Vertical take-off and landing unmanned aerial vehicle with 3D laser radar sensor

Abstract

A vertical take-off and landing drone (1) comprises a chassis (3), a propulsion system (5) mounted on the chassis (3), an electronic device (12) comprising a flight control system, and a 3D lidar sensor (10) mounted on the chassis. The 3D lidar sensor has a laser beam 360 DEG rotation axis (R) and an azimuth scan angle (alpha) in the range of 70 DEG to 110 DEG. The propulsion system comprises a plurality of propellers (6) with motors (7) configured for wing-free flight, including static hover flight, the vertical take-off and landing drone comprising a yaw axis (Z) about which it can rotate. The 3D lidar sensor is statically mounted on the chassis such that the lidar laser beam 360 DEG axis of rotation (R) is tilted at a lidar tilt angle (beta) of 35 DEG to 50 DEG with respect to the yaw axis (Z).

Description

Technical Field

[0001] The present invention relates to a vertical take-off and landing (VTOL) unmanned aerial vehicle (UAV) with a laser detection and ranging (LIDAR) sensing system. Background Art

[0002] It is common to provide vehicles, including unmanned aerial vehicles (UAVs), with lidar sensing systems, which use light in the form of pulsed lasers to measure the distance of objects in the sensor's environment. This can be used, for example, to guide a moving vehicle and avoid collisions with objects in the direction of the vehicle's travel, or simply to map the 3D space around the drone. Lidar sensors can also be used to scan and map objects and structures around the drone.

[0003] There are several popular types of LIDAR:

[0004] -1D LiDAR: uses a laser beam to measure in a single direction;

[0005] - Scanning 2D LiDAR: a laser beam continuously performs 360° rotations in one plane, providing a scan in that plane, i.e. a 2D scan with a “horizontal field of view” of 360° (less if there are some obstacles, but usually 270° or more);

[0006] - Scanning 3D LiDAR: Multiple laser beams or sensor arrays are able to provide distance sensing in different directions (typically distributed over an angular range of 15° to 95°) and continuously perform 360° rotation, providing 3D scanning with a 360° horizontal field of view and a 15° to 95° vertical field of view;

[0007] - Flash LiDAR: In this case, the entire field of view is illuminated by a wide divergent laser beam in a single pulse. A solid-state sensor array collects 3D range data within the field of view, usually defined by a lens (similar to a standard camera).

[0008] As mentioned above, a typical scanning 3D LiDAR may have a rotating laser beam that rotates 360° around a rotation axis, typically with a scanning angle of 15° to 95° relative to the vertical axis. In order to increase the amount of scanning around the drone, it is known to mount the LiDAR on an electric mobile mechanism. However, for vertical take-off and landing drones, such a mobile mechanism requires additional motors and structural mechanisms, thereby increasing the weight and cost of the drone. Since weight is a key factor affecting the flight performance and autonomy of the drone, this mechanism is a significant drawback of using a movable LiDAR sensing device. In addition, despite the presence of a movable mechanism, the drone's propulsion system and components will still block part of the LiDAR sensing space. Summary of the invention

[0009] In view of the above, an object of the present invention is to provide a vertical take-off and landing drone with a lidar sensing system that is lightweight and can easily scan the surrounding space horizontally and vertically (e.g., to achieve a spherical scanning range). In particular, for indoor lidar surveys, objects of interest may be located in all directions around the drone.

[0010] It would be advantageous to provide a vertical take-off and landing drone that is cost-effective to manufacture and operate.

[0011] It would be advantageous to provide a vertical take-off and landing drone that is safe and well protected from collision with objects.

[0012] A specific object of the present invention is to provide a vertical take-off and landing drone for inspection applications that can operate safely and efficiently in confined or indoor environments.

[0013] It would be advantageous to provide a compact vertical take-off and landing drone for inspection.

[0014] It would be advantageous to provide a vertical take-off and landing drone for inspection with high flight autonomy.

[0015] It would be advantageous to provide a rugged, vertical take-off and landing drone for indoor environmental inspections.

[0016] The objective of the present invention is achieved by providing a vertical take-off and landing drone according to claim 1.

