Perch UAV with retractable crawler

Abstract

To provide an unmanned aerial vehicle for an effective perching UAV having a releasable crawler for inspecting or maintaining a structure.SOLUTION: A UAV 100 includes a body, and three or more legs connected to the body and configured to land and perch the UAV on a curved ferromagnetic surface 50. Each leg includes a first portion connected to the body, a second portion including a magnet 120 and configured to magnetically attach and maintain the magnetic attachment of the leg to the ferromagnetic surface during the landing and perching, and a passive articulation joint connecting the first and second portions and configured to passively articulate the second portion with respect to the first portion in response to the second portion approaching the ferromagnetic surface. The UAV further includes a releasable crawler 150 including magnetic wheels, which detach the crawler from the body during the perching and maneuver the crawler on the ferromagnetic surface while magnetically attaching the crawler to the ferromagnetic surface after the detachment.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 772,700, filed on November 29, 2018, entitled "PERCHING UAV WITH RELEASABLE CRAWLER" under 35 U.S.C. § 119(e), and claims the benefit of U.S. Application No. 16 / 689,864, filed on November 20, 2019, entitled "PERCHING UAV WITH RELEASABLE CRAWLER" under 35 U.S.C. § 120, the entire contents of each of which are incorporated herein by reference.

[0002] The present disclosure generally relates to the inspection and maintenance of structures, and more particularly to a perching unmanned aerial vehicle (UAV) having a releasable and re - docking crawler for inspecting and maintaining structures.

Background Art

[0003] The inspection and maintenance of exposed metal assets such as pipes and storage tanks can be difficult or unrealistic for humans in some environments. In such situations, the use of automated UAVs (drones) can provide an auxiliary alternative that can be implemented. However, such inspection and maintenance tasks are often best performed using direct contact with the asset or by operating the UAV on the asset rather than hovering at a distance from the asset. In particular, performing a full - circumference scan of a pipe (or other asset) using a drone is a difficult task.

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=2,7]]<y With regard to these and other problems in the art, this disclosure aims to provide a technical solution for an effective perch-type UAV having a retractable crawler for inspecting or maintaining structures. [Means for solving the problem]

[0005] According to one embodiment, an unmanned aerial vehicle (UAV) is provided. The UAV includes a body constructed to enable the UAV to fly, and three or more legs connected to the body and configured to land and perch the UAV in flight on a curved ferromagnetic surface. Each leg includes a first part connected to the body, a second part having a magnet and configured to magnetically attach the leg to the ferromagnetic surface during landing and to maintain the magnetic attachment of the leg to the ferromagnetic surface during perching, and a passive articulated joint connecting the first part to the second part, configured such that the second part passively articulates with respect to the first part during landing in response to the second part approaching the ferromagnetic surface. The UAV further includes a releasable crawler, the releasable crawler having magnetic wheels configured to detach the crawler from the body during perching and to steer the crawler on the ferromagnetic surface while the crawler magnetically attaches to the ferromagnetic surface after detachment.

[0006] In one embodiment, the crawler further comprises a probe or tool configured to inspect or maintain a ferromagnetic surface during operation.

[0007] In one embodiment, the crawler further comprises a wireless communication circuit configured to communicate wirelessly with a UAV or a base station.

[0008] In one embodiment, the magnetic wheel is further configured to re-dock the crawler to the main body after steering.

[0009] In one embodiment, each magnet is a permanent magnet.

[0010] In one embodiment, each magnet is equipped with a switchable permanent magnet.

[0011] In one embodiment, each magnet is equipped with an electromagnet.

[0012] In one embodiment, the UAV further comprises a separation actuator configured to apply a lever to one or more second portions of the magnetically attached landing gear to the ferromagnetic surface in order to assist in magnetically separating one or more of the magnetically attached landing gear from the ferromagnetic surface during takeoff from the ferromagnetic surface of the perched UAV.

[0013] In one embodiment, the UAV further comprises a laser scanner connected to the main body and configured to provide sensing data for orienting the UAV during landing.

[0014] In one embodiment, the magnetic wheel comprises four magnetic wheels, and the crawler further comprises two motors, each configured to drive two of the four magnetic wheels.

[0015] In one embodiment, the magnetic wheel comprises an omniwheel or a mecanum wheel.

[0016] According to another embodiment, an unmanned aerial vehicle (UAV) is provided. The UAV is constructed to enable the UAV to fly and includes a first body and substructure having a plurality of first mounting points. The substructure comprises a second body having a plurality of corresponding second mounting points, the second body being mounted to the first body at corresponding pairs of the first and second mounting points, and three or more legs connected to the second body and configured to land and perch the UAV flying on a curved magnetic surface. Each leg comprises a first part connected to the second body, a second part having a magnet and configured to magnetically attach the leg to a ferromagnetic surface during landing and to maintain magnetic attachment of the leg to the ferromagnetic surface during perching, and a passive articulated joint connecting the first part to the second part, configured such that the second part passively articulates with respect to the first part during landing in response to the second part approaching the ferromagnetic surface. The substructure further comprises a releasable crawler, the releasable crawler having magnetic wheels configured to separate the crawler from the second body during perch operation and to steer the crawler on the ferromagnetic surface while magnetically attaching the crawler to the ferromagnetic surface after separation.

