Patent Publication Number: US-10788455-B2

Title: Extended reach inspection apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a divisional application of U.S. application Ser. No. 14/803,758, filed Jul. 20, 2015 (now U.S. Pat. No. 9,939,411) which is a continuation-in-part application of U.S. application Ser. No. 13/547,190, filed Jul. 12, 2012 (now U.S. Pat. No. 9,086,386). The contents of both are hereby incorporated herein by reference in their entirety. 
    
    
     FIELD 
     The present disclosure relates to nondestructive inspection/evaluation (NDI/NDE), and more particularly to an extended reach apparatus and sensors used in NDI/NDE that detect defects in structures and parts. 
     BACKGROUND 
     Increases in the complexity of aerospace structures have made NDI/NDE, which terms are used interchangeably herein, more and more difficult to apply successfully and cost-effectively. Often, a region of a particular structure requires inspection, but is inaccessible for the application of conventional NDE methods. In some cases, inspection requirements of regions with limited access have prompted part removal to improve access, or expensive redesigns altogether. Conventional tools include extenders and manipulation arms to reach into limited access areas and to aid probe placement on or near limited access areas of aircraft. Such areas may be cavities or obstructed areas, and include, for example, the interior of aircraft wings. 
     When in operation, certain sensors for detection of defects in a surface are preferably seated on the surface, or at least require maintaining no more than a maximum clearance from the surface. When a sensor, for example an eddy current sensor, is not completely seated on the surface, which may be referred to as “lift-off,” the result may be a reduced sensitivity to small cracks. 
     A sensor may be applied to a surface that is not completely flat and require movement of the probe along the surface, or may be mounted to a rotating end of a probe for NDE in limited access areas. Either case may result in lift-off. For the rotating application, if the probe end is not exactly perpendicular to the surface to be inspected, the rotating path of the sensor will be eccentric; although the sensor may be flush with the surface at one point along the path, at an opposite point on the path (or some other location) there will be lift-off. Accordingly, an apparatus is needed that addresses lift-off to provide adequate sensitivity for detection of defects over the full range of motion of the sensor. 
     SUMMARY 
     In accordance with an embodiment, an extended reach inspection apparatus may include a scanner device and a robotic manipulator arm. The robotic manipulator arm may include a plurality of arm segments including a distal end arm segment and a proximal end arm segment. A movable joint may couple the distal end arm segment to the robotic manipulator arm. A telescoping extension mechanism may be coupled to the distal end arm segment. The scanner device is mounted to the telescoping extension mechanism for moving the scanner device between a retracted position proximate to the robotic manipulator arm and an extended position at a distance from the robotic manipulator arm. A control handle may be coupled to the proximal end arm segment of the plurality of arm segments for manipulating the robotic manipulator arm. 
     In accordance with another embodiment, an extended reach inspection apparatus may include a robotic manipulator arm and a scanner device. The scanner device is coupled to the robotic manipulator arm. The scanner device may include a probe having a longitudinal axis, a first end, and a second, free end defining an opening, wherein the opening is offset from the longitudinal axis. The scanner device may also include a sensor for inspecting a target and providing an electrical output. The sensor is received in the opening and when the probe is rotated about the longitudinal axis, the sensor moves in a substantially circular path. The scanner device may additionally include a bias means received in the opening in-between the first end of the probe and the sensor to urge the sensor away from the first end of the probe. 
     In accordance with another embodiment, a method may include inserting a robotic manipulator arm through at least one inspection port of an enclosed structure. The robotic manipulator arm may include a plurality of arm segments and a telescoping extension mechanism coupled to a distal end arm segment of the plurality of arm segments. A scanner device is mounted to the telescoping extension mechanism for moving the scanner device between a retracted position proximate to the robotic manipulator arm and an extended position at a distance from the robotic manipulator arm for performing an inspection. The method may also include operating a movable joint that couples the distal segment to the robotic manipulator arm to position the scanner relative to a component for performing the inspection. The method may additionally include moving the telescoping extension mechanism to position the scanner over the component for performing the inspection. 
     In accordance with an embodiment and any of the previous embodiments, the telescoping extension mechanism may include a base platform. The scanner device may be coupled to one side of the base platform and a track follower may be mounted to an opposite side of the base platform. The telescoping extension mechanism may also include a telescope extension track mounted to the distal end arm segment of the robotic manipulator arm. The track follower is configured to move along the telescope extension track between the retracted position and the extended position. The telescoping extension mechanism may also include a motor that moves the track follower along the telescope extension track. The controller controls the motor to move the scanner device between the retracted position and the extended position. 
     In accordance with an embodiment and any of the previous embodiments, the distal end arm segment may include a stationary portion coupled to the robotic manipulator arm by the movable joint and a rotatable portion rotationally coupled to the stationary portion. The distal end arm segment includes a longitudinal axis defined through the stationary portion and the rotatable portion. The rotatable portion is rotatable about the longitudinal axis relative to the stationary portion. The extended reach inspection apparatus may also include an indexing feature for determining an angle of rotation of the rotatable portion relative to the stationary portion. 
