Methods of hoisting wind turbine blade repair vehicles and wind turbine blade repair vehicle hoisting systems

Abstract

A method of hoisting a robotic maintenance device (36) to a wind turbine blade (24) to repair the wind turbine blade (24) includes wrapping a rope (46) in a loop around a wind turbine blade (24) and positioning a repair vehicle assembly (38) beneath the loop. The repair vehicle assembly (38) includes a tool platform (42) for a robotic maintenance device (36) capable of repairing a wind turbine blade (24). The repair vehicle assembly (38) includes two winches (44) secured to the platform. The winches (44) are configured to receive the rope (46). The method includes operably coupling the rope (46) to the winches (44) and operating at least one winch (44) to wind in the rope (46). The repair vehicle assembly (38) is lifted toward the wind turbine blade (24). The method includes operating one winch (44) to wind in the rope (46) while operating the other winch (44) to let out the rope (46). The repair vehicle assembly (38) is moved around a circumference of the wind turbine blade (24) to be on the leading edge (32) of the blade (24).

Description

[0001] METHODS OF HOISTING WIND TURBINE BLADE REPAIR VEHICLES AND WIND TURBINE BLADE REPAIR VEHICLE HOISTING SYSTEMS

[0002] Technical Field

[0003] This application relates generally to wind turbines, and more particularly relates to repair vehicle hoisting systems and to methods of hoisting blade repair vehicles onto a wind turbine blade for repairing blade damage.

[0004] Background

[0005] Wind turbines are used to produce electrical energy using a renewable resource and without combusting a fossil fuel. Generally, a wind turbine converts kinetic energy from the wind into electrical power. A conventional 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 primarily to single rotor designs.

[0006] 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.

[0007] As noted above, blades interact with the wind to generate mechanical rotation of the rotor, which can then be converted into electrical energy. A wind turbine blade is a complex structure that must be constructed to withstand long-term service in an abusive environment, while also maximizing lift and minimizing drag forces. The blades move at varying speeds through the ambient environment surrounding the wind turbine, but often this movement is at high speed. Consequently, the blades will typically experience erosion and other environmental related damage over time during operation, such as from friction from the air as well as impacts from rain droplets, particulate matter, debris, or other items in the air. Environmental damage, particularly erosion, is especially problematic along a leading edge of the wind turbine blade, which faces into the direction of wind movement. The erosion along the leading edge of the blade adversely affects the aerodynamic qualities of the blade over time, resulting in lower power production for given incoming wind speeds. Such environmental damage on the blades can be corrected by routine maintenance and repair procedures.

[0008] The blades are typically formed from a shell of layered 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. The shell encloses internal components of the blade and isolates them from the environment, including shear webs and spar caps, for example. The outer skin may be 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, including base materials typically made from fiber composites and the like. One recently developed repair method using a robotic device to repair the eroded surfaces of a wind turbine blade can be reviewed in PCT International Patent Publication No. WO2021 / 121521 , owned by the same owner of the present application.

[0009] Automated robotic maintenance devices, such as that disclosed in the ‘521 Publication referenced above, are positioned on the leading edge of a stopped (and locked) wind turbine blade to repair erosion on the leading edge of the blade. Typically, the blade to be worked upon is positioned in a generally horizontal orientation with the blade pitched so that the leading edge faces upwardly such that the robotic device can then be placed upon the leading edge of the blade. Repairs are then made to the blade by the robotic device as the device is moved along the blade using an internal drive system. Placing the robotic device on the leading edge of a wind turbine blade can be problematic. Typically, the vehicle is lifted into position by a helicopter, a drone, or with a crane. However, the use of these ancillary devices to position a robotic device on the leading edge of the wind turbine blade is expensive and complicates the repair process.

[0010] In view of the above, there is a desire to improve delivery of a robotic device on a leading edge of a wind turbine blade. Thus, further improvements for robotic maintenance and repair systems for wind turbine blades are desired.

