Patent Description:
Inspecting and operating on surfaces presents challenges to humans, particularly in confined spaces, large spaces, overhead areas, and when working on surfaces that are delicate or have pressure sensitivities. Inspection of these type of locations also presents risks to the humans that are asked to perform actions in such hazardous conditions. In some applications aerial drones may service to carry out such tasks but suffer their own limitations including a substantial risk of causing damage to the object or surface being inspected should the aerial done come into contact with the object. Aerial drones may also require special operator certifications and are restricted from use in certain airspaces.

<CIT> describes a bridge and tunnel structure, an automatic wall-climbing radar photoelectric robot system used for nondestructive detection and diagnosis of bridge and tunnel structural diseases, which mainly includes a control terminal, a wall-climbing robot and a server. The wall-climbing robot uses a rotary wing system to generate reverse thrust, and at the same time adopts omnidirectional wheel technology, it can move flexibly in close contact with the rough bridge and tunnel structure, and does not need to close bridges and tunnels during detection, and does not affect traffic. Only by arranging several UWB base stations and charging and data receiving devices on the bridge and tunnel structure, through UWB positioning, laser SLAM and IMU navigation technology, different working areas can be divided in bridges and tunnels, and multiple wall-climbing robots can work at the same time. It can realize automatic path planning and automatic obstacle avoidance, and can realize unattended regular automatic inspection.

Aspects of the present invention are set out in the appended claims and optional features are set out in the dependent claims. According to certain embodiments, a device comprises a body, a mechanical propulsion system affixed to the body to cause the body to traverse a multi-oriented surface and to prevent contact between the body and the multi-oriented surface, a thrust system to apply a thrust force to the device that opposes a gravitational force acting on the device, and a payload with at least one sensor to detect a characteristics of the multi-oriented surface.

According to certain embodiments a system for detecting the characteristics of a multi-oriented surface comprises at least one device, each of which comprises a body, a mechanical propulsion system affixed to the body to cause the body to traverse a multi-oriented surface and to prevent contact between the body and the multi-oriented surface, a thrust system to apply a thrust force to the device that opposes a gravitational force acting on the device, and a payload with at least one sensor to detect a characteristics of the multi-oriented surface. The system further comprises a controller to control each device and detect the characteristics of the multi-oriented surface using the sensors.

According to certain embodiments a method of detecting the characteristics of a multi-oriented surface is achieved by traversing the multi-oriented surface by at least one device, each of which comprises a body, a mechanical propulsion system affixed to the body to cause the body to traverse a multi-oriented surface and to prevent contact between the body and the multi-oriented surface, and a thrust system to apply a thrust force to the device that opposes a gravitational force acting on the device, and by then detecting characteristics of the multi-oriented surface by a number of sensors.

Certain embodiments may provide one or more technical advantages. As an example, certain embodiments provide advantages for allowing a drone to move about the surface of an object that may have a complicated topology and/or a delicate surface. As another example, certain embodiments provide advantages for enabling a drone to move about an inverted surface of an object that may be non-magnetic or may be intolerant of vacuum forces. Another example may be that certain embodiments provide the advantage of achieving better efficiency and/or ensuring complete adhesion of the drone to a partially-inverted surface through controlling the direction and point at which the thrust force acts upon the drone. Certain embodiments may include all, some, or none of the above-described advantages. Other advantages will be apparent to those of ordinary skill in the art.

For a more complete understanding of the present disclosure, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:.

The following description is presented to enable one of ordinary skill in the art to make and use the invention. Descriptions of specific embodiments and applications are provided only as examples and various modifications will be readily apparent to those skilled in the art. The general principles described herein may be applied to other embodiments and applications without departing from the scope of the invention. Thus, the present invention is not to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features described herein. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail.

Embodiments of the present disclosure and its advantages are best understood by referring to <FIG> of the drawings, like numerals being used for like and corresponding parts of the various drawings.

