Unmanned aerial vehicle laser positioning and visual guidance system and method

Abstract

The invention relates to the technical field of unmanned aerial vehicle positioning, and discloses an unmanned aerial vehicle laser positioning and visual guiding system and method, and the system comprises a laser guiding device, an unmanned aerial vehicle burying device and a control system. The unmanned aerial vehicle burying device comprises an unmanned aerial vehicle, a rotary steering engine, an executing mechanism, a camera, a supporting connecting rod and a distance measuring sensor. One end of the supporting connecting rod is arranged on the unmanned aerial vehicle; the rotary steering engine is arranged at the tail end of the supporting connecting rod and in the middle of the executing mechanism; the camera and the distance measuring sensor are arranged at the tail end of the executing mechanism; and the control system adjusts the flight attitude and position of the unmanned aerial vehicle and the attitude of the execution mechanism through a spatial positioning algorithm according to the laser spot image captured by the camera and the distance information of the distance measuring sensor. According to the invention, the unmanned aerial vehicle is adopted as a mobile platform, the distance measuring sensor, the visual sensor and the execution mechanism are combined, the unmanned aerial vehicle space positioning and visual navigation are realized through the laser spot position, and the precise burying of the monitoring target is completed.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle positioning, and in particular to a laser positioning and visual guidance system and method for unmanned aerial vehicle. Background Art

[0002] Urban rail transit carries a large amount of transportation demand in the city. The status of its tunnels, elevated piers, bridges and other structures affects the operational safety of urban rail transit. Ensuring its safety has become one of the important tasks of urban management. Existing technical means of tunnel structure safety monitoring usually require burying cooperative monitoring targets at the monitored characteristic points, and continuously measuring their spatial position deformation through instruments and equipment to evaluate the structural safety status of the monitored object.

[0003] When monitoring targets need to be buried at higher locations, such as the vaults of large-section tunnels, the tops of elevated piers, and the webs of bridges, they must be installed manually. Traditional manual installation methods require workers to use scaffolding, aerial work vehicles and other equipment to reach the required height, which not only leads to low work efficiency, but also comes with high safety risks. To make matters more complicated, such operations within the construction area of ​​rail transit tunnels must be approved by relevant departments in advance, and the time window for operations is usually very limited.

[0004] Conventional drones use GNSS modules to achieve spatial positioning. However, in application scenarios such as tunnels, elevated piers and bridges, the GNSS measurement signal will be interfered by the obstruction of the external environment, resulting in the inability to accurately complete spatial positioning. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention proposes a UAV laser positioning and vision guidance system and method to solve the above-mentioned technical problems.

[0006] In the first aspect, a UAV laser positioning and visual guidance system is provided, comprising:

[0007] A laser guide device, used for emitting laser light and forming a high-brightness laser spot on the surface of the location to be installed;

[0008] The UAV embedding device includes a UAV, a rotary servo, an actuator, a camera, a supporting connecting rod and two ranging sensors;

[0009] One end of the support connecting rod is fixed to the top of the drone, and the other end is connected to the rotary steering gear;

[0010] The rotary servo is fixed to the middle position between the end of the supporting connecting rod and the actuator, and is used to adjust the pitch angle of the actuator;

[0011] The camera is arranged at the middle position of the end of the actuator;

[0012] The two distance measuring sensors are symmetrically arranged at the end of the actuator and located on both sides of the camera;

[0013] The control system is used to adjust the flight attitude and position of the UAV and the attitude of the actuator through the spatial positioning algorithm according to the laser spot image captured by the camera and the distance information measured by the ranging sensor, so as to achieve accurate installation of the monitoring target.

[0014] Furthermore, the laser guiding device includes a manual total station, a measuring robot or other laser emitting equipment that can form a light spot on the surface to be installed.

[0015] Furthermore, the actuator includes a drive motor, a lead screw, a slide and a spring;

[0016] The actuator is a bar-shaped device with a fixed flange in the middle for fixing to the rotary steering gear;

[0017] A stepping drive motor is provided at the end of the actuator, which drives the slide table to move axially through a screw rod, and the other end of the actuator is connected to a camera and two distance measuring sensors;

[0018] The end of the slide is connected to a spring and is used to push the monitoring target to separate from the fixed steel needle and be installed on the surface to be monitored.