[0017] In one embodiment, the crawler further comprises a probe or tool configured to inspect or maintain a ferromagnetic surface during operation.

[0018] In one embodiment, the crawler further comprises a wireless communication circuit configured to communicate wirelessly with a UAV or a base station.

[0019] In one embodiment, the magnetic wheel is further configured to re-dock the crawler to the second body after steering.

[0020] In one embodiment, each magnet is a permanent magnet.

[0021] In one embodiment, each magnet is equipped with a switchable permanent magnet.

[0022] In one embodiment, each magnet includes an electro-permanent magnet.

[0023] In one embodiment, the UAV further includes a separation actuator configured to apply a lever to one or more second portions of the legs magnetically attached to the ferromagnetic surface in order to assist in magnetically separating one or more of the magnetically attached legs from the ferromagnetic surface during takeoff from the ferromagnetic surface of the perched UAV.

[0024] In one embodiment, the UAV further includes a laser scanner connected to the first body and configured to provide sensing data for orienting the UAV during landing.

[0025] In one embodiment, the magnetic wheel includes four magnetic wheels, and the crawler further includes two motors each configured to drive two of the four magnetic wheels.

[0026] In one embodiment, the magnetic wheel includes an omni-wheel or a mecanum wheel.

[0027] In one embodiment, the lower structure further includes a docking mechanism configured to fix the crawler to the second body during flight and a height adjustment mechanism configured to adjust the height of the crawler with respect to the ferromagnetic surface during perching.

[0028] In one embodiment, the first body further has a corresponding plurality of third attachment points, and the second body is configured to be separated from the first body at the first attachment point and attached to the first body at a corresponding pair of the third and second attachment points.

[0029] In one embodiment, the first body includes a movable mounting base, the movable mounting base has the first attachment point, and is configured to move the first attachment point with respect to the remaining portion of the first body.

[0030] In one embodiment, the UAV further comprises a motor configured to move a mounting platform during flight.

[0031] In one embodiment, the movable mounting base is further configured to rotate the first mounting point around the axis of the first body.

[0032] Any combination of the various embodiments and implementations disclosed herein can be used. These and other embodiments and features can be understood from the following descriptions of specific embodiments, together with the accompanying drawings and claims. [Brief explanation of the drawing]

[0033] [Figure 1A] Figure 1A shows an example of a UAV perched on a structure (e.g., a pipe) according to one embodiment, the UAV having a retractable crawler for inspecting or maintaining the structure. [Figure 1B] Figure 1B shows an example of a UAV perched on a structure (e.g., a pipe) according to one embodiment, the UAV having a detachable crawler for inspecting or maintaining the structure. The crawler is not attached to the UAV (e.g., crawling on the structure). [Figure 2A] An exploded view and a cross-sectional view of an exemplary UAV or drone according to one embodiment, the diagram showing a substructure having perching legs for perching to a structure. [Figure 2B] An exploded view and cross-sectional view of an exemplary UAV or drone according to one embodiment, which comprises a substructure having crawlers for releasing the UAV perched on a structure for inspection or maintenance of the structure. [Figure 3A] This is a cross-sectional view of an exemplary UAV having modular mounting points for attaching the lower structure shown in Figures 2A and 2B, according to one embodiment. [Figure 3B]This is a cross-sectional view of a UAV having a substructure attached to the UAV in a lateral orientation and an upward orientation, respectively, according to one embodiment. [Figure 3C] This is a cross-sectional view of a UAV having a substructure attached to the UAV in a lateral orientation and an upward orientation, respectively, according to one embodiment. [Figure 4A] This is a cross-sectional view of an exemplary UAV having rotatable mounting points for attaching the substructures shown in Figures 2A to 3C, along with substructures attached to the UAV in a bottom orientation, top orientation, and lateral orientation, respectively, according to one embodiment. [Figure 4B] This is a cross-sectional view of an exemplary UAV having rotatable mounting points for attaching the substructures shown in Figures 2A to 3C, along with substructures attached to the UAV in a bottom orientation, top orientation, and lateral orientation, respectively, according to one embodiment. [Figure 4C] This is a cross-sectional view of an exemplary UAV having rotatable mounting points for attaching the substructures shown in Figures 2A to 3C, along with substructures attached to the UAV in a bottom orientation, top orientation, and lateral orientation, respectively, according to one embodiment. [Modes for carrying out the invention]

[0034] Please note that the drawings are for illustrative purposes only and do not necessarily need to be to scale; the same or similar features will have the same or similar reference numbers throughout.

