Abstract:
A method for inspecting structures that includes using a plurality of independent unmanned mobile vehicles. The unmanned mobile vehicles are equipped with a control and guidance system for enabling each unmanned mobile vehicle to operate autonomously. Each unmanned mobile vehicle may be programmed with an operating program that defines a path of travel for it, relative to a structure to be inspected. The unmanned mobile vehicles are deployed so that they cooperatively form a swarm that travels about the structure. At least one of said unmanned mobile vehicles is used to obtain inspection data of a portion of the structure as it executes its respective operating program.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application takes priority from U.S. Patent Application Nos. 61/032,624 filed Feb. 29, 2008, and 61/032,609 filed Feb. 29, 2008. The disclosures of the above applications are incorporated herein by reference. 
         [0002]    This application is related in general subject matter to U.S. patent application Ser. No. ______, entitled “TRAFFIC AND SECURITY MONITORING SYSTEM AND METHOD” (Boeing Reference 08-0125A) filed concurrently herewith and assigned to the Boeing Company. This disclosure of this application is incorporated herein by reference. 
     
    
     FIELD 
       [0003]    The present disclosure relates to systems and methods for performing inspection activities, and more particularly to a system and method for enabling remote inspection of structures or objects by a plurality of unmanned mobile vehicles. 
       BACKGROUND 
       [0004]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
         [0005]    In-person human based inspections of structures and various types of objects can be time consuming, expensive, difficult and often dangerous for an individual to perform. Examples of structures that pose significant challenges in inspecting are bridges, dams, levees, power plants, power lines or electrical power grids, water treatment facilities; oil refineries, chemical processing plants, high rise buildings, infrastructure associated with electric trains and monorail support structures, just to name a few. 
         [0006]    The use of static cameras (i.e., fixedly mounted cameras) to provide periodic pictures of a structure or object requiring periodic visual inspection has met with limited effectiveness. Static cameras have a limited field-of-view. Therefore, inspecting a large area, such a power line stretching hundreds of meters or more, is difficult or impossible without using a large number of such cameras. Furthermore, once a camera is mounted in place, it may not be easily accessible for repair or maintenance. The mounting of the camera may require it to be exposed to the elements, which can decrease the reliability and/or cost of operation of the camera. 
         [0007]    A static camera mounted near a top of a bridge, to obtain periodic pictures of a structural portion of the bridge, may also be difficult and/or costly to access by an individual if a repair or maintenance becomes necessary. The act of requiring an individual to access a camera mounted high atop a bridge, dam, etc., could also entail significant risk to human safety for the worker or workers charged with such a task. 
         [0008]    Occasionally an infrastructure may require inspection where because of environmental, chemical or biological elements the inspection would place a human worker at significant risk to his or her health. Such a situation might be found inside a manufacturing facility, where a periodic regular inspection of a portion of the facility or machines operating within it, in areas where harmful chemicals may be present, needs to be made. Inspection of structural portions of an offshore oil drilling platform would be another example where environmental factors could make the inspection of various parts of the platform by humans fraught with hazard. Still other structures, for example large antennas or telescopes located on mountains, can present situations where inspection by a human presents significant risk to the individual&#39;s safety. 
         [0009]    In some inspection applications human piloted helicopters have been used to inspect various infrastructures. However, human piloted helicopters can be expensive to operate in terms of asset cost (helicopter, fuel and maintenance) and operational cost (pilot salary). In addition, inspection is limited by the available number of pilots and helicopters and can be hazardous in some instances, such as during rain or dust storms. Also, the use of human piloted helicopters is sometimes simply not possible during inclement weather. 
         [0010]    Remote controlled (RC) helicopters are lower in cost but require a trained RC pilot, and thus inspecting a large area with multiple helicopters requires a large number of expensive trained RC pilots. In addition, precision inspection and the time duration during which an inspection operation may be performed can be limited because of the available number of RC pilots and RC helicopters. 
       SUMMARY 
       [0011]    In one aspect the present disclosure relates to a method for inspecting structures. The method may comprise: 
         [0012]    using a plurality of independent unmanned mobile vehicles; 
         [0013]    equipping each of the unmanned mobile vehicles with a control and guidance system for enabling each unmanned mobile vehicle to operate autonomously; 
         [0014]    programming each unmanned mobile vehicle with an operating program that defines a path of travel for each unmanned mobile vehicle, relative to a structure to be inspected; 
         [0015]    deploying each unmanned mobile vehicle so that the unmanned mobile vehicles cooperatively form a swarm that travels about the structure; and 
         [0016]    using at least one of the unmanned mobile vehicles to obtain inspection data of a portion of the structure as it executes its respective operating program. 