During manufacturing and assembly of large objects inspection and quality control may be critical, particularly for highly-sophisticated products. A large portion of this inspection and quality control is carried out by human workers. However, there may be regions of the manufactured object that are difficult to be inspected or worked on by humans. The reasons for this may range for difficult to access areas, areas that may be completely inaccessible to humans or may other wise by confined or at great elevation requiring special certification or other precautions. These difficulties may lead to additional expense, delays, or may also present greater risk of damage to the manufactured object (e.g., where the manufactured object may be easily damaged by dropped tools). In addition to the challenges present to human workers, better efficiencies may be achieved by employing inspection drones. The use of drones may supplement the manned-workforce. The use of drones may also be used to deploy a fleet of drones that may be coordinated to maximize efficiency. Such a fleet of drones may be deployed for use in any manner of coordination. This control and coordination may be carried out by individual control of each drone by a separate operator or controlled in groups by an operator. It is also possible to employ either semi-autonomous or completely autonomous control. Such forms of control and coordination may use pre-arranged inspection routes or inspection courses that may enable more efficiently completion of the task.

Recently, aerial drones have become more prevalent. These aerial drones, such as quadcopter or multi-rotor drones, present certain benefits as described above by have their own set of limitations. Current aerial drones are generally not well suited for performing inspections in particular orientations and may also have difficultly transitioning between orientations. Furthermore, an aerial drone may present a greater risk of causing damage to the objected to be inspected. For example, quadcopters with exposed blades may cause significant damage to an object if the rotating blades come into contact with the surface of the object. Another drawback of aerial drones is that in particular locations they may have certain restrictions, for example, Federal Aviation Administration approval or line of sign restrictions. Of course, the rapid consumption of power reserves required to continuously suspend the aerial drone makes such aerial drones less effective for carrying out inspections where an object may have a large surface to inspect that could otherwise be accomplished beneath a drone resting on the surface. Other types of drones, such as those that use magnets or suction forces to adhere to a surface, may not be suitable for many applications. For instance, this mechanism of adhering to a surface would not be suitable for non-magnetic objects or objects that have a surface that is intolerant of vacuum forces (e.g., thin-film surfaces or surfaces that may be destroyed by small scrapes). A number of other drawbacks to existing designs are also well known in the art. <FIG> illustrates an example crawler drone <NUM> that that may be used to traverse a multi-oriented surface <NUM>. Multi-oriented surface <NUM> may include a particularly challenging surface to completely traverse. For example, in the aerospace manufacturing industry a multi-oriented surface <NUM> may be either the internal or external surface of an aircraft fuselage, a confined fuel tank incorporated into the wing of an aircraft, or a tall vertical stabilizer that would otherwise require a human technician to use scaffolding and a harness to reach. Multi-oriented surface <NUM> may also be located in an environment inhospitable to humans such as an environment with extreme temperature or where contaminants and other environmental pollutants are present.

There may be a number of characteristics associated with the multi-oriented surface <NUM>. For instance, the characteristics of the multi-oriented surface <NUM> may include the tensile strength, pressure rating, and magnetic properties of the multi-oriented surface <NUM>. The characteristics of the multi-oriented surface <NUM> may also include, for example, one or more defects <NUM> in the manufacturing of the multi-oriented surface <NUM>. As an example, defect <NUM> may include any form of flaw such as a surface scratch, blemish, cracks, delamination, spalling, cavities, improper welds, or other assembly flaws.

Crawler drone <NUM> may have a body <NUM> providing structure to the drone and supporting other systems of crawler drone <NUM>. Crawler drone <NUM> may also have a mechanical propulsion system <NUM> affixed to the crawler drone <NUM>. As illustrated, the mechanical propulsion system <NUM> of crawler drone <NUM> includes four wheels. The mechanical propulsion system <NUM> may include any number of wheels, continuous tracks, omni-directional ball wheels, and casters depending on the application and the characteristics of the particular multi-oriented surface <NUM>. For instance, wheels of a greater width or tracks may be selected for a particularly delicate multi-oriented surface <NUM> to ensure greater distribution of the weight of crawler drone <NUM> or greater of the thrust force through the mechanical propulsion system <NUM> onto the multi-oriented surface <NUM>. The mechanical propulsion system <NUM> may also include a motor 102a to turn the wheels or tracks of the crawler drone <NUM> to enable the crawler drone to drive or traverse the multi-oriented surface <NUM>. The mechanical propulsion system <NUM> may include any number of electric motors, in the illustrated embodiment the mechanical propulsion system <NUM> include one electric motor 102a at each of the wheels.