[0011] Summary

[0012] To these and other ends, embodiments of the invention are directed to a method of hoisting a robotic maintenance device to a wind turbine blade on a wind turbine rotor of a wind turbine to repair the wind turbine blade. The method includes wrapping a rope in at least one loop around a wind turbine blade and positioning a repair vehicle assembly beneath the at least one loop. In one embodiment, the repair vehicle assembly includes a tool platform configured to receive a robotic maintenance device capable of repairing a wind turbine blade. The repair vehicle assembly also includes at least two winches secured to the tool platform. The at least two winches are configured to receive the rope. The method further includes operably coupling the rope to the at least two winches and operating at least a first winch of the at least two winches to wind in the rope whereby the repair vehicle assembly is lifted toward the wind turbine blade.

[0013] In one embodiment, following operating at least the first winch, the method includes operating one of the first winch and a second winch of the at least two winches to wind in the rope while operating the other one of the first winch and the second winch of the at least two winches to let out the rope whereby the repair vehicle assembly is moved around a circumference of the wind turbine blade.

[0014] In one embodiment, prior to wrapping the rope, the method further includes movably securing a weight to the rope. Wrapping the rope includes securing the weight in the at least one loop. In one embodiment, prior to wrapping the rope, the method further includes rotating the rotor to position the wind turbine blade at a 12 o’clock position.

[0015] In one embodiment, wrapping the rope includes placing each end portion of the rope in a package. In one embodiment, placing each end portion of the rope in the package includes attaching the package proximate a root end of the wind turbine blade.

[0016] In one embodiment, following wrapping, the method further includes rotating the rotor to position the wind turbine blade at a 9 o’clock position.

[0017] In one embodiment, following rotating the wind turbine blade, the method further includes releasing each end portion of the rope so that the rope hangs under gravity from the wind turbine blade.

[0018] In one embodiment, operably coupling the rope to each of the at least two winches includes securing a second weight on the rope before operably coupling the rope to at least one winch of the at least two winches.

[0019] In one embodiment, positioning the repair vehicle assembly includes placing the repair vehicle assembly at or near the ground.

[0020] In one embodiment, positioning the repair vehicle assembly includes orienting the repair vehicle assembly upside down.

[0021] In one embodiment, operating at least the first winch includes operating the at least two winches to wind in the rope.

[0022] In one embodiment, operating the at least two winches includes counter rotating the at least two winches to wind in the rope.

[0023] In one embodiment, following winding the rope onto the first winch, the repair vehicle assembly is located adjacent a leading edge of the wind turbine blade. In one embodiment, following operating one of the first winch and the second winch of the at least two winches to wind in the rope while operating the other one of the first winch and the second winch of the at least two winches to let out the rope, the method further includes pitching the wind turbine blade to a 0° position whereby the repair vehicle assembly rests on the wind turbine blade under gravity.

[0024] In one embodiment, following operating one of the first winch and the second winch, the method further includes repairing the wind turbine blade.

[0025] In one embodiment, the repair vehicle assembly further includes the robotic maintenance device and wherein following pitching, the method further includes repairing the wind turbine blade with the robotic maintenance device. In one embodiment, repairing the wind turbine blade includes moving the robotic maintenance device off the tool platform and on to the wind turbine blade.

[0026] In one embodiment, the repair vehicle assembly further includes a drive coupled to the tool platform, the drive being configured to move the repair vehicle assembly. Repairing the wind turbine blade includes operating the drive to move the repair vehicle assembly along the wind turbine blade.

[0027] According to one aspect of the invention, a wind turbine blade repair vehicle hoisting system includes a tool platform configured to receive a robotic maintenance device capable of repairing a wind turbine blade. The hoisting system includes a rope configured to be wrapped around a wind turbine blade, two weights that are movably coupled to the rope, and at least two winches that are secured to the tool platform. The at least two winches operably receive the rope.

[0028] In one embodiment, the at least two winches are arranged on the tool platform so that during operation counter rotation of the winches winds in the rope.

[0029] Brief Description of the Drawings

[0030] 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.