[0019] Furthermore, the spatial positioning algorithm comprises the following steps:

[0020] In the rough alignment step, the drone is manually controlled to make a laser spot appear in the camera, and the spot is ensured to appear in the center of the image plane as much as possible;

[0021] The yaw angle adjustment step is to adjust the yaw angle of the drone according to the distance difference measured by the distance measuring sensor at the end of the actuator, so that the XOZ plane of the body coordinate system is perpendicular to the surface to be installed; during the yaw angle adjustment process, the Y and Z directions of the drone are adjusted at the same time to ensure that the laser spot is in the center of the camera image plane;

[0022] The pitch angle adjustment step is to adjust the pitch angle of the actuator servo according to the distance difference measured by the ranging sensor so that the actuator axis direction is perpendicular to the surface to be installed; during the pitch angle adjustment process, the Z-direction flight position of the drone is adjusted at the same time to ensure that the laser spot is located at the center of the camera image plane;

[0023] Target approach adjustment step: According to the pitch angle of the actuator servo, adjust the X and Z positions of the drone at the same time to make the drone close to the laser spot position to be installed;

[0024] In the precise alignment step, the flight position of the drone in the X, Y, and Z directions is adjusted simultaneously according to the mapping relationship between the image plane and the spatial position for precise alignment.

[0025] Furthermore, in the yaw angle adjustment step, the calculation of the rotation angle value of the drone is based on the distance difference between two ranging sensors at the end of the actuator and the distance between the two ranging sensors.

[0026] Furthermore, in the step of adjusting the UAV's Y and Z flight positions, the UAV position adjustment algorithm is based on the position of the laser spot in the image plane, the center position of the image plane, the pixel difference between the laser spot and the center position, the camera resolution, and the stop threshold.

[0027] Furthermore, in the pitch angle adjustment step, the determination of whether the end of the actuator is perpendicular to the surface to be installed is based on a change in the sign of the distance difference measured by the distance measuring sensor.

[0028] Furthermore, it also includes a ground station for receiving images and distance information transmitted by the drone, calculating adjustment parameters of the drone and the actuator based on a spatial positioning algorithm, and then sending adjustment instructions to the drone.

[0029] In a second aspect, a method for laser positioning and visual guidance of a UAV is provided, based on the laser positioning and visual guidance system of a UAV described in any one of the above, comprising the following steps:

[0030] A high-brightness laser spot is formed on the surface of the location to be installed by a laser guiding device;

[0031] Control the drone to fly near the location to be installed and capture the laser spot image through the camera;

[0032] According to the captured images and the distance information measured by the ranging sensor, the flight attitude and position of the UAV, as well as the attitude of the actuator, are adjusted through the spatial positioning algorithm;

[0033] When the UAV and the actuator reach the predetermined position and posture, the actuator is controlled to install the monitoring target;

[0034] After the installation is complete, take photos of the installation point and control the drone to return to the ground.

[0035] The invention adopting the above technical solution has the following advantages:

[0036] The present invention adopts a UAV as a mobile platform, combines ranging sensors, visual sensors and actuators, and realizes the spatial positioning and visual navigation of the UAV through the position of the laser spot, thereby completing the precise burial and installation of the monitoring target, significantly improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation of the present invention, the following will briefly introduce the drawings required for use in the specific implementation. In all the drawings, each element or part is not necessarily drawn according to the actual scale.

[0038] Figure 1 This is a structural diagram of a UAV laser positioning and visual guidance system and method of the present invention;

[0039] Figure 2 A schematic diagram of the structure of a UAV in a UAV laser positioning and vision guidance system of the present invention;

[0040] Reference numerals:

[0041] UAV burying device 1, laser guidance device 2,

[0042] UAV 21 , rotary servo 22 , actuator 23 , camera 24 , and distance sensor 25 . DETAILED DESCRIPTION

[0043] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0044] like Figure 1-2 As shown, a UAV laser positioning and visual guidance system of the present invention comprises:

[0045] A laser guiding device 2, used for emitting laser light and forming a high-brightness laser spot on the surface of the location to be installed;

[0046] The drone embedding device 1 includes a drone 21, a rotary steering gear 22, an actuator 23, a camera 24, a supporting connecting rod and two distance measuring sensors 25;

