TG).
SYSTEM AND METHOD FOR PERFORMING AN INTERNAL INSPECTION ON
A WIND TURBINE ROTOR BLADE
FIELD OF THE INVENTION
[0001] The present subject matter relates generally to wind turbines and, more
particularly, to a system and method for performing an internal inspection on a wind
turbine rotor blade.
BACKGROUND OF THE INVENTION
[0002] Wind power is considered one of the cleanest, most environmentally
friendly energy sources presently available, and wind turbines have gained increased
attention in this regard. A modern wind turbine typically includes a tower, generator,
gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic
energy from wind using known foil principles and transmit the kinetic energy through
rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox
is not used, directly to the generator. The generator then converts the mechanical
energy to electrical energy that may be deployed to a utility grid.
[0003] The maintenance of wind turbine components is critical to the ongoing
operation of a wind turbine. Thus, maintenance operations, such as inspections, are
routinely performed on wind turbine rotor blades to ensure that they are in optimal
operating condition. For example, visual inspections of the interior of a rotor blade
may be performed to identify cracks, debonding issues and other potential defects. To
perform such visual inspections, conventional methods typically require that an
operator enter the internal cavities of the blade, which can be very dangerous. Other
known internal inspection methods include the use of a robotic crawler configured to
traverse the interior of the rotor blade. However, the expense of such robotic crawlers
generally prohibits their widespread use.
[0004] Accordingly, there is a need for a safe and low cost system for performing
an internal inspection on a wind turbine rotor blade.
BRIEF DESCRIPTION OF THE INVENTION
[0005] Aspects and advantages of the invention will be set forth in part in the
following description, or may be obvious from the description, or may be learned
through practice of the invention.
[0006] In one aspect, the present subject matter discloses a system for performing
an internal inspection on a rotor blade of a wind turbine. The system may generally
include a sensing device and a cable for raising and lowering the sensing device
within the rotor blade. The system may also include a positioning device attached to
at least one of the sensing device and the cable. The positioning device may generally
be configured to space the sensing device apart from an interior surface of the rotor
blade as the sensing device is raised and lowered within the rotor blade.
[0007] In another aspect, the present subject matter discloses a method for
performing an internal inspection on a rotor blade. The method may generally include
coupling a sensing device to a cable, lowering the sensing device within the rotor
blade and maintaining the sensing device spaced apart from an interior surface of the
rotor blade as the sensing device is moved within the rotor blade.
[0008] These and other features, aspects and advantages of the present invention
will become better understood with reference to the following description and
appended claims. The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] A full and enabling disclosure of the present invention, including the best
mode thereof, directed to one of ordinary skill in the art, is set forth in the
specification, which makes reference to the appended figures, in which:
[0010] FIG. 1 illustrates a perspective view of a wind turbine of conventional
construction;
[001 1] FIG. 2 illustrates a perspective view of one embodiment of a system for
performing an internal inspection on a wind turbine rotor blade in accordance with
aspects of the present subject matter;
[0012] FIG. 3 illustrates a partial, perspective view of a portion of the system
shown in FIG. 2; and,
[0013] FIG. 4 illustrates a perspective view of another embodiment of a system
for performing an internal inspection on a wind turbine rotor blade in accordance with
aspects of the present subject matter.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Reference now will be made in detail to embodiments of the invention,
one or more examples of which are illustrated in the drawings. Each example is
provided by way of explanation of the invention, not limitation of the invention. In
fact, it will be apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing from the scope or
spirit of the invention. For instance, features illustrated or described as part of one
embodiment can be used with another embodiment to yield a still further embodiment.
Thus, it is intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and their equivalents.
[0015] In general, the present subject matter discloses a system for performing an
internal inspection on a rotor blade. For example, in several embodiments, a system
is disclosed having one or more sensing devices coupled to a cable for raising and
lowering the sensing device(s) within the rotor blade. The system may also include a
positioning device configured to space the sensing device(s) apart from an interior
surface of the rotor blade as it is raised and lowered within the blade.
[0016] As used herein, the term "inspection" refers to any operation, action and/or
test performed on a wind turbine that is designed to monitor, sense, locate, measure
and/or detect a condition of any component of the wind turbine and, particularly, a
condition of a rotor blade of the wind turbine. For example, inspections may include,
but are not limited to, visual inspections of the interior of the rotor blades, optical
nondestructive evaluation (NDE) tests (e.g., shearography tests), thermography tests
and other related operations/tests. Additionally, the term "sensing device" may refer
to any suitable sensor, equipment, mechanism and/or any other item that may be
utilized to monitor, sense, located, measure and/or detect the condition of a
component of a wind turbine. Thus, sensing devices may include, but are not limited
to, visual cameras, infrared cameras, ultraviolet cameras, video cameras, other
suitable cameras, ultrasonic detectors, x-ray detectors, other suitable imaging devices
and sensors, light sources (e.g., a light-emitting diode (LED) array), proximity sensors,
position sensors, displacement sensors, linear encoders, measurement devices, laser
scaling devices, magnetic sensing equipment, ultrasound equipment, microwave
instrumentation, active infrared equipment, optical NDE testing equipment,
thermography testing equipment and any other suitable equipment, sensors,
mechanisms and/or items.
[0017] Thus, in several embodiments, the system of the present subject matter
may be configured to perform an internal visual inspection on a wind turbine rotor
blade. For example, it may be desirable to visually inspect the internal cavities of the
rotor blade for anomalies, such as debonding issues, cracks and other defects.
Accordingly, in such embodiments, the disclosed sensing device(s) may comprise one
or more suitable optical and/or imaging devices configured to monitor, locate, sense,
measure and/or detect such anomalies. For instance, in a particular embodiment of
the present subject matter, the sensing device(s) may comprise one or more remote
controlled pan tilt zoom (PTZ) cameras configured to capture images of the interior of
a rotor blade.
[001 8] Referring now to the drawings, FIG. 1 illustrates a wind turbine 10 of
conventional construction. The wind turbine 10 generally includes a tower 1 with a
nacelle 14 mounted thereon. A plurality of rotor blades 16 are mounted to a rotor hub
18, which is, in turn, connected to a main flange that turns a main rotor shaft. The
wind turbine power generation and control components are housed within the nacelle
14. The wind turbine 10 of FIG. 1 is generally provided for illustrative purposes only
to place the present subject matter in an exemplary field of use. Thus, it should be
appreciated that the present subject matter is not limited to any particular type of wind
turbine configuration.
[0019] Referring now to FIGS. 2 and 3, there is illustrated one embodiment of a
system 200 for performing an internal inspection of a rotor blade 16 of a wind turbine
10. In particular, FIG. 2 illustrates a perspective view of one embodiment of the
system disposed within the rotor blade 16 and the hub 18 of a wind turbine 10 in
accordance with aspects of the present subject matter. Additionally, FIG. 3 illustrates
a perspective view of a portion of the system shown in FIG. 2.
[0020] In general, the system 200 may include one or more sensing devices 202
configured to be raised and lowered within a rotor blade 16, such as within an internal
cavity 204 of the rotor blade 16, to permit an internal inspection of the blade 6 to be
performed. Additionally, the system 200 may include a positioning device 206
configured to space the sensing device(s) 202 apart from one or more interior surfaces
208 of the rotor blade 16. As such, the relative positioning of the sensing device(s)
202 with respect to the interior surfaces 208 may be maintained as the sensing
device(s) 202 is raised and lowered within the rotor blade 16. It should be appreciated
that, as used herein, the term "interior surface" may refer to any interior surface or
wall of the rotor blade 16, including the interior surfaces/walls of the blade shell and
any interior surfaces/walls of internal rotor blade components (e.g., spar caps, shear
webs and the like). Additionally, the term "internal cavity" refers to any internal
space or volume defined within the rotor blade 16.
[0021] As particularly shown in FIG. 2, in several embodiments of the present
subject matter, the disclosed system 200 may also include a cable 210 configured to
be displaced vertically so as to raise and lower one or more of the sensing devices 202
within the rotor blade 16. Thus, the cable 210 may generally include a first end 212
configured to be coupled to the sensing device(s) 202, such as by being directly
attached to the sensing device(s) 202 or by being indirectly attached to the sensing
device(s) 202 through the positioning device 206. Additionally, the cable 2 0 may
include a second end 14 configured to be disposed at location within the wind
turbine hub 18. Thus, in several embodiments, the second end 214 of the cable 210
may be coupled to a pulley mechanism 216 positioned within the hub 18 to that allow
the sensing device(s) 202 to be raised and lowered within the rotor blade 16 in a
controlled manner. In general, the pulley mechanism 216 may comprise any suitable
mechanism configured to provide a means for controlling the displacement of the
cable 210. For example, the pulley mechanism 216 may comprise a pulley, a manual
or automatic winch or any other similar lifting device. In other embodiments, it
should be appreciated that the cable 202 need not be coupled to a pulley mechanism
216. For example, an operator located within the wind turbine hub 8 may simply
raise and lower the sensing device(s) 202 by hand.
[0022] It should be appreciated that, in alternative embodiments, the sensing
device(s) 202 may be configured to be raised and lowered within the rotor blade 16
using any other suitable means. For example, in one embodiment, an elongated pole,
a telescoping rod or any other suitable device may be utilized to move the sensing
device(s) 202 up and down within the rotor blade 16.
[0023] As indicated above, the positioning device 206 of the disclosed system 200
may generally be configured to space the sensing device(s) 202 apart from the interior
surfaces 208 of the rotor blade 16 as the sensing device(s) 202 is raised and lowered
within the blade 16. For example, the positioning device 206 may be configured to
maintain the sensing device(s) 202 at a central location within the internal cavity 204
within which the sensing device(s) 202 is being raised or lowered. Additionally, the
positioning device 206 may also serve to stabilize the sensing device(s) 202 within the
rotor blade 16. In particular, the positioning device 206 may be configured to steadily
guide the sensing device(s) 202 between the interior surfaces 208 of the rotor blade 16
as the sensing device(s) 202 is raised and lowered.
[0024] Thus, in several embodiments of the present subject matter, the positioning
device 206 may include a plurality of outwardly extending legs 2 8 configured to
contact the interior surfaces 208 of the rotor blade 16. For example, as shown in the
illustrated embodiment, the positioning device 206 may have a tripod-like
configuration and may include three legs 18 extending outwardly from a base 220.
Each leg 218 may generally extend between a first end 222 configured to be attached
to the base 220 and a second end 224 configured to contact an interior surface 208 of
the rotor blade 16. As such, the legs 218 of the positioning device 206 may generally
provide a self-centering effect to the sensing device(s) 202 as it is moved within the
rotor blade 16. It should be appreciated that, in alternative embodiments, the
positioning device 206 may generally include any number of legs 218 extending
outwardly from the blade 16, such as fewer than three legs 218 or greater than three
legs 218.
[0025] In general, the base 220 of the positioning device 206 may be configured
to support the legs 218 within the rotor blade 16. Thus, the first end 222 of each leg
218 may generally be configured to be attached to the base 220 using any suitable
means. For example, in several embodiments of the present subject matter, the first
end 222 of each leg 218 may be configured to be pivotally attached to the base 220,
such as by using any suitable hinged and/or pivotal attachment mechanism. As such,
the legs 218 may generally be configured to rotate or pivot about the base 220 to
account for the variation in size of the rotor blade 16 between the blade root 146 and
the blade tip 148. In particular, as shown in dashed lines in FIG. 2, the contact
between the second end 224 of each leg 218 and the interior surfaces 208 of the rotor
blade 16 may cause the legs 218 to rotate upward about the base 220 as the
positioning device 206 is moved in the direction of the blade tip 148. Such upward
rotation of the legs 218 may generally allow the positioning device 206 and, thus, the
sensing device(s) 202 to be lowered within the rotor blade 16 to position generally
adjacent the blade tip 148. Similarly, as the positioning device 206 is moved in the
direction of the blade root 146, the legs 218 may be configured to rotate downward
about the base 220 to permit the legs 218 to spread out within the increasing size of
the internal cavity 204 and, thus, ensure that the second ends 224 of the legs 218
remain in contact with the interior surfaces 208 of the rotor blade 16.
[0026] Additionally, the second end 224 of each leg 2 18 may generally be
configured to rub/slide against or otherwise engage the interior surfaces 208 of the
rotor blade 16 to allow the sensing device(s) 202 to be properly positioned and/or
stabilized as it is raised and lowered within the blade 16. Thus, in several
embodiments, the second ends 224 of the legs 218 may include a contact feature
configured to reduce friction at the interface between the ends 224 and the interior
surfaces 208. For example, in one embodiment, a rubber guide/pad and/or any other
flexible member may be attached to the second ends 224 of the legs 218 to provide a
smooth and/or flexible, low-friction interface. Alternatively, as shown in the
illustrated embodiment, a roller 226 (e.g., a wheel, caster and/or any other suitable
rolling mechanism) may be disposed at the second end 224 of each leg 218 to permit
the end 224 to roll against an interior surface 208 of the rotor blade 16 and, thus,
provide a low friction interface between the legs 218 and the interior surface 208. It
should be appreciated that such a low-friction interface may assist the legs 2 18 in
rotating about the base 220 as the sensing device(s) 202 is moved between the blade
root 146 and the blade tip 148.
[0027] Moreover, as shown in the illustrated embodiment, one or more tensioning
devices 228 may be coupled between each of the legs 218. In general, the tensioning
devices 228 may be configured to bias the legs 2 outwardly against the interior
surfaces 208 of the rotor blade 16 and, thus, may provide a means for maintaining the
legs 2 18 in contact with the interior surfaces 208 as the sensing device(s) 202 is raised
and lowered within the blade 6. As such, the tensioning devices 228 may also assist
in centering the sensing device(s) 202 within the rotor blade 16. As shown, in one
embodiment, the tensioning devices 228 may comprise springs secured between each
of the legs 218. However, in other embodiments, the tensioning devices 228 may
comprise any other suitable devices and/or items capable of providing a biasing or
tensioning force between the legs 218.
[0028] Moreover, in several embodiments of the present subject matter, the legs
218 may include telescoping features to allow the length of each leg 218 to be
adjustable. Thus, in one embodiment, the legs 218 may include a spring loaded
telescoping feature configured to bias the legs 218 outwardly towards the interior
surfaces 208 of the rotor blade 16. For example, the legs 218 may be formed from
two or more spring loaded, telescoping cylinders. It should be appreciated that such a
spring loaded feature may be particularly advantageous in embodiments in which the
legs 218 are pivotally attached to the base 220. In particular, the spring loaded feature
may prevent the positioning device 206 from becoming stuck within the rotor blade
6 as the legs rotate about the base 220 past a horizontal position (e.g., at an angle
generally perpendicular to the longitudinal direction of the cable 210).
[0029] Additionally, it should be appreciated that the legs 218 may generally be
formed from any suitable material. For example, in several embodiments of the
present subject matter, the legs 218 may be formed from a rigid material, such as
various different metals, plastics and/or any other suitable rigid materials.
Alternatively, the legs 218 may be formed from a flexible or semi-rigid material that
allows the legs 218 to bow or flex as they move along the interior surfaces of the rotor
blade 16. Such bowing or flexing may generally provide a natural spring force
through the legs 218 that biases the legs 218 outwardly against the interior surfaces
208 of the rotor blade 16. Additionally, the ability to bow or flex may provide a
means for removing the disclosed system 200 from a rotor blade 16 in the event that a
component of the system 200 becomes stuck behind a cross-member, gusset, shear
web or similar obstruction within the blade 16. Thus, in one embodiment of the
present subject matter, the legs 218 may be formed from a lightweight, foam material,
such as polyethylene foams, polystyrene foams, urethane foams and/or any other
suitable closed-cell or open-cell foam material. However, in other embodiments, the
legs 218 may be formed from any other suitable flexible or semi-rigid material.
[0030] It should be appreciated that, in addition to supporting the legs 218, the
base 220 of the positioning device 206 may also serve as an attachment mechanism
for attaching the sensing device(s) 202 to the cable 210. For example, as shown in the
illustrated embodiment, the base 220 may be attached directly to the first end 212 of
the cable 210. In such an embodiment, the sensing device 202 may generally be
configured to be mounted to a portion of the base 220, such as by being attached to
the opposing side of the base 220 and/or by being coupled to the base 220 through a
separate mounting plate and/or other mounting device 230 disposed between the
sensing device 202 and the base 220. In other embodiments, the positioning device
206 may be configured to be disposed below the sensing device 202. As such, the
sensing device 202 may be directly attached to the cable 210, with the positioning
device 206 being directly or indirectly coupled to a portion of the sensing device 202.
[003 1] It should also be appreciated that, in alternative embodiments of the
present subject matter, the positioning device 206 need not include the above
described base 220. For example, the legs 218 of the positioning device 206 may be
attached directly to the cable 210 and/or the sensing device 202.
[0032] Referring now to FIG. 4, there is illustrated another embodiment of a
system 300 for performing an internal inspection on a rotor blade 16 of a wind turbine
10. In general, the illustrated system 300 may be configured similarly to the system
200 described above with reference to FIGS. 2 and 3 and may include many and/or all
of the same feature and/or components. Thus, the system 300 may generally include
one or more sensing devices 302 and a cable 304 configured to raise and lower the
sensing device(s) 302 within the rotor blade 16. For example, the cable 302 may be
configured to extend from generally adjacent the sensing device(s) 302 to a location
within the wind turbine hub 18, such as by being coupled to a pulley mechanism 306
disposed within the hub 18. Additionally, the system 300 may include a positioning
device 308 configured to space the sensing device(s) 302 apart from one or more
interior surfaces 208 of the rotor blade 16. As such, the relative position of the
sensing device(s) 302 with respect to the interior surfaces 208 may be maintained as
the sensing device(s) 302 is raised and lowered within the rotor blade 16.
[0033] However, unlike the system 200 described above, the positioning device
308 may be configured to control the position of the sensing device(s) 302 within the
rotor blade 16 by expelling a pressurized fluid (e.g., air or any other suitable fluid)
against the interior surfaces 208 of the blade 16. For example, in several
embodiments, the positioning device 308 may comprise any suitable member having
one or more inlets 310 for receiving a pressurized fluid and one or more outlets 312
from expelling the pressurized fluid against the interior surfaces 208 of the rotor blade
16. Thus, in the illustrated embodiment, the positioning device 308 may define an
inlet 310 configured to be in fluid communication with a pressurized fluid source 314.
For instance, as shown, an air hose or other suitable fluid line 316 may be coupled
between the inlet 310 and an air compressor or other pressurized fluid source 314
disposed within the wind turbine hub 18 to permit a pressurized fluid to be supplied to
the positioning device 308. In such an embodiment, it should be appreciated that the
air hose or other fluid line 316 may also serve as a replacement for the cable 304 and,
thus, may be utilized to raise and lower the sensing device(s) 302 within the rotor
blade 16.
[0034] Additionally, as shown, a plurality of fluid outlets 312 may be defined
around the outer perimeter of the positioning device 308. In general, the outlets 312
may be configured to expel the fluid flowing through the positioning device 308
against the interior surfaces 208 of the rotor blade 16 so as to control location of the
sensing device(s) 302 within the blade 16. Thus, in several embodiments, the
diameter or other dimensions of the outlets 312 and/or the input pressure of the
pressurized fluid may generally be chosen such that the pressurized fluid may be
expelled from the positioning device 308 with a sufficient force to provide the desired
positioning control.
[0035] It should be appreciated that, in alternative embodiments of the present
subject matter, the systems 200, 300 described above with reference to FIGS. 2-4
need not include a positioning device 206, 308. For example, in one embodiment, the
systems 200, 300 may simply comprise one or more sensing devices 202, 302
configured to be lowered into the interior of the rotor blade 16 with a cable 210, 304.
[0036] It should also be appreciated that, in several embodiments, the sensing
device(s) 202, 302 disclosed herein may be configured to be communicatively
coupled (e.g., through a wireless or wired connection) to a display device, processing
equipment and/or any other suitable device (not shown) to allow images and/or other
information captured by the sensing device(s) 202, 302 to be transmitted, viewed
and/or recorded while the internal inspection is being performed. For example, the
sensing device(s) 202, 302 may be communicatively coupled to a display device (e.g.,
a laptop or any other suitable equipment having a display screen) such that the
operator performing the inspection may view the images and/or other information as it
is captured by the sensing device(s) 202, 302. Thus, in the embodiments described
above with reference to FIGS. 2-4, a display device may be located within the wind
turbine hub 18 such that the operator may manipulate the position of the sensing
device(s) 202, 302 within the rotor blade 16 (e.g., by raising and/or lowering the
sensing device(s) 202, 302 using the cable 210, 304) based on the images and/or other
information displayed on such display device.
[0037] Moreover, in further embodiments, one or more of the disclosed sensing
devices 202, 302 may be communicatively coupled to a device controller and/or any
other device that allows the sensing device(s) 202, 302 to be operated remotely
through a wired or wireless connection. For instance, in a particular embodiment of
the present subject matter, the sensing device(s) 202, 302 may comprise one or more
remote controlled pan tilt zoom (PTZ) cameras. As is generally understood, PTZ
cameras may be configured to rotate in various directions and zoom in and out to
adjust the field of view of the camera. Thus, the operator performing the inspection
may automatically adjust the orientation of the camera to allow various different
images of the interior of the rotor blade 16 to be captured. Such a feature may be
particularly advantageous in embodiments in which the operator is provided with a
display screen for viewing the images and/or other information captured by the PTZ
camera, as the orientation of the camera may be adjusted based on the
images/information viewed on the display screen.
[0038] Additionally, in several embodiments, the sensing device(s) 202, 302 of
the present subject matter may include a combination of optical equipment (e.g., one
or more cameras) and one or more light sources configured to illuminate the areas of
interest of the rotor blade 16. For example, in the embodiments described above with
reference to FIGS. 2-4, one or more light sources may be attached to and/or built into
the positioning device 206, 308, the optical equipment and/or any other suitable
component of the system (e.g., the cable 210, 304) to enhance the ability of the optical
equipment to capture images of the interior of the rotor blade 16. In general, it should
be appreciated that any suitable light source may be utilized within the scope of the
present subject matter. However, in a particular embodiment of the present subject
matter, the light source may comprise a light-emitting diode (LED) array or other
light source specifically configured to enhance the appearance of cracks and/or other
surface defects of the rotor blade 16.
[0039] Further, in several embodiments, the sensing device(s) 202, 302 of the
present subject matter may include one or more sensors and/or other mechanisms for
detecting the location of the sensing device(s) 202, 302 and/or the positioning device
206, 308 relative to the interior surfaces of the rotor blade 16. For example, a
proximity sensor or a similar sensor may be built into or mounted to one or more of
the sensing device(s) 202, 302 and/or the positioning device 206, 308 to provide
information regarding the proximity of the sensing device(s) 202, 302 and/or the
positioning device 206, 308 relative to the interior surfaces of the rotor blade 16.
[0040] In embodiments in which the sensing device(s) 202, 302 are configured to
capture images of the interior of the rotor blade 16, the sensing device(s) 202, 302
may also include one or more sensors and/or other mechanisms for determining the
scale of the images captured by the sensing device(s) 202, 302. For example, in one
embodiment, the sensing device(s) 202, 302 may comprise a combination of one or
more cameras and one or more laser scaling devices. Each laser scaling device may
be configured to project two or more laser beams of known spacing into the field of
view of one or more of the cameras such that the size of cracks and other surface
defects captured within the images may be accurately calculated.
[0041] Additionally, in further embodiments, one or more of the sensing devices
202, 302 of the present subject matter may comprise a means for detecting and/or
determining the vertical position of another sensing device(s) 202, 302 and/or the
positioning device 206, 308 along the span 104 of the rotor blade 16. As such, the
spanwise locations of any defects detected by the sensing device(s) 202, 302 may be
easily identified. For example, in one embodiment, one or more cables 210, 304 of
the disclosed systems 200, 300 may be metered or marked to allow the vertical
position of one or more sensing device(s) 202, 302 and/or the positioning device 206,
308 to be determined. In another embodiment, a suitable measurement device (e.g., a
tape measure) may be coupled to one or more of the cables 210, 304. Alternatively,
one or more of the sensing devices 202, 302 may comprise one or more linear
encoders, position encoders and/or any other suitable linear measurement sensors.
For example, in embodiments in which the cables 210, 304 are coupled through a
pulley mechanism 216, 306 or other rotational lifting device, a linear encoder may be
coupled to the mechanism/device to allow for the accurate determination of the linear
displacement of the cable 210, 304. Similarly, a linear encoder may be coupled to one
or more of the rollers 226 of the legs 218 described above with reference to FIGS. 2
and 3 to provide information regarding the position of the sensing device(s) 202
and/or the positioning device 206.
[0042] It should be appreciated that, as used herein, the term "cable" refers to any
length of material which may be configured to function as described herein. As such,
the cables 210, 304 of the present subject matter may include any suitable cables,
wires, ropes, tapes, chains, hoses or lines formed from any suitable material. For
example, in a particular embodiment, the disclosed cables 210, 304 may comprise one
or more electrical cables for supplying power to the sensing device(s) 202, 302. In
another embodiment, the cables 210, 304 may comprise air hoses or any other type of
fluid line for supplying fluid to the positioning device 308.
[0043] This written description uses examples to disclose the invention, including
the best mode, and also to enable any person skilled in the art to practice the invention,
including making and using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the claims, and may
include other examples that occur to those skilled in the art. Such other examples are
intended to be within the scope of the claims if they include structural elements that
do not differ from the literal language of the claims, or if they include equivalent
structural elements with insubstantial differences from the literal languages of the
claims.
WHAT IS CLAIMED IS:
1. A system for performing an internal inspection on a rotor blade of a
wind turbine, the system comprising:
a sensing device;
a cable for raising and lowering said sensing device within the rotor blade; and
a positioning device attached to at least one of said sensing device and said
cable, said positioning device being configured to space said sensing device apart
from an interior surface of the rotor blade as said sensing device is raised and lowered
within the rotor blade.
2. The system of claim 1, wherein said positioning device comprises a
plurality of legs configured to contact the interior surface of the rotor blade.
3. The system of claim 2, wherein each of said plurality of legs includes a
roller configured to contact the interior surface.
4. The system of claim 2, further comprising a tensioning device coupled
between each of said plurality of legs.
5. The system of claim 2, wherein each of said plurality of legs includes
telescoping features.
6. The system of claim 2, wherein each of said plurality of legs is formed
from a flexible material.
7. The system of claim 2, wherein each of said plurality of legs is
pivotally attached to a base.
8. The system of claim 7, wherein said base is attached to at least one of
said sensing device and said cable.
9. The system of claim 2, wherein said plurality of legs is configured to
maintain said sensing device in a central location within an internal cavity of the rotor
blade.
10. The system of claim 1, wherein said sensing device comprises a pan
tilt zoom camera.
11. The system of claim 1, further comprising a second sensing device,
said second sensing device being configured to detect a location of at least one of said
sensing device and said positioning device relative to the rotor blade.
12. The system of claim 1, wherein said positioning device is configured to
expel a pressurized fluid against the interior surface of the rotor blade in order to
space said sensing device apart from the interior surface.
13. The system of claim 12, wherein said positioning device defines an
inlet configured to be in fluid communication with a pressurized fluid source.
14. The system of claim 12, wherein said positioning device defines a
plurality of outlets configured to expel the pressurized fluid against the interior
surface of the rotor blade.
15. A method for performing an internal inspection on a rotor blade, the
method comprising:
coupling a sensing device to a cable;
lowering said sensing device within the rotor blade; and,
maintaining said sensing device spaced apart from an interior surface of the
rotor blade as said sensing device is moved within the rotor blade.
16. The method of claim 15, wherein maintaining said sensing device
spaced apart from the interior surface of the rotor blade comprises contacting the
interior surface of the rotor blade with a plurality of legs.
17. The method of claim 15, wherein maintaining said sensing device
spaced apart from the interior surface of the rotor blade comprises expelling a
pressurized fluid against the interior surface.
18. The method of claim 15, further comprising detecting a location of said
sensing device relative to the interior surface of the rotor blade.
19. The method of claim 15, wherein said sensing device comprises a
camera, further comprising remotely controlling said camera as said camera is moved
within the rotor blade.
20. The method of claim 15, further comprising determining a vertical
location of said sensing device along the span of the rotor blade.