[0031] Fig. 1 is a front elevation view of a wind turbine;

[0032] Fig. 2 is an elevation view of one embodiment of a repair vehicle hoisting system in accordance with an embodiment of the invention;

[0033] Fig. 3 is a front elevation view of a wind turbine depicting rotation of a wind turbine rotor and staging of a repair vehicle hoisting system according to one aspect of the invention;

[0034] Fig. 4 is an enlarged side elevation view of a disassembled repair vehicle hoisting system in a staged position for use on a wind turbine blade in accordance with an embodiment of the invention;

[0035] Fig. 5 is an enlarged side elevation view of the repair vehicle hoisting system of Fig. 2 during deployment in accordance with an embodiment of the invention;

[0036] Fig. 6 is a cross-sectional view of a wind turbine blade taken along section line 6-6 of Fig. 3 illustrating positioning of the repair vehicle hoisting system in accordance with an embodiment of the invention;

[0037] Fig. 7 is a cross-sectional view of a wind turbine blade taken along section line 6-6 of Fig. 3 illustrating positioning of the repair vehicle hoisting system in accordance with an embodiment of the invention;

[0038] Fig. 8 is a cross-sectional view of a wind turbine blade following rotation of the blade to 0° tip angle in accordance with an embodiment of the invention;

[0039] Fig. 9 is an enlarged front elevation view of the wind turbine rotor depicting the repair vehicle hoisting system during longitudinal movement along a wind turbine blade in accordance with one embodiment of the invention; and Fig. 10 is an enlarged front elevation view of the wind turbine rotor depicting the repair vehicle hoisting system during longitudinal movement along a wind turbine blade in accordance with one embodiment of the invention.

[0040] Detailed Description

[0041] With reference to Figs. 1 -10, an exemplary embodiment of a repair vehicle hoisting system 10 and a method of using the repair vehicle hoisting system 10 to elevate a repair vehicle to repair a wind turbine blade are shown. According to some embodiments, the repair vehicle hoisting system 10 is configured to receive a robotic maintenance device and position that device on a wind turbine blade. Following placement, the repair vehicle hoisting system 10 is configured to translate along a surface of the wind turbine blade such that localized repairs may be performed with the robotic maintenance device. Exemplary embodiments of the repair vehicle hoisting system 10 enable delivery of the robotic maintenance device from a location at or near the ground directly to the targeted wind turbine blade. Advantageously, embodiments of the hoisting system 10 and method of using the hoisting system 10 eliminate the need for use of ancillary devices, such as helicopters, cranes, and drones (i.e., an unmanned aerial vehicle), to deliver a maintenance device to the targeted wind turbine blade and to remove the maintenance device from the wind turbine blade once repairs are completed. In essence, the exemplary repair vehicle is self-hoisting and hoisting system 10 is a self-contained equipment package deliverable to the wind turbine. These beneficial characteristics simplify the logistics of conducting repair processes and so reduce the expense of repairing one or more wind turbine blades on a wind turbine.

[0042] 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.

[0043] As the wind turbine 12 is utilized to produce electrical power, one or more of the wind turbine blades 24 may experience environmental damage from prolonged, continuous exposure to the environment. 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.

[0044] Erosion damage is generally characterized as a loss of material from an exposed surface portion of the wind turbine blade 24. Material loss may be uniformly distributed but is often non-uniform across the leading edge 32 or any other surface of the wind turbine blade 24. Rather than losing a uniform skin of material from a surface, erosion may include localized surface imperfections, such as random pitting and shallow gouges or crack-like features that may be a result of localized, connected pitting. More specifically, the erosion damage may include some areas in which the outer topcoat layer is worn away and a second layer of material underneath the topcoat is thereby exposed. This damage severity is often referred to as “category 1” damage. At locations at which the outer topcoat layer and the second layer of material are worn away leaving a third layer of material exposed, the damage severity is categorized as “category 2” damage. Similarly, for reference, deeper cuts and erosions defining more significant damage are typically categorized at higher levels of seventy, such as category 3, 4, or 5 damage. By identifying and properly correcting lower levels of erosion damage promptly, more significant damage of the blade 24 can be avoided thereby also avoiding greater operational downtime needed to repair higher severity damage. In any case, erosion damage may cause the wind turbine blade 24 to become less efficient at rotating the rotor 20.