         [0017]    In another aspect a method for inspecting structures is disclosed. The method may comprise: 
         [0018]    using a plurality of independent unmanned mobile vehicles; 
         [0019]    equipping each of the unmanned mobile vehicles with a control and guidance system for enabling each unmanned mobile vehicle to operate autonomously; 
         [0020]    programming each unmanned vehicle with an operating program that defines a unique path of travel for each unmanned mobile vehicle, relative to a structure to be inspected; 
         [0021]    deploying each unmanned mobile vehicle so that the unmanned mobile vehicles cooperatively form a swarm that travels about the structure; 
         [0022]    using the unmanned mobile vehicles to obtain images of portions of the structure as each unmanned mobile vehicle executes its respective operating program; and 
         [0023]    causing each unmanned mobile vehicle to wirelessly transmit the images to a remote centralized inspection station. 
         [0024]    In another aspect of the present disclosure a system is disclosed for inspecting structures. The system may comprise: 
         [0025]    a plurality of independent unmanned mobile vehicles; 
         [0026]    each of the unmanned mobile vehicles having a control and guidance system for enabling each unmanned mobile vehicle to operate autonomously; 
         [0027]    each of the unmanned mobile vehicles including an operating program that defines a path of travel for each unmanned mobile vehicle, relative to a structure to be inspected, so that in operation the unmanned mobile vehicles cooperatively form a swarm that moves about the structure; and 
         [0028]    at least one of the unmanned mobile vehicles including an imaging device to obtain an image of a portion of the structure as it executes its respective operating program. 
         [0029]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0031]      FIG. 1  is a block diagram of one implementation of a system in accordance with the present disclosure; 
           [0032]      FIG. 2  is a block diagram of the onboard system that may be carried on each of the UAVs shown in  FIG. 1 ; and 
           [0033]      FIG. 3  is a flowchart of major operations that may be performed by the system of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
         [0035]    Referring to  FIG. 1 , there is shown a system  10  for inspecting structures. The system  10  includes a plurality of unmanned mobile vehicles  12  that may be used move around a structure  14  requiring periodic inspection. In this example the unmanned mobile vehicles are illustrated as unmanned aerial vehicles, and more specifically as unmanned rotorcraft (hereinafter after simply referred to as “UAVs”  12 ), although it will be appreciated that other forms of unmanned vehicles such as unmanned land vehicles  12 ′ and unmanned marine vessels  12 ″ (both surface and underwater) could readily be adapted for use with the present system  10 . Also, while the structure  14  is illustrated as a bridge, the system  10  is equally well adapted for use in inspecting a wide range of other structures including, but not limited to, power lines, power generating facilities, power grids, dams, levees, stadiums, large buildings, large antennas and telescopes, water treatment facilities, oil refineries, chemical processing plants, high rise buildings, and infrastructure associated with electric trains and monorail support structures. The system  10  is also particularly well suited for use inside large buildings such as manufacturing facilities and warehouses. Virtually any structure that would be difficult, costly, or too hazardous to inspect by a human piloted vehicle or a human remote controlled (RC) vehicle may potentially be inspected using the system  10 . 
         [0036]    In  FIG. 1 , only five UAVs  12   a - 12   e  are shown to avoid cluttering the drawing. However, it will be appreciated that a greater or lesser plurality of UAVs  12  could be implemented to meet the needs of a specific inspection task. For large structures such as the bridge  14  shown in  FIG. 1 , potentially  10 - 20  UAVs  12  may be desired. Smaller structures may only require 2-5 UAVs to perform the needed inspection task. Each UAV  12   a - 12   e  includes an onboard system  16  that is able to navigate the UAV  12  in accordance with a preprogrammed flight plan and to enable inspection data for the structure being inspected to be obtained. The inspection data may comprise pictures, video or audio data, as will be explained in more detail in the following paragraphs. 