[0035] In various exemplary embodiments, a perchable UAV is provided having a retractable crawler for inspecting or maintaining structures such as pipes or storage tanks that are located at high elevation or otherwise difficult to access.

[0036] The UAV is a hybrid UAV with advanced capabilities to perform contact inspection work on curved ferromagnetic surfaces, such as carbon steel pipes, storage tanks, and other structures. The UAV can fly towards the pipe to be inspected and land autonomously (commonly referred to as perching), deploy retractable magnetic crawlers to crawl around the pipe, and perform intricate inspection work, for example, at any orientation angle. The crawlers can also be configured to perform maintenance on the pipe. As will be understood from the following discussion, the UAV can land, for example, on, to the side of, or directly below a pipe or other structure, and in each example, it is said to have landed on the structure.

[0037] As mentioned earlier, inspecting and maintaining exposed metal assets such as pipes and storage tanks can be difficult or impractical for people. For example, one of the biggest challenges in the oil and gas industry is the periodic inspection of elevated assets found at refineries, gas plants, offshore platforms, and other plants and facilities. These assets include pipes and structures at height that are difficult to access during inspection or maintenance work. Sometimes the only way for people to inspect or maintain them is to erect scaffolding so that inspectors or engineers can approach the assets and perform manual inspections, for example, using ultrasonic (UT) sensors for thickness measurement. Such scaffolding is expensive and poses a significant cost barrier to frequent inspections, as well as raising safety concerns, mainly in the form of the risk of falling and tripping.

[0038] Therefore, in exemplary embodiments, a perching UAV with a detachable crawler provides a solution to the aforementioned technical problems by having two vehicles in a mother-child configuration. Each vehicle is designed or optimized to perform the most suitable performance. The vehicles include a perching UAV that can fly over and land on pipes, and a small magnetic crawler that is carried by the UAV and released from the UAV after landing or stopping. The crawler can move around on the pipe to perform inspection scans, such as thickness measurement using UT sensors. For example, in some embodiments, both the UAV and the crawler magnetize onto the curved surface of the pipe or other asset being inspected or maintained. Thus, the crawler can perform a complete longitudinal or circumferential scan of the asset (even upside down relative to gravity).

[0039] This provides a more feasible approach than having the entire UAV crawl around the pipe, which would require larger and heavier motors and carry the risk of collisions with nearby pipes and assets, especially where clearance constraints are limited. Perched UAVs also save energy (e.g., electrical energy, battery energy, etc.) by perching to the pipe (or on top of the pipe, for example) as opposed to hovering near the pipe. Perching the UAV to the surface of the pipe also makes it easier to detach or re-dock any detachable crawlers from the UAV than when the UAV is hovering next to the pipe. Furthermore, perching provides greater stability and reduced risk compared to hovering.

[0040] Figures 1A and 1B illustrate an exemplary UAV 100 perched on a structure 50 (e.g., a pipe) according to one embodiment, the UAV 100 having a retractable crawler 130 for inspecting or maintaining the structure 50. The crawler 130 is shown attached to the UAV 100 in Figure 1A and not attached to the UAV 100 (e.g., crawling over the structure 50) in Figure 1B. For ease of explanation, the structure 50 is assumed throughout to be larger than the UAV 100 (e.g., significantly larger). For example, the structure 50 is larger than the UAV 100 in all dimensions. Or, the landing area provided by the structure 50 is larger than the landing area of ​​the UAV 100. Furthermore, for ease of explanation, the structure 50 (or any structure described herein) is assumed to be a pipe, such as a pipe with a diameter of 8 inches or more.

[0041] Figures 1A and 1B show the mother-child configuration in operation. Figure 1A shows the UAV 100 after landing on pipe 50, with the crawler 130 still docked. Figure 1B shows the crawler 130 after being released from the UAV 100 to perform inspection work. The crawling capability provided by the detachable crawler 130 grants the UAV 100 important capabilities for inspection and maintenance work, such as easier accessibility (e.g., not having to land at the exact spot where inspection or maintenance is performed). Crawling also provides circumferential and longitudinal scanning. For example, in the oil and gas industry, it is important to perform a full scan of pipe 50 to find the minimum steel thickness in a specific area of ​​pipe 50. Such scans often involve circumferential and longitudinal scans, and crawling is well suited to this. Crawling also provides power efficiency during multiple inspections (e.g., crawling between multiple inspection sites on the same pipe is more power efficient than flying).