     In accordance with an embodiment and any of the previous embodiments, the extended reach apparatus may also include a midspar support apparatus configured to support the robotic manipulator arm between two spars of an enclosed structure. The midspar support apparatus may include a head fitting configured to releasably attach to an inspection port support member and the inspection port support member may be releasably attachable to a first inspection port in a first spar. The midspar support apparatus may also include a plurality of collapsible leg members extending from the head fitting. The plurality of collapsible leg members may be configured to contact a second spar opposite the first spar. The plurality of collapsible leg members are collapsible to fit through a second inspection port in the second spar. 
     Other aspects and features of the present disclosure, as defined solely by the claims, will become apparent to those ordinarily skilled in the art upon review of the following non-limited detailed description of the disclosure in conjunction with the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description of embodiments refers to the accompanying drawings, which illustrate specific embodiments of the disclosure. Other embodiments having different structures and operations do not depart from the scope of the present disclosure. 
         FIG. 1  is an example of an NDI/NDE system and side view of an example of a robotic manipulator arm of the NDI/NDE system including a scanner device with a probe in accordance with an embodiment of the present disclosure. 
         FIG. 2A  is a side view of the scanner device mounted to a telescoping extension mechanism of the exemplary robotic manipulator arm with the telescoping extension mechanism in a retracted position in accordance with an embodiment of the present disclosure. 
         FIG. 2B  is a side view of the scanner device mounted to the telescoping extension mechanism of the exemplary robotic manipulator arm with the telescoping extension mechanism in an extended position and a spring biased portion of the base platform in an uncompressed position in accordance with an embodiment of the present disclosure. 
         FIG. 2C  is a side view of the scanner device mounted to the telescoping extension mechanism of the exemplary robotic manipulator arm with the telescoping extension mechanism in the extended position and spring biased portion of the base platform in a fully compressed position in accordance with an embodiment of the present disclosure. 
         FIG. 3A  is a side view of the distal end arm segment of the exemplary robotic manipulator arm showing a first index mark on a rotatable portion of the distal end arm segment for positioning the distal end arm segment in a home position in accordance with an embodiment of the present disclosure. 
         FIG. 3B  is a side view of the distal end arm segment of the exemplary robotic manipulator arm showing the first index mark on the rotatable portion and a second index mark on a stationary portion of the distal end arm segment being aligned for positioning the rotatable portion in about a 90 degree position with respect to the stationary portion in accordance with an embodiment of the present disclosure. 
         FIG. 4  is a perspective view of an exposed portion of an interior of an enclosed structure illustrating application of the exemplary robotic manipulator arm of  FIG. 1 . 
         FIG. 5  is a perspective view of an exposed portion of an interior of an enclosed structure between the two spars showing an example of a midspar support apparatus in accordance with an embodiment of the present disclosure. 
         FIG. 6A  is a perspective view of a back side of an example of an inspection port support member for use with a midspar support apparatus in accordance an embodiment of the present disclosure. 
         FIG. 6B  is a perspective view of a front side of the exemplary inspection port support member of  FIG. 6A . 
         FIG. 7A  is a perspective view of the exemplary robotic manipulator arm of  FIG. 1  arranged in a first configuration for inspecting elements of a back side of a spar in accordance with an embodiment of the present disclosure. 
         FIG. 7B  is a perspective view of the exemplary robotic manipulator arm of  FIG. 1  arranged in a second configuration for inspecting elements of a front side of a spar in accordance with an embodiment of the present disclosure. 
         FIG. 8  is a front end perspective view of an example of a scanner device including a probe in accordance with an embodiment of the present disclosure. 
         FIG. 9  is a side view of an example of a probe in accordance with an embodiment of the present disclosure. 
         FIG. 10  is a side perspective view of the exemplary probe of  FIG. 9 . 
         FIG. 11  is another side perspective view of the exemplary probe of  FIG. 9 . 
         FIG. 12  is a bottom perspective view of the exemplary probe of  FIG. 9 . 
         FIG. 13  is a side perspective view of the exemplary scanner device including a probe of  FIG. 8 . 
         FIG. 14  is an example of a high frequency eddy current impedance plane display that may result from application of the exemplary probe of  FIG. 9  in inspecting an aluminum structure in accordance with an embodiment of the present disclosure. 
         FIG. 15  is an example of a high frequency eddy current impedance plane display that may result from application of the exemplary probe of  FIG. 9  in inspecting a titanium structure in accordance with another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description of embodiments refers to the accompanying drawings, which illustrate specific embodiments of the disclosure. Other embodiments having different structures and operations do not depart from the scope of the present disclosure. Like reference numerals may refer to the same element or component in the different drawings. 