[0045] Exemplary repair vehicle hoisting systems 10 are utilizable to assist in the repair of various categories of blade damage, described above. To that end, an exemplary repair vehicle hoisting system 10 is usable to lift a robotic maintenance device 36 (see Fig. 9)(which may also be referred to as a "robotic repair device" or just "robotic device") to a wind turbine blade 24. Specifically, personnel operate repair vehicle hoisting system 10 to lift the robotic maintenance device 36 from a location at or near the ground to a location at or near the blade 24 at which the blade 24 is repairable.

[0046] In one embodiment, the repair vehicle hoisting system 10 may move the robotic maintenance device 36 along the length of the blade 24. The robotic maintenance device 36 may then inspect and repair any identified damage to the surface of the wind turbine blade 24. In other words, the robotic maintenance device 36 is coupled to the repair vehicle hoisting system 10 during inspection and repair of the wind turbine blade 24.

[0047] In another embodiment, the robotic maintenance device 36 is separable from the repair vehicle hoisting system 10 during inspection and repair of the wind turbine blade 24. In that regard, personnel utilize the repair vehicle hoisting system 10 to lift the robotic maintenance device 36 to the wind turbine blade 24. Once positioned, the robotic maintenance device 36 may be remotely controlled to separate from the hoisting system 10 to complete repairs on the wind turbine blade 24. Once repairs are completed, the robotic maintenance device 36 is reassembled with the hoisting system 10 and lowered from the blade 24. In either configuration, the robotic maintenance device 36 is not further specifically described herein but exemplary devices include, but are not limited to, those described in commonly owned International Publication Nos. WO2023 / 280362 and WO2023 / 104269, which is incorporated by reference herein in its entirety. By way of example only, the robotic maintenance device 36 may be used to repair category 1 damage and category 2 damage to the outer skin of the wind turbine blade 24. In the exemplary embodiment shown, and with reference to Figs. 1 , 2, and 3, the repair vehicle hoisting system 10 may be transported to the wind turbine 12 to inspect and complete necessary repairs to one or more of the blades 24. As an example, Figs. 1 and 3 show a transport trailer 40 for storing and transporting the repair vehicle hoisting system 10. After unloading from the transport trailer 40, the repair vehicle hoisting system 10 is staged prior to hoisting the robotic maintenance device 36 to one of the blades 24. The selected robotic maintenance device 36 is coupled to the repair vehicle hoisting system 10. In one embodiment, the robotic maintenance device 36 is launched from a boat (not shown) for application to an offshore wind turbine.

[0048] With reference to Figs. 2 and 3, the exemplary repair vehicle hoisting system 10 includes a repair vehicle assembly 38. In the embodiment shown, the repair vehicle assembly 38 includes the robotic maintenance device 36. The repair vehicle assembly 38 further includes a tool platform 42 on which the robotic maintenance device 36 is shown mounted or stored during hoisting. One or more winches 44 are attached to the tool platform 42. Each winch 44 is configured to receive an end of a rope, cable, or other tension member 46 (generally referred to hereafter as a “rope 46”). One or both winches 44 are configured to wind in and leave out the rope 46. As an example, it is anticipated that a winch with at least 200 m rope length capacity is required for a tower height of 100 m. By way of example, and not limitation, the rope 46 may have a length equivalent to the hub height of the wind turbine 12 plus a length of the look around the blade 24 plus a contingency length for wind lengthening of the rope 46 between the blade 24 and the ground. An exemplary rope 46 may be HPPE (e.g., Dynema® fiber) core and high friction braided wrapping with a diameter of 5 mm to 6 mm. At that diameter dimension, the winch 44 may have a bobbin that is 125 mm wide and a core diameter of 100 mm. Further, when tightly wound on the bobbin of the winch 44, the wrapped diameter may be approximately 250 mm. Other exemplary ropes may be flat (rather than circular cross section), such as those used in web slings. These rope configurations may be less damaging to the surface of the blade 24 due to a larger contact surface area with the blade 24. The relatively large contact surface may also enable a firmer grip on the blade 24.