The wheels or tracks of mechanical propulsion system <NUM> may supported by a suspension system <NUM>. As illustrated, the suspension system <NUM> is integrated as part of crawler drone <NUM> and may be affixed to body <NUM>. The suspension system <NUM> may serve to ensure that all of the wheels or a sufficient portion of the tracks of mechanical propulsion system <NUM> remains in contact with the multi-oriented surface <NUM>. In certain embodiments the suspension system may have actuators 103a for the purpose of raising, lowering, or adjusting the tilt or orientation of the body <NUM> and the entire crawler drone <NUM> with respect to the multi-oriented surface <NUM>. This may be done to lift the body <NUM> of crawler drone <NUM> over a protrusion of the multi-oriented surface <NUM> so as to ensure that the crawler drone <NUM> may be completely contact free as it traverses the multi-oriented surface <NUM>, other than the contact between the mechanical propulsion system <NUM> and the multi-oriented surface <NUM>. Additionally, actuators 103a may be selectively engaged to tilt the crawler drone <NUM>. This may have particular benefits as will be described in further detail with respect to the descriptions of <FIG>.

The crawler drone <NUM> also includes a thrust system <NUM> to provide a normal force on the crawler drone <NUM>. The normal force applied to the crawler drone <NUM> by the thrust system <NUM> may assist the crawler drone <NUM> in adhering to multi-oriented surface <NUM>. When the thrust system <NUM> is sized correctly it may provide a sufficient normal force to ensure that the mechanical propulsion system <NUM> of the crawler drone <NUM> maintains contact with the multi-oriented surface <NUM> through the full range of orientations, including a completely inverted orientation. In such an instance the thrust system <NUM> must provide a thrust force that is greater than the gravitation force acting upon the crawler drone <NUM>. The appropriate thrust force is further detailed with respect to the disclosure of <FIG> herein. It is also recognized that the thrust system <NUM> may also be configured so as to reduce the negative suction pressure at the bottom of the crawler drone <NUM> that may otherwise be problematic to the face of particularly delicate multi-oriented surfaces <NUM>. This may be accomplished by, for example, locating the intakes for the thrust system <NUM> at the sides of the body <NUM> so as to draw in air at the sides and avoid the possibility of a vacuum occurring on the face of the multi-oriented surface <NUM>.

As illustrated in <FIG> the thrust system is incorporated into body <NUM> but other configurations for thrust system <NUM> are also envisioned, for example, external rotor blades. Furthermore, in certain embodiments thrust system <NUM> may include more than one ducted fan, for instance four ducted fans may all be located about the periphery of body <NUM> such that the power of each ducted fan may be controlled to cause a moment to act about the center of gravity of the crawler drone <NUM>. This moment may be beneficial to cause the suspension system <NUM> to slump thereby resulting in the angle of the thrust force applied to the crawler drone <NUM> by the thrust system <NUM> to be slightly off from normal. In certain other embodiments, the thrust system <NUM> may include control vanes to adjust the angle of the thrust force. As may be appreciated, this angling of the thrust force may help to control the force applied by the mechanical propulsion system <NUM> to the multi-oriented surface <NUM> in situations where the characteristics of the multi-oriented surface <NUM> cannot support a large force. This angling of the thrust force may also be beneficial in assisting the mechanical propulsion system <NUM> in mounting an inclined portion of the multi-oriented surface. This angled thrust force will be described in further detail with respect to the descriptions associated with <FIG>.

Crawler drone <NUM> also includes a payload <NUM> for accomplishing a host of tasks. As illustrated, crawler drone <NUM> has a sensor for detecting defects <NUM> associated with the multi-oriented surface <NUM>. The sensor of payload <NUM> may be any combination of a visual-spectrum camera, an infrared camera, a thermal camera, a laser scanner, an X-ray module, an ultrasonic non-destructive testing module, or any other type of sensor for determine characteristics associated with the multi-oriented surface <NUM>. As the crawler drone <NUM> traverses the multi-oriented surface <NUM> the sensor of payload <NUM> may detect a defect <NUM>. These detected defects <NUM> may be captured in the recorded data or otherwise identified. For example, the crawler drone <NUM> may indicate the presence of the defect <NUM> by placing a marker on the multi-oriented surface <NUM> that is near the defect <NUM>. Such markers may include an ink mark, a paint mark, a sticker, or other conceivable marker. In certain other embodiments payload <NUM> may also include a tool for making repairs to the defect <NUM> of the multi-oriented surface <NUM>. Tools equipped to the payload <NUM> may include a paint applicator, a sealant applicator, a glue applicator, a sanding apparatus, a deburring apparatus, a cutting apparatus, a welding apparatus, a rivet applicator, a marker, a sticker applicator, or any other tool as may readily be apparent to one of skill in the art of manufacturing. In other embodiments, the payload <NUM> may also include a tool delivery system for transporting a tool to a human work or other system to carry out the repair.