[0017] The present invention discloses a vertical take-off and landing UAV, comprising a chassis, a propulsion system mounted on the chassis, electronic equipment including a flight control system, and a 3D laser radar sensor mounted on the chassis. The 3D laser radar sensor has a 360° rotation axis (R) of a laser beam and a scanning angle (hereinafter referred to as an azimuth scanning angle) (α) ranging from 70° to 110° relative to the laser radar rotation axis, the propulsion system comprises a plurality of propellers, the motors on the propellers are configured for wingless flight, including static hovering flight, and the vertical take-off and landing UAV comprises a yaw axis (Z), about which it can rotate.

[0018] The 3D LiDAR sensor is statically mounted on the chassis so that the LiDAR laser beam 360° rotation axis (R) is tilted relative to the yaw axis (Z) at a LiDAR tilt angle (β) of 35° to 50°.

[0019] In an advantageous embodiment, the lidar tilt angle (β) is 45° or in the range of 43° to 47°.

[0020] In a preferred embodiment, the lidar sensor is mounted in a hole in the center portion of the chassis, and a pair of motors located at the rear side of the drone have a different height in the yaw axis direction than a second pair of motors located at the front side of the vertical take-off and landing drone.

[0021] In a preferred embodiment, the chassis comprises a central portion and branches extending radially outwards from the central portion relative to the yaw axis (Z), the propellers being mounted at the ends of said branches.

[0022] In a preferred embodiment, the propulsion system comprises at least three non-coaxial spaced apart propellers, preferably four non-coaxial spaced apart propellers, and the 3D lidar sensor is mounted between the propellers.

[0023] In a preferred embodiment, the propulsion system includes a fan duct surrounding each propeller.

[0024] In a preferred embodiment, the propulsion system includes four propellers, including a pair of rear propellers and a pair of front propellers, the rotation axes of the rear propellers are spaced apart by a spacing (Lb), and the rotation axes of the front propellers are spaced apart by a spacing (Lf). The spacing (Lb) of the rear propellers is greater than the spacing (Lf) of the front propellers, and the laser radar sensor is installed between the pair of rear propellers.

[0025] In a preferred embodiment, the laser radar sensor is mounted on the chassis via a mounting bracket, and the laser radar is detachably connected to the chassis via the mounting bracket.

[0026] In a preferred embodiment, each propeller has a propeller center axis (C), and at least two propellers with a propeller center axis (C) have a propeller tilt angle (γ) relative to the yaw axis (Z), and the propeller tilt angle is in the range of 1° to 10°, preferably in the range of 2° to 8°.

[0027] In a preferred embodiment, the inclined propeller central axes diverge on the top side of the drone and converge on the bottom side of the drone.

[0028] In a preferred embodiment, the vertical take-off and landing drone further comprises an external protective cage surrounding the chassis, wherein the external protective cage comprises a plurality of beams connected to each other and surrounding the chassis.

[0029] In a preferred embodiment, the external protective cage includes a front side with an opening that is larger than the opening formed by the interconnecting beams surrounding the top, bottom, sides and back of the drone, the front side opening being configured to facilitate access to a battery that is removably mounted to a chassis within the external protective cage.

[0030] In a preferred embodiment, the VTOL UAV further comprises an image capture system, and optionally a lighting system and other sensors, mounted on the front side of the UAV at the opening of the outer protective cage surrounding the chassis.

[0031] In a preferred embodiment, the azimuth scanning angle (α) of the 3D laser radar is in the range of 85° to 95°.

[0032] In a preferred embodiment, the flight control system includes a module configured to automatically maintain a constant rotation rate of the VTOL UAV about the yaw axis to ensure uniform scanning.

[0033] Other objects and advantages of the present invention will appear from the claims, the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1a is a perspective view of a vertical take-off and landing drone according to one embodiment of the present invention;

[0035] Figure 1b yes Figure 1a An exploded perspective view of an embodiment of the present invention;

[0036] Figure 2a yes Figure 1a A side view of an embodiment of the present invention;

[0037] Figure 2b yes Figure 1a A top view of an embodiment of the present invention;

[0038] Figure 2c yes Figure 1a A front view of an embodiment of the present invention;

[0039] Figure 2d yes Figure 1a A rear view of an embodiment of a vertical take-off and landing UAV;

[0040] Figure 3a yes Figure 1a A top view of the vertical take-off and landing drone with the outer protective cage removed;

[0041] Figure 3b yes Figure 3a A side view of an embodiment of the present invention;

[0042] Figure 4a is a perspective view of a vertical take-off and landing drone according to another embodiment of the present invention;