[0049] In the exemplary embodiment, one or more rope pickups 48 are attached to the tool platform 42 and are configured to grab the rope 46 from the surface of the blade 24, as is described below, particularly during movement of the repair vehicle assembly 38 on the wind turbine blade 24. One or more weights 50 may be slidably attached to the rope 46 between the two winches 44. By way of example only, the weight 50 may have a mass in the range of 1 kg to 10 kg.

[0050] In an exemplary embodiment, a plurality of wheels 52 are also coupled to the tool platform 42. The wheels 52 are configured to contact the blade 24 and to position the robotic maintenance device 36 in spaced apart relation to the surface of the blade 24. The wheels 52 permit the repair vehicle assembly 38 to be movable along the blade 24 during installation of the hoisting system 10 and during blade repair procedures. By way of example only, and not limitation, there may be a total of six wheels 52 movably coupled to the tool platform 42 via a plurality of corresponding legs 54. In the exemplary embodiment, two of the wheels 52 may be grooved (e.g., concave configuration) in a shape that cooperates with the curvature of the wind turbine blade 24, such as the curvature of the leading edge 32 of the wind turbine blade 24. The grooved wheels 52 may thereby enhance tracking of vehicle 38 during movement along on the leading edge 32 of the wind turbine blade 24 (e.g., shown in Fig. 9). The remaining four wheels 52 and legs 54 may be paired and extend in opposing outward directions beyond a perimeter of the tool platform 42. The pairs of wheels 52 and legs 54 laterally support the tool platform 42 in spaced apart relation to the surface of the blade 24. The four wheels 52 and legs 54 may be selectively pivotable relative to the tool platform 42 from a disengaged position to an engaged position on the wind turbine blade 24. Further, the wheels 52 and legs 54 may be configured to balance the repair vehicle assembly 38 when the repair vehicle assembly 38 is positioned on the leading edge 32 of the wind turbine blade 24. Although not shown, a drive including a drivetrain and power supply may be operably coupled to the wheels 52, for example the grooved wheels 52, so that an operator may direct the repair vehicle assembly 38 along the blade 24 via selectively operating the drive, which may cause rotation of the grooved wheels 52 against the blade 24.

[0051] In accordance with an exemplary method of hoisting the repair vehicle assembly 38 to one of the wind turbine blades 24, and with reference to Figs. 3 and 4, the repair vehicle hoisting system 10 may be initially separated into one or more portions. For example, the rope 46 and at least one of the weights 50 may be detached from the repair vehicle assembly 38 prior to coupling the rope 46 to a blade 24. As shown in Fig. 3, once separated, the repair vehicle assembly 38 is staged at or near the ground level proximate the tower 14. In the exemplary embodiment shown in Fig. 3, the repair vehicle assembly 38 is shown upside down on the ground with the wheels 52 and legs 54 in the disengaged position.

[0052] With reference to Fig. 4, once the rope 46 and at least one of the weights 50 are separated from the repair vehicle assembly 38, the rope 46 and weight 50 may be transported from the ground into the nacelle 16. At that location, personnel install the rope 46 and weight 50 on the wind turbine blade 24 to be repaired. In the exemplary embodiment, personnel install the rope 46 and weight 50 on the wind turbine blade 24 while the rotor 20 is oriented to position the wind turbine blade 24 at 12 o’clock (shown in Fig. 1 ). Rope installation may be accomplished, for example, with a pole having a length sufficient to wrap at least one loop of the rope 46 around the root end 26 of the blade 24. As shown, the rope 46 is wrapped one and one-half times around the root end 26 of the blade 24. Also shown, each end portion of the rope 46 may be contained in a respective package 56, such as a bag, to ease handling of the rope 46. The packages 56 may be temporarily attached to the wind turbine blade 24 at a location, such as near the root end 26, from which the end portions of the rope 46 may be dropped toward the ground. The weight 50 is captured on the rope 46 in the loop around the wind turbine blade 24.