The crawler drone <NUM> may also include a controller <NUM>. As illustrated, the controller <NUM> is mounted to the body <NUM> of the crawler drone <NUM>. This configuration may be used for an autonomous crawler drone <NUM> but may also be used for manual or semi-autonomous control where the directions are provided to the controller <NUM> through wireless communication (e.g., Bluetooth, Wi-Fi, or other radio telecommunications). However, in certain other embodiments, the controller may be located remote to the crawler drone <NUM>. For example, a tether may be communicatively coupled with the crawler drone <NUM> to provide direction and control to the crawler drone. Controller <NUM> may also have various inputs and outputs to facilitate the retrieval of data from the sensor of payload <NUM> (e.g., USB, MicroSD, remote media streaming, as well as other storage devices).

<FIG> illustrate a sequence of transitions performed by a simplified representation of a crawler drone <NUM>, such as that illustrated in <FIG>, as it traverses a complex multi-oriented surface <NUM>. A number of simplified forces acting upon the crawler drone <NUM> are represented in each of the <FIG>. These forces correspond as follows: FT is the thrust force applied by the thrust system <NUM>; FN is the effective normal force from the multi-oriented surface <NUM> acting upon the crawler drone <NUM>; mg is the force of gravity acting upon the crawler drone <NUM>; and Ff is the friction force acting on the wheels of the mechanical propulsion system <NUM>. For the four-wheeled embodiment illustrated in <FIG> it is understood that there would be four friction forces, and four normal forces acting along the points of contact of each of the four wheels of the mechanical propulsion system <NUM>, however these forces have been simplified in their representations throughout <FIG> for clarity. Furthermore, the various forces as illustrated are not all to scale but in combination with the following descriptions serve to inform some of the functionality of the crawler drone <NUM>.

As illustrated in <FIG>, when the crawler drone <NUM> is scaling a vertically-oriented multi-oriented surface <NUM> the thrust force is directed towards the bottom of the multi-oriented surface that, in combination with the friction force of the mechanical propulsion system <NUM>, causes the crawler drone <NUM> to adhere to the multi-oriented surface. With a sufficient thrust force from the thrust system <NUM>, the mechanical propulsion system <NUM> may locomote around the multi-oriented surface <NUM>. As illustrated in <FIG> the crawler <NUM> my traverse the vertical-portion of the multi-oriented surface in an upward direction until it reaches the position as illustrated in <FIG>. By slightly angling the thrust force applied to the crawler drone <NUM> by to the thrust system <NUM>, the normal component of the thrust force may lessen the force applied to the multi-oriented surface <NUM> and the vertical component may also assist the mechanical propulsion system <NUM> in overcoming the gravitational force in the direction of travel.

As illustrated in <FIG>, the suspension system <NUM> may be capable of lifting the body <NUM> of the crawler drone <NUM>, such as by actuators <NUM>, above any point of the multi-oriented surface <NUM> to avoid any damage that might result from contact or even with placing the thrust system <NUM> within close proximity of the multi-oriented surface <NUM>.

As the crawler drone <NUM> transitions from the vertical orientation of <FIG>, to an inclined orientation of <FIG>, then to a horizontal orientation as illustrated in <FIG>, the thrust force produced by the thrust system <NUM> may be progressively decreased until, in some embodiments, it may ultimately be completely reduced to a zero-magnitude condition once the crawler drone is on a level plane, such as illustrated in <FIG>. In <FIG> the crawler drone <NUM> may traverse the multi-oriented surface <NUM> powered entirely by the mechanical propulsion system <NUM>. In other embodiments the crawler drone <NUM> may traverse the multi-oriented surface <NUM> by applying a thrust force by the thrust system <NUM> angled in the direction of travel, in such a case the friction force would act in the opposite direction as that illustrated in <FIG>.

