Patent Publication Number: US-11643206-B2

Title: Power line inspection vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 16/778,269, filed Jan. 31, 2020, the contents of which are incorporated by reference in their entirety herein for all purposes. 
    
    
     TECHNICAL FIELD 
     This disclosure relates in general to the field of aircraft, and more particularly, to unmanned aerial vehicles for inspecting aerial power line components. 
     BACKGROUND 
     This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art. 
     Maintenance of the electric power grid system requires constant inspection. Traditionally this inspection is performed by linemen physically traversing the power lines, access from helicopters, and use of small drones. Human inspection is dangerous, expensive, and often requires that the power lines be deactivated. Drones have limited flight times and require a human operator to be within line-of-sight, reducing the applicability of drones for power line inspections. 
     SUMMARY 
     An exemplary unmanned aerial vehicle (UAV) mountable to a conductor of an aerial power transmission line system includes a body having a rotor system, a motivation system attached to the body to motivate the UAV along the conductor, a battery carried by the body and electrically connected to at least one of the rotor system and the motivation system, a monitoring tool mounted with the body and an inductive coil carried by the body and in electric connection with the battery, wherein the inductive coil is configured to harvest electricity from the aerial power transmission line system and charge the battery. 
     An exemplary method of inspecting an aerial power transmission line includes flying an unmanned aerial vehicle to a conductor of the aerial power transmission line system, the UAV comprising a body having a rotor assembly, a set of wheels coaxially aligned, and a battery, positioning the set of wheels on the conductor, inspecting the conductor with a monitoring tool, moving the UAV along the conductor and harvesting electricity from the aerial power transmission line system and charging the battery. 
     This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIG.  1    illustrates an exemplary unmanned aerial vehicle according to one or more aspects of the disclosure. 
         FIG.  2    illustrates an exemplary energy harvesting system according to one or more aspects of the disclosure. 
         FIGS.  3 - 7    illustrate an exemplary unmanned aerial vehicle traversing and inspecting an aerial power transmission line system. 
     
    
    