[0053] With reference to Figs. 3 and 5, once the rope 46 and weight 50 are installed on the wind turbine blade 24, the rotor 20 is rotated, such as in a counterclockwise direction, as is shown in Fig. 3, so that the targeted blade 24 at 9 o’clock. When the targeted blade 24 is locked in the 9 o’clock position, personnel release the ends of the rope 46 from the packages 56. As shown in Fig. 5, under gravity, the end portions of the rope 46 fall to the ground. The rope 46 extends from the wind turbine blade 24 to at or near the ground. Personnel attach the rope 46 to the repair vehicle assembly 38. At the wind turbine blade 24, the weight 50 remains secured by the loop in the rope 46 at the root end 26 of the wind turbine blade 24. At the ground, by way of example, the rope 46 is threaded through a second weight 50 and operably coupled to the two winches 44 of the repair vehicle assembly 38. Operation of the winches 44 therefore winds the rope 46 onto the winch 44 or lets the rope 46 off the winch 44. In one embodiment, the weight 50 at ground level proximate the repair vehicle assembly 38 is positioned on the rope 46 extending toward the leeward side of the wind turbine blade 24 (i.e. , the left side of the rope 46 in Fig. 5). As shown, in the exemplary embodiment, the rope 46 is coupled to the winches 44 when the repair vehicle assembly 38 is in an upside-down position. Once the repair vehicle hoisting system 10 is reassembled in the staged position shown in Fig. 5, personnel may utilize the repair vehicle hoisting system 10 to raise the repair vehicle assembly 38 toward the wind turbine blade 24 as is generally indicated by arrow 58.

[0054] To that end, with reference to Figs. 5 and 6, in one embodiment, personnel operate winches 44 to take in the rope 46 to lift the repair vehicle assembly 38 from the ground. While only one winch 44 may be needed to lift the repair vehicle assembly 38 toward the wind turbine blade 24, in one embodiment, both winches 44 are utilized to lift the repair vehicle assembly 38. As an example, one winch 44 rotates clockwise to pull in the rope 46 while the other winch 44 rotates counterclockwise to pull in the rope 46. That is, the pair of winches 44 are oriented on the tool platform 42 so that counter rotation of the winches 44 causes the rope 46 to be pulled onto each of the winches 44. This lifts the repair vehicle assembly 38 toward the wind turbine blade 24 to a position spaced apart from the bottom side of the blade 24, as is shown in Fig. 6. In the exemplary embodiment shown, the repair vehicle assembly 38 may not be in contact with the wind turbine blade 24.

[0055] With continued reference to Fig. 6, at the position of the repair vehicle assembly 38 shown, the weight 50 in the loop of the rope 46 is between the repair vehicle assembly 38 and the wind turbine blade 24, and the weight 50 proximate the repair vehicle assembly 38 is positioned on the leeward side of the wind turbine blade 24. Once at or near this position of the repair vehicle assembly 38 relative to the blade 24, an operator may cause the winch 44 positioned on the leeward side of the blade 24 to let out rope 46 while simultaneously causing the winch 44 on the windward side of the blade 24 to wind in rope 46. That is, the operator may operate the winches 44 to rotate in the same direction.

[0056] With reference to Fig. 7, coordination between the winches 44 moves the repair vehicle assembly 38 around the circumference of the blade 24 toward the leading edge 32. As the repair vehicle assembly 38 moves toward the leading edge 32, the second weight 50 positioned proximate the repair vehicle assembly 38 during reassembly of the repair vehicle hoisting system 10 while on the ground remains in a spaced apart position proximate the first weight 50 initially secured with the loop and the rope 46 to the wind turbine blade 24. That is, the second weight 50 is stationary while the repair vehicle assembly 38 translates around the circumference of the blade 24. As shown, as a result, both weights 50 are located between the wind turbine blade 24 and the ground.