[0042] In Figures 1A and 2B, the UAV100 utilizes four articulated magnets 120 (such as permanent magnets or switchable permanent magnets). To accommodate the landing of the UAV100 on the pipe 50, each magnet 120 (or more precisely, its magnetic field) articulates perpendicular to the pipe 50 when the UAV100 lands on or perches on the pipe 50.

[0043] In some embodiments, the magnetic field of the articulated magnet 120 can be actively switched on and off (for example, to allow for easy removal after the work is completed). As a form of real-time feedback, a laser scanner 110 (e.g., optical detection and ranging, or LIDAR) is included to measure the relative position of the pipe to the UAV 100 during automated landing movement, etc. In some embodiments, the miniature crawler 130 is connected by wires (e.g., for power and communication) and includes a UT sensor, four magnetic wheels 140, and two motors to drive the wheels 140 in corresponding pairs (e.g., front and rear). The wires also allow the remaining electronics and batteries for performing inspection or maintenance to be located inside the UAV body 100. This reduces the size, weight, and complexity of the crawler 130.

[0044] In some other embodiments, the crawler 130 includes a different number of wheels 140 (e.g., two or three wheels, or four or more) and their types (to some examples, Omni wheels, Mecanum wheels, etc.). Unlike unmanned ground vehicles (UGVs), the magnetic crawler 130 must contend with various curvatures and directions (as shown throughout) of pipe inspection or maintenance. Therefore, in some embodiments, the magnetic crawler 130 has a special locomotion system for navigating the curvature of pipes (or similar curvatures from other curved structures or blood vessels).

[0045] In some embodiments, communication between the crawler 130 and the UAV 100 is wired. For example, using a small spool of thin cord, the crawler 130 can be connected to the UAV 100 for power and communication. This eliminates the need to house batteries and other electronics within the crawler 130, for example, and allows for a smaller crawler and reduced overall weight by utilizing some components already present in the UAV 100.

[0046] In some other embodiments, communication between the crawler 130 and the UAV 100 is wireless. Here, the crawler 130 includes its own battery and electronics to provide a more independent vehicle. This may be useful, for example, when the UAV 100 picks up the crawler 130 from the ground and deploys it to the pipe 50. At that point, the UAV 100 can fly off to perform some other inspection work and then return to pick up the crawler 130. This is also useful when multiple crawlers 130 (e.g., a group of crawlers 130) are inspecting multiple assets. The UAV 100 picks them up one by one or in batches from the ground to the destination and retrieves them upon completion of the work. In different embodiments, the wireless connection may be between the crawler 130 and either the UAV 100 or the operator's control station, or between the UAV 100 and the operator's control station.

[0047] In one embodiment, the UAV 100 includes a body constructed to enable the flight of the UAV 100 (e.g., having rotors, control devices and guidance devices, etc.). The UAV 100 also includes three or more legs connected to the body and configured to land and perch the flying UAV 100 on a curved ferromagnetic surface 50. Each leg includes an upper (or main) portion connected to the body and a lower portion containing permanent magnets 120. The lower portion is configured to magnetically attach the leg to the ferromagnetic surface 50 during landing and to keep the leg magnetically attached to the ferromagnetic surface while perching. Furthermore, passive articulated joint connections connect the upper and lower parts of the leg and passively articulate (e.g., pivot) the lower part relative to the upper part in response to the lower part approaching the ferromagnetic surface 50 during landing. The UAV 100 further includes a releasable crawler 130 having magnetic wheels 140. The magnetic wheel 140 makes it possible to separate the crawler 130 from the UAV 100 while perching, and after separation, it becomes possible to move the crawler 130 on the ferromagnetic surface 50 while magnetically attaching it to the ferromagnetic surface 50.

[0048] In different embodiments, different landing mechanisms can be used for the UAV100. These may include various types of adhesion mechanisms, such as magnetic or non-magnetic. Examples of magnetic landing mechanisms include magnets that can be blocked or overcome by mechanical means during takeoff from the pipe 50. Such magnets include switchable permanent magnets, permanent magnets with an actuating lever to assist in removal during takeoff, permanent electromagnets, and electromagnets. However, it should be noted that continuous power consumption can be disadvantageous for electromagnets. Non-magnetic adhesion mechanisms can be used on non-ferromagnetic surfaces such as stainless steel, composite pipes, and concrete walls. Such mechanisms include microspines, suction cups, grippers, and crawls, which are gecko-inspired dry adhesives (such as synthetic bristles).

[0049] Different embodiments utilize different crawler loads or designs. For simplicity, these loads or designs are categorized into two basic categories: inspection and maintenance. Inspection loads and designs include various types of sensors commonly used in the oil and gas industry for inspecting pipes and structures. For example, in some embodiments, UT sensors are used for thickness measurement. For simplicity of explanation, UT sensors for thickness measurement are used occasionally throughout to represent exemplary devices and applications for inspection and maintenance. However, other embodiments are not limited to such devices or applications. For example, other inspection sensors or probes may be used instead of or in addition to UT sensors, depending on the task, and these include (but are not limited to) eddy current sensors and alternating current field measuring (ACFM) sensors.