[0043] Figure 4b yes Figure 4a A side view of an embodiment of the present invention;

[0044] Figure 5a yes Figure 4a A view of an embodiment of the invention with the outer protective cage removed;

[0045] Figure 5b yes Figure 5a A side view of an embodiment of the present invention. DETAILED DESCRIPTION

[0046] Referring to the accompanying drawings, according to an embodiment of the present invention, a vertical take-off and landing UAV 1 includes an external protective cage 2, a chassis 3 connected to the external protective cage and installed in the external protective cage, a power source 4 (for example, in the form of a battery) installed on and supported by the chassis, a propulsion system 5 installed on and supported by the chassis, and an electronic unit 12 installed on and supported by the chassis.

[0047] The vertical take-off and landing drone also includes a sensor system, which includes a 3D lidar sensor 10.

[0048] The VTOL drone may include other sensors and inspection equipment, such as an image capture system9.

[0049] The electronics unit 12 comprises electronics for controlling the propulsion system, for flight control and other operations such as wireless communication with other devices, processing of measurement and sensor data, navigation and various functions known per se in a vertical take-off and landing UAV (VTOL UAV).

[0050] In a preferred embodiment, the outer protective cage 2 is formed by beams connected together to form a generally spherical cage around the chassis and propulsion system, such a structure is known per se. The electronic unit and the power supply can be mounted on the chassis and well protected by the outer protective cage and the chassis. The image capture system 9 and the projection light and other sensors can be mounted on one side of the protective cage, the opening 15 of the protective cage being larger than the openings between the thin beams connected together to form the rest of the cage. This opening 15 can also be used to facilitate the removal and insertion of batteries or other payloads to be mounted on the chassis inside the outer protective cage. The mounting of the image capture system and the projection light at the opening 15 can provide an uninterrupted wide viewing angle for the image capture system.

[0051] In a preferred embodiment, the propulsion system comprises a plurality of propellers 6 , each propeller 6 comprising propeller blades 13 coupled to an electric motor 7 .

[0052] In a preferred embodiment, the propulsion system comprises four propellers 6 arranged around the yaw axis Z of the drone. The propellers are arranged around the yaw axis so that they can lift the VTOL drone in a vertical direction parallel to the yaw axis Z and keep the VTOL drone in static (hovering) stable flight, with the yaw axis aligned with the vertical direction. Perpendicular to the yaw axis Z, the VTOL drone comprises axes that can be considered as the pitch axis Y and the roll axis X. The positions of the pitch axis and the roll axis can be defined relative to the orientation of the drone, which is given by the image sensor 9 corresponding to the front of the drone. According to convention, the side of the drone opposite to the front (front) can be defined as the back (rear) of the drone. The horizontal plane XY can be defined as the plane orthogonal to the yaw axis Z when the drone is in a static stable flight position, in which case the yaw axis Z of the drone should be parallel to the vertical direction and its horizontal plane XY should be parallel to the horizontal direction.

[0053] Each propeller 6 has a propeller center axis C, which may be parallel or substantially parallel to the yaw axis Z, or in a preferred embodiment, the propeller center axis C may have an inclination angle γ relative to the yaw axis Z, the inclination angle preferably being within 1°-10°, preferably between 2° and 8°. The propeller center axes are inclined so that they diverge above the propeller and converge below the propeller, an arrangement that can provide greater flight stability at low speeds and make it easier to control the flight. The motor 7 of each propeller is preferably independently controlled by a propulsion control unit of the electronic unit 12.

[0054] According to a preferred embodiment, the chassis 3 comprises a central portion 3a and branches 3b extending outwardly from the central portion 3a to branch ends (ends), and the motors 7 of the propellers 6 are mounted at the branch ends (ends). Each propeller 6 may also include a fan duct 8 around the tip of the propeller blade 13, such fan ducts and propeller arrangements are well known per se and are configured to improve the aerodynamic performance of the propulsion system. The fan duct 8 may be fixed to the chassis and form part of the chassis, thereby providing structural resistance to the chassis.

[0055] In an advantageous embodiment, the motors 7 of the front propellers 6f on the front side of the drone are spaced apart by a spacing Lf (front motor spacing) that is smaller than the spacing Lb (rear motor spacing) between the motors of the rear propellers 6b. This configuration provides a better scanning beam path for a 3D LIDAR sensor 10 mounted on the chassis between a pair of branches on the rear side of the drone.