[0047] One end of the supporting connecting rod is fixed to the top of the drone 21, and the other end is connected to the rotating steering gear 22;

[0048] The rotary servo 22 is fixed at the middle position between the end of the supporting connecting rod and the actuator 23, and is used to adjust the pitch angle of the actuator 23;

[0049] The camera 24 is arranged at the middle position of the end of the actuator 23;

[0050] Two distance measuring sensors 25 are symmetrically arranged at the end of the actuator 23 and located on both sides of the camera 24;

[0051] The control system is used to adjust the flight attitude and position of the UAV 21 and the attitude of the actuator 23 through a spatial positioning algorithm according to the laser spot image captured by the camera 24 and the distance information measured by the ranging sensor 25, so as to achieve accurate installation of the monitoring target.

[0052] Specifically, the present invention adopts the UAV 21 as a mobile platform, combines the ranging sensor 25, the visual sensor and the actuator 23, and realizes the spatial positioning and visual navigation of the UAV 21 through the laser spot position, thereby completing the precise burial and installation of the monitoring target, which significantly improves the work efficiency.

[0053] In some embodiments, the laser guiding device 2 includes a manual total station, a measuring robot or other laser emitting equipment that can form a light spot on the surface to be installed.

[0054] In some embodiments, the actuator 23 includes a drive motor, a lead screw, a slide, and a spring;

[0055] The actuator 23 is a bar-shaped device, with a fixed flange in the middle for fixing with the rotary steering gear 22;

[0056] A stepping drive motor is provided at the end of the actuator 23, which drives the slide table to move axially through a screw rod. The other end of the actuator 23 is connected to a camera 24 and two distance sensors 25;

[0057] The end of the slide is connected to a spring, which is used to push the monitoring target away from the fixed steel needle and install it on the surface to be monitored.

[0058] In some embodiments, the spatial localization algorithm includes the following steps:

[0059] ① Rough alignment step, manually controlling the flight of the drone 21 to make a laser spot appear in the camera 24, and try to ensure that the spot appears in the center of the image;

[0060] ② Yaw angle adjustment step: according to the distance difference measured by the distance measuring sensor 25 at the end of the actuator, the yaw angle of the drone 21 is adjusted so that the XOZ plane of the body coordinate system is perpendicular to the surface to be installed;

[0061] ③ During the yaw angle adjustment process, adjust the Y and Z flight positions of the drone at the same time to ensure that the laser spot is in the center of the camera image plane;

[0062] ④ Pitch angle adjustment step: according to the distance difference measured by the ranging sensor 25, adjust the pitch angle of the actuator servo so that the axis direction of the actuator 23 is perpendicular to the surface to be installed; during the pitch angle adjustment process, adjust the Z-direction flight position of the drone at the same time to ensure that the laser spot is located at the center of the camera image plane;

[0063] ⑤ Target approach adjustment step: according to the pitch angle of the actuator 23 servo, the X-direction and Z-direction positions of the drone are adjusted simultaneously, so that the drone 21 is close to the laser spot position to be installed;

[0064] ⑥Precise alignment step: According to the mapping relationship between the image plane and the spatial position, the flight position of the drone in the X, Y and Z directions is adjusted simultaneously for precise alignment.

[0065] In some embodiments, in the yaw angle adjustment step, the calculation of the rotation angle value of the drone 21 is based on the distance difference between the two ranging sensors 25 at the end of the actuator and the distance between the two ranging sensors 25.

[0066] Specifically, the pitch angle θ of the actuator 23 is adjusted pit To the horizontal position, i.e. θ pit = 0°, the ground station obtains the distance D between the end distance measuring sensor 25 of the execution structure and the surface to be installed in real time, which are recorded as Assume that the distance difference between the two distance measuring sensors at the end of the actuator is 25 Drone 21 adjusts the yaw angle to θ yaw , the distance between the two ranging sensors 25 is L, then the yaw angle rotation angle value of the drone 21 at each sampling moment is calculated as shown in the following formula:

[0067]