[0050] In yet another embodiment, the crawler 130 is comprised of one or more tools and used for maintenance purposes. For example, the crawler 130 can be used to perform light maintenance tasks such as cleaning, surface treatment, and coating repair. In yet another embodiment, the crawler 130 is comprised of one or more cameras and used for visual inspection. For example, in some embodiments, the cameras are used for simple visual inspection tasks, such as tasks where it is necessary to acquire only video or photographs of an area of ​​interest, but it is difficult to inspect that area directly by the UAV 100.

[0051] In some embodiments, the crawler 130 is configured to leave markers (such as paint or QR codes) in areas of interest (such as locations where sensor readings are outside normal levels or where faults are detected). For example, these locations may be where critical thickness levels are detected. In some such embodiments, after the crawler 130 re-docks and the UAV 100 flies away, the UAV 100 scans these markers and creates a 3D reconstruction of the environment showing the exact locations of these markers. In some such embodiments, the UAV 100 uses an onboard RGB-D camera to detect the markers and calculates their positions relative to the UAV 100. The absolute positions of the markers can be calculated or otherwise determined using the UAV's GPS position. Note that while the UAV 100 is scanning the markers, the crawler 130 can, for example, remain on the pipe 50 or re-dock with the UAV 100.

[0052] In some embodiments, the crawler 130 uses radio localization to identify the location of asset problems using virtual markers or the like. In other words, the location of defects can be identified, albeit with less precision, even without physical markers. This is because the crawler's position relative to the UAV 100 can be calculated (or otherwise determined) using radio sensors. For example, in some such embodiments, the UAV 100 carries an ultra-wideband (UWB) sensor array, which receives radio signals from another UWB transmitter mounted on the crawler 130. This makes it possible to measure the crawler's relative position regardless of whether the UAV 100 is in flight or mounted on the pipe 50. In some embodiments, whenever an operator discovers a defect while crawling, the crawler's position relative to the UAV 100 is tagged and captured. The absolute location of these defects can then be determined using the UAV's GPS sensors. In some embodiments, if GPS is unavailable, the UAV's position is estimated based on flight path and IMU data from a GPS-enabled home base.

[0053] In some embodiments, pre-calculated (or determined) inspection locations are transmitted from the UAV 100 to an operating computer or ground station. The inspection locations are then visualized, for example, on a pre-created 3D model of the plant under inspection, or in a 3D model that can be constructed from the UAV's onboard sensors (e.g., a depth camera or 3D LiDAR). Furthermore, in some such embodiments, the visualized locations are annotated with the corresponding measured thickness (or other detected value or information).

[0054] Figures 2A and 2B are exploded and cross-sectional views of an exemplary UAV200 or drone according to one embodiment, respectively, comprising (1) a substructure 220 having perching legs 280 for perching to a structure 150 (a carbon steel pipe or other curved ferromagnetic surface 150), and (2) a substructure having crawlers 260 for releasing the UAV200 perched to the structure 150 for inspection or maintenance of the structure 150. The crawlers 260 have magnetic wheels 270 for steering while adhering to the curved ferromagnetic surface 150 (e.g., regardless of orientation with respect to gravity, even upside down). For ease of explanation, pipes are used throughout as an example of a structure having a curved ferromagnetic surface. However, the embodiments described are equally applicable to other such structures, such as cylindrical or spherical storage tanks having a curved ferromagnetic surface. The UAV200 or drone may include rotors (such as four or six rotors) and a control unit for adjusting the rotation speed of each rotor to balance the load on the UAV200 or to move the UAV200 in a desired direction.

[0055] Referring to Figures 2A and 2B, the UAV 200 includes a set of mounting points 210 for mating with a set of similar mounting points 230 on the substructure 220. In this way, any compatible UAV / substructure combination (e.g., compatible mounting points and effective load capacity / weight) can be assembled to suit the desired purpose, in this case a retractable crawler 260 for deploying onto and inspecting or maintaining the structure 150. For this purpose, the substructure 220 includes a set of perching legs 280 (e.g., four such legs 280), each having articulated magnets 290. The articulated magnets 290 are mounted on the legs 280 so as to be oriented toward the curved ferromagnetic surface 150 and able to adhere to the curved ferromagnetic surface 150 when the UAV 200 approaches and perches on the surface 150.

[0056] Therefore, as shown in Figure 2A, the articulated joint allows the magnet 290 to pivot within multiple axes, such as when the joint includes a universal joint, within the housing of the magnet 290 relative to the surface 150 on which the leg 280 perches. As illustrated, the pivot is possible around the axis of the leg 280 or the joint, and angles such as φ relative to the axis and optionally additional angles θ can be assumed. The UAV 200 and substructure 220 are primarily configured to perch and deploy the crawler 260 over (or near) the structure, or to retrieve it from over (or near) the structure (for example, to keep the rotor of the UAV 200 at the appropriate level before, during, and after perching).

[0057] Furthermore, the substructure 220 includes a height adjustment mechanism 240 (e.g., a motor or other actuator) for lowering the crawler 260 from the perched UAV 200 to the surface 150, or raising the crawler 260 from the surface 150 to the perched UAV 200. To assist this, a docking mechanism 250 connects the height adjustment mechanism 240 to the crawler 260 using a docking port or the like. After the crawler 260 is deployed to the surface 150, the docking port allows it to detach from the perched UAV 200 (e.g., be tossed away), or when ready to leave the surface 150, the docking port allows the crawler 260 to engage with the perched UAV 200 (e.g., run into or onto the surface), for example, to return to a home base or other structure or component to be inspected or maintained. The docking mechanism 250 may also allow for the transfer of information or energy between the UAV 200 and the crawler 260. For example, instrumentation data could be downloaded from the crawler 260 to the UAV 200, or the crawler 260's battery could be recharged using the UAV 200.

[0058] More specifically, in some embodiments, a height adjustment mechanism 240 is used to adjust the height of the crawler 260 based on the pipe diameter (for example, to successfully release it at surface 150). For example, with a large pipe (or plane), the height of the docked crawler 260 to surface 150 will be higher than with a small diameter pipe. Therefore, with a large pipe (or plane), the crawler 260 will deploy to a lower height to reach surface 150, while with a small diameter pipe, the crawler 260 will deploy and release at a higher point. Furthermore, in some embodiments, the height adjustment mechanism 240 is used to re-dock the crawler 260 after the work is completed. This allows the docking mechanism 250 to be at the correct height relative to the crawler 260. Again, different pipe diameters will result in different corresponding heights. In some embodiments, the height adjustment mechanism 240 is used to pull the crawler 260 and break its magnetization to the ferromagnetic surface 150.

[0059] In some embodiments, the height adjustment mechanism 240 is operated by a motor or the like. In some embodiments, the height adjustment mechanism 240 is passive when not used to separate the crawler 260. For example, in one such embodiment, the height adjustment mechanism 240 is spring-loaded so that when the UAV 200 perches and deploys the crawler 260, it can always push the pipe 150 in its maximum possible extension state.

[0060] In a UAV200 with a substructure 220, it is desirable to approach and land near the top surface of the pipe 150 (e.g., at or near the 12 o'clock position) at a straight or nearly straight angle, typically providing adhesion of the landing gear 280 and a proper perch. The perching landing gear 280 has features useful for successful perching and adhesion to the pipe 150. For example, each landing gear 280 of the perch mechanism features articulated magnets 290 (such as permanent magnets or switchable permanent magnets). The articulation of the landing gear 280 is passive when the UAV200 (more precisely, the attached substructure 220) is fairly close to the target ferromagnetic surface 150, such as in response to the initial contact between the magnets 290 and the ferromagnetic surface 150, in that the articulated magnets 290 are designed to articulate with respect to the axis shown in Figure 2A in response to the magnetic attraction of the magnets 290 and the ferromagnetic surface 150. It should be noted that the substructure 220 can be mounted on any UAV having a suitable mounting point (e.g., for mating with mounting point 230) and effective load capacity (e.g., for transporting and deploying the substructure 200 during flight).

[0061] In some embodiments, after deployment and completion of work, the crawler 260 re-docks with the UAV 200, or more specifically, with the docking mechanism 250. The process of re-docking and takeoff from the ferromagnetic surface 150 by the UAV 200 using the crawler 260 also includes magnetically separating the crawler 260 from the surface 150. In some such embodiments, the UAV 200 uses a height adjustment mechanism 240 to leverably separate the crawler 260 from the magnetic attraction between the crawler 260's magnetic wheels 270 and the ferromagnetic surface 150. In some other such embodiments, the magnetic wheels 270 use switchable magnets to disable adhesion to the ferromagnetic surface 150 after re-docking. In yet another few such embodiments, the docking mechanism 250 includes a ramp located on the pipe 150 and attached to the UAV 200. In such embodiments, the crawler 260 ascends the ramp while re-docking (as if parking on an inclined roadway). In this way, the crawler wheel motor is used to forcibly separate the magnets of the magnetic wheel 270 using the driving torque of the crawler 260. The ramp can be made of a metallic material (e.g., steel) or a non-magnetic material, depending on factors such as weight and strength. In each such embodiment, the magnetic attraction of the UAV 200 is achieved so that the UAV 200 can fly to the next location, along with the crawler 260 as an effective load that is safely held by the UAV 200.

[0062] Figure 3A is a cross-sectional view of an exemplary UAV 300 according to one embodiment, having modular mounting points 310 for attaching the substructure 220 shown in Figures 2A and 2B. Meanwhile, Figures 3B and 3C are cross-sectional views of a UAV 300 according to one embodiment, having substructures 220 attached to the UAV 300 in a lateral and upward orientation, respectively. This modular approach makes it possible to attach the substructure 220 (effective load) to the bottom, front, or top of the UAV 300, for example, so that it can perch on the top, side, or bottom of the pipe 150, respectively.

[0063] One of the biggest challenges when inspecting pipes in a refinery is that many pipes are not accessible from above due to obstacles such as racks, structures, and other pipes. In these cases, it is desirable to access or perch such surfaces from other locations, such as the side or bottom of the structure. The UAV300, along with a substructure 220 attached to a suitable set of mounting points 310, can perch above, to the side, or to the bottom of a pipe 150 using adaptable perching legs 280, as shown in Figures 3A, 3B, and 3C, respectively.

[0064] More specifically, each leg 280 is designed with articulated magnets 290, which divide the leg 200 into two separate parts: a main body securely attached to the substructure 220 and a movable (or articulated) magnet 290. This provides the leg 280 with at least rotational degrees of freedom, thereby allowing the magnets 290 to passively readjust their orientation (e.g., vertical) toward the pipe 150 during landing, enabling full or near-full adhesion.

[0065] To facilitate the explanation of the 2D side view, it should be noted that features such as the rotor of the UAV300 may be shown in contact with other parts of the UAV300 (such as the perching legs 280). However, this is because the depth dimension (where such features do not overlap) is not shown. The rotor of the UAV300 does not obstruct the substructure 220 in any configured orientation of the substructure 220 (for example, the substructure 220 is between the rotors when viewed from above).

[0066] It should also be noted that changing the location of the understructure 220 alters the center of gravity of the UAV300. Therefore, the UAV300 needs to compensate for this change. In some embodiments, the UAV300's onboard flight controller is configured (e.g., by logic circuits, code, etc.) to ensure that the UAV300 maintains stable hovering regardless of weight distribution. For example, if the front of the UAV300 becomes heavier, the controller is configured to sense the slight tilt and compensate for it by increasing the thrust or rotational speed of the heavier side (rotor) to keep the UAV300 level and stable. In some embodiments (as shown in Figures 4A to 4C), heavy components such as batteries are placed on a rotating rail opposite to the understructure 220 to reduce the effects of changes in the center of gravity. This makes it easier for the flight controller to keep the UAV200 stable even when the understructure 220 is not directly beneath the UAV200.

[0067] Figures 4A, 4B, and 4C are cross-sectional views of an exemplary UAV400 having a rotatable mounting point 410 for mounting the understructures 220 shown in Figures 2A to 3C, along with understructures 220 mounted to the UAV400 in a bottom orientation, top orientation, and lateral orientation, respectively, according to one embodiment. In some embodiments, the UAV400 includes a motor or actuator for rotating the mounting point 410 to a preferred orientation, including during flight (e.g., dynamic rotation). In some other embodiments, the mounting point 410 can be manually rotated to a desired orientation prior to the mission (e.g., static rotation).

[0068] In an exemplary motorized embodiment, an electric system (e.g., an electric mounting point 410 and a motor for rotating the mounting point 410 around the UAV 400) allows the operator to change the orientation of the understructure 220 (effective load) simply by pressing a button. In another embodiment, the UAV 400 automatically changes the orientation of the understructure 220 (e.g., during flight) in response to factors such as obstacles observed or known around the pipe 150. With these in mind, Figures 4A, 4B, and 4C illustrate how the electric system changes the orientation of the perching legs 280 to land on, below, or to the side of the pipe 150, respectively.

[0069] For example, in one embodiment, the UAV has a controller configured (by computer code, etc.) to plan the safest location on the pipe 150 to perch, such as on top of, beside, or bottom of the pipe 150, or somewhere in between. In the exemplary motorized embodiment shown in Figures 4A to 4C, rotation is achieved via a circular rail around the body 400 of the UAV. Therefore, to maintain a proper center of gravity during rotation, a heavy component such as a battery can be placed on the rail (for example, opposite the mounting point 410) to act as a counterweight.

[0070] In an exemplary user-adjustable (e.g., manual) embodiment, the rotation of the substructure 220 is manually adjusted by the user instead of being motorized. This can be done, for example, to save weight, complexity, power, etc. An exemplary technique for achieving this manual adjustment is to loosen a hand screw to unlock the manual rotation of the substructure 220 around the circular rail, and then relock it once the substructure 220 is in the desired position.

[0071] The methods described herein may be performed in part or in whole by machine-readable software or firmware on a tangible (e.g., non-temporary) storage medium. For example, such software or firmware may be in the form of a computer program adapted to perform some or all of the steps of any method described herein, and when the program is executed on a computer or a suitable hardware device (e.g., an FPGA), the computer program may be implemented on a computer-readable medium. Examples of tangible storage mediums include computer storage devices, including computer-readable media such as disks, thumb drives, and memory, and do not include propagated signals. While propagated signals may reside on tangible storage mediums, propagated signals themselves are not examples of tangible storage mediums. The software may be preferred to run on parallel or serial processors so that the method steps can be executed in any preferred order or concurrently.

[0072] It should be further understood that similar figures in the drawings represent similar elements across several drawings, and not all components and / or steps described and shown in relation to the drawings are required for all embodiments or configurations.

[0073] The terms used herein are for the purpose of describing only specific embodiments and are not intended to limit the disclosure. Where used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that, where used herein, the terms “comprises” and / or “comprising” express the presence of the described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0074] The terms of orientation are used herein solely for convention and reference purposes and should not be interpreted as restrictive. However, it is acknowledged that these terms may be used relative to the viewer. Therefore, no restriction is implied or inferred. Furthermore, the use of ordinal numbers (e.g., 1st, 2nd, 3rd) is for distinction, not counting. For example, "3rd" does not imply that there is a corresponding "1st" or "2nd." Also, the expressions and terminology used herein are for explanatory purposes only and should not be considered restrictive. The use herein of "including," "comprising," or "having," "containing," "involving," and their variations is intended to encompass the items listed thereafter, their equivalents, and additional items.

[0075] The subject matter described above is provided merely as an example and should not be construed as limiting. Various modifications and changes can be made to the subject matter described herein without following the exemplary embodiments and uses described and stated, and without departing from the true intent and scope of this disclosure as set forth in the subsequent claims. [Explanation of symbols]

[0076] 50. Curved ferromagnetic surfaces (structures, pipes) 100 UAV Unit 110 Laser Scanner 120 joint magnets 130 Magnetic Crawler (Miniature Crawler) 140 Magnetic Wheels 150 Curved ferromagnetic surface 200 Legs 210 mounting points 220 Undercarriage 230 mounting points 240 Adjustment mechanism 250 Docking Mechanism 260 Crawler 270 Magnetic Wheels 280 Legs 290 magnets 310 Modular mounting points 400 main unit 410 Electric mounting points

Claims

1. It is an unmanned aerial vehicle (UAV), A body constructed to enable the aforementioned UAV to fly, Three or more legs connected to the main body and configured to land and perch the flying UAV on a curved ferromagnetic surface, wherein each leg is The first part connected to the main body, A second part is provided with a magnet and is configured to magnetically attach the leg portion to the ferromagnetic surface during landing and to maintain the magnetic attachment of the leg portion to the ferromagnetic surface while in the perch, A three or more leg portion comprising: a passive articulated joint connecting the first portion to the second portion, configured such that the second portion passively articulates with the first portion during landing in response to the second portion approaching the ferromagnetic surface; A separation actuator is provided, configured to apply a lever to one or more of the second portions of the legs that are magnetically attached to the ferromagnetic surface, in order to assist in magnetically separating one or more of the magnetically attached legs from the ferromagnetic surface during the liftoff of the perched UAV from the ferromagnetic surface, A releasable crawler equipped with magnetic wheels, wherein the magnetic wheels are In the perch, the crawler is separated from the main body, A UAV comprising a detachable crawler, configured to perform the following actions: maneuvering the crawler on the ferromagnetic surface while magnetically attaching the crawler to the ferromagnetic surface after separation.

2. The UAV according to claim 1, wherein the crawler further comprises a probe or tool configured to inspect or maintain the ferromagnetic surface during the operation.

3. The UAV according to claim 1, further comprising a wireless communication circuit configured to wirelessly communicate with the UAV or base station.

4. The UAV according to claim 1, wherein the magnetic wheel is further configured to re-dock the crawler to the main body after the steering is complete.

5. The UAV according to claim 1, wherein each magnet is a permanent magnet.

6. The UAV according to claim 5, wherein each magnet is a switchable permanent magnet.

7. The UAV according to claim 6, wherein each magnet is equipped with a permanent electromagnet.

8. The UAV according to claim 1, further comprising a laser scanner connected to the main body and configured to provide sensing data for orienting the UAV during landing.

9. The UAV according to claim 1, wherein the magnetic wheel comprises four magnetic wheels, and the crawler further comprises two motors, each configured to drive two of the four magnetic wheels.

10. The UAV according to claim 1, wherein the magnetic wheel comprises an omniwheel or a mecanum wheel.

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