     Certain terminology is used herein for convenience only and is not to be taken as a limitation on the embodiments described. For example, words such as “proximal”, “distal”, “top”, “bottom”, “upper,” “lower,” “left,” “right,” “horizontal,” “front,” “back,” “vertical,” “upward,” and “downward” merely describe the configuration shown in the figures or relative positions. The referenced components may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise. 
       FIG. 1  is an example of an NDI/NDE system  10  including an example of an extended reach inspection apparatus  11  in accordance with an embodiment of the present disclosure. The extended reach inspection apparatus  11  may include a robotic manipulator arm  12  and an end effector  15 . The end effector  15  may include a scanner device  14  with an inspection probe  16 . The scanner device  14  may include any type of NDI/NDE inspection or scanning device, such as for example an eddy current inspection device, ultrasonic inspection device, x-ray inspection device or other NDI/NDE inspection device. The probe  16  may include, for example, an eddy current sensor, a magnetic sensor, an ultrasonic sensor, or other NDI/NDE type sensor. The robotic manipulator arm  12  may include a plurality of arm segments  18 - 22 . In the example robotic manipulator arm  12  shown in  FIG. 1 , the plurality of arm segments may include a distal end arm segment  18 , a proximal end arm segment  20  and one or more intermediate arm segments  22   a ,  22   b  and  22   c . The exemplary robotic manipulator arm  12  shown in  FIG. 1  includes three intermediate arm segments  22   a - 22   c . Other embodiments may include more or less intermediate arm segments depending on the application or environment. The arm segments  18 - 22   c  may be coupled to one another by multi-axis movable joints  24   a ,  24   b ,  24   c ,  24   d  and  24   e . The multi-axis movable joints  24   a - 24   e  allow the arm segments  18 - 22   c  to be articulated relative to one another as illustrated in  FIGS. 7A and 7B . Each multi-axis movable joint  24   a - 24   e  may permit the respectively coupled arm segments  18 - 22   c  to be positioned at different angles relative to one another. The multi-axis movable joints  24   a - 24   e  may also permit the coupled arm segments  18 - 22   c  to be rotated relative to one another. For example, multi-axis movable joint  24   a  may be a universal joint or U-joint that allows the angle of the robotic manipulator arm  12  to differ a certain number of degrees from the proximal end arm segment  20  that is releasably attachable to an access hole or port as described with reference to  FIG. 4 . Multi-axis joints  24   b  and  24   c  may each be a motorized elbow joint that may permit the respectively joined arm segments to be positioned at different angles between about 0 degrees and about 90 degrees. Joint  24   d  may be a rotating joint that rotates arm segment  22   c  at different angles between about 0 degrees and about 180 degrees clockwise or counterclockwise about a longitudinal axis  19  that may be defined through the robotic manipulator arm  12  as illustrated in  FIG. 1  with all arm segments  22   a - 22   c  extending linearly. Multi-axis joint  24   e  may be motorized elbow joint that may permit the distal end arm segment  18  to be positioned at different angles between about 0 degrees and about 90 degrees relative to the arm segment  22   c.    
     The movable joints  24   a - 24   e  may be motorized joints and may be remotely controlled by a controller  26 . An electrical cable  28  may operatively connect the controller  26  to the proximal end arm segment  20  of the robotic manipulator arm  12  to supply electrical power and control operation of the robotic manipulator arm  12 . The electrical cable  28  may include electrical power wiring and control wiring for each of the movable joints  24   a - 24   e . The electrical cable  28  may also include signal wiring for controlling operation of the scanner device  14  and for transmitting electrical signals to and from the scanner in response to performing an inspection by the inspection probe  16  on a target or component similar to that described herein. Electrical power wiring and signal wiring may extend through an interior of the robotic manipulator arm  12  for controlling operation of the movable joints  24   a - 24   e  and the scanner device  14  and for transmitting signals responsive to the inspection tests. An end of electrical cable  28  may include a suitable plug  28   a  as best shown in  FIG. 4  that may be plugged into a matting receptacle  29  on the proximal end arm segment  20 . 
     The controller  26  may include a plurality of control devices or manipulators  30   a ,  30   b ,  30   c , etc., such as rotatable dials, joy sticks or other types of control devices, for controlling the movable joints  24   a - 24   e  for articulating and rotating the arm segments  18 - 22   c  for positioning the scanner device  14  and inspection probe  16  for inspection of a component or target as described herein. 
     The robotic manipulator arm  12  may also include a control handle  32  coupled to the proximal end arm segment  20  for manipulating the robotic manipulation arm  12 . The control handle  32  may be used by an operator for positioning and adjusting placement of the robotic manipulator arm  12  for performing inspections. 
     The NDI/NDE system  10  may also include a probe camera monitor  34 . As described in more detail herein with reference to  FIG. 8 , a probe camera  36  may be associated with the scanner device  14  for positioning the inspection probe  16  relative to a component or target for inspection. The probe camera  36  may be video camera. The probe camera  36  may be incorporated within the scanner device  14  or may be an integral component of the scanner device  14  as illustrated by the probe camera  36  being shown by a broken line in  FIG. 1 . Images from the probe camera  36  may be viewed on the probe camera monitor  34  for manipulating the robotic manipulation arm  12  for positioning the inspection probe  16  relative to a target or component for inspection. A centerline of the probe camera  36  is parallel to a centerline of the probe  16  but offset a preset distance. The probe camera  36  may then be disposed directly over a target or component being inspected, such as a fastener connecting parts of an aircraft wing or other parts as viewed by an operator on the probe camera monitor  34 . The robotic manipulator arm  12  may then be adjusted the preset distance in a predetermined direction to directly center the inspection probe  16  over the fastener for inspecting the fastener and an area around a circumference of the fastener. 
     NDI/NDE system  10  may also include a wide angle camera  38  and a wide angle camera monitor  40 . The wide angle camera  38  may be coupled to an articulating arm  42 . The articulating arm  42  may position the wide angle camera  38  for use in configuring the robotic manipulator arm  12  for inspection of a component or target. 
     The distal end arm segment  18  may include a stationary portion  18   a  and rotatable portion  18   b  that is rotationally coupled to the stationary portion  18   a . The longitudinal axis  19  may be defined through the stationary portion  18   a  and the rotatable portion  18   b . The rotatable portion  18   b  is rotatable about the longitudinal axis  19  relative to the stationary portion  18   a . A motorized rotation joint  24   f  may rotate the rotatable portion  18   b  between about 0 degrees and about 180 degrees clockwise or counterclockwise relative to the stationary portion  18   a . The motorized rotation joint  24   f  may be remotely controlled by the controller  26 . 
     The robotic manipulator arm  12  may also include a telescoping extension mechanism  44  coupled to the distal end arm segment  18  of the robotic manipulator arm  12 . The telescoping extension mechanism  44  may be attached to the rotatable portion  18   b  of the distal end arm segment  18 . The scanner device  14  is mounted to the telescoping extension mechanism  44  for moving the scanner device  14  between a retracted position proximate the robotic manipulator arm  12  and an extended position at a distance from the robotic manipulator arm  12  for performing an inspection similar to that described herein. Referring also to  FIGS. 2A-2C ,  FIG. 2A  is a side view of the scanner device  14  mounted to the telescoping extension mechanism  44  of the exemplary robotic manipulator arm  12  with the telescoping extension mechanism  44  in a retracted position in accordance with an embodiment of the present disclosure.  FIG. 2B  is a side view of the scanner device  14  with the telescoping extension mechanism  44  in an extended position. The telescoping extension mechanism  44  may include a base platform  46 . The scanner device  14  may be coupled to one side of the base platform  46 . The base platform  46  may include a stationary portion  46   a  and a spring biased portion  46   b . The spring biased portion  46   b  may be configured to slide relative to the stationary portion  46   a  and resiliently compress as illustrated in  FIG. 2C  when the inspection probe  16  is in contact with a component or target during an inspection to maintain contact between the inspection probe  16  and the component when performing an inspection. 
     A track follower  48  is mounted to an opposite side of the base platform  46 . The scanner device  14  may be attached to the spring biased portion  46   b  of the base platform  46  and the track follower  48  may be mounted to the stationary portion  46   a  of the base platform  46 . The track follower  48  may include a first segment  48   a  and a second segment  48   b . A telescope extension track  50  is mounted to the rotatable portion  18   b  of the distal end arm segment  18  of the robotic manipulator arm  12 . The track follower  48  is configured to move along the telescope extension track  50  between the retracted position and the extended position. 
     The telescoping extension mechanism  44  also includes a motor  52  that moves the track follower  48  along the telescope extension track  50 . The motor  52  may be mounted to the stationary portion  46   a  of the base platform  46  at a predetermined distance from the spring biased portion  46   b  to permit compression of the spring biased portion  46   b  when the inspection probe  16  is in contact with a component or target for performing an inspection. The controller  26  ( FIG. 1 ) may control the motor  52  to move the scanner device  14  between the retracted position as shown in  FIG. 2A  and the extended position as shown in  FIG. 2B . The motor  52  may drive a wheel, a gear or other arrangement (not shown in  FIGS. 2A-2B ) that may engage the telescope extension track  50  for moving the scanner device  14  between the retracted position and the extended position. For example, the telescope extension track  50  may include a rack gear and the motor  52  may drive a pinion gear for moving the scanner device  14  between the positions. 
     An electrical cable  54  may be connected between the stationary portion  18   a  of the distal end arm segment  18  and the telescoping extension mechanism  44  and the rotatable portion  18   b  of the distal end arm segment  18 . The electrical cable  54  may include a first plug  56   a  that connects to electrical wiring in the stationary portion  18   a  of the distal end arm segment  18 . As previously described, electrical power wiring and signal wiring may extend through the interior of the robotic manipulator arm  12  for controlling operation of the scanner device  14 , telescoping extension mechanism  44  and multi-axis movable joints  24   a - 24   f . The electrical cable  54  may also include a second plug  56   b  for electrically connecting to a receptacle  58  on the stationary portion  46   a  of the base platform  46  adjacent to the motor  52 . The electrical cable  54  is of a sufficient length to allow the rotatable portion  18   b  of the distal end arm segment  18  to rotate a predetermined angle of rotation relative to the stationary portion  18   a  and for the telescope extension mechanism  44  to extend to the extended position. For example, the rotatable portion  18   b  may be rotated between about 0 degrees and at least about 180 degrees clockwise and counterclockwise relative to the stationary portion  18   a.    
     Referring also to  FIGS. 3A and 3B , the extended reach inspection apparatus  11  may include an indexing feature  60  for determining an angle of rotation of the rotatable portion  18   b  of the distal end arm segment  18  relative to the stationary portion  18   a .  FIG. 3A  is a side view of the distal end arm segment  18  showing a first index mark  62  at a predetermined location on the rotatable portion  18   b  of the distal end arm segment  18  for positioning the distal end arm segment  18  in a home position in accordance with an embodiment of the present disclosure.  FIG. 3B  is a side view of the distal end arm segment  18  showing the first index mark  62  aligned with a second index mark  64  at a predetermine location on the stationary portion  18   a  for positioning the rotatable portion  18   b  in a 90 degree position with respect to the stationary portion  18   a  in accordance with an embodiment of the present disclosure. Accordingly, the rotatable portion  18   b  is at a first angle of rotation relative to the stationary portion  18   a  when the first index mark  62  and the second index mark  64  are aligned and the rotatable portion  18   b  is at a second angle of rotation relative to the stationary portion  18   a , for example 90 degrees, when the first index mark  62  and the second index mark  64  are not aligned. 
       FIG. 4  is a perspective view of an exposed portion of an interior of an enclosed structure  66  illustrating application of the exemplary robotic manipulator arm  12  of  FIG. 1 . The enclosed structure  66  may be an interior portion of an aircraft, such as a wing or other flight control surface that has limited accessibility except through inspection ports or holes. For example, the enclosed structure  66  may be a midspan of a wing or other portion of an aircraft between a first spar  68  and second spar  70 . The robotic manipulator arm  12  may be extended through a first access hole or port  72  in the first spar  68  into the enclosed structure  66 . The access hole or port  72  is large enough for the distal end arm segment  18  of the robotic manipulator arm  12  and the scanner device  14  to pass through. In one embodiment the access hole or port  72  may be approximately five inches in diameter. A support bracket  74  may be mounted in the opening  72  to support the proximal end arm segment  20  of the robotic manipulator arm  12 . 
     The robotic manipulator arm  12  may also be extended through at least a second access hole or inspection access port  76  in the second spar  70 . A midspar support apparatus  78  may be inserted and deployed in the enclosed structure  66  between the first spar  68  and the second spar  70  to support the robotic manipulator arm  12 . Referring also to  FIG. 5 ,  FIG. 5  is a perspective view of the exposed portion of the interior of the enclosed structure  66  of  FIG. 4  between the two spars  68  and  70  showing an example of the midspar support apparatus  78  in accordance with an embodiment of the present disclosure. An inspection port support member  80  may be releasably attached to the second inspection access port  76  in the second spar  70  to support the robotic manipulator arm  12  extending through the second inspection access port  76 . The inspection port support member  80  may protect the second inspection access port  76  and second spar  70  from damage. An example of the inspection port support member  80  will be described in more detail with reference to  FIGS. 6A and 6B . The midspar support apparatus  78  may include a head fitting  82  configured to releasably attach to the inspection port support member  80  that is releasable attachable to the inspection access port  76  in the second spar  70 . The midspar support apparatus  78  may also include a plurality of collapsible leg members  84   a ,  84   b  and  84   c  extending from the head fitting  82 . The plurality of collapsible leg members  84   a ,  84   b  and  84   c  may be configured to contact the first spar  68  opposite the second spar  70 . The plurality of collapsible leg member  84   a ,  84   b  and  84   c  may each be adjustable in length and may each include a locking mechanism  86  to retain each leg at a selected length. The plurality of collapsible leg members  84   a ,  84   b  and  84   c  may be collapsible to fit through the first inspection access port  72  in the in the first spar  68 . 
     A protective pad  88  may be disposed between the first spar  68  and the second spar  70 . The protective pad  88  may also be extendable over a face  91  of the first spar  68 . The protective pad  88  protects the interior area of the enclosed structure  66  between the first spar  68  and the second spar  78  and the face of the first spar  68  from damage during installation and removal of the midspar support apparatus  78  and the robotic manipulator arm  12  during an inspection procedure. For an interior area that is within an aircraft, aircraft components, such as wings and other flight control surfaces may be manufactured from a lightweight honeycomb sandwich structure including a cellular layer including a multiplicity of honeycomb shaped cells disposed or sandwiched between an inner layer of material and outer layer of material. The honeycomb sandwich structure may be damaged if impacted by the robotic manipulator arm  12  or midspar support apparatus  78 . 
     Referring also to  FIGS. 6A and 6B ,  FIG. 6A  is a perspective view of a back side of an example of the inspection port support member  80  for use with the midspar support apparatus  78  in accordance an embodiment of the present disclosure.  FIG. 6B  is a perspective view of a front side of the inspection port support member  80  of  FIG. 6A . The inspection port support member  80  may include a substantially rectangular shaped main body  89  with a flat top portion  90  to extend across the inspection access port  76  as shown in  FIGS. 4 and 5 . The robotic manipulator arm  12  may rest on the flat top portion  90  and slide along the flat top portion  90  between appendages  92   a  and  92   b  during an inspection procedure. Appendage  92   a  and  92   a  may extend from the main body  89  at opposite ends of the flat top portion  90 . The appendages  92   a  and  92   b  may prevent the robotic manipulator arm  12  from striking an interior the inspection access port  76  opening and causing damage when the robotic manipulator arm  12  moved or positioned for performing an inspection. 
     The inspection port support member  80  may also include a substantially semi-circular shaped lip  94  extending from the flat top portion  90  ( FIG. 6A ). The semi-circular shaped lip  94  is configured to matingly contact or releasably attach to an interior lower edge of the second inspection access port  76 . The semi-circular lip  94  may have an upside down J-shape or may be hook shaped to releasably attach to or hang over the interior lower edge of the second inspection access port  76 . 
     The inspection port support member  80  may also include a threaded opening  96 . The threaded opening  96  may be configured to matingly receive a screw  98  ( FIG. 5 ) captured by the head fitting  82  for attaching the inspection support member  80  to the midspar support apparatus  78 . 
       FIG. 7A  is a perspective view of the exemplary robotic manipulator arm  12  of  FIG. 1  arranged in a first configuration for inspecting elements of a back side  700  of a spar  702  in accordance with an embodiment of the present disclosure.  FIG. 7B  is a perspective view of the exemplary robotic manipulator arm  12  of  FIG. 1  arranged in a second configuration for inspecting elements of a front side  704  of a second spar  706  in accordance with an embodiment of the present disclosure. As illustrated in  FIGS. 7A and 7B , the distal end arm segment  18  and the intermediate arm segments  22   b  and  22   c  may be articulated by the multi-axis movable joints  24   b ,  24   c  and  24   d  for inspecting different components or targets within an enclosed structure, such as an interior or an aircraft wing or other structure. 
       FIG. 8  is an end perspective view of the scanner device  14 , which includes an embodiment of an inspection probe  16  mounted to the scanner device  14 . In this embodiment, the inspection probe  16  may include an eddy current sensor  100 , including a coil of wire. The scanner device  14  may be a micro eddy current rotating scanner, which may include a motor. It is not necessary for other embodiments of the system  10  ( FIG. 1 ) or the inspection probe  16  that the scanner device  14  be a rotating type. The distal end of the scanner device  14  may include lights  102 , for example LEDs, to illuminate the enclosure and the target to be inspected, and a camera lens  104  to provide an image to the probe camera  36  ( FIG. 1 ) in the scanner device  14 . Another video camera could also be mounted in proximity of the inspection probe  16  to provide additional situational awareness. A knob  106  has a threaded bolt  109  on it that may be loosened to remove the scanner device  14  from the base platform  46  of the telescoping extension mechanism  44  ( FIGS. 1-2C ). The other end of the threaded bolt  109  may bear against a cylinder (not shown in  FIG. 8 ) to which the scanner device  14  is attached. 
     A tether  107  may be looped around the threaded bolt  109  of the knob  106  and another end of the tether  107  may be secured to the inspection probe  16 . The scanner device  14  may include a scanner body  200 . The inspection probe  16  may extend from the scanner body  200  on a rotating shaft  202  or spindle. The inspection probe  16  is removable from the scanner device  14  and may be dislodged from the scanner body  200  if the inspection probe  16  strikes an object during insertion or removal of the robotic manipulator arm  12  during an inspection procedure. The tether  107  connects the probe  16  to the scanner body  200  to prevent loss of the probe within an interior of a structure under inspection. The tether  107  will retain the inspection probe  16  with the scanner body  200  in response to the inspection probe  16  being pulled from the scanner device  14 . In accordance with an embodiment, a collar  204  may be attached to the shaft  202 . The collar  204  may include a groove  206  for receiving and retaining the tether  107 . The tether  107  may be looped around the groove  206  in the collar  107  and fastened to retain the tether  107  within the groove  206 . In another embodiment, the collar  107  may be a bearing fastened to the shaft  202  with a groove in an exterior portion of the bearing. The bearing allows the shaft  202  to rotate within the bearing and the tether  107  fastened within the groove in the exterior portion of the bearing is allowed free movement or to remain stationary as the shaft  202  rotates during performance of an inspection. 
       FIGS. 9-12  show an embodiment of the inspection probe  16  with an embodiment of an eddy current sensor  100 . The inspection probe  16  may include a spindle  110 , a central member  112  mounted to the spindle  110 , and a housing  114  mounted to the central member  112 . In this embodiment, the housing  114  is translucent. The sensor  100  may be received in an opening which may be a bore  120  in the housing  114  or be otherwise slidably mounted to the housing  114 . The central member  112  may be mounted to the spindle  110  with a set screw  122  ( FIG. 11 ). The housing  114  may be cylindrical, may encase the sides of the central member  112 , and extends distally below the bottom of the central member  112 . Below the distal end of the central member  112  the housing  114  may define a substantially cylindrical opening  124  and have a cylindrical wall  126 . The cylindrical wall  126  may be of adequate thickness to receive the sensor  100  in the bore  120  in the wall  126 , as shown, or other configurations may be provided to attach the sensor  100  to the inspection probe  16 . In the example shown in  FIG. 9 , the inspection probe  16  may be configured for inspecting the metal  902  around a fastener  904  of a component of a structure  906 , such as an aircraft wing or other structure. The opening  124  in the housing  114  is large enough to receive the end of the fastener  904  that protrudes from the structure. 
     A spring  130 , such as a coil spring as schematically shown, a leaf spring, compressible and resilient material, or other biasing means may be provided in between the proximal end of the bore  120  and the proximal end of the sensor  110 , and urges the sensor  100  distally such that the sensor  100  may extend out of the bore  120  past the distal surface  132  of the housing  114 . The spring loading increases the probe&#39;s compliance to the surface of the structure  906  under inspection. Seating of the eddy current sensor  100  over the fastener so that the sensor  100  lies as flat as possible on the structure  906  is generally desirable for conducting a proper inspection. The sensor  100  is retained in the bore  120  with a pin  134  that extends laterally through an opening  136  in the housing wall  126  and passes through a slot  138  in the sensor  100 . The proximal side  140  of the slot  138  is blocked by the pin  134  as the spring  130  urges the sensor  100  to withdraw from the bore  120 . The proximal side  140  of the slot  138  is located such that the sensor  100  may extend a predetermined distance X from the bore  120  below the distal surface  132  of the housing  114 . 
     In addition, a joint  142  may be provided in the spindle  110  at the connection to the central member  112 . The joint  142  may be, for example, a gimbal joint, a ball and socket type joint, or the like, and in the embodiment of an inspection probe  16  described herein, may allow for a deflection of, for example, at least approximately 12 degrees, with a preferred angle of at least 15 degrees between the spindle  110  and the longitudinal axis of the inspection probe  16 . Joint deflection may be greater with other embodiments, and particularly in embodiments where the sensor  100  can extend a greater predetermined distance X from the bore  120  below the distal surface  132  of the housing  114  than in the exemplary embodiment described herein. 
     The joint  142  may be designed to transfer scan rotation through an angle as needed, but to return to a zero angle position when the end is free, which may be referred to as self-aligning. This self-aligning may be accomplished in a variety of ways, for example in a ball and socket type joint, using a non-spherical ball and socket that pulls slightly out and extends an inner spring when an angle away from the longitudinal axis of the inspection probe  16  is created. The spindle  110  and joint  142  rotate during scanning, as does the rest of the inspection probe  16 . 
     In one exemplary embodiment, the inside diameter of the housing  114  is 0.5 inches, the housing wall  126  thickness distally from the central member  112  is 0.112 inches, the radius from the longitudinal axis of the inspection probe  16  to the longitudinal axis of the sensor  100  is 0.183 inches, and the predetermined distance X that the sensor  100  may extend past the distal surface  132  of the housing  114  is 0.008 inches. 
     The probe materials may include, for example, for the central member  112 , spindle  110 , spring  130 , and pin  134 , metals such as steel, stainless steel, or other steel alloy. The housing  114  may be molded plastic or other nonconductive material, which may be translucent to facilitate assembly and visualization of a fastener during scanning. The sensor  100  may be made of materials as known to one of ordinary skill in the art. 