[0068] During the yaw angle adjustment process, the Y and Z flight positions of the drone 21 are adjusted simultaneously to ensure that the laser spot is located at the center of the camera image plane. h , P v ), the center position of the image plane (P h_ctr , P v_ctr ), the pixel difference between the laser spot and the center position is ( d p_h , d p_v ), the resolution of camera 24 is (R h , R v ), the stopping threshold is (P h_thr , P v_thr ), the UAV Y and Z direction flight adjustment distance (D y ,D z ), then the UAV Y-axis and Z-axis flight position adjustment algorithm is as follows:

[0069]

[0070] In some embodiments, in the Y-axis and Z-axis flight position adjustment steps, the position adjustment algorithm of the drone 21 is based on the position of the laser spot in the image plane, the center position of the image plane, the pixel difference between the laser spot and the center position, the camera resolution and the stop threshold.

[0071] In some embodiments, in the pitch angle adjustment step, the determination of whether the end of the actuator 23 is perpendicular to the surface to be installed is based on the change in the sign of the distance difference measured by the distance measuring sensor 25 .

[0072] Specifically, the ground station obtains in real time the distance D between the ranging sensor 25 and the surface to be installed, which are respectively denoted as D LS1 , D LS2 , assuming that the pitch angle of the actuator servo 23 rotates θ step , and record t i The distance sensor 25 measures the distance between the end of the execution and the belt installation surface. Calculate the difference between the distance of the distance measuring sensor 25 at the current moment and the distance of the previous moment respectively If two distance sensors appear If the sign of the value changes, it means that t i_1 At this moment, the end of the actuator 23 is perpendicular to the surface to be installed, and the pitch angle of the servo perpendicular to the installation surface is recorded as

[0073] θ pit-ν =(i-1)*θ step Formula 3

[0074] When adjusting the pitch angle, the light spot may exceed the image interface. You need to adjust the Z-direction flight distance of the drone at the same time until the light spot is at the center of the camera phase plane.

[0075] Automatically adjust the position of the drone 21 to be close to the position of the laser spot to be installed;

[0076] After the above two adjustments, the attitude of the actuator 23 of the drone 21 has been adjusted. The flight position of the drone in the X and Z directions can be adjusted to approach the light spot to be installed. The flight position of the drone in the X and Z directions is set to (D x ,D z ), stop threshold Dthr, distance D between the distance measuring sensor 25 and the surface to be installed;

[0077]

[0078] Precise alignment: After establishing the mapping relationship between the image plane and the spatial position according to the above steps, the image is precisely aligned according to the laser spot. Suppose the flight position of the drone in the X, Y, and Z directions is (D x ,D y ,D z), the pixel difference between the laser spot and the center position is ( d p_h ,d p_v ), the camera resolution is (R h ,R v ), the stopping threshold is (P h_thr , P v_thr ), the positioning algorithm is as follows:

[0079]

[0080] In some embodiments, a ground station is also included for receiving images and distance information transmitted by the drone 21 , calculating adjustment parameters of the drone 21 and the actuator 23 based on a spatial positioning algorithm, and then sending adjustment instructions to the drone 21 .

[0081] In some other embodiments, a method for laser positioning and visual guidance of a drone is provided, based on any one of the above-mentioned laser positioning and visual guidance systems of a drone, comprising the following steps:

[0082] Step 1: forming a high-brightness laser spot on the surface of the location to be installed by means of a laser guiding device 2;

[0083] Step 2: Control the drone 21 to fly to the vicinity of the location to be installed, and capture the laser spot image through the camera 24;

[0084] Step 3: According to the captured image and the distance information measured by the ranging sensor 25, the flight attitude and position of the UAV 21 and the attitude of the actuator 23 are adjusted through the spatial positioning algorithm;

[0085] Step 4: When the UAV 21 and the actuator 23 reach a predetermined position and posture, the actuator 23 is controlled to install the monitoring target;

[0086] Step 5: After the installation is completed, take photos of the installation points and control the drone 21 to return to the ground.

[0087] The coordinate axes of the X, Y, and Z directions of the drone in this embodiment conform to the right-hand rule definition of the body coordinate system.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and should all be included in the scope of the claims and specification of the present invention.