         [0037]    The preprogrammed flight plan carried by each UAV  12   a - 12   e  enables each UAV to follow a unique flight path around a portion of the structure. For Example, UAV  12   a  may include a flight plan that enables it to fly out to the bridge  14  and circle repeatedly around column  14   a , while the flight program of UAV  12   b  causes UAV  12   b  to fly down and up along path  14   b . UAV  12   c  may be assigned to fly back and forth under the bridge  14  closely along its horizontal steel structures. Thus, it will be appreciated that for each UAV  12   a - 12   b , its preprogrammed flight plan (and therefore flight path), is unique and is formed with respect to a designated portion of the structure that it is intended to inspect. In this manner each UAV  12  can traverse a specific designated portion of the bridge  14 . Once airborne, the UAVs  12   a - 12   e  form what can be viewed as a “swarm’ of vehicles that enable an extremely thorough inspection of various areas of a structure may otherwise be difficult, costly and/or hazardous for a human piloted vehicle to inspect. Generally, the larger the plurality of UAVs  12  employed in any given inspection task, the shorter the time it will take to complete the inspection task. 
         [0038]    For inspection applications, it is anticipated that unmanned rotorcraft, such as unmanned helicopters, may be especially advantageous for use as the UAVs  12 . This is because of the ability of an unmanned helicopter to hover and move at very slow speeds. The vertical take-off and landing capability of remote controlled unmanned helicopters also may be highly advantageous in many applications, especially when operating inside of structures or facilities such as manufacturing plants, warehouses, etc., or when inspecting complex facilities such as oil refineries or chemical processing that may have many tall structures clustered (e.g., smoke stacks) clustered closely together. In these applications, the use of a fixed wing unmanned vehicle would necessitate a clear, lengthy area for take-off and landing, and would be difficult, if not impossible, to maneuver around the various vertical structures or within a building. The ability to hover and/or move only vertically, if needed, enables unmanned remote controlled helicopters fly close to and inspect large vertical structures such as vertical support posts of bridges, antennas, or closely against other vertical surfaces such as dams, where the use of a fixed wing unmanned vehicle may have difficulty inspecting. 
         [0039]    The UAVs  12  could also be deployed from another airborne vehicle, such as a large transport helicopter or fixed wing aircraft. Such a deployment would obviously save fuel for the UAVs  12 , which would enable them to stay airborne for a longer period of time than would otherwise be possible if the UAVs  12  had to take off from a ground based location under their own power. 
         [0040]    The system  10  further may include a remote centralized inspection station  18  for receiving wireless communications from each of the UAVs  12   a - 12   e . The centralized inspection station  18  may include an antenna  20 , a computer control system  22 , a display  24  for viewing by an inspection technician or operator, such as an CRT, LCD or plasma screen, and a wireless transceiver. The wireless transceiver  26  is in communication with the antenna  20  for enabling wireless communication between the computer control system  22  and the onboard system  16  of each UAV  12   a - 12   e . The computer control system  22  may be used to send commands or to monitor various operating performance parameters of each UAV  12   a - 12   e  such as fuel remaining, battery power remaining, etc. The computer control system  22  may also be used generate commands to alter the flight plan of any one of the UAVs  12 , as will be described in the following paragraphs. 
         [0041]    While the centralized inspection station  18  is illustrated as being a terrestrial based station, it could just as readily be formed as a mobile inspection station  18 ′ on an aircraft or human piloted rotorcraft. A land based, mobile inspection station  18 ″ could also be formed. Accordingly, the centralized inspection station  18  does not necessarily need to be a fixed structure or facility. It is also possible for each of the UAVs  12   a - 12   e  to communicate with the centralized inspection station  18  via a transponded satellite  29  and/or using a wide area network or a local area network. 
         [0042]    Referring to  FIG. 2 , the onboard system  16  that may be carried by each UAV  12   a - 12   e  is shown. It will be appreciated, however, that the onboard system  16  carried by each UAV  12   a - 12   e  could include different components, depending on the specific portion of the structure that a given UAV  12  is programmed to inspect. Thus, it is not necessary that the onboard system  16  of each UAV be identical. 
         [0043]    The onboard system  16  may include a guidance and control hardware and software system  30  that is able to implement one or more different, stored flight plans from a memory  30 A. The onboard system  30  may include a global positioning system (GPS)/inertial navigation system  32  for controlling the orientation of its associated UAV  12  and assisting in carrying out the preprogrammed flight plan stored in the memory  30   a . A wireless transceiver  34  and an on board antenna  36  enable bidirectional, wireless electromagnetic wave communications with the centralized inspection station  18 . 
         [0044]    The onboard system  16  may also include a plurality of different sensors for providing useful inspection information to the centralized inspection station  18 . For example, a still camera (color and/or black and white)  38  may be used to obtain still images of portions of the structure  14  being inspected. A video camera  40  may be used to obtain color and/or black and white video of the bridge  14 . An infrared camera  42  could also be used to obtain infrared still images or infrared video. An audio microphone  44  could be used to pick up audio signals emanating from the structure being inspected. This feature could be particularly valuable for inspecting large machines inside a manufacturing facility, where the presence of specific types of sounds might be indicative of an imminent machine or component failure. For example, the detection of grinding sounds coming from an elevated portion of a large machine might indicate that a bearing failure is imminent, but such sounds might otherwise not be perceptible by individuals working on a floor of the manufacturing facility where other noise sources are present to mask the grinding noise. 
         [0045]    The onboard system  16  may also include a vehicle health monitoring subsystem  44 , a battery  48  for powering the electronic devices carried on the UAV  12 , as well as a fuel level sensor  50 . The vehicle health monitoring subsystem  44  may be used to monitor the battery level of the battery  48  and the fuel reservoir level sensor  50  and generate suitable signals that may be periodically transmitted to the centralized inspection station  18 . If an issue develops with any one of the UAVs  12 , for example a sudden drop in battery power to an unacceptable level, this enables the centralized inspection station  18  to be wirelessly informed of this condition. The centralized inspection station  18  may then wirelessly upload modified flight programs to the other UAVs  12  that would enable the remaining UAVs  12  to finish the needed inspection task. 
         [0046]    The onboard system  16  may optionally also include an image/audio memory  52  for maintaining electronic copies of the images, video or audio captured during an inspection process. If this option is implemented, then an interface  54  may be included on each UAV  12  that enables an external device, for example a lap top computer, to be coupled to the interface  54  and used to download the stored images and/or audio obtained during the previously executed inspection process. The interface  54  could be formed by a conventional RS-232, RS-422, or any other suitable interface. The interface  54  could also be implemented using Blue-tooth technology so that a wireless connection can be made with the image/audio memory  52 . The interface  54  could also be used for enabling a wired connection to the UAV  12  to upload programs or other information without the need for a wireless transceiver to be used on the UAV  12 . The use of the image/audio memory  52  may be advantageous in environments where periodic high levels of electromagnetic interference are to be expected, which could affect the ability of the acquired images and audio data to be reliably transmitted via electromagnetic wave signals to the centralized inspection station  18 . 
         [0047]    The onboard system  16  may also include additional sensors such as an ultrasound sensor, an X-Ray sensor  58 , a magnetic sensor  60  or a Hall Effect sensor  62 . It will be appreciated that the specific type of inspection operation(s) that the system  10  is expected to be used to perform will likely determine the specific form of sensors that will need to be included in the onboard system. 
         [0048]    The onboard system  16  may also optionally include a dynamic flight reallocation plan system  64 . The dynamic flight plan reallocation system  64  may be used to dynamically change the flight plan used for each UAV  12   a - 12   e  in the event one of the UAVs becomes inoperable for any reason, is required to land because of a fuel, battery or detected sensor problem, or for any other reason. By “dynamically” change, it is meant that the system  64  is able to automatically and virtually instantaneously determine which one of a plurality of alternative flight plans should be implemented by the remaining UAVs  12  still in operation so that the overall inspection task can be completed by the remaining UAVs. Thus, if UAV  12   a  becomes inoperable for any reason, or one of its sensors becomes inoperable, the dynamic flight plan reallocation system  64  of each UAV  12   b - 12   e  determines which one of a plurality of alternative pre-stored flight plans it should implement for the remaining UAVs  12   b - 12   d  to be able carry out the remainder of the entire inspection task, and the guidance and control hardware  30  will then implement the alternative flight plan in real time. By “real time” it is meant essentially instantaneously. The alternative flight plans may be stored in a memory that is included within the dynamic flight plan reallocation system  64 , or the alternative flight plans may be stored in the memory  30 A. 
         [0049]    Referring to  FIG. 3 , a flowchart  100  is illustrated that sets forth the operations of one exemplary implementation of the system  10 . At operation  102  a flight plan program is loaded into the flight plan memory  30   a  of each UAV  12   a - 12   e . The flight plan is specific to a designated portion (or portions) of the bridge  14  that the UAV  12  is assigned to inspect. The flight plan is such that it causes its associated UAV  12  to travel on a flight path that takes it sufficiently close to a predetermined portion of the bridge  14  to obtain the needed inspection data, which in this example would be either still images or video. 