[0056] According to one aspect of the present invention, the 3D lidar sensor 10 includes a laser beam or multiple laser beams that rotate 360° around a laser beam rotation axis R. The 360° rotating laser beam also includes an azimuth scanning angle α of 70° to 110° relative to the rotating laser center axis R, typically about 85° to 95°, for example about 90°. The tilt angle β of the lidar relative to the yaw axis Z is in the range of 40° to 50°, preferably 45° or about 45° relative to the yaw axis. The 3D lidar sensor 10 is fixedly coupled to the chassis 3, such as directly fixedly coupled to the chassis or fixedly coupled via a mounting bracket 14. The term "azimuth scanning angle" used herein refers to the scanning angle relative to the rotation axis R of the lidar beam. The term may also be expressed as "scanning angle relative to the rotation axis R"

[0057] In one advantageous embodiment, the mounting bracket may be configured to enable the 3D LiDAR sensor to be releasably coupled to the chassis such that the LiDAR sensor may be removed for maintenance, replacement, or operation of the drone without the LiDAR.

[0058] like Figure 3b As shown, when the axis of the laser radar is 45° or approximately 45° (i.e., β=45°) relative to the yaw axis Z, the scanning range of the laser radar can at least scan from the vertical position to the horizontal position. By operating the drone to rotate 90° or more around its yaw axis Z, the 3D laser radar sensor 10 can be used to scan the entire spherical space around the drone.

[0059] Since the 3D lidar sensor 10 can be statically fixed to the chassis, the additional weight of the lidar system can be kept to a minimum (particularly by eliminating the need for an electrically powered moving mechanism), while the drone can still scan the entire 360° spherical range around it by rotating 360° around its yaw axis Z. In this operation, the drone can maintain a stationary hovering position, thereby being able to perform scanning functions in a constrained environment. In other words, when the drone rotates around its yaw axis Z, no additional space or volume is required in the drone environment to implement the lidar scanning function. Therefore, the vertical take-off and landing drone can easily scan the entire three-dimensional environment around the drone, avoiding un-scanned blind spots.

[0060] The flight control system of the electronic device 12 may include a software module configured to control the flight of the drone in conjunction with the scanning operation. For example, the module may be configured to automatically maintain a constant rotation speed of the drone around its yaw axis, performing a partial rotation (e.g., 90°) or a full rotation (e.g., 360°) or more to ensure a uniform scan of the surrounding environment. The control system may be used to automatically fly the drone in an environment while maintaining a constant yaw rotation speed during long-distance flights.

[0061] In such Figures 4a to 5b In the alternative embodiment shown, the chassis may include a hollow center section frame 3a with a central opening in which the 3D LiDAR sensor 10 is fixedly mounted at an inclination angle β of the LiDAR 360° rotation axis R relative to the yaw axis Z, the inclination angle β being in the range of 40° to 50°, preferably 45° or about 45°. In this embodiment, the paired propellers of the front 6f and rear 6b ​​are offset O in the direction of the yaw axis so that they are substantially aligned in different horizontal planes. The latter configuration allows the LiDAR laser beam to scan at least 90° from the yaw axis Z to the horizontal plane XY without being disturbed by the propulsion system.

[0062] List of characteristic reference numerals:

[0063] Vertical Take-Off and Landing UAV (VTOL UAV)1

[0064] External protective cage 2

[0065] Front opening 15

[0066] Chassis 3

[0067] Center section 3a

[0068] Branch 3b

[0069] Power source (battery) 4

[0070] Propulsion system 5

[0071] Propeller 6

[0072] Front propeller 6f

[0073] Rear propeller 6b

[0074] Motor 7

[0075] Fan duct 8

[0076] Sensing system Image capture system 9

[0077] 3D laser radar (LIDAR, laser detection and ranging) sensor 10 mounting bracket 14

[0078] Electronic equipment 12

[0079] Flight control system yaw axis Z

[0080] Pitch axis Y

[0081] Roll axis X

[0082] Horizontal plane XY

[0083] Propeller center axis C

[0084] Propeller pitch angle γ

[0085] Lidar Axis R

[0086] Lidar tilt angle β

[0087] Laser radar azimuth scanning angle (scanning angle relative to the laser radar rotation axis) α front motor spacing Lf

[0088] Rear motor spacing Lb

Claims

1. A vertical take-off and landing unmanned aerial vehicle (1), comprising: A chassis (3), a propulsion system (5) mounted on the chassis (3), electronic equipment (12) including a flight control system, and a 3D laser radar sensor (10) mounted on the chassis, the 3D laser radar sensor having a laser beam 360° rotation axis (R) and an azimuth scanning angle (α) in the range of 70° to 110°, the propulsion system comprising a plurality of propellers (6) with electric motors (7), the propellers being configured for wingless flight, including static hovering flight, the vertical take-off and landing unmanned aerial vehicle comprising a yaw axis (Z) and rotating about the yaw axis, characterized in that the 3D laser radar sensor is statically mounted on the chassis so that the laser radar laser beam 360° rotation axis (R) is tilted relative to the yaw axis (Z) at a laser radar tilt angle (β) in the range of 35° to 50°.

2. The vertical take-off and landing UAV according to claim 1, characterized in that: The laser radar tilt angle (β) is 45°, or in the range of 43° to 47°.

3. A vertical take-off and landing UAV according to any one of the preceding claims, characterized in that: The laser radar sensor (10) is installed in a hole in the central part of the chassis, and the height of a pair of motors located at the rear side of the UAV in the yaw axis direction is different from the height of a second pair of motors located at the front side of the vertical take-off and landing UAV.

4. The vertical take-off and landing UAV according to claim 1 or 2, characterized in that: The chassis (3) comprises a central part (3a) and branches (3b) extending radially outwards from the central part relative to the yaw axis (Z), the propeller (6) being mounted at the end of the branches.

5. A vertical take-off and landing UAV according to any one of the preceding claims, characterized in that: The propulsion system (5) comprises at least three non-coaxial spaced apart propellers, preferably four non-coaxial spaced apart propellers, and the 3D lidar sensor (10) is mounted between the propellers.

6. A vertical take-off and landing UAV according to any one of the preceding claims, characterized in that: The propulsion system includes a fan duct (8) surrounding each of the propellers.

7. A vertical take-off and landing UAV according to any one of the preceding claims, characterized in that: The propulsion system comprises four propellers, including a pair of rear propellers with a rotation axis spaced apart by a spacing (Lb) and a pair of front propellers with a rotation axis spaced apart by a spacing (Lf), wherein the rear propeller spacing (Lb) is greater than the front propeller spacing (Lf), and the laser radar sensor (10) is installed between the pair of rear propellers.

8. A vertical take-off and landing UAV according to any one of the preceding claims, characterized in that: The laser radar sensor (10) is mounted on the chassis (3) via a mounting bracket (10), and the laser radar is detachably connected to the chassis via the mounting bracket (14).

9. A vertical take-off and landing UAV according to any one of the preceding claims, characterized in that: Each of the propellers has a propeller center axis (C), and the propeller center axes of at least two propellers have a propeller tilt angle (γ) relative to the yaw axis (Z), and the propeller tilt angle (γ) is in the range of 1° to 10°, preferably in the range of 2° to 8°.

10. A vertical take-off and landing drone according to the preceding claim, characterized in that The inclined propeller central axis diverges on the top side of the drone and converges on the bottom side of the drone.

11. A vertical take-off and landing UAV according to any one of the preceding claims, characterized in that: Also included is an outer protective cage (2) surrounding the chassis, the outer protective cage comprising a plurality of beams interconnected with each other and surrounding the chassis.

12. A vertical take-off and landing drone according to the preceding claim, characterised in that The outer protective cage includes a front side having an opening (15) that is larger than the opening formed by interconnecting beams around the top, bottom, sides and back of the drone, the opening being configured for accessing a battery (4) removably mounted on the chassis within the outer protective cage.

13. A vertical take-off and landing UAV according to any one of the preceding claims, characterized in that: Also included is an image capture system (9), and optionally a lighting system and other sensors, which are mounted on the front side of the drone at an opening (15) in an outer protective cage (2) surrounding the chassis.

14. A vertical take-off and landing UAV according to any one of the preceding claims, characterized in that: The 3D lidar includes an azimuth scanning angle (α) in the range of 85° to 95°.

15. A vertical take-off and landing UAV according to any one of the preceding claims, characterized in that: The flight control system includes a module configured to automatically maintain a constant rotation rate of the VTOL UAV about the yaw axis to ensure uniform scanning.

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