     DETAILED DESCRIPTION 
     It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various illustrative embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. For example, a figure may illustrate an exemplary embodiment with multiple features or combinations of features that are not required in one or more other embodiments and thus a figure may disclose one or more embodiments that have fewer features or a different combination of features than the illustrated embodiment. Embodiments may include some but not all the features illustrated in a figure and some embodiments may combine features illustrated in one figure with features illustrated in another figure. Therefore, combinations of features disclosed in the following detailed description may not be necessary to practice the teachings in the broadest sense and are instead merely to describe particularly representative examples. In addition, the disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not itself dictate a relationship between the various embodiments and/or configurations discussed. 
     In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present application, the devices, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms such as “inboard,” “outboard,” “above,” “below,” “upper,” “lower,” or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the device described herein may be oriented in any desired direction. As used herein, the terms “connect,” “connection,” “connected,” “in connection with,” and “connecting” may be used to mean in direct connection with or in connection with via one or more elements. Similarly, the terms “couple,” “coupling,” and “coupled” may be used to mean directly coupled or coupled via one or more elements. 
     With reference to the figures,  FIG.  1    illustrates an exemplary unmanned aerial vehicle (UAV), generally denoted by the numeral  10 , that is mountable to a conductor of an aerial power transmission line system. UAV  10  includes a body  12  having a rotor system  14 , a motivation system  16  attached to the body to motivate the UAV along the conductor, a battery  18  carried by the body and electrically connected to at least one of the rotary system  14  and the motivation system  16 , one or more monitoring tools  20  mounted with the body, and an energy harvesting system  22  configured to harvest electricity from the aerial power transmission line system and charge battery  18  and or to power one or more of the UAV systems directly. UAV  10  includes avionics, such a processor  24 , e.g. controller, in communication with the various UAV systems and having software and instructions for operating UAV  10  in response to instructions from a local or remote operator and/or to operate autonomously. UAV  10  may include navigation sensors  26 , such as global positioning sensors and proximity sensors, in communication with processor  24 . Processor  24  is configured to communicate with a remote site to transmit data from the one or more monitoring tools  20  and or receive instructions. 
     Rotor system  14  includes rotor assemblies  28  including motors  30  driving rotor blades  32 . Rotor assemblies  28  may be gimballed. Motors  30  are electrically connected to battery  18  and or electricity harvesting system  22 . Those skilled in the art with benefit of this disclosure will understand that battery  18  includes other electric storage devices, such as capacitors. 
     Motivation system  16  is configured to physically contact the aerial conductor (transmission line) and support the weight of the UAV and in some embodiments move UAV  10  along the aerial conductor. Motivation system  16  includes a set  34  of wheels  36  that are coaxially aligned to engage the same conductor. In the illustrated embodiment, UAV  10  has a single set  34  of wheels to engage and support UAV  10  on a single conductor. The exemplary set  34  of wheels  36  has two wheels  36 ; however, the set of wheels may have more than two wheels. Additional co-axial wheels  36  may facilitate stability when motivation system  16  is used to move UAV  10  across a power line component such as a splice, suspender clamp, or cable spacer. In some embodiments, wheels  36  are electrically driven to rotate and to move UAV  10  along a conductor. In the illustrated example, each wheel  36  includes a motor  38 . Wheels  36  may include V-shaped grooves  40  to engage the conductor and conductor components. 
     Wheels  36  are connected to body  12  by arms  42 . Arms  42  position wheels  36  above body  12 . The center of gravity  45  of UAV  10  is positioned in the same plane as co-axial set  34  of wheels so that a single set  34  of wheels  36  support UAV  10  from a single conductor. 
     UAV  10  may include one or more monitoring tools  20 . In  FIG.  1   , UAV  10  includes a camera for a monitoring tool. The camera may be an infrared camera. Monitoring tool  20  may be gimballed to provide visual coverage of the components to be visually inspected. For example, monitoring tool  20  may be used to inspect and monitor the conductor from which the UAV is suspended, adjacent conductors, conductor components, suspension towers and the like. Monitoring tools  20  may include other sensors and devices used to inspect and monitor aerial transmission line systems. 
     An exemplary energy harvesting system  22  is now described with reference to  FIGS.  1  and  2   . With additional reference to the other figures, energy harvesting system  22  includes a coil  44 , for example open air or magnetic core, and an AC/DC power rectifier  46 . In the exemplary embodiment of  FIG.  1   , coil  44  is positioned at wheels  36  so as to be in close proximity to the AC power transmission line  48 . For example, coil  44  extends between the legs  42  connecting the set of wheels to body  12 . Wires  47  may extend from coil  44  through legs  42  to the AC/DC power rectifier  46  positioned in body  12  (e.g., frame) with the battery and other avionics. When UAV  10  is proximate to an AC transmission line  48 , i.e. conductor, a portion of the magnetic field  49  generated by transmission line  48  is converted by harvesting system  22  into power. The rectified power is used by battery  18  management system to recharge the batteries for use by UAV systems, such as rotor motors  30 , wheel motors  38 , controller  24 , and monitoring tools  20  and sensors  26 . 
     A method of inspecting an aerial power transmission line system  50  is now described with reference to  FIGS.  1 - 7   . Aerial power transmission line system  50  includes one or more power lines, generally referred to as conductor  48 , suspended above ground  52  by suspension towers  54 . Aerial power transmission line system  50  is illustrated herein as a high-voltage system, however, UAV  10  and the methods disclosed herein may be used in other systems. Aerial power transmission line system  50  may include various components, generally denoted  56 , that need to be inspected and the components may be an obstacle to be navigated by UAV  10 . A non-exclusive list of components  56  includes conductor splices, connectors, cable-spacers, dampers, suspension towers, suspension clamps, and marker balls. As will be understood by those skilled in the art with benefit of this disclosure, UAV  10  may navigate around, over, or past these components, e.g. obstacles, by operating the wheels to drive across the component and by operation of the rotor assemblies to fly around the component or to aide in powering the UAV across the component with the wheels contacting the conductor and the component. As is well known, conductors  48  have spans that have downgrades  58  where the conductor is declined downward from the tower in the direction of the UAV travel and inclines  60  where the UAV has to travel upward on the conductor. In accordance to some embodiments, the UAV rotor assemblies may be operated to brake and slow the descent of the UAV on downgrades  58  and the UAV rotor assemblies may be operated to help the UAV climb inclines  60  while maintaining wheels  36  on the conductor. 
     At  FIG.  3   , UAV  10  is deployed from the ground  52  and flown to and landed on a conductor  48 , shown in  FIG.  4   . UAV  10  is landed by suspending UAV  10  on conductor  48  by set  34  of wheels  36 . In this example, UAV  10  is suspended from a single conductor  48 . UAV  10  may be deployed in direct response from an operator or UAV  10  may be self-deployed, for example, in response to instructions included in the on-board processors. In accordance to some embodiments, UAV  10  may be self-deployed and autonomous for example to continuously monitor a section of a transmission line. Monitoring tools  20  may be operated to inspect conductor  48  and components of transmission line system  50  when UAV  10  is proximate to system  50  as well as when UAV is suspended from a conductor. 
     With reference to  FIGS.  4  and  5   , UAV  10  is being moved along conductor  48  in the direction  62 . UAV  10  may be moved in the direction  62  by electrically driving one or more of the wheels of the set of wheels. When descending downgrade  58 , the rotor assemblies may be driven to brake and slow the descent of UAV  10 . In  FIGS.  4  and  5   , UAV  10  passes over a component  56 , such as a cable splice. In this example, UAV  10  passes over component  56  while maintaining wheels  36  on conductor  48 .  FIG.  5    illustrates UAV  10  ascending incline  60 . UAV  10  may operate the rotor assemblies to provide upward lift along incline  60 . 
       FIGS.  6  and  7    illustrates UAV  10  navigating past a component  56  by flying around the component. As UAV  10  approaches the obstacle component  56 , the rotor assemblies are operated to lift UAV off of the conductor  48  on a first side ( FIG.  6   ) of the obstacle and to fly around the obstacle component  56  and land on the conductor  48  on the second side ( FIG.  7   ) of the obstacle. Monitoring tools  20 , in particular a camera can be operated to inspect the system when UAV is removed from conductor  48 . 
     Conditional language used herein, such as, among others, “can,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include such elements or features. 
     The term “substantially,” “approximately,” and “about” is defined as largely but not necessarily wholly what is specified (and includes what is specified; e.g., substantially 90 degrees includes 90 degrees and substantially parallel includes parallel), as understood by a person of ordinary skill in the art. The extent to which the description may vary will depend on how great a change can be instituted and still have a person of ordinary skill in the art recognized the modified feature as still having the required characteristics and capabilities of the unmodified feature. In general, but subject to the preceding, a numerical value herein that is modified by a word of approximation such as “substantially,” “approximately,” and “about” may vary from the stated value, for example, by 0.1, 0.5, 1, 2, 3, 4, 5, 10, or 15 percent. 
     The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the disclosure. Those skilled in the art should appreciate that they may readily use the disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure and that they may make various changes, substitutions, and alterations without departing from the spirit and scope of the disclosure. The scope of the invention should be determined only by the language of the claims that follow. The term “comprising” within the claims is intended to mean “including at least” such that the recited listing of elements in a claim are an open group. The terms “a,” “an” and other singular terms are intended to include the plural forms thereof unless specifically excluded.