In <FIG> the crawler drone <NUM> is shown transitioning the multi-oriented surface <NUM> from a horizontal orientation to a vertical orientation. Here, the thrust system <NUM> may again need to be engaged to ensure a sufficient friction force may result at each of the points of contact of the mechanical propulsion system <NUM>. Additionally, depending on the length of overhang between the body <NUM> of the crawler drone <NUM> and the radius of transition or curvature of the multi-oriented surface <NUM>, the suspension system <NUM> may raise the body <NUM> or extend the mechanical propulsion system <NUM> to avoid contact with the multi-oriented surface <NUM>.

For purposes of brevity, the next orientation shown in <FIG> occurs after the crawler drone has transitioned through the vertical portion. Reference may be made to the description with respect to <FIG> for the intermediate operation of the crawler drone <NUM> between <FIG>. In many respects, the operation of the crawler drone <NUM> in traversing the concave transition of <FIG> will be similar to that of <FIG> with the notable distinction that the thrust force will be greater in the partially-inverted orientation of <FIG>. This effect occurs because the thrust force of the thrust system <NUM> as oriented in <FIG> is opposed to the gravitational force acting on the crawler drone <NUM> compared with the orientation show in in <FIG>.

Lastly, as illustrated in <FIG>, the crawler drone <NUM> is in a completely-inverted orientation. In order to remain adhered to the multi-oriented surface <NUM>, the thrust system <NUM> must produce a thrust force at least as great as the gravitational force acting on the crawler drone <NUM>. In certain embodiments, when in the fully inverted orientation, the thrust system may be at its greatest thrust output, however, as described further with respect to <FIG>, in certain instances this may not be the case.

<FIG> illustrates a simplified free body diagram of a crawler drone <NUM> moving in an ascending direction along a sloped multi-oriented surface <NUM>. As illustrated, the crawler drone <NUM> has mechanical propulsion system <NUM> illustrated as a pair of wheels in contact with the multi-oriented surface <NUM>. A thrust force FT is also illustrated as effectively acting upon a point <NUM> within body <NUM> of the crawler drone <NUM>. Additionally, the center of gravity <NUM> of the crawler drone <NUM> is represented as a point. Other nomenclature illustrated include: θ - The angle of slope of the multi-oriented surface <NUM>; mg - The gravitation force acting upon the crawler drone <NUM>; FT - The thrust force produced by the thrust system <NUM>; β - The angle of the thrust force off from normal to the multi-oriented surface <NUM>; L - The length of the wheelbase of the mechanical propulsion system <NUM>; LC - The distance between the front of the mechanical propulsion system <NUM> and the center of gravity <NUM>; LT - The distance between the front of the mechanical propulsion system <NUM> and the point <NUM> upon which the thrust force acts; hC - The distance from the center of gravity <NUM> of the crawler drone <NUM> to the multi-oriented surface <NUM>; hT - The distance from the point <NUM> upon which the thrust force acts to the multi-oriented surface <NUM>; FNf,Nr - The normal force applied to the front and rear wheels of the mechanical propulsion system <NUM>, respectively; and Fff,fr - The frictional force applied to the front and rear wheels of the mechanical propulsion system <NUM>, respectively.

Consideration of the distances between the point <NUM> and the center of gravity <NUM> may be used to control the rotational moment applied to the crawler drone <NUM>. This distance from the point <NUM> to the center of gravity <NUM> may be controlled, for example, where a thrust system <NUM> includes more than one ducted fan by controlling the different fan speeds to locate the point of the effective thrust force to be closer to those fans with a greater magnitude. This moment may induce a rotational force causing the suspension system <NUM> to slump in response to the rotational force. The slumping of the suspension system <NUM> therefore causes the body <NUM> of the crawler drone <NUM> to change its angle slightly. By doing so, even for embodiments of crawler drones <NUM> that have a fixed angle thrust system <NUM> the angle β of the thrust force may be controlled. Additionally, as previously described, the angle β may be adjusted either by the thrust system <NUM>, by an active suspension system <NUM> with actuators 103a, by the thrust system <NUM> in combination with the suspension system <NUM>, or any combination thereof.

As a simple example, when the thrust force is held at a constant, as the angle β increases the normal forces FNf,Nr acting on the mechanical propulsion system <NUM> will decrease and the force parallel to the multi-oriented surface <NUM> will increase, hereinafter this parallel force that is a component of the thrust force will be referred as a pushing force. For a range of thrust forces, there will be a corresponding angle β such that the pushing force will equal the sliding component of the gravitational force acting on the crawler drone <NUM> such that the crawler drone <NUM> may be stable in place without rolling down the multi-oriented surface <NUM> having a slope of θ. Either increasing the thrust force, increasing the angle β of the thrust force for the same slope of θ, or a combination thereof may cause the crawler drone <NUM> to move up the slope of the multi-oriented surface <NUM> or used in combination to assist the mechanical propulsion system <NUM> to traverse up the multi-oriented surface <NUM>. Likewise, as the thrust force and the angle β of the thrust force are decreased the sliding component of the gravitational force may tend to cause the crawler drone <NUM> to roll down the multi-oriented surface <NUM>. This may be advantageous when it is desired to descend a multi-oriented surface by allowing the gravitational force to inherently cause the crawler drone <NUM> to traverse down the multi-oriented surface thereby achieving a reduction in the energy expenditure by either or both of the thrust system <NUM> and the mechanical propulsion system <NUM>.

Furthermore, as the angle θ of the slope of the multi-oriented surface <NUM> increases the angle β of the thrust force or the magnitude of the thrust force must correspondingly increase. These effects may be better described with respect to the three-dimensional depiction of a simplified crawler drone <NUM> as illustrated in <FIG> along with the associated thrust force diagram of <FIG>.

<FIG> introduces some additional concepts to the simplified two-dimensional free body diagram of <FIG>. Here, as illustrated, the crawler drone <NUM> has a body <NUM> along with a mechanical propulsion system <NUM>. In certain embodiments the mechanical propulsion system <NUM> may include four wheels for traversing the multi-oriented surface <NUM>. For the sake of clarity, those concepts introduced with respect to <FIG> will not be repeated here and the focus will instead be directed to concepts unique to the three-dimensional representation of the crawler drone <NUM> on a multi-oriented surface <NUM>.

Vector notation has been implemented for the illustration of the crawler drone <NUM> in <FIG>. In contrast to the two-dimensional representation, here the friction forces on each wheel of the mechanical propulsion system <NUM> there two components of the friction force illustrated as applied to each wheel. First is a friction force Ff in the direction of travel êt and second is a friction force Ff perpendicular to the direction of travel êb which accounts for the slipping force resultant from the gravitational force Fg acting on the crawler drone <NUM>. The third force acting on each of the wheels is the normal force FN. Each of these three forces for the four wheels are followed by a series of letters to indicate which wheel the force corresponds to. The notation scheme is as follows: Force friction or normal, front or rear, left or right, direction. For instance, the friction force Ffflêb could otherwise be expressed as the friction force Ff for the wheel in the front f left l in the direction of êb. Likewise, the normal force FNrr corresponds to the normal force FN applied to the rear r right r wheel of the mechanical propulsion system <NUM>. These friction and normal forces acting on the mechanical propulsion system <NUM> all occur at the points of contact between the wheels and the multi-oriented surface <NUM> which may extend further away from the center of gravity than the edge of the body <NUM>, here the distance from the point of contact and the axis of rotation about the center of gravity <NUM> would be half the distance of L and half the distance of W. These distances are important to consider possible tipping of the crawler drone <NUM> across the entire range of slope angles θ of the multi-oriented surface <NUM>.

As illustrated, the crawler drone <NUM> is traveling in the direction êt along the multi-oriented surface <NUM> having a slope of angle θ. This represents a heading angle ϕ of ninety degrees whereas a heading angle ϕ of zero degrees would correspond to directly up the slope θ of the multi-oriented surface <NUM>. Likewise, a heading angle ϕ of one hundred and eighty degrees would correspond to directly down the slope θ of the multi-oriented surface <NUM>. In addition, internal forces resisting the change in movement of the crawler drone <NUM> have been accounted for and represented by FI. <FIG> is a chart where the surface represents the minimum thrust force necessary for an example crawler drone such as the one illustrated in <FIG> that undergoes the set of forces applied to it as described with respect to <FIG>. This chart plots the thrust force required to be produced by the thrust system <NUM> along the vertical axis. Along the other two axes are the angle of slope θ or surface incline of the multi-oriented surface <NUM> and the heading angle ϕ of the crawler across the entire range of surface orientations and headings. Any thrust force of a magnitude greater than that indicated by the surface of the plot should be sufficient to ensure that the crawler drone <NUM> remains adhered to the multi-oriented surface <NUM> without falling, sliding, or tipping at the particular heading ϕ and slope θ. It is recognized, however, that a greater thrust force may consume energy reserves at a greater rate and may further impart an undesirably-large force on the multi-oriented surface <NUM> in certain instances.

This insight may be used to control the instantaneous thrust force to allow for some safety margin but not overconsume energy reserves, thus prolonging the duration that a crawler drone <NUM> may perform its operations. Furthermore, the thrust force may be controlled in relation to the normal force that would be applied to the multi-oriented surface <NUM> to prevent damage during the course of performing the operations of the crawler drone <NUM>. This insight may further be used to pre-compute an ideal path or course for a crawler drone <NUM>. For example, the crawler drone <NUM> may have a path that operates in a predominately inverted orientation to begin with while the power reserves or battery of crawler drone is at its maximum and then move to less-steep orientations as the power reserves are depleted where the energy expenditure would be less strenuous. Where multiple crawler drones <NUM> are employed as platoons or in a fleet the amount of operations to be performed in areas that require greater thrust forces may be more efficiently spread among the number of crawler drones <NUM>. These considerations and others may be programed or computed by the controller <NUM> either at the outset or may be dynamically calculated and communicated with other crawler drones <NUM> or human operators.

Claim 1:
A device comprising:
a body (<NUM>, <NUM>, <NUM>);
a mechanical propulsion system (<NUM>, <NUM>, <NUM>) affixed to the body (<NUM>, <NUM>, <NUM>), the mechanical propulsion system (<NUM>, <NUM>, <NUM>) configured to:
cause the body (<NUM>, <NUM>, <NUM>) to traverse a multi-oriented surface (<NUM>, <NUM>, <NUM>, <NUM>); and
prevent contact between the body (<NUM>, <NUM>, <NUM>) and the multi-oriented surface (<NUM>, <NUM>, <NUM>, <NUM>);
a thrust system (<NUM>) configured to apply a thrust force to the device, wherein the thrust force opposes a gravitational force acting on the device;
a payload (<NUM>) comprising at least one sensor configured to detect one or more characteristics associated with the multi-oriented surface (<NUM>, <NUM>, <NUM>, <NUM>); and
a suspension system (<NUM>) comprising two or more actuators (103a), wherein the suspension system is configured to:
adjust the orientation of the body (<NUM>, <NUM>, <NUM>); and
maintain contact between the mechanical propulsion system (<NUM>, <NUM>, <NUM>) and the multi-oriented surface (<NUM>, <NUM>, <NUM>, <NUM>);
wherein the mechanical propulsion system (<NUM>, <NUM>, <NUM>) is affixed to the body (<NUM>, <NUM>, <NUM>) by the suspension system (<NUM>) and wherein:-
(i) the suspension system (<NUM>) is further configured to adjust the orientation of the body (<NUM>, <NUM>, <NUM>) such that the direction of the thrust force is more incidental to the direction of the gravitation force;
(ii) wherein the suspension system (<NUM>) is further configured to adjust the orientation of the body (<NUM>, <NUM>, <NUM>) such that the direction of the thrust force is more opposed to the direction of slide of the mechanical propulsion system (<NUM>, <NUM>, <NUM>); and
(iii) wherein the suspension system (<NUM>) is further configured, using actuators (103a), to raise, lower or adjust the tilt of the body (<NUM>, <NUM>, <NUM>) with respect to the multi-oriented surface (<NUM>, <NUM>, <NUM>, <NUM>) in response to a topology of the multi-oriented surface (<NUM>, <NUM>, <NUM>, <NUM>).