity surface of the box girder. It is necessary to design a crack detection robot and detection method for the box girder, which can perform surface inspection on the cavity surface of the box girder. Summary of the invention

[0007] A crack detection robot and detection method for a box girder of the present invention can perform surface detection on the cavity surface of a steel box girder without the need for detection personnel to enter the steel box girder.

[0008] A crack detection robot for a box beam of the present invention comprises a remote control vehicle, wherein the forward direction of the remote control vehicle is set along the X direction; the remote control vehicle comprises a vehicle chassis, front wheels and rear wheels, wherein the drive shaft axes of the front wheels and the rear wheels are set along the Y direction, the X direction is perpendicular to the Y direction, and magnetic suction devices are arranged at the front end and the rear end of the vehicle chassis, wherein the magnetic suction device is located at the front end of the vehicle chassis as a first magnetic suction device, and the magnetic suction device is located at the rear end of the vehicle chassis as a second magnetic suction device, and the magnetic suction device is located at the lower surface of the vehicle chassis; The magnetic device includes: A base, fixed to the lower surface of the vehicle chassis; The movable shaft is rotatably connected to the base and can rotate relative to the base around its own axis, and the axis of the movable shaft is along the Y direction; A driven gear is fixedly connected to the movable shaft, and the axis of the driven gear coincides with the axis of the driven gear; A connecting rod, one end of which is fixed on the side of the movable shaft, and the axis is arranged along the radial direction of the movable shaft; The magnetic plate is a permanent magnet connected to the other end of the connecting rod; The control motor is a servo motor, used to rotate the movable shaft; the control motor is electrically connected to the control terminal; The driving gear is fixed to the rotating shaft of the control motor, and the axis of the driving gear coincides with the axis of the control motor; the driving gear meshes with the driven gear; The remote control car is provided with a first angle measuring device and a second angle measuring device, both of which are electrically connected to the control terminal, and the control terminal can control the rotation of the control motors of the first magnetic attraction device and the second magnetic attraction device according to the angles monitored by the first angle measuring device and the second angle measuring device; A visual recognition device for capturing images of the inner surface of the box beam is fixedly installed on the upper surface of the vehicle chassis.

[0009] Further, the first angle measuring device includes three laser rangefinders, and the laser emission points of the three laser rangefinders of the first angle measuring device are respectively point 1, point 2, and point 3, and the laser emission directions of the three laser rangefinders of the first angle measuring device are along the X direction and facing forward; the plane formed by point 1, point 2, and point 3 is assumed to be plane Q, the X direction is perpendicular to the plane Q, and when observed in the X direction, point 1, point 2, and point 3 are not collinear; The second angle measuring device also includes three laser rangefinders. The laser emission points of the three laser rangefinders of the second angle measuring device are respectively point four, point five, and point six. The laser emission directions of the three laser rangefinders of the second angle measuring device are perpendicular to the vehicle floor and face downward. The plane formed by point four, point five, and point six is ​​assumed to be plane M. Plane M is parallel to the plane where the vehicle floor is located. When observed from a perspective perpendicular to plane M, point four, point five, and point six are not collinear. The first angle measuring device and the second angle measuring device are both electrically connected to the control terminal.

[0010] Furthermore, the visual recognition device comprises: A first rotating motor, the non-rotating shaft end of which is fixed on the upper surface of the vehicle chassis; the rotating shaft of the first rotating motor is perpendicular to the plane where the vehicle chassis is located; and the first rotating motor is electrically connected to the control terminal; A mounting plate fixed on the rotating shaft of the first rotating motor; Two brackets, fixed on the upper surface of the mounting plate; The mounting shaft is rotatably connected to the two brackets, and the axis of the mounting shaft is parallel to the plane where the chassis is located; A second rotating motor, used to rotate the mounting shaft; and electrically connected to the control terminal; Camera, mounted on the mounting shaft.

[0011] Furthermore, the two laser rangefinders corresponding to point one and point two are at the same height.

[0012] The two laser rangefinders corresponding to point one and point two are at the same height. The control terminal can make the two laser rangefinders corresponding to point one and point two at the same height, indicating that the robot's forward direction X direction is parallel to the end face of the box beam.

[0013] Furthermore, a lighting system is installed on the vehicle chassis, and the lighting system is electrically connected to the control terminal, and the control terminal can control the lighting system to change the brightness.

[0014] The lighting system can provide light. When the visual recognition device takes an image, the image will not be too dark due to the presence of the lighting system, which is more conducive to identifying cracks.

