Robotic maintenance devices and methods using robotic maintenance devices to inspect and / or repair defects on a wind turbine blade

Abstract

A robotic maintenance device (10) is disclosed for inspecting, measuring, and repairing a wind turbine blade (24) of a wind turbine (12). The device (10) includes a frame, a drive system (42) coupled to the frame (40), a robotic arm system (54) movably coupled to the frame (40) and including an end effector (64) configured to hold one or more tools (66), and a material dosing system (110). The dosing system (110) includes a housing (114) for receiving one or more canisters (116) of a material- to-be-dispensed, a plunger mechanism (120) configured to displace the material-to- be-dispensed from the one or more canisters (116), a heating element (136) proximate the one or more canisters (116) and configured to apply heat to the one or more canisters (116), and a nozzle (112) held by the end effector (64) and configured to dispense the material-to-be-dispensed from the canisters (116) when the plunger mechanism (120) is activated. A method of using a robotic maintenance device to repair wind turbine blades is also disclosed.

Description

[0001] ROBOTIC MAINTENANCE DEVICES AND METHODS USING ROBOTIC MAINTENANCE DEVICES TO INSPECT AND / OR REPAIR DEFECTS ON A WIND TURBINE BLADE

[0002] Technical Field

[0003] This application relates generally to wind turbines, and more particularly, relates to robotic devices and methods for repairing defects within an interior and / or on an exterior of a wind turbine blade without necessitating removal of the blade from the tower of the wind turbine.

[0004] Background

[0005] Wind turbines are used to produce electrical energy using a renewable resource and without combusting a fossil fuel. A wind turbine converts kinetic energy from the wind into electrical power. A wind turbine installation includes a foundation, a tower supported by the foundation, and an energy generating unit positioned atop of the tower. The energy generating unit typically includes one or more nacelles to house several mechanical and electrical components, such as a generator, gearbox, and main bearing, and the wind turbine also includes a rotor operatively coupled to the components in the nacelle through a main shaft extending from the nacelle. Single rotor wind turbines and multi-rotor wind turbines (which may have multiple nacelles) are known, but for the sake of efficiency, the following description refers to single rotor designs. The rotor, in turn, includes a central hub and a plurality of blades extending radially therefrom and configured to interact with the wind to cause rotation of the rotor. The rotor is supported on the main shaft, which is either directly or indirectly operatively coupled with the generator which is housed inside the nacelle. Consequently, as wind forces the blades to rotate, electrical energy is produced by the generator. Wind power has seen significant growth over the last few decades, with many wind turbine installations being located both on land and at offshore locations.

[0006] As noted above, blades interact with the wind to generate mechanical rotation of the rotor, which can then be converted into electrical energy. The blades move through the ambient environment, typically at high speed and carry significant structural loads by which a rotor is rotated to thereby drive the generator. Consequently, the blades will typically experience surface erosion and, possibly, damage from continuous exposure to structural stress during operation. As an example of erosion, the blades are typically formed from a shell of fiber composite, aluminum, or similar material with an outer skin defined by a series of layers of coatings (polymeric elastomers, paint, etc.) surrounding and covering an outer surface of the shell. In one example, the outer skin is defined by several different layers of material, including at least an outermost topcoat, a second layer underneath the outermost topcoat, and a third layer underneath the second layer. Other layers are typically present underneath the third layer as well. The topcoat, second layer, and third layer may be formed from different colors of material to more easily reveal how deep an erosion or damaged portion goes into the outer skin of the blade. Damage to the blade outer skin can be categorized into several different levels of severity based on which layer is damaged. For example, an erosion to the third layer would be a “category 2” level of severity, which would be higher than a cut to the second layer, which would be a “category 1” level of severity. For low levels of damage or erosion, such damage can be repaired by depositing / painting a coating onto the area to fill in the damage and restore the blade to the original condition along the leading edge thereof. One example of such a repair system is shown in PCT International Patent Publication No. WO2018 / 113875. It will be understood that other types of repair or maintenance actions can also be taken to correct these types of damage on the wind turbine blade. Not only is exterior damage possible, but structural problems can also occur internally.

[0007] During operation, each blade is subjected to significant structural loading from wind and other sources. The structural loads on the wind turbine blade cause stress in and deformation of each blade. As an example, typically, there are three primary structural components of a wind turbine blade that are designed to carry and distribute the structural loads during operation of the wind turbine. The shell of the wind turbine blade is one of those structures. The shell’s aerodynamic shape interacts with the wind to produce lift and thereby rotation of the rotor. Another portion of each wind turbine blade that carries and distributes loads are spar caps. Each wind turbine blade may include a spar cap on an upwind side and a downwind side of the shell. The spar caps generally extend in a longitudinal direction along a length of the blade and are designed to carry and distribute flapwise bending loads to the rotor. Spar caps are perhaps the most significant load bearing structure of each blade. The spar caps are structurally connected to one another by a third member - shear webs. The shear webs provide some torsional and edgewise bending stiffness but mainly contribute to shear stiffness of the wind turbine blade. Each shear web is an internal longitudinal member that is spaced apart from the leading and trailing edges, is generally parallel to a longitudinal axis of the wind turbine blade, and extends generally the length of the spar caps. As an example of internal positioning, shear webs may be positioned at 15% and 50% of a chord length at a cross section of the shell. Thus, when the wind turbine blade is viewed in cross section, the shear webs may visually divide a generally hollow interior volume of the shell into a plurality of smaller hollow regions. During operation, it is possible for cracks to appear in areas of the spar caps and shear webs. Such erosion, damage, and cracking in and on the blades can be corrected by routine maintenance and repair procedures.

[0008] Both internal and external inspection and repairs to the wind turbine blades have conventionally been conducted in a multitude of manners. For one, the blade can be disassembled from the remainder of the wind turbine and lowered to the ground. Repairs are then conducted at ground level at the wind turbine location or at a repair facility. Such a repair process is time-consuming and costly because the blade must first be disassembled, moved, and then reassembled once the repair is complete. Another process includes a human technician, who with a rope rappels along the wind turbine blade or climbs into the internal void space of the blade while the blade is attached to the rotor hub. In this manner, the operator can evaluate and make repairs as needed. While disassembly is not required such a repair process is timeconsuming and costly because of the need for experienced technicians and adherence to confined space safety precautions to make the repairs manually. As yet another process, for external surfaces of the shell, a technician may conduct maintenance and repair from a platform hoisted into position adjacent the blade on the wind turbine. The platform may be supported by the nacelle or the hub of the wind turbine or extend from a cherry picker or boom-style lift stationed on the ground. In all these methods, the wind turbine must be stopped and locked in one position prior to repair. As such, wind turbine operators incur significant power production losses during maintenance and repair of the wind turbine blades. This may lead some operators to delay repair processes. Delay can permit small structural defects to grow and become more significant structural damage, which requires more involved repair processes and thus take disproportionately longer to complete. As the wind turbine industry matures, a desire has emerged for improved maintenance of wind turbine blades for one or both speed and accuracy of repair processes. The problem though is such automated maintenance devices are not always designed for reliable use on a wind turbine blade still connected to the rotor and hub of a wind turbine, and such systems can still be slow in operation or lack precision. As a result, many options have not been adopted and manual repair by technicians continues to be quicker and more efficient in many circumstances. Further improvements in maintenance and repair systems are desired.

[0009] Accordingly, wind turbine manufacturers and operators are seeking improved options for conducting maintenance and repair on the wind turbine blades of modern wind turbine designs.

[0010] Summary

[0011] To these and other ends, embodiments of the invention are directed to a robotic maintenance device for inspecting, measuring, and repairing a wind turbine blade of a wind turbine. The robotic maintenance device includes a frame. A drive system is coupled to the frame and is configured to move the robotic maintenance device relative to the wind turbine blade. The robotic maintenance device includes a robotic arm system including one or more segments movably coupled to the frame. The robotic arm system includes an end effector movably coupled to the one or more segments and is configured to hold one or more tools. The robotic maintenance device includes a material dosing system. The material dosing system includes a housing for receiving one or more canisters of a material-to-be-dispensed. A plunger mechanism is operatively coupled to the housing and is configured to displace the material-to-be- dispensed from the one or more canisters. A heating element is proximate the one or more canisters in the housing and is configured to apply heat to the one or more canisters. A nozzle is held by the end effector and is coupled to the housing. The nozzle is configured to dispense the material-to-be-dispensed from the canisters when the plunger mechanism is activated.

[0012] In one embodiment, the heating element is a silicone heating element in the form of a sheet or a tape. In another embodiment, at least one canister of material-to-be-dispensed contains a predetermined volume of material-to-be-dispensed. In yet another embodiment, the predetermined volume of material-to-be-dispensed is related to a volume of material needed for repair of a defect on the wind turbine blade.

[0013] In a further embodiment, a vision system is coupled to one or both the frame and the robotic arm system and is configured to permit remote viewing of the wind turbine blade. In yet another embodiment, the vision system is one or more of a natural light stereo camera, a fiber optic camera, and a stereo vision module.

[0014] In another embodiment, a measuring system is operatively coupled to one or both of the frame and the robotic arm system. The measuring system is configured to measure surfaces of the wind turbine blade. In one embodiment, the measuring system provides information by which 3D maps of surfaces of the wind turbine blade can be generated. In one embodiment, the measuring system is one or both of a LIDAR system and a laser profilometer system configured to quantitatively map surfaces of the wind turbine blade.

[0015] Embodiments of the invention are also directed to a method for inspecting, measuring, and repairing defects, if any, in an interior of a wind turbine blade on a wind turbine having a rotor to which the wind turbine blade is attached. The wind turbine blade has a shell, one or more spar caps, and one or more shear webs that collectively define a tubular region within the shell. The method includes rotating the rotor to position the wind turbine blade in a generally horizontal orientation and positioning a robotic maintenance device into the shell. The robotic maintenance device includes a frame. A drive system is coupled to the frame and is configured to move the robotic maintenance device relative to the wind turbine blade. A robotic arm system includes one or more segments movably coupled to the frame and includes an end effector that is movably coupled to the one or more segments and is configured to hold one or more tools. The robotic maintenance device further includes a material dosing system. The material dosing system includes a housing and one or more canisters of a material-to- be-dispensed. The one or more canisters is received in the housing. A plunger mechanism is operatively coupled to the housing and is configured to displace the material-to-be-dispensed from the one or more canisters. A heating element is proximate the one or more canisters in the housing and is configured to apply heat to the one or more canisters. A nozzle is held by the end effector, is coupled to the housing, and is configured to dispense the material-to-be-dispensed from the canisters when the plunger mechanism is activated. The method further includes applying heat from the heating element to the one or more canisters so that a temperature of the material-to-be-dispensed is greater than ambient temperature. The method also includes activating the plunger mechanism to dispense the heated material-to-be dispensed from the nozzle onto the wind turbine blade.

[0016] In one embodiment, positioning the robotic maintenance device includes positioning the robotic maintenance device in the tubular region.

[0017] In another embodiment, the robotic maintenance device further includes a measuring system operatively coupled to one or more of the frame and the robotic arm system. The method further includes measuring one or more surfaces of the wind turbine blade with the measuring system.

[0018] In a further embodiment, following measuring, the method includes calculating a volume of a defect identified in the one or more surfaces measured, and activating the plunger mechanism includes dispensing a volume of the heated material-to-be dispensed related to the calculated volume.

[0019] In yet another embodiment, the robotic maintenance device further includes a vision system that is coupled to one or both the frame and the robotic arm system and is configured to permit remote viewing of the wind turbine blade. The method further includes viewing the shell with the vision system.

[0020] The steps and elements described herein can be reconfigured and combined in different combinations to achieve the desired technical effects in different styles of wind turbines, as may be needed in the art.

[0021] Brief Description of the Drawings

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

[0023] Fig. 1 is an elevation view of a wind turbine according to one embodiment of the invention.

[0024] Fig. 2 is an elevation view of a robotic maintenance device according to one embodiment of the invention.

[0025] Fig. 3 is a top perspective view of the robotic maintenance device of Fig. 2.

[0026] Fig. 4 is a top perspective view of a material dosing system of a robotic maintenance device according to one embodiment of the invention.

[0027] Fig. 5 is an elevation view of a wind turbine according to one embodiment of the invention depicting rotation of a rotor into a maintenance position according to one embodiment.

[0028] Fig. 6 is a cross-sectional view of a wind turbine blade of Fig. 5 taken along section line 6-6 with a robotic maintenance device shown positioned within the wind turbine blade according to one embodiment.

[0029] Fig. 7 is a partial cross-sectional view of a wind turbine blade of Fig. 5 with a robotic maintenance device shown positioned within the wind turbine blade according to one embodiment.

[0030] Fig. 8 is a perspective of a material dosing system applying a material to a wind turbine blade according to one embodiment.

[0031] Detailed Description

[0032] With reference to Figs. 1 through 8, embodiments of a robotic maintenance device for repairing a wind turbine blade and a method for repairing damage to the wind turbine blade are shown. Use of the robotic maintenance device replaces a technician for direct inspection and repair of the wind turbine blade and so embodiments of the invention do not require adherence to safety protocols associated with direct manual inspection and repair. According to one or more embodiments, the robotic maintenance device permits remote visual access to a wind turbine blade, remote mapping of the blade, remote measurement of selected regions of the blade and, if necessary, remote repair of any damage identified. In particular, the robotic maintenance device is useful for movably accessing an interior of a wind turbine blade, although the device is also useful for traversing an exterior of a wind turbine blade. By remote access, a technician may be positioned within a nacelle or at ground level outside of the wind turbine and operate the robotic maintenance device from a distance while the device is within or on the wind turbine blade. No direct hands-on access to the wind turbine blade is therefore required.

[0033] To those ends, the maintenance device is configured to perform one or more of the following: image a selected area of the blade, measure a surface on the interior or exterior surface of the blade including measuring damage in the surface, clean selected areas of the blade, and dispense repair materials, such as, a resin or the like, with or without heating, on the blade to repair any identified damage or to reinforce existing structure. In exemplary embodiments, the vision system includes, but is not limited to, a laser profilometer by which the device can quantitatively scan and determine topography of the selected area of the blade. The vision system allows for accurate dimensional measurements and / or 3D mapping by which it is possible to calculate whether repair is needed and, if so, to also estimate quantities of materials needed for completion of the repair. The vision system may alternatively or in addition, include one or more cameras by which the technician can capture images of the blade. Cameras may include those which are sensitive to light visible to the human eye (e.g., wavelengths of 400 nm to 700 nm) and / or to infrared light (e.g., wavelengths of 780 nm and greater) by which digital images of selected areas are viewable and imageable. Operators may then evaluate the selected areas visually or as enhanced by nonvisible light. Advantageously, the robotic maintenance device and operational method produce a high quality and precise damage measurements while the blade remains connected to the wind turbine. By completing inspection, measurement, and, if necessary, repair with the blade connected to the wind turbine operational downtime and costs are minimize. In addition, the robotic maintenance device avoids reliance on a technician’s visual in-person inspection and repair at areas inside or on the outside of the wind turbine blade. Other advantages and effects of the embodiments of this invention will be evident from the following description.

[0034] To those and other ends and with reference to Fig. 1 , a wind turbine 12 is shown and includes a tower 14, a nacelle 16 disposed at the apex of the tower 14, and a rotor 20 operatively coupled to a generator (not shown) housed inside the nacelle 16. The rotor 20 of the wind turbine 12 includes a central hub 22 and a plurality of wind turbine blades 24 that project outwardly from the central hub 22 at locations circumferentially distributed around the hub 22. As shown, the rotor 20 includes three wind turbine blades 24, but the number of blades 24 may vary from one wind turbine to another. Each wind turbine blade 24 is elongated and includes a root end 26, which is configured to be coupled to the central hub 22 when mounted to the rotor 20, and a tip end 30 longitudinally opposite to root end 26. The wind turbine blades 24 are configured to interact with air flow to produce lift that causes the rotor 20 to spin generally within a plane defined by the wind turbine blades 24. As the rotor 20 spins, the wind turbine blades 24 pass through the air with a leading edge 32 on the windward side of wind turbine blade 24 and a trailing edge 34 on the leeward side of the wind turbine blade 24.

[0035] As the wind turbine 12 is utilized to produce electrical power, one or more of the wind turbine blades 24 may experience damage from continuous use, including from exposure to the environment and / or from sustained structural loading. While not being particularly limited to any source, environmental damage to any of the blades 24 may include erosion damage on the surface of the wind turbine blades 24 due to abrasion of particulates in the air as the air flows across the surface of the wind turbine blades 24. Given its windward orientation, the leading edge 32 of the wind turbine blade 24 often absorbs most of the damage during operation of the wind turbine 12. In that regard, erosion damage may occur in an erosion zone that includes the leading edge 32, but it may also occur in other areas in the surface of the blade 24. Structural damage to any of the blades 24 may include damage associated with fatigue. Damage from fatigue may manifest itself by the presence of cracks at stress concentrations, such as at notches, at holes, at sharp corners, and at surface scratches on the interior and / or the exterior of any single one of the blades 24. Exemplary robotic maintenance devices 10 are utilizable to inspect and repair various categories of blade damage, described above. The wind turbine blades 24 shown in Fig. 1 are spaced apart from the ground surface by a significant distance, which normally renders maintenance and repair actions difficult for both internal and external damage. However, embodiments of the robotic maintenance device 10 improve inspection, measurement, and repair processes and can make inspection, measurement, and repair more safe and less time-consuming while also improving the efficacy of any repair made, as will be set forth in detail below.

[0036] With reference to Figs. 2 and 3, an exemplary robotic maintenance device 10 for inspecting and repair of a wind turbine blade 24 is shown. The robotic maintenance device 10 includes a frame 40 on which and from which additional systems are attached and / or extend. In the exemplary embodiment, the robotic maintenance device 10 is made movable by drive system 42 coupled to the frame 40. The operator remotely controls the drive system 42 via radio signals, for example, to move the robotic maintenance device 10 while the device 10 is in or on any single one of the wind turbine blades 24. The exemplary drive system 42 shown includes a final drive 44 and an idler drive 46 on each side of the frame 40. The drive system 42 may be a skid-steer type of drive in which opposing sides have drives 44, 46 that are independently operable to enhance the turnability of the device 10. The one or both the drives 44, 46 on each side of the frame 40 are operable to rotate and thereby propel the robotic maintenance device 10 in a forward direction, backward direction, and rotate in either a clockwise or counterclockwise directions. The drives 44, 46 may be coupled to and driven by one or more motors (not labeled) that are powered by a power pack / battery cell 50. In the exemplary embodiment, one or more tracks 52 encircle and are coupled to drives 44, 46. The tracks 52 may be made of a slip resistance material and are configured to contact a surface of the wind turbine blade 24 and provide a stable footing from which the operator may use the device 10 to inspect, measure, and repair the wind turbine blade 24. While the exemplary embodiment includes a tracked drive system, embodiments of the invention are not limited to the drive system shown. Other drive systems are contemplated by which the device 10 is movable relative to a wind turbine blade 24. Specifically, the drive system 42 may include a quadruped, such as any of the Go robots available from Unitree Robotics. By way of additional example, other drive systems 42 contemplated include a four-wheeled system or six-wheeled system with or without a track.

[0037] With continued reference to Figs. 2 and 3, a robotic arm system 54 is movably attached to the frame 40. The operator may remotely move the robotic arm system 54 via one or more linear actuators or motors (not labeled) to a plethora of configurations to bring one or more tools (described below) mounted to the robotic arm system 54 to a specific location. To that end, the robotic arm system 54 includes a base segment 56 movably coupled to the frame 40 on a side opposite the drive system 42. The base segment 56 is rotatable at joint 62 about an axis 60 relative to the frame 40. In the exemplary embodiment, one or more arm segments (described below) are independently movable relative to the base segment 56. The robotic arm system 54 includes an end effector 64 that is configured to hold one or more tools 66 by which the operator can remotely conduct repair or other actions on the wind turbine blade 24. The operator remotely operates the robotic arm system 54 to position the end effector 64 (and tool 66) in a location on the wind turbine blade 24 within reach of the frame 40.

[0038] In the embodiment shown, a primary arm segment 70 is movably coupled to the base segment 56 at joint 72. As shown in Fig. 3, at the joint 72 between the primary arm segment 70 and the base segment 56, the primary arm segment 70 is rotatable about axis 74 that intersects the base segment 56. In the exemplary embodiment, the axis 74 intersects the axis 60. Rotational movement of the primary arm segment 70 is shown by arrow 76 in Fig. 3. In the exemplary embodiment, the robotic arm system 54 includes a secondary arm segment 80 that is movably coupled to the primary arm segment 70 at joint 82. The joint 82 is spaced apart from joint 72 generally by a length of the primary arm segment 70. As shown, the secondary arm segment 80 is pivotable about an axis 84 at joint 82. In the exemplary embodiment, the axis 74 is parallel to the axis 84. Each of axes 74 and 84 is perpendicular to the axis 60.

[0039] In addition, in the exemplary embodiment, the secondary arm segment 80 may be a telescoping-type arm segment. For example, in addition to pivotable movement (shown by arrow 96 in Fig. 2) about axis 84 at joint 82, a first portion 86 of the secondary arm segment 80 may be extendable relative to a second portion 88. Linear movement of the second portion 88 relative to the first portion 86 may be along an axis 94. In the exemplary embodiment, the first portion 86 and the second portion 88 may each be concentric with respect to the axis 94 so that relative movement of the first portion 86 and the second portion 88 is coincident with axis 94, which produces a telescoping like extension-retraction movement of the secondary arm segment 80. Relative movement of the portions 86, 88 is shown by arrow 92 in Fig. 2. With the telescoping movement, the end effector 64 is linearly movable toward and away from and in a direction perpendicular to the axis 84 along axis 94. In addition or alternatively, the second portion 88 may be rotatable relative to the first portion 86 about the axis 94. In the exemplary embodiment, the first portion 86 rotates about axis 94 and so is configured to spin relative to the second portion 88. This motion shown by arrow 100 in Fig. 3.

[0040] With reference to Figs. 2 and 3, the end effector 64 is movably coupled to the secondary arm segment 80 at joint 102, which defines an axis 104. The end effector 64 is therefore rotatable about the axis 104 according to arrow 106 in Fig. 3. As shown, the end effector 64 receives the tool 66. By the joints and axes arrangement, the robotic arm system 54 is configured to position the tool 66 at locations around the robotic device 10.

[0041] Further in that regard and referring to Figs. 2, 3, and 4, in the exemplary embodiment, the robotic maintenance device 10 includes a material dosing system 110 that is shown attached to the frame 40 and is operatively coupled to the robotic arm system 54. While shown attached to the frame 40, the material dosing system 110 may be carried on the robotic arm system 54 or at another location. The material dosing system 110 is configured to dispense a material, such as a resin, at a location reachable by the robotic arm system 54. In this embodiment, the tool 66 held in position on the end effector 64 is a nozzle 112 from which material in the material dosing system 110 is dispensable.

[0042] Further to dosing material from the nozzle 112, the material dosing system 110 includes a housing 114 for receiving canisters 116 of the material to be dispensed. As an example, there may be two canisters 116, each canister 116 for dispensing one part of a two-part epoxy. In one embodiment, the canisters 116 may include predetermined amount, which may be referred to as a dose, of material. For example, if a damaged region is identified, a volume of material needed to repair the damaged region may be calculated. The canisters 116 may be prefilled with a dose of material needed to fill the damaged region. A plunger mechanism 120 is coupled to the housing 114 and cooperates with the canisters 116 to selectively dispense material from the canister 116. The operator may then remotely control movement of the plungers mechanism 120 to dose material from the canisters 116 through the nozzle 112 onto a surface of the wind turbine blade 24. While operator control of the robotic maintenance device 10 is described, embodiments of the invention include automated control in which the device 10 is controlled autonomously by an on-board PC module.

[0043] To that end, the plunger mechanism 120 includes an electrical connection 122 for receiving electrical power, such as from the power pack 50, and control signals as activated by the operator. The plunger mechanism 120 includes a plunger assembly 124 including one or more plungers 126. The plungers 126 are positioned to engage with the material in the canisters 116. As the plungers 126 move inwardly relative to the housing 114 (according to arrow 130 in Fig. 4), the material in the canisters 116 is displaced from the canisters 116. Ultimately, with that displacement, material is extruded from the nozzle 112. Activation of the plunger assembly 124 may be achieved by a control arm 132 coupled to a control arm actuator 134. While a nozzle 112 is one example of the tool 66 held in position on the end effector 64, in addition or alternatively to the nozzle 112, other tools 66 held on the end effector 64 may include one or more of a cleaning tool (e.g. a nozzle for spraying a cleaning chemical), grippers, and a material removal tool (e.g., a drill), to name a few.

[0044] In addition to the canisters 116, the housing 114 may include at least one heating element 136 for heating, such as by conduction, the material within the canisters 116. The heating element 136 may be an electric resistance heater and so may be electrically coupled to the power pack 50 or another power supply. As one example, the heating element 136 is a silicone heating element in the form of a sheet or a tape. The heating element 136 may be in direct contact with one or both canisters 116. Selectively powering the heating element 136 generates heat and may be utilized to keep the material in the canisters 116 at optimum dosing / reaction temperature. Advantageously, an operator may dose material from the material dosing system 110 at a set temperature and one that is independently controllable from the ambient temperature determined by weather. For example, when the environmental temperature is at freezing or below, the material in the canisters 116 may be kept at a temperature of 20 °C or higher and by way of further example, temperature of the material in the canisters 116 may be kept at 30 °C or higher. Therefore, for example, one or both parts of a two-part epoxy may be held at an optimum reaction temperature and / or dosing temperature prior to dispensing.

[0045] The operator may selectively activate the plunger mechanism 120 to cause the plungers 126 to displace material from canister 116. In the exemplary embodiment, material displaced from the canisters 116 enters a mixing tube 140. For a dualcanister system, material from one canister is mixed with material from the other canister. This may be beneficial for a two-part epoxy in which the parts in separate canisters must be mixed together before dispensing. As shown in the exemplary embodiment, a tube 142 couples the mixing tube 140 to the nozzle 112. Displacement of the material from the canisters 116 and through the mixing tube 140 enters the tube 142 before exiting the material dosing system 110 at the nozzle 112.

[0046] In accordance with embodiments of the invention and with continued reference to Figs. 2, 3, and 4, the robotic maintenance device 10 is remotely movable in or on a wind turbine blade 24. Remote operation may be by way of a cable connection or via radio signal or the like from the device 10 to a computer / controller operable by the operator. The operator, who may not have line of sight to the robotic maintenance device 10 and so is unable to maneuver the device 10 based on that line of sight, is able to guide the robotic maintenance device 10 and maneuver the robotic arm system 54 from a viewpoint on the robotic maintenance device 10. In other words, the operator’s point of view is from a position on the device 10. To that end, the robotic maintenance device 10 includes one or more vision systems 148 to enable the operator to see the immediate vicinity around the device 10. The vision systems 148 are configured to enable the operator to drive the device 10 from a perspective of the device 10 while also viewing or measuring selected areas of the surfaces of the wind turbine blade 24. In the exemplary embodiment, at least one of the vision systems 148 is movably coupled to the frame 40. The vision system 148 may therefore be a natural light and / or IR stereo camera 150 with a light source. The natural light and / or IR stereo camera 150 may be selectively operatively pivotable about axis 152 and axis 154 so the operator can rotate and pivot the camera and light 150 to view areas of the wind turbine blade 24 in an area surrounding the device 10.

[0047] The vision system 148 may include one or more additional cameras. As an example, the robotic maintenance device 10 may include a fiber optic camera 160 that is carried on the robotic arm system 54. With the fiber optic camera 160, the operator may closely observe operation of the tool 66, such as dosing the material from the system 110. Additional or alternative cameras may include a stereo vision module 162 mounted to frame 40. As shown, the stereo vision module 162 is mounted on the frame 40. This permits the module 162 to be utilized for depth vision applications, including, but not limited to autonomous control functions so that the robot can “selfguide” by using control algorithms adapted for collision avoidance and path / line following operations and / or photogrammetry / measurement.

[0048] Embodiments of the robotic maintenance device 10 are capable of measuring surfaces of the wind turbine blade 24. The measurements provide a relative distance relationship to the surrounding surfaces of the wind turbine blade 24. The measurements may therefore be displayed to show a 3D map of the surface and so be capable of providing a topological map of the measured surface. To that end, the device 10 includes one or more measuring systems 168 coupled to the frame 40 and / or to the robotic arm system 54 and by which the surfaces of the wind turbine blade 24 are quantitatively measured. The measurements may then be analyzed to identify defects and structural issues, such as damage from erosion and cracks from deformation and the like. From calculation of the measurements, defects on the wind turbine blade 24 may be analyzed. 3D maps of the surface, including the defects may be generated from the measurements. Measurement analysis may provide a quantitative assessment of the defect, which may then be utilized to calculate a volume of material needed to repair the identified defect. By way of example only in which the defect is a crack, calculations from the measurements and / or maps may produce a volume of a crack formed in the surface of the wind turbine 24. The calculated volume may be utilized to fill one or more of the canisters 116 with an amount (e.g., volume) of material necessary to repair the crack. During repair, the canister 116 is emptied of the calculated volume at the identified crack. In one embodiment, the measuring systems 168 include a LIDAR (Light Detection and Ranging) system 170 coupled to the frame 40 and / or the robotic arm system 54 for spatial scanning. The system 170 emits laser light to measure distances to the surface and provide data that is sufficient to create detailed, high-resolution 3D map of the measured surfaces of the wind turbine blade 24. The laser light may be in the nearinfrared spectrum to be reflected from surfaces toward a LIDAR sensor. The system measures the time it takes for each laser pulse to travel to the surface and back and relates that time of flight to a distance measurement. The data generated may be a dense “point cloud” of 3D coordinates (X, Y, and Z) representing the surfaces of the wind turbine blade 24. The point cloud is processed into 3D models, detailed maps, or even digital elevation models (DEMs) showing the height variations on the surface of the wind turbine blade 24.

[0049] In addition or alternatively to the LIDAR system 170, the measuring system 168 may include a laser profilometer system 172. The laser profilometer system 172 is a high- precision measurement system that includes a laser by which detailed surface profiles of the wind turbine blade are made. The laser profilometer system 172 may measure surface roughness, texture, and shape of the wind turbine blade 24 with micron-level accuracy. In use, the system 172 emits a laser beam from a diode or fiber laser (not labeled). This beam is directed toward the surface of the object to be measured. The laser beam hits the surface of the object and reflects back toward a detector (not labeled). The laser and detector are set at a known angle to each other. By measuring the position of the reflected laser spot on the detector, the system 172 calculates the distance between the sensor and the surface based on triangulation principles. By continuously scanning the surface, the system 172 can capture the height of the surface at multiple points, creating a detailed profile or height map. In an exemplary embodiment of the system 172, the laser beam is split into two parts. One part reflects off the surface, while the other reflects off a reference mirror. An interference pattern created by the two beams and allows for extremely precise measurements down to nanometer scales. The system 172 collects data which is processed to form a 2D or 3D surface map. In one embodiment, the system 172 includes a parallax laser with grid projection. Therefore, instead of just projecting a single laser line or spot, the system 172 projects a grid pattern (a series of laser lines or dots) onto the wind turbine blade surface. This grid pattern can be projected onto flat or curved surfaces. The grid typically consists of vertical and horizontal laser lines, which intersect to create a series of evenly spaced points. This grid allows the system to capture more detailed information about the surface’s geometry, creating a higher-resolution profile of the surface.

[0050] In an exemplary embodiment, the LIDAR system 170 measures a distance to a surface. One or both camera systems 150, 160 may then be focused on the measured distance to ensure a sharp image of the surface. The laser profilometer system 172 may then project a grid onto the surface. One or both camera systems 150, 160 may then capture an image of the surface with the grid.

[0051] With reference to Figs. 3 and 3A, in an exemplary embodiment, a cleaning system 202 is coupled to the frame 40. In the embodiment shown, the cleaning system 202 is attached to the frame 40 near the housing 114 of the material dosing system 110. The exemplary cleaning system 202 is configured to dispense a cleaning fluid onto a surface to be repaired. The cleaning fluid prepares the surface for an adhesive, for example, by removing loose debris and possibly priming the surface for improved reaction to the adhesive. As an example only, and not limitation, the cleaning fluid is isopropyl alcohol. As shown, the cleaning system 202 includes a fluid pump 204 coupled to a reservoir 206 for holding the cleaning fluid. A tube 208 is attached to the pump 204 at one end and extends the length of the robotic arm system 54 to a location proximate the nozzle 112 of the material dosing system 110 at which the other end of the tube 208 terminates at nozzle 210. During operation, the cleaning fluid is pumped from the reservoir 206, pushed through the tube 208 and is ejected from the nozzle 210 at high pressure.

[0052] With reference to an exemplary embodiment shown in Fig. 3A, the robotic arm system 54 may be equipped with a gripper tool 214 on end effector 64. The gripper tool 214 may be in addition to the nozzle 112, as shown, or as an alternative to the nozzle 112. The operator may use the gripper tool 214 to grasp various objects. In the exemplary embodiment of Fig. 3A, the device 10 includes one or more coupling devices 210. By way of example and not limitation, the coupling devices 210 include a shackle, a grab hook, and a magnetic hook coupled to a cable. Each of the devices 210 may be carried by the device 10. With the gripper tool 214, the operator may manipulate one or more of the devices 210 for attachment to an object. As an example of use of one or more of the devices 210, the operator may use the gripper to attach the shackle 210 to a broken or dislodged lightening rod. Once attached, the lightening rod may be withdrawn from the blade 24 via the cable.

[0053] In exemplary embodiments, and with reference to Figs. 5, 6, 7, and 8, an operator may use the robotic maintenance device 10 to inspect, measure, and repair an interior region of a wind turbine blade 24. Initially, and with reference to Fig. 5, the rotor 20 may be rotated to an orientation in which one blade 24 is at a 9 o’clock position (or 3 o’clock position). The blade 24 therefore extends parallel with the ground. Rotating the rotor 20 may include rotating the rotor 20 counterclockwise. Although other pitch angles are useable, the blade 24 may be pitched to a position in which the leading edge 32 faces up (i.e., 90 ° pitch angle) as shown in Fig. 6. With the rotor 20 locked in an orientation in which one blade 24 is in the horizontal orientation (Fig. 5) and rotated to a pitch angle which provides a generally flat horizontal surface on the interior of the blade 24, the robotic maintenance device 10 may be introduced from within the hub 22 into an interior of the blade 24 at the root end 26. This is shown in Figs. 6 and 7.

[0054] With reference to Figs. 6 and 7, a cross section of the blade 24 is shown in which the robotic maintenance device 10 is positioned in an interior of the blade 24. In the exemplary embodiment of the wind turbine blade 24, the blade 24 includes a shell 180 that generally defines an aerodynamic exterior shape of the blade 24. The strength of the blade 24 is provided by numerous load carrying members. In that regard, spar caps 182, one on each of an upwind side and a downwind side of the shell 180, extend in a longitudinal direction along a length of the blade 24 and are designed to carry and distribute flapwise bending loads to the central hub 22 (Fig. 5). Spar caps 182 are structurally connected to one another by one or more shear webs 184. The shear webs 184 provide some torsional and edgewise bending stiffness but mainly contribute to shear stiffness of the wind turbine blade 24. Each shear web 184 is an internal longitudinal member, that is it extends into and out of the page in Fig. 6 and is spaced apart from the leading edge 32 and trailing edge 34. As shown in the example, the robotic maintenance device 10 is introduced within a tubular region 190 bounded by the shear webs 184 and the spar caps 182. While shown in the tubular region 190, the robotic maintenance device 10 may be introduced into other regions defined by the shell 180 though the blade 24 may be pitched to provide a horizontal or near horizontal surface on which the robotic maintenance device 10 may provide a stable platform from which to inspect, measure, and repair, if needed, the surfaces of any portion of the blade 24.. The operator may therefore consistently move the device 10 within the tubular region 190 to inspect and repair any damage or defects identified.

[0055] With reference to Fig. 7, the operator may move the device 10 within the tubular region 190 according to arrow 192 by activating the drive system 42. To aid in driving the device 10, the operator may activate one or more of the vision systems 148, such as the natural light stereo camera system 150 as is indicated by light cone 194 in Fig. 7. Alternatively or simultaneously with the system 150, the operator may activate one or more of the measuring systems 168. For example, the operator may activate the LIDAR system 170 and / or the laser profilometer 172 to measure the surfaces of the tubular region 190 according to measurement cone 196. Data from the LIDAR system 170 and / or the laser profilometer 172 may be utilized to generate a 3D map of the region 190. From that 3D map, deviations in the shape or dimensions of the design of the wind turbine blade 24 may be identified. Further, defects, such as cracks, may be identified. Advantageously, areas in need of repair or reinforcement in the tubular region 190 may be identified while the operator drives the device 10 along the length of the tubular region 190 toward the tip end 30 of the blade 24.

[0056] In locations identified by the operator, the operator may dispense material from the material dosing system 110. As an example, and with reference to Fig. 8, the material dosing system 110 may heat and dispense an epoxy 192 or other material along an edge between the shear web 184 and spar cap 182. The operator may observe dispensing of the material 192 via the fiber optic camera 160. Adjustments in the position of the nozzle 112 may then be made during dispensing.

[0057] After inspection and any repair, the operator may reinspect and remeasure the repaired area to evaluate the repair. Additional repairs may be conducted. Once complete, the operator may drive device 10 out of the blade 24 or the device 10 may be withdrawn via a cable 200 coupled to the frame 40 at one end and extending to the hub 20. Advantageously, in the event of a power failure or other unplanned maintenance event of the device 10, the device 10 may be safely extracted from the blade 24. For example, the cable 200 may be attached to a winch (not shown). Activation of the winch pulls the device 10 backward through the region 190 and into the hub 22 at root end 26 of the blade 24.

[0058] While the present invention has been illustrated by a description of various preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Thus, the various features of the invention may be used alone or in any combination depending on the needs and preferences of the user.

Claims

Claims1. A robotic maintenance device (10) for inspecting, measuring, and repairing a wind turbine blade (24) of a wind turbine (12), the robotic maintenance device comprising: a frame (40); a drive system (42) coupled to the frame (40) and configured to move the robotic maintenance device (10) relative to the wind turbine blade (24); a robotic arm system (54) including one or more segments (56, 70, 80) movably coupled to the frame (40) and including an end effector (64) movably coupled to the one or more segments (56, 70, 80) and configured to hold one or more tools (66); and a material dosing system (110) including:(i) a housing (114) for receiving one or more canisters (116) of a material-to-be-dispensed,(ii) a plunger mechanism (120) operatively coupled to the housing (114) and configured to displace the material-to-be-dispensed from the one or more canisters (116),(iii) a heating element (136) proximate the one or more canisters (116) in the housing (114) and configured to apply heat to the one or more canisters (116), and(iv) a nozzle (112) held by the end effector (64) and coupled to the housing (114) and configured to dispense the material-to-be- dispensed from the canisters (116) when the plunger mechanism (120) is activated.

2. The robotic maintenance device of claim 1 , wherein the heating element is a silicone heating element in the form of a sheet or a tape.

3. The robotic maintenance device of any preceding claim, further comprising at least one canister of material-to-be-dispensed, wherein the at least one canister contains a predetermined volume of material-to-be-dispensed.

4. The robotic maintenance device of claim 3, wherein the predetermined volume of material-to-be-dispensed is related to a volume of material needed for repair of a defect on the wind turbine blade.

5. The robotic maintenance device of any preceding claim, further comprising: a vision system (148) coupled to one or both the frame (40) and the robotic arm system (54) and configured to permit remote viewing of the wind turbine blade (24).

6. The robotic maintenance device of claim 5, wherein the vision system (148) is one or more of a natural light stereo camera (150), a fiber optic camera (160), and a stereo vision module (162).

7. The robotic maintenance device of any preceding claim, further comprising: a measuring system (168) operatively coupled to one or both of the frame (40) and the robotic arm system (54), the measuring system (168) being configured to measure surfaces of the wind turbine blade (24).

8. The robotic maintenance device of claim 7, wherein the measuring system (168) provides information by which 3D maps of surfaces of the wind turbine blade (24) can be generated.

9. The robotic maintenance device of any one of claims 7 or 8, wherein the measuring system (168) is one or both of a LIDAR system (170) and a laser profilometer system (172) configured to quantitatively map surfaces of the wind turbine blade (24).

10. A method for inspecting an interior of a wind turbine blade (24) on a wind turbine (12) having a rotor (20) to which the wind turbine blade (24) is attached, the wind turbine blade (24) having a shell (118), one or more spar caps (182), and one or more shear webs (184) that collectively define a tubular region (190) within the shell (118), the method comprising: rotating the rotor (20) to position the wind turbine blade (24) in a generally horizontal orientation;positioning a robotic maintenance device (10) into the shell (118), the robotic maintenance device (10) comprising: a frame (40); a drive system (42) coupled to the frame (40) and configured to move the robotic maintenance device (10) relative to the wind turbine blade (24); a robotic arm system (54) including one or more segments (56, 70, 80) movably coupled to the frame (40) and including an end effector (64) movably coupled to the one or more segments (56, 70, 80) and configured to hold one or more tools (66); and a material dosing system (110) including:(i) a housing (114),(ii) one or more canisters (116) of a material-to-be-dispensed, the one or more canisters (116) being received in the housing (114),(iii) a plunger mechanism (120) operatively coupled to the housing (114) and configured to displace the material-to-be-dispensed from the one or more canisters (116),(iv) a heating element (136) proximate the one or more canisters (116) in the housing (114) and configured to apply heat to the one or more canisters (116), and(v) a nozzle (112) held by the end effector (64) and coupled to the housing (114) and configured to dispense the material-to-be-dispensed from the canisters (116) when the plunger mechanism (120) is activated; applying heat from the heating element (136) to the one or more canisters (116) so that a temperature of the material-to-be-dispensed is greater than ambient temperature; and activating the plunger mechanism (120) to dispense the heated material-to-be dispensed from the nozzle (112) onto the wind turbine blade (24).

11. The method of claim 10, wherein positioning the robotic maintenance device (10) includes positioning the robotic maintenance device (10) in the tubular region (190).

12. The method of claim 10 or claim 11 , wherein the robotic maintenance device (10) further comprises:a measuring system (168) operatively coupled to one or more of the frame (40) and the robotic arm system (54), the method further comprising: measuring one or more surfaces of the wind turbine blade (24) with the measuring system (168).

13. The method of claim 12, wherein following measuring, calculating a volume of a defect identified in the one or more surfaces measured, and wherein activating the plunger mechanism (120) includes dispensing a volume of the heated material-to-be dispensed related to the calculated volume.

14. The method of any of claims 10-13, wherein the robotic maintenance device (10) further comprises: a vision system (148) that is coupled to one or both the frame (40) and the robotic arm system (54) and is configured to permit remote viewing of the wind turbine blade (24) and the method further comprises: viewing the shell (180) with the vision system (148).

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