       FIG. 13  shows a detail view of the end effector  15  or scanner device  14  in use. Angle θ is the predetermined deflection angle that the joint  142  provides. As shown, the joint  142  allows a deflection of approximately 15 degrees between the spindle  110  and the longitudinal axis Y-Y of the inspection probe  16 . The distance that the sensor  100  can extend past the distal surface  132  of the housing  114  makes this relatively high degree of deflection possible. When the inspection probe  16 , and the sensor  100  with it, rotates when the housing  114  is not parallel to the target surface, there will be one point on the path of rotation where the distal surface  132  of the housing  114  is closest to the target, preferably with the sensor  100  touching the target surface, and a point on the opposite side of the path of rotation where the distal surface  132  of the housing  114  is farthest away from the target surface, and without the extension of the sensor  100  lift-off will be experienced. The extending of the sensor  100  past the distal surface  132  of the housing  114  reduces the amount of lift-off or eliminates lift-off, and may keep the sensitivity of the sensor  100  adequate to provide meaningful NDE data over the entire path of rotation. The sensor  100  extending also allows the deflection angle to be increased in the design of the joint  142 . An increased available deflection angle facilitates applying and using the inspection probe  16 . 
       FIG. 14  shows a high frequency eddy current impedance plane display  150  as may result from application of an inspection probe  16  including an eddy current sensor  100  applied to an aluminum structure. This display  150  may aid an operator/inspector in knowing when the inspection probe  16  is coupled to the structure to allow proper inspection. Resistance is plotted on the X-axis and Reactance is plotted on the Y-axis. The eddy current probe is “nulled” in air, which appears on the display  150  at the far left at the label “AIR” where there is no magnetic field measurement, as opposed to the often used technique of nulling the inspection probe  16  while on the part being inspected, and then, as the inspection probe  16  is brought down over the fastener  902 , the eddy current display “dot” comes down to the position where the inspection probe  16  is coupled with the part or structure  906 . 
     Curve A in  FIG. 14  represents decreasing magnetic field readings from right to left, which corresponds to increased lift-off from right to left. Multiple flaw indications are shown in  FIG. 14 . These flaw indications are curves B through F, which are each the result of the sensor  100  detecting the same 0.050 inch deep Electrical Discharge Machining (EDM) notch, but with different distances of lift-off. The curves B through F are also labeled with dimensions that designate the distance of lift-off in inches for each of the respective curves. To obtain a desirable 3:1 signal-to-noise ratio (S/N), in testing with the example discussed above in the discussion of  FIGS. 9-12 , the lift-off of the sensor  100  from the part could not be more than 0.016 inches. Below 0.016 inch lift-off, the inspection probe  16  and structure  906  was considered to be coupled. If the lift-off was greater than this amount, the flaw indication may be detectable, but the S/N was less than desirable and it may become difficult to distinguish a crack in the part from lift-off. 
     In a test with an eddy current sensor mounted to a probe without a spring to extend the sensor out of the housing, and a spindle with a joint allowing an angle of incidence of 10.5 degrees off of a line perpendicular to the target surface, the dot traveled along curve A approximately within range G as the sensor rotated. With a spring that allowed the sensor to extend 0.008 inches out of the housing, the joint angle could be increased to 15 degrees, and the dot traveled approximately only within range H, providing improved ability to accurately detect flaws. 
     There are some significant differences between aluminum and titanium structures when eddy current testing for surface flaws. Titanium electrical conductive is significant less than aluminum. This requires a much different coil driver frequency, which generate the eddy currents in the structure, to detect the surface flaw. These driver frequencies in titanium are much higher, which causes the eddy current depth-of-penetration to be significantly less, and detection of the crack more sensitive to different amounts of lift-off, or coil distances lifted-off the surface of the structure. 
       FIG. 15  shows a high frequency eddy current impedance plane display  160  as may result from application of an inspection probe  16  including an eddy current sensor  100  applied to a titanium structure. Each of the curves in  FIG. 15  are labeled with dimensions that designate the distance of lift-off in inches from a surface of the structure.  FIG. 14  shows the flaw amplitude decreasing with increasing amounts of lift-off of the coil for the aluminum structure.  FIG. 15  shows the flaw amplitude decreasing with increasing amounts of lift-off of the coil for the titanium structure. As shown in  FIG. 14  the amount of lift-off for roughly a 50% decrease in amplitude is 0.016-inches, where in  FIG. 15  the amount of lift-off for roughly a 50% decrease in amplitude is 0.008-inches. Also, it can be seen that in aluminum ( FIG. 14 ) that a lift-off of 0.032-inches can still detect the flaw, where with titanium the maximum amount of lift-off to detect the flaw is 0.016-inches. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art appreciate that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown and that the embodiments herein have other applications in other environments. This application is intended to cover any adaptations or variations of the present disclosure. The following claims are in no way intended to limit the scope of the disclosure to the specific embodiments described herein.