[0015] Furthermore, a box girder crack detection method, based on the box girder crack detection robot according to claim 4, comprises the following steps: S1: Adaptation orientation; The specific steps include: S1.1: The operator places the robot on one of the surfaces of the box beam cavity from one end of the box beam, ensuring that the front and rear wheels of the robot are simultaneously placed on one of the surfaces of the box beam cavity; and ensuring that the front of the robot faces the other surface of the box beam cavity; S1.2: After the operator turns on the robot, the control terminal controls the three laser rangefinders of the first angle measuring device to emit lasers once. The lasers of the three laser rangefinders irradiate the other surface in step S1.1 and then reflect. The three laser rangefinders respectively measure the distance of the other surface, and the control terminal obtains the distance monitored by the three laser rangefinders. S1.3: Determine whether the distances between the two laser rangefinders at the same height in the first angle measuring device are equal, and determine whether the adaptation orientation is completed; S1.3.1: If the distances between the two laser rangefinders at the same height in the first angle measuring device are not equal and the adaptation orientation is not completed, the control terminal controls the robot to adjust the direction accordingly. The meaning of adjusting the direction is: the control terminal controls the robot to rotate along the plane where the chassis is located; repeat step S1.3.1, the control terminal continuously controls the three laser rangefinders in the first angle measuring device to emit lasers and measure the distance of another surface until the distances between the two laser rangefinders at the same height are equal, the adaptation orientation is completed, and the robot no longer rotates along the plane where the chassis is located; S1.3.2: If the distances between the two laser rangefinders at the same height are equal, the adaptation is complete and the robot no longer rotates along the plane of the chassis; S2: Adaptation angle between the first magnetic device and the second magnetic device; The specific steps include: S2.1: Determine the angle α between the plane where the chassis is located and another surface in front; After the orientation adaptation is completed, the control terminal continuously controls the three laser rangefinders of the first angle measuring device to emit lasers multiple times at a designed frequency. Each time the three lasers are irradiated to another surface and then reflected, the first magnetic device calculates the angle α between the other surface in front of the robot and the robot chassis according to the distance monitored by the three laser rangefinders. In this laser emission, the distances of the other surface in front monitored by the three laser rangefinders are H1, H2 and H3 respectively, where H1=H2. S2.2: Determine the angle β between the plane of the chassis and the surface on which the rear wheels come into contact; The control terminal continuously controls the three laser rangefinders of the second magnetic device to emit lasers multiple times at a designed frequency. Each time the three lasers are irradiated to the surface that the rear wheel contacts and then reflected, the second magnetic device calculates the angle β between the plane where the chassis is located and the surface that the rear wheel contacts based on the distance monitored by the three laser rangefinders. If the surface that the rear wheel contacts is parallel to the surface of the chassis, the angle β=0. S2.3: Calculate the angle of the second magnetic device; determine the state of the first magnetic device and determine the angle of the first magnetic device; The specific steps include: S2.3.1: Calculate the angle of the second magnetic device; looking from the Y direction, let the end of the magnetic plate in the second magnetic device away from the active axis be A', the point where the active axis 9 is located be O', draw a ray parallel to the chassis from O' to the rear of the chassis, and let a point on the ray be B', then ∠A'O'B'=90-β; S2.3.2: Observe in the Y direction, assume that the end of the magnetic plate in the first magnetic device away from the movable axis is point A, the point where the movable axis is located is point O, and a ray is drawn from point O to the forward direction, and a point on the ray is point B; if H1, H2 and H3 are all greater than or equal to the set threshold R, the front end of the robot is far away from the other surface, and the first magnetic device and the second magnetic device maintain the same angle, that is; ∠AOB=∠A'O'B'=90-β; S2.3.3: If any one of H1, H2 and H3 is less than the threshold R, the front end of the robot is close to the other surface, then ∠AOB = 90-α; S3: The operator controls the robot to move forward a distance D and then stop through the control terminal. During the moving process, the control terminal executes S2, and the control terminal controls the first magnetic attraction device and the second magnetic attraction device to adapt to the angle through the method in S2; S4: After the robot stops, the operator rotates the first rotary motor and the second rotary motor in the visual recognition device through the control terminal respectively, and the camera automatically focuses and takes an image of the box beam surface. The visual recognition device identifies cracks through image recognition technology. If cracks are identified, the visual recognition device sends the information to the control terminal; the display connected to the control terminal displays the cracks; S5: Repeat S3-S4 until the robot moves one circle along the end face of the box girder; because the distance of one circle of the end face of the box girder is a known quantity, the operator can determine whether the robot has completed one circle according to the distance D of each walk of the robot multiplied by the number of walks, until the robot moves one circle along the end face of the box girder, the operator no longer moves the robot in the forward direction, and the visual recognition device captures an image of one circle of the end face of the box girder; S6: The operator sends a lateral movement command to the robot through the control terminal, and the control terminal causes the robot to lateral move a distance N in the direction perpendicular to the end face of the box beam and then stop; the robot continues to move around the inner cavity of the box beam once again, and takes images of the inner cavity of the box beam in a circle in the manner of steps S3 and S4; S7: Repeat S6 until the robot moves out from the other end of the box beam and completely inspects the entire surface of the inner cavity of the box beam.

[0016] Beneficial Effects

[0017] This robot can move on the inner surface of the box beam, and when the front wheels and the rear wheels are respectively on different surfaces of the inner surface of the box beam, the two magnetic suction devices can respectively control the angles through the control terminal, so that the two magnetic suction devices are respectively magnetically attracted to the corresponding inner surfaces of the box beam, so that the magnetic suction plate is as close to the inner surface of the box beam as possible to ensure sufficient magnetic suction force. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of the robot; Figure 2 This is a top view of the robot chassis and wheels; Figure 3 It is a structural schematic diagram of a magnetic attraction device; Figure 4 It is a schematic diagram of the structure of a visual recognition device; Figure 5 It is a schematic diagram of the position of the robot when it is on two adjacent surfaces of the cross frame box beam; Figure 6 is a distribution position diagram of three laser rangefinders of the first angle measuring device; Figure 7This is a schematic diagram of the robot being placed on the bottom plate of the box beam; Figure 8 This is a schematic diagram of the angle between the first magnetic attraction device of the robot and the front plane; Fig. 9 It is a schematic diagram of the angle of the plane where the second magnetic attraction device of the robot abuts against the rear wheel.

[0019] 1. Chassis; 2. First magnetic device; 3. Second magnetic device; 4. First angle measuring device; 5. Second angle measuring device; 6. Visual recognition device; 7. Lighting system; 8. Base; 9. Active shaft; 10. Driven gear; 11. Connecting rod; 12. Magnetic plate; 13. Control motor; 14. Driving gear; 15. First rotating motor; 16. Mounting plate; 17. Bracket; 18. Mounting shaft; 19. Camera; DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0021] See Figure 1 A crack detection robot for a box girder includes a remote control car, which is connected to a control terminal by wire. An operator sends a movement signal to the remote control car through the control terminal, and manually controls the remote control car to move forward or sideways.

[0022] See Figure 2 The remote control car belongs to the prior art. The remote control car includes a chassis 1, two front wheels and two rear wheels. Both the front wheels and the rear wheels use Mecanum wheels. Assume that the remote control car of this embodiment is placed on a horizontal plane, the chassis 1 is a rectangular plate, and the chassis 1 is rectangular in a top view. The direction of the drive shaft of the front wheel or the rear wheel of the remote control car is set as the Y direction, and one of the sides of the chassis 1 is parallel to the Y direction; the direction perpendicular to the Y direction is set as the X direction, and the positive direction of the X direction is set as the aforementioned forward direction, that is, Figure 1 The left side is the front, and the negative direction is the back, that is, Figure 1 The middle right is the back. Figure 1 The direction inwards of the paper is the positive direction of the Y direction, that is, the aforementioned lateral movement direction.

[0023] From the top view, let the point on the front end of the front wheel be point P1, let the point on the front end of the chassis 1 be point P2, and point P1 is located in front of point P2. Similarly, let the point on the rear end of the rear wheel be point m1, let the point on the rear end of the chassis 1 be point m2, and point m1 is located behind point m2. The use of this design is that when the remote control car moves forward along the X direction, and the front and rear wheels of the remote control car are respectively on the two adjacent surfaces of the box beam cavity, that is, Figure 5 When the front and rear ends of the vehicle chassis 1 are not in contact with the movement of the remote control vehicle, it can be ensured that the front wheels and rear wheels of the remote control vehicle are always in contact with the surface of the box beam cavity, and the front and rear ends of the non-vehicle chassis 1 are in contact with the surface of the box beam cavity.

[0024] Two magnetic devices are installed on the lower surface of the vehicle chassis 1. The magnetic devices are used to maintain magnetic attraction between the remote control car and the inner wall of the box beam cavity, thereby ensuring that the remote control car does not fall on the inner wall of the box beam cavity and also meeting the friction required for the movement of the remote control car. The two magnetic devices are respectively arranged on the front end and rear end lower surfaces of the vehicle chassis 1.

[0025] See Figure 3 , the magnetic suction device includes: The base 8 is mounted on the lower surface of the vehicle chassis 1 by means of bolts.

[0026] The movable shaft 9 is passed through the base 8. The base 8 is provided with a hole for the movable shaft 9 to pass through. The axis of the movable shaft 9 is parallel to the axis of the driving shaft of the wheel, that is, the axis of the movable shaft 9 is along the Y direction. The movable shaft 9 is rotatably connected to the base 8 by means of a bearing, and the movable shaft 9 can rotate relative to the base 8 around its own axis.

[0027] The driven gear 10 has a circular hole in the middle. The driven gear 10 is sleeved on the movable shaft 9 through the circular hole. The driven gear 10 and the movable shaft 9 are welded and fixed. The axis of the driven gear 10 coincides with the axis of the movable shaft 9.

[0028] One end of the connecting rod 11 is welded and fixed on the side of the movable shaft 9, and the axis of the connecting rod 11 is arranged along the radial direction of the movable shaft 9. When designing the connecting rod 11, ensure that the connecting rod 11 does not interfere with the driven gear 10. In this embodiment, two connecting rods 11 are provided.

[0029] The magnetic attraction plate 12 is a permanent magnet in a plate shape. In this embodiment, the magnetic attraction plate 12 is an artificial permanent magnet, such as a neodymium magnet. The magnetic attraction plate 12 is bonded to the other end of the connecting rod 11 by glue.

[0030] The control motor 13 is installed on the base 8 at the non-rotating shaft end by bolts. The control motor 13 is a small servo motor with a power-off self-locking function, and the servo motor can accurately control the rotation angle under the control signal of the control terminal, so that the magnetic suction plate 12 generates magnetic attraction with the cavity surface of the corresponding box beam at a set angle. The control motor 13 is electrically connected to the control terminal by wire, and the control terminal automatically controls the rotation angle of the control motor 13 according to the corresponding control signal. The two magnetic suction devices are controlled separately by the control terminal, and the two do not interfere with each other.

[0031] The driving gear 14 has a circular hole in the middle. The driving gear 14 is sleeved on the rotating shaft of the control motor 13 by means of the circular hole. The driving gear 14 is welded and fixed to the rotating shaft of the control motor 13. The axis of the driving gear 14 coincides with the axis of the rotating shaft of the control motor 13. The driving gear 14 meshes with the driven gear 10.

[0032] The control motor 13 of the corresponding magnetic attraction device can realize the rotation of the magnetic attraction plate 12. The specific action process is: the control terminal sends a corresponding control signal, the control terminal makes the control motor 13 rotate the corresponding angle, the control motor 13 rotates the driven gear 10 through the driving gear 14, and the driven gear 10, the movable shaft 9, the connecting rod 11, and the magnetic attraction plate 12 rotate relative to the base 8 around the axis of the movable shaft 9 as a whole. Through the above rotation, the magnetic attraction plate 12 can adaptively generate magnetic attraction with the surface corresponding to the box beam cavity, ensuring that the remote control car and the box beam cavity surface have sufficient magnetic attraction. The magnetic attraction plate of this solution does not directly contact and adsorb with the inner cavity surface of the box beam.

[0033] The magnetic device located at the front end of the vehicle chassis 1 is assumed to be the first magnetic device 2, and the other magnetic device located at the rear end of the vehicle chassis 1 is correspondingly the second magnetic device 3. A first angle measuring device 4 is installed on the upper surface of the front end of the vehicle chassis 1, and a second angle measuring device 5 is installed on the lower surface of the rear end of the vehicle chassis 1. The first angle measuring device 4 is electrically connected to the control terminal in a wired manner, and the second angle measuring device 5 is also electrically connected to the control terminal in a wired manner. The control terminal controls the first magnetic device 2 and the second magnetic device 3 to be at corresponding different angles according to the angles monitored by the first angle measuring device 4 and the second angle measuring device 5, respectively.

[0034] See Figure 1 Specifically, the first angle measuring device 4 includes at least three laser rangefinders, all of which are fixedly mounted on the upper surface of the vehicle chassis 1. This embodiment uses three laser rangefinders, and the lasers emitted by the three laser rangefinders of the first angle measuring device 4 are all along the X direction, and the three lasers are all facing the front of the vehicle. The laser emission points of the three laser rangefinders are respectively point one, point two, and point three. The plane formed by point one, point two, and point three is assumed to be surface Q, and the X direction is perpendicular to surface Q. Looking from the X direction, point one, point two, and point three are not collinear. The three laser rangefinders are electrically connected to the control terminal.

[0035] In this embodiment, see Figure 6 , the two laser rangefinders (laser rangefinder 1 and laser rangefinder 2) corresponding to point 1 and point 2 are at the same height, and the height of the two laser rangefinders corresponding to point 3 is higher than the two laser rangefinders corresponding to point 1 and point 2. The purpose of arranging three laser rangefinders in this way is that when the two laser rangefinders corresponding to point 1 and point 2 are set at the same height, it is only necessary to ensure that the distances measured by the laser rangefinders corresponding to point 1 and point 2 are equal, no matter where the remote control car is located, it indicates that the X direction of the remote control car is parallel to the end face of the box beam. If the distances measured by the laser rangefinders corresponding to point 1 and point 2 are not equal, it indicates that the X direction of the remote control car is not parallel to the end face of the box beam, then the control terminal will automatically control the remote control car to turn along the plane where the chassis of the remote control car is located, so that the distances measured by the two corresponding laser rangefinders corresponding to point 1 and point 2 are equal again, so that the X direction of the remote control car is parallel to the end face of the box beam again.

[0036] Similarly, the second angle measuring device 5 also includes at least three laser rangefinders, all of which are fixedly mounted on the lower surface of the vehicle chassis 1. This embodiment uses three laser rangefinders, and the lasers emitted by the three laser rangefinders are perpendicular to the vehicle floor and face downward. The laser emission points of the three laser rangefinders are denoted as point 4, point 5, and point 6. The plane formed by point 4, point 5, and point 6 is denoted as plane M. Plane M is parallel to the plane where the vehicle chassis is located. When observed from a perspective perpendicular to plane M, point 4, point 5, and point 6 are not collinear. The three laser rangefinders are electrically connected to the control terminal.

[0037] Assume that the remote control car has been placed in the above-mentioned manner, that is, the forward direction of the remote control car is parallel to the end face of the box beam. And assume that the front and rear wheels of the remote control car are placed on the same surface of the inner cavity of the box beam at the same time. The position diagram of the remote control car at this time is as follows Figure 7 shown. Figure 7 It is assumed that the front and rear wheels of the remote control car are in contact with the bottom plate surface of the box beam inner cavity. If the bottom plate of the box beam inner cavity is set horizontally, then the chassis of the remote control car is set horizontally. In other cases, the front and rear wheels of the remote control car are in contact with other surfaces of the box beam inner cavity at the same time. For the convenience of expression, this scheme is described as the case where the front and rear wheels of the remote control car are in contact with the bottom plate.

[0038] The three laser rangefinders of the first angle measuring device 4 respectively emit a laser beam forward along the X direction. After the three laser beams are irradiated to the surface of the web in front of the remote control vehicle, part of the laser is reflected back to the corresponding laser rangefinder along the original optical path. The laser rangefinder obtains the distance from the laser emission holes of the three laser rangefinders to the surface of the web according to the time difference between emitting and receiving the laser and multiplying it by the speed of light.

[0039] Assume that the reflection points of the three laser rangefinders on the web are K1, K2 and K3; because the position coordinates of the three laser rangefinders are known, the coordinates of K1, K2 and K3 can be calculated according to the distances from the corresponding laser rangefinders to the web, so the only plane equation 1 can be constructed according to the coordinates of K1, K2 and K3, and this plane equation is the plane equation of the web plane. And because the plane where the chassis is located is a horizontal plane, the horizontal plane can construct a unique plane equation 2, and according to the plane angle formula, the angle between plane equation 1 and plane equation 2 can be calculated, and the angle is α, α∈(0,,90);See Figure 8 , looking at the Y direction, let the end of the magnetic plate 12 in the first magnetic device 2 away from the movable axis 9 be point A; the point where the movable axis 9 is located is point O; draw a ray from point O to the forward direction, and a point on the ray is point B; according to the relationship between the sum of the interior angles of a triangle, ∠AOB=90-α, at this time, the magnetic plate of the first magnetic device 2 is closest to the web.

[0040] Similarly, the second angle measuring device 5 can calculate the plane equation 3 where the bottom plate of the box beam cavity is located. According to the plane angle formula, the angle between the plane equation 3 and the plane equation 2 is calculated. Obviously, when the front and rear wheels of the remote control car are on the same surface of the box beam cavity, that is, Figure 8 In the state, the angle between plane equation three and plane equation two does not exist, and the two are parallel to each other. If plane equation three is parallel to plane equation two, the virtual angle β between the two is regarded as 0 degrees.

[0041] When the front and rear wheels of the remote control car are located on different surfaces of the box beam cavity, that is, Fig. 9 When, in the same manner as described above, the first magnetic device 2 can still calculate the angle α between the front belly plate and the chassis. Similarly, the second magnetic device 3 can also calculate the actual angle β between plane equation three and plane equation two, β∈(0,,90).

[0042] Looking in the Y direction, let the end of the magnetic plate 12 in the second magnetic device 3 away from the movable shaft 9 be end A', the point where the movable shaft 9 is located be point O', and draw a ray parallel to the chassis from point O' to the rear of the chassis, with a point on the ray being B', then ∠A'O'B'=90-β.

[0043] The control terminal adjusts the angles of the two magnetic devices with the plane of the vehicle chassis, ie, ∠AOB=90-α and ∠A'O'B'=90-β, according to the angles α and β monitored by the two corresponding angle measuring devices.

[0044] See Figure 1 and Figure 4A visual recognition device 6 is provided on the upper surface of the vehicle chassis 1. The visual recognition device 6 is used to capture the surface image of the box beam cavity. The visual recognition device 6 can identify cracks on the surface of the box beam cavity by using image recognition technology. If cracks appear, the image of the cracks is sent to the control terminal. The image recognition technology belongs to the prior art.

[0045] The visual recognition device 6 comprises: The non-rotating shaft end of the first rotating motor 15 is installed on the upper surface of the vehicle chassis 1 by bolts, and the rotating shaft of the first rotating motor 15 is perpendicular to the plane where the vehicle chassis 1 is located. The first rotating motor 15 is electrically connected to the control terminal by wire, and the first rotating motor 15 is manually controlled to rotate by a person through the control terminal.

[0046] The mounting plate 16 is welded and fixed on the rotating shaft of the first rotating motor 15 , and can rotate along with the rotating shaft of the first rotating motor 15 .

[0047] Two brackets 17 are welded and fixed on the upper surface of the mounting plate 16 .

[0048] The mounting shaft 18 is simultaneously passed through the two brackets 17. The two brackets 17 are provided with holes for the mounting shaft 18 to pass through. The holes on the two brackets 17 are provided with bearings. The mounting shaft 18 is connected to the two brackets 17 by means of the two bearings. The mounting shaft 18 can rotate relative to the brackets 17 around its own axis by means of the bearings. The axis of the mounting shaft 18 is parallel to the plane where the chassis is located.

[0049] The non-rotating shaft end of the second rotating motor (not shown) is fixedly mounted on one of the brackets 17 by bolts, the rotating shaft axis of the second rotating motor coincides with the axis of the mounting shaft 18, and the rotating shaft of the second rotating motor is welded and fixed to the mounting shaft 18. The second rotating motor is electrically connected to the control terminal by wire, and the second rotating motor is manually controlled to rotate by a person through the control terminal. Both the first rotating motor and the second rotating motor are small servo motors that can be self-locked when powered off.

[0050] The camera 19 is mounted on the mounting shaft 18 by means of bolts. The mounting shaft 18 is provided with a bolt hole. The axis of the bolt hole is arranged along the radial direction of the mounting shaft 18. The bolt hole is located in the middle of the mounting shaft 18. After the mounting bolt is inserted into the bolt hole, the mounting bolt is screwed into the housing of the camera 19, thereby connecting the camera 19 and the mounting shaft 18 into a whole. The rotation of the first rotary motor 15 can make the camera 19 rotate around the rotating shaft of the second rotary motor; the rotation of the second rotary motor can make the camera 19 rotate around the axis of the mounting shaft 18.

[0051] A lighting system 7 is installed on the upper surface of the vehicle chassis 1. The lighting system 7 is an LED lamp with variable light intensity and is electrically connected to the control terminal via a wired manner. People can manually control the brightness of the lighting system 7 via a wired manner to ensure that the camera 19 can clearly capture the crack image. Example

[0052] A method for detecting cracks in a box girder comprises the following steps: S1: Adaptation orientation; The specific steps include: S1.1: The operator places the robot on one surface of the box girder cavity from one end of the box girder, ensuring that the front wheels and rear wheels of the robot are placed on one surface of the box girder cavity at the same time; and ensuring that the front of the robot faces the other surface of the box girder cavity; for ease of operation, in this embodiment, the operator places the robot on the bottom plate with the front of the robot facing the web of the box girder cavity.

[0053] S1.2: After the operator turns on the robot, the control terminal controls the three laser rangefinders of the first angle measuring device to emit lasers once. The lasers of the three laser rangefinders irradiate the other surface in step S1.1 and then reflect. The three laser rangefinders respectively measure the distance of the other surface, and the control terminal obtains the distance monitored by the three laser rangefinders. S1.3: Determine whether the distances between the two laser rangefinders at the same height in the first angle measuring device are equal, and determine whether the adaptation orientation is completed; S1.3.1: If the distances between the two laser rangefinders at the same height in the first angle measuring device are not equal and the adaptation orientation is not completed, the control terminal controls the robot to adjust the direction accordingly. The meaning of adjusting the direction is: the control terminal controls the robot to rotate along the plane where the chassis is located; repeat step S1.3.1, the control terminal continuously controls the three laser rangefinders in the first angle measuring device to emit lasers and measure the distance of another surface until the distances between the two laser rangefinders at the same height are equal, the adaptation orientation is completed, and the robot no longer rotates along the plane where the chassis is located; S1.3.2: If the distances between the two laser rangefinders at the same height are equal, the adaptation is complete and the robot no longer rotates along the plane of the chassis; S2: The first magnetic device and the second magnetic device adapt to the angle; The specific steps include: S2.1: Determine the angle α between the plane where the chassis is located and another surface in front; After the orientation adaptation is completed, the control terminal continuously controls the three laser rangefinders of the first angle measuring device to emit lasers multiple times at a designed frequency. Each time the three lasers are irradiated to another surface and then reflected, the first magnetic device calculates the angle α between the other surface in front of the robot and the robot chassis according to the distance monitored by the three laser rangefinders. In this laser emission, the distances of the other surface in front monitored by the three laser rangefinders are H1, H2 and H3 respectively, where H1=H2. S2.2: Determine the angle β between the plane of the chassis and the surface on which the rear wheels come into contact; The control terminal continuously controls the three laser rangefinders of the second magnetic device to emit lasers multiple times at a designed frequency. Each time the three lasers are irradiated to the surface that the rear wheel contacts and then reflected, the second magnetic device calculates the angle β between the plane where the chassis is located and the surface that the rear wheel contacts based on the distance monitored by the three laser rangefinders. If the surface that the rear wheel contacts is parallel to the surface of the chassis, the angle β=0. S2.3: Calculate the angle of the second magnetic device; determine the state of the first magnetic device and determine the angle of the first magnetic device; The specific steps include: S2.3.1: Calculate the angle of the second magnetic device; looking from the Y direction, let the end of the magnetic plate in the second magnetic device away from the active axis be A', the point where the active axis 9 is located be O', draw a ray parallel to the chassis from O' to the rear of the chassis, and let a point on the ray be B', then ∠A'O'B'=90-β; S2.3.2: Observe in the Y direction, assume that the end of the magnetic plate in the first magnetic device away from the movable axis is point A, the point where the movable axis is located is point O, and a ray is drawn from point O to the forward direction, and a point on the ray is point B; if H1, H2 and H3 are all greater than or equal to the set threshold R, the front end of the robot is far away from the other surface, and the first magnetic device and the second magnetic device maintain the same angle, that is; ∠AOB=∠A'O'B'=90-β; S2.3.3: If any one of H1, H2 and H3 is less than the threshold R, the front end of the robot is close to the other surface, then ∠AOB = 90-α; S3: The operator controls the robot to move forward a distance D and then stop through the control terminal. During the moving process, the control terminal executes S2, and the control terminal controls the first magnetic attraction device and the second magnetic attraction device to adapt to the angle through the method in S2; S4: After the robot stops, the operator rotates the first rotary motor and the second rotary motor in the visual recognition device through the control terminal respectively, and the camera automatically focuses and takes an image of the box beam surface. The visual recognition device identifies cracks through image recognition technology. If cracks are identified, the visual recognition device sends the information to the control terminal; the display connected to the control terminal displays the cracks; S5: Repeat S3-S4. The operator operates the robot to continue walking a distance D according to step S3 and then stops, and presses S4 to capture the image of the inner surface of the box girder. Because the distance of one circle of the end face of the box girder is a known quantity, the operator can determine whether the robot has completed one circle by multiplying the distance D walked by the robot each time by the number of walks. Until the robot walks one circle in a direction parallel to the end face of the box girder, the operator no longer moves the robot in the forward direction.

[0054] S6: The operator sends a lateral movement command to the robot through the control terminal, and the control terminal causes the robot to lateral move a distance N in a direction perpendicular to the end face of the box beam and then stop; in the manner of steps S3 and S4, the robot continues to move around the inner cavity of the box beam once again, and takes images of the inner cavity of the box beam for one circle; S7: Repeat S6 until the robot moves out from the other end of the box beam and completely inspects the entire surface of the inner cavity of the box beam.

[0055] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A box girder crack detection robot, characterized in that: The remote control car comprises a remote control car, and the forward direction of the remote control car is set to be along the X direction; the remote control car comprises a chassis, front wheels and rear wheels, and the drive shaft axes of the front wheels and rear wheels are set to be along the Y direction, and the X direction is perpendicular to the Y direction. The front end and the rear end of the chassis are both provided with magnetic suction devices, and the magnetic suction device located at the front end of the chassis is the first magnetic suction device, and the magnetic suction device located at the rear end of the chassis is the second magnetic suction device, and the magnetic suction device is located on the lower surface of the chassis; The magnetic device includes: A base, fixed to the lower surface of the vehicle chassis; The movable shaft is rotatably connected to the base and can rotate relative to the base around its own axis, and the axis of the movable shaft is along the Y direction; A driven gear is fixedly connected to the movable shaft, and the axis of the driven gear coincides with the axis of the driven gear; A connecting rod, one end of which is fixed on the side of the movable shaft, and the axis is arranged along the radial direction of the movable shaft; The magnetic attraction plate is a permanent magnet connected to the other end of the connecting rod; The control motor is a servo motor, used to rotate the movable shaft; the control motor is electrically connected to the control terminal; The driving gear is fixed to the rotating shaft of the control motor, and the axis of the driving gear coincides with the axis of the control motor; the driving gear meshes with the driven gear; The remote control car is provided with a first angle measuring device and a second angle measuring device, both of which are electrically connected to the control terminal, and the control terminal can control the rotation of the control motors of the first magnetic attraction device and the second magnetic attraction device according to the angles monitored by the first angle measuring device and the second angle measuring device; A visual recognition device for capturing images of the inner surface of the box beam is fixedly installed on the upper surface of the vehicle chassis.

2. A box girder crack detection robot according to claim 1, characterized in that: The first angle measuring device comprises three laser rangefinders. The laser emission points of the three laser rangefinders of the first angle measuring device are point 1, point 2 and point 3 respectively. The laser emission directions of the three laser rangefinders of the first angle measuring device are along the X direction and face forward. The plane formed by point 1, point 2 and point 3 is assumed to be plane Q. The X direction is perpendicular to the plane Q. When observed in the X direction, point 1, point 2 and point 3 are not collinear. The second angle measuring device also includes three laser rangefinders. The laser emission points of the three laser rangefinders of the second angle measuring device are respectively point four, point five, and point six. The laser emission directions of the three laser rangefinders of the second angle measuring device are perpendicular to the vehicle floor and face downward. The plane formed by point four, point five, and point six is ​​assumed to be plane M. Plane M is parallel to the plane where the vehicle floor is located. When observed from a perspective perpendicular to plane M, point four, point five, and point six are not collinear. The first angle measuring device and the second angle measuring device are both electrically connected to the control terminal.

3. A box girder crack detection robot according to claim 2, characterized in that: The visual recognition device comprises: A first rotating motor, the non-rotating shaft end of which is fixed on the upper surface of the vehicle chassis; the rotating shaft of the first rotating motor is perpendicular to the plane where the vehicle chassis is located; and the first rotating motor is electrically connected to the control terminal; A mounting plate fixed on the rotating shaft of the first rotating motor; Two brackets, fixed on the upper surface of the mounting plate; The mounting shaft is rotatably connected to the two brackets, and the axis of the mounting shaft is parallel to the plane where the chassis is located; A second rotating motor, used to rotate the mounting shaft; and electrically connected to the control terminal; Camera, mounted on the mounting shaft.

4. A box girder crack detection robot according to claim 2, characterized in that: The two laser rangefinders corresponding to point one and point two are at the same height.

5. The crack detection robot for box beams according to claim 2, characterized in that: A lighting system is installed on the vehicle chassis, and the lighting system is electrically connected to a control terminal, and the control terminal can control the lighting system to change brightness.

6. A box girder crack detection method, based on the box girder crack detection robot according to claim 4, characterized in that: Steps: S1: Adaptation orientation; The specific steps include: S1.1: The operator places the robot on one of the surfaces of the box beam cavity from one end of the box beam, ensuring that the front and rear wheels of the robot are simultaneously placed on one of the surfaces of the box beam cavity; and ensuring that the front of the robot faces the other surface of the box beam cavity; S1.2: After the operator turns on the robot, the control terminal controls the three laser rangefinders of the first angle measuring device to emit lasers once. The lasers of the three laser rangefinders irradiate the other surface in step S1.1 and then reflect. The three laser rangefinders respectively measure the distance of the other surface, and the control terminal obtains the distance monitored by the three laser rangefinders. S1.3: Determine whether the distances between the two laser rangefinders at the same height in the first angle measuring device are equal, and determine whether the adaptation orientation is completed; S1.3.1: If the distances between the two laser rangefinders at the same height in the first angle measuring device are not equal and the adaptation orientation is not completed, the control terminal controls the robot to adjust the direction accordingly. The meaning of adjusting the direction is: the control terminal controls the robot to rotate along the plane where the chassis is located; repeat step S1.3.1, the control terminal continuously controls the three laser rangefinders in the first angle measuring device to emit lasers and measure the distance of another surface until the distances between the two laser rangefinders at the same height are equal, the adaptation orientation is completed, and the robot no longer rotates along the plane where the chassis is located; S1.3.2: If the distances between the two laser rangefinders at the same height are equal, the adaptation is complete and the robot no longer rotates along the plane of the chassis; S2: Adaptation angle between the first magnetic device and the second magnetic device; The specific steps include: S2.1: Determine the angle α between the plane where the chassis is located and another surface in front; After the orientation adaptation is completed, the control terminal continuously controls the three laser rangefinders of the first angle measuring device to emit lasers multiple times at a designed frequency. Each time the three lasers are irradiated to another surface and then reflected, the first magnetic device calculates the angle α between the other surface in front of the robot and the robot chassis according to the distance monitored by the three laser rangefinders. In this laser emission, the distances of the other surface in front monitored by the three laser rangefinders are H1, H2 and H3 respectively, where H1=H2. S2.2: Determine the angle β between the plane of the chassis and the surface on which the rear wheels come into contact; The control terminal continuously controls the three laser rangefinders of the second magnetic device to emit lasers multiple times at a designed frequency. Each time the three lasers are irradiated to the surface that the rear wheel contacts and then reflected, the second magnetic device calculates the angle β between the plane where the chassis is located and the surface that the rear wheel contacts based on the distance monitored by the three laser rangefinders. If the surface that the rear wheel contacts is parallel to the surface of the chassis, the angle β=0. S2.3: Calculate the angle of the second magnetic device; determine the state of the first magnetic device and determine the angle of the first magnetic device; The specific steps include: S2.3.1: Calculate the angle of the second magnetic device; looking from the Y direction, let the end of the magnetic plate in the second magnetic device away from the active axis be A', the point where the active axis 9 is located be O', draw a ray parallel to the chassis from O' to the rear of the chassis, and let a point on the ray be B', then ∠A'O'B'=90-β; S2.3.2: Observe in the Y direction, assume that the end of the magnetic plate in the first magnetic device away from the movable axis is point A, the point where the movable axis is located is point O, and a ray is drawn from point O to the forward direction, and a point on the ray is point B; if H1, H2 and H3 are all greater than or equal to the set threshold R, the front end of the robot is far away from the other surface, and the first magnetic device and the second magnetic device maintain the same angle, that is; ∠AOB=∠A'O'B'=90-β; S2.3.3: If any one of H1, H2 and H3 is less than the threshold R, the front end of the robot is close to the other surface, then ∠AOB = 90-α; S3: The operator controls the robot to move forward a distance D and then stop through the control terminal. During the moving process, the control terminal executes S2, and the control terminal controls the first magnetic attraction device and the second magnetic attraction device to adapt to the angle through the method in S2; S4: After the robot stops, the operator rotates the first rotary motor and the second rotary motor in the visual recognition device through the control terminal, and the camera automatically focuses and takes an image of the box beam surface. The visual recognition device identifies cracks through image recognition technology. If cracks are identified, the visual recognition device sends the information to the control terminal; the display connected to the control terminal displays the cracks; S5: Repeat S3-S4 until the robot moves one circle along the end face of the box girder; because the distance of one circle of the end face of the box girder is a known quantity, the operator can determine whether the robot has completed one circle according to the distance D of each walk of the robot multiplied by the number of walks, until the robot moves one circle along the end face of the box girder, the operator no longer moves the robot in the forward direction, and the visual recognition device captures an image of one circle of the end face of the box girder; S6: The operator sends a lateral movement command to the robot through the control terminal, and the control terminal causes the robot to lateral move a distance N in the direction perpendicular to the end face of the box beam and then stop; the robot continues to move around the inner cavity of the box beam once again, and takes images of the inner cavity of the box beam in a circle in the manner of steps S3 and S4; S7: Repeat S6 until the robot moves out from the other end of the box beam and completely inspects the entire surface of the inner cavity of the box beam.

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