         [0050]    At operation  104  the UAVs  12   a - 12   e  are deployed to form an inspection “swarm”. When the UAVs  12  reach the bridge  14  they each begin acquiring inspection data for the portion of the bridge that they have been designated to inspect. The inspection data may consist of still images, video, audio, or even a combination thereof. At operation  108  the UAVs  12   a - 12   e  transmit their acquired inspection data to the centralized inspection station  18  via their transceivers  34  and antennas  36 . Alternatively the UAVs  12   a - 12   e  could each store their acquired inspection data in their image/audio memory  52  for future downloading once they land, as indicated at operation  108   a.    
         [0051]    At operation  110 , if the acquired inspection data has been transmitted wirelessly from the UAVs  12   a - 12   e , then it may be displayed and/or analyzed using the display  24  and/or computer control system  22  of the centralized inspection station  22 . At operation  112  a check is then made to make sure that all of the UAVs  12   a - 12   e  are operating properly. If the vehicle health monitoring subsystem  46  on any of the UAVs  12   a - 12   e  has reported a problem with a component or a problem that requires the UAV to land immediately, this condition will be reported to the centralized inspection station  18  via a wireless signal from the affected UAV  12 . At this point, the computer control system  22  of the centralized inspection station  18  may be used to transmit a new, alternative flight plan to each of the UAVs  12  that remain in service. This enables the remaining UAVs  12  to carry out the remainder of the inspection task. The new, alternative flight plan could instead be provided to merely one or more of the remaining UAVs, rather than to all of the remaining UAVs. Operations  106 - 112  may then be repeated. Alternatively, if implemented, the dynamic flight plan reallocation system  64  on each UAV  12  may be used to dynamically determine and implement a new flight that enables the remaining UAVs to complete the inspection task. 
         [0052]    At operation  116  a determination is made of the percentage of coverage area of the bridge  14  that has been inspected. For example, it may be accepted that once about 99% of the bridge  14  has been inspected, that a guaranteed probability of detection of a defect or flaw has reached a certain value, and the task may be considered to be completed. The predetermined probability of detection value is checked at operation  118  to determine if the inspection task is essentially now complete. If so, the UAVs  12   a - 12   e  will land, as indicated at operation  120 . If not, then operations  106 - 112  are repeated until the predetermined probability of detection value has been reached. 
         [0053]    The system  10  and methodology described herein may be used to inspect a wide range of structures and objects, both stationary and moving. An example of a moving object that may require inspection is a fixed wing aircraft in flight. Using the system  10 , the UAVs  12  could be used to fly above, behind, below, or possibly even ahead of the aircraft while it is in flight. The UAVs  12  may be used to obtain images or audio data of the fixed wing aircraft, such as the position of flaps or ailerons, that may be used for real time analysis (i.e., essentially instantaneous analysis). Alternatively, the collected inspection data may be saved by each of the UAVs  12  and downloaded at a later time for analysis. 
         [0054]    A particular advantage of the system  10  is that the data acquired by each UAV  12  may be either downlinked in real time to the centralized inspection station  18 , thus permitting real time analysis of the data, or saved for analysis at a later time. For data such as video, that requires greater bandwidth to downlink, this feature may be advantageous in certain applications where bandwidth of the downlink is limited, and any potential flaws in the structure being inspected would not be of such nature as to produce conditions that threaten human safety or property. Yet other applications will exist where it would be important to be immediately apprised of a major structural flaw, such as on a bridge heavily traveled by cars and trucks. In such an instance, if a major structural flaw was discovered on a bridge, the real time downlinking capability of the system  10  would enable the acquired inspection images to be processed in real time. 
         [0055]    It will be appreciated that the system  10  and methodology will also have particular utility with regard to the inspection of structures that are submerged, or partially submerged, underwater. By using suitable submersible unmanned vehicles, inspection data such as pictures or video of submerged portions of bridges, oil drilling platforms, and even submerged portions of ships can be obtained for analysis. 
         [0056]    The various embodiments of the system  10  all provide the advantage that a human operator is not required to pilot each inspection vehicle, nor is a human operator required to remotely control each inspection vehicle. In many applications this is expected to provide a significant cost savings. The system  10  is also beneficial from the standpoint that human pilots do not need to be used in inspection applications that would pose a significant risk to human safety or health. 
         [0057]    While various embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the present disclosure. The examples illustrate the various embodiments and are not intended to limit the present disclosure. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.