Claims

1. A UAV laser positioning and visual guidance system, characterized in that: include: A laser guide device, used for emitting laser light and forming a high-brightness laser spot on the surface of the location to be installed; The UAV embedding device includes a UAV, a rotary servo, an actuator, a camera, a supporting connecting rod and two ranging sensors; One end of the support connecting rod is fixed to the top of the drone, and the other end is connected to the rotary steering gear; The rotary servo is fixed to the middle position between the end of the supporting connecting rod and the actuator, and is used to adjust the pitch angle of the actuator; The camera is arranged at the middle position of the end of the actuator; The two distance measuring sensors are symmetrically arranged at the end of the actuator and located on both sides of the camera; The control system is used to adjust the flight attitude and position of the UAV and the attitude of the actuator through the spatial positioning algorithm according to the laser spot image captured by the camera and the distance information measured by the ranging sensor, so as to achieve accurate installation of the monitoring target.

2. The system according to claim 1, characterized in that The laser guiding device includes a manual total station, a measuring robot or other laser emitting equipment that can form a light spot on the surface to be installed.

3. The system according to claim 1, characterized in that The actuator includes a driving motor, a lead screw, a slide and a spring; The actuator is a bar-shaped device with a fixed flange in the middle for fixing to the rotary steering gear; A stepping drive motor is provided at the end of the actuator, which drives the slide table to move axially through a screw rod, and the other end of the actuator is connected to a camera and two distance measuring sensors; The end of the slide is connected to a spring and is used to push the monitoring target to separate from the fixed steel needle and be installed on the surface to be monitored.

4. The system according to claim 1, characterized in that The spatial positioning algorithm comprises the following steps: In the rough alignment step, the drone is manually controlled to make a laser spot appear in the camera, and the spot is ensured to appear in the center of the image plane as much as possible; The yaw angle adjustment step is to adjust the yaw angle of the drone according to the distance difference measured by the distance measuring sensor at the end of the actuator, so that the XOZ plane of the body coordinate system is perpendicular to the surface to be installed; during the yaw angle adjustment process, the Y and Z directions of the drone are adjusted at the same time to ensure that the laser spot is in the center of the camera image plane; The pitch angle adjustment step is to adjust the pitch angle of the actuator servo according to the distance difference measured by the ranging sensor so that the actuator axis direction is perpendicular to the surface to be installed; during the pitch angle adjustment process, the Z-direction flight position of the drone is adjusted at the same time to ensure that the laser spot is located at the center of the camera image plane; Target approach adjustment step: According to the pitch angle of the actuator servo, adjust the X and Z positions of the drone at the same time to make the drone close to the laser spot position to be installed; In the precise alignment step, the flight position of the drone in the X, Y, and Z directions is adjusted simultaneously according to the mapping relationship between the image plane and the spatial position for precise alignment.

5. The system according to claim 4, characterized in that In the yaw angle adjustment step, the calculation of the rotation angle value of the drone is based on the distance difference between the two ranging sensors at the end of the actuator and the distance between the two laser ranging sensors.

6. The system according to claim 4, characterized in that In the step of adjusting the UAV's Y and Z flight positions, the UAV position adjustment algorithm is based on the position of the laser spot in the image plane, the center position of the image plane, the pixel difference between the laser spot and the center position, the camera resolution, and the stop threshold.

7. The system according to claim 4, characterized in that In the pitch angle adjustment step, the determination of whether the end of the actuator is perpendicular to the surface to be installed is based on the change in the sign of the distance difference measured by the distance measuring sensor.

8. The system according to claim 1, characterized in that It also includes a ground station for receiving images and distance information transmitted by the drone, calculating adjustment parameters of the drone and actuator based on a spatial positioning algorithm, and then sending adjustment instructions to the drone.

9. A method for laser positioning and visual guidance of an unmanned aerial vehicle, characterized in that: The UAV laser positioning and vision guidance system according to any one of claims 1 to 8 comprises the following steps: A high-brightness laser spot is formed on the surface of the location to be installed by a laser guiding device; Control the drone to fly near the location to be installed and capture the laser spot image through the camera; According to the captured images and the distance information measured by the ranging sensor, the flight attitude and position of the UAV, as well as the attitude of the actuator, are adjusted through the spatial positioning algorithm; When the UAV and the actuator reach the predetermined position and posture, the actuator is controlled to install the monitoring target; After the installation is complete, take photos of the installation point and control the drone to return to the ground.

Images