[0057] With reference now to Figs. 7 and 8, in the exemplary embodiment, once the repair vehicle assembly 38 is adjacent the leading edge 32 of the wind turbine blade 24 (Fig. 7), the wind turbine blade 24 is pitched to its 0° position (Fig. 8). While Fig. 7 depicts the repair vehicle assembly 38 as contacting the wind turbine blade 24, it is not necessary for the repair vehicle assembly 38 to be in contact with the wind turbine blade 24 at this position. Rotation of the wind turbine blade 24 is generally shown by arrows 60 in Fig 8. In other words, the repair vehicle assembly 38 remains in a stationary position relative to the wind turbine blade 24 while the blade 24 is rotated. Following rotation, the repair vehicle assembly 38 rests on the wind turbine blade 24 under gravitational force. The weights 50 create tension in the rope 46 and slide along the rope 46 as the blade 24 is rotated. In this way, the weights 50 hang on the bottom side of the blade 24. While rotation of the blade 24 is described in the exemplary embodiment, embodiments of the method are not limited to rotation blade 24 to the 0° position following movement of the repair vehicle assembly 38. By way of example, in one embodiment, coordination of the winches 44 may be utilized to bring the repair vehicle assembly 38 to the leading edge 32 without changing the pitch of the wind turbine blade 24. That is, the blade 24 may be at a 0° position prior to hoisting the repair vehicle assembly 38 from at or near the ground.

[0058] With reference to Figs. 8 and 9, once the wind turbine blade 24 is in the position shown, the wheels 52 on the repair vehicle assembly 38 are lowered to the engaged position and so the wheels 52 are brought into contact with the wind turbine blade 24. The rope pickups 48 are operated to grab and lift the rope 46 from contact with the wind turbine blade 24 generally in an area beneath the tool platform 42. One or both winches 44 let out rope 46. As the rope 46 lengthens, the weights 50 create gaps between the rope 46 and the trailing edge 34 of the wind turbine blade 24. This is generally shown in Fig. 9, in which the rope 46 is let out to a distance sufficient to position the weights 50 below the trailing edge 34 at max cord. Personnel may then move repair vehicle assembly 38 along the leading edge 32 of the wind turbine blade 24 from the root end 26 to the tip end 30 to conduct repairs of any damage upon the wind turbine blade 24. Advantageously, the rope 46 prevents the repair vehicle assembly 38 from falling to the ground should the repair vehicle assembly 38 run off the blade 24.

[0059] Once the blade repairs are completed, personnel may utilize the repair vehicle hoisting system 10 to lower the robotic maintenance device 36 to ground level. In general, this process comprises the steps of the hoisting procedure, described above, but in reverse order. Specifically, personnel may move the repair vehicle assembly 38 to near the root end 26 of the wind turbine blade 24. The wheels 52 and legs 54 may be pivoted to the disengaged position. The rope pickups 48 may drop the rope 46 into contact with the wind turbine blade 24. The rope 46 is drawn in to more closely encircle the root end 26 of the wind turbine blade 24. Personnel may pitch the wind turbine blade 24 to its 90° position (a counter-clockwise rotation) at which orientation the leading edge 32 and the repair vehicle assembly 38 are rotated to a 9 o’clock position (see, e.g., Fig. 7). This orientation is when viewed from the root end 26 of the wind turbine blade 24 and looking toward the tip 30. Personnel may then coordinate operation of winches 44 to let out rope on one side and wind in the rope 46 on the other side thereby moving the repair vehicle assembly 38 from a 9 o’clock position toward a location between the ground and the wind turbine blade 24, i.e., in a 6 o’clock position. At this location, personnel may operate both winches 44 to let out rope 46 to lower the repair vehicle assembly 38 to at or near the ground. The rope 46 is then disconnected from the repair vehicle assembly 38, and the rope 46 is removed from the wind turbine blade 24. An identical procedure may then be repeated for each of the three wind turbine blades 24.

[0060] In one exemplary embodiment, and with reference to Fig. 10, the repair vehicle hoisting system 10 includes a set of stilts 60 instead of, or in addition to, the wheels 52 and legs 54. As shown, the tool platform 42 may rest on the stilts 60 against the wind turbine blade 24. The robotic maintenance device 36 may be a wheeled device, as shown or have a drive system such as that shown in commonly owned WO 2021 / 121522 and WO 2023 / 104269. Once the tool platform 42 is brought to rest against the wind turbine blade 24, the robotic maintenance device 36 is movable off the tool platform 42, such as via a ramp, and directly onto the surface of the wind turbine blade 24. The robotic maintenance device 36 may then be driven along the leading edge 32 of the wind turbine blade 24 while the tool platform 42 remains in a stationary position on the wind turbine blade 24. Once repairs are complete, the robotic maintenance device 36 is reloaded onto the tool platform 42. The reverse procedure shown in Figs. 3-8 is utilized for lowering the repair vehicle assembly 38 to at or near the ground. For example, once the robotic maintenance device 36 is secured on the tool platform 42, personnel may pitch the wind turbine blade 24 to its 90° position (i.e. , the leading edge 32 is in a 9 o’clock position as viewed from the root of the blade 24 toward the tip 30). At this orientation, the repair vehicle assembly 38 is at a 9 o’clock position (see, e.g., Fig. 7). Personnel may then coordinate operation of winches 44 to let out rope on one side and wind in the rope 46 on the other side thereby moving the repair vehicle assembly 38 toward a location between the ground and the wind turbine blade 24. At this location, personnel may operate both winches 44 to let out rope 46 to lower the repair vehicle assembly 38 to at or near the ground. The rope 46 is then disconnected from the repair vehicle assembly 38, and the rope 46 is removed from the wind turbine blade 24. An identical procedure may then be repeated for each of the three wind turbine blades 24.

[0061] 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. Accordingly, aspects of the present invention should not be limited to the specific wind turbine application disclosed herein. Moreover, the various features of the invention may be used alone or in any combination depending on the needs and preferences of the user, and the features described in the different embodiments are not dependent on one another for operation of the invention.

Claims

CLAIMS:1 . A method of hoisting a robotic maintenance device (36) to a wind turbine blade (24) on a wind turbine rotor (20) of a wind turbine (12), the method comprising: wrapping a rope (46) in at least one loop around a wind turbine blade (24); positioning a repair vehicle assembly (38) beneath the at least one loop, the repair vehicle assembly (38) comprising: a tool platform (42) configured to receive the robotic maintenance device (36) capable of repairing the wind turbine blade (24); and at least two winches (44) secured to the tool platform (42), the at least two winches (44) being configured to receive the rope (46); operably coupling the rope (46) to the at least two winches (44); operating at least a first winch (44) of the at least two winches (44) to wind in the rope (46) whereby the repair vehicle assembly (38) is lifted toward the wind turbine blade (24).

2. The method of claim 1 , further comprising: following operating at least the first winch (44), operating one of the first winch (44) and a second winch (44) of the at least two winches (44) to wind in the rope (46) while operating the other one of the first winch (44) and the second winch (44) of the at least two winches (44) to let out the rope (46) whereby the repair vehicle assembly (38) is moved around a circumference of the wind turbine blade (24).

3. The method of claim 1 or claim 2, wherein prior to wrapping the rope (46), the method further comprises: movably securing a weight (50) to the rope (46), and wherein wrapping the rope (46) includes securing the weight (50) in the at least one loop.

4. The method of any preceding claim, wherein prior to wrapping the rope (46), the method further comprises: rotating the rotor (20) to position the wind turbine blade (24) at a 12 o’clock position.

5. The method of any preceding claim, wherein following wrapping, the method further comprises: rotating the rotor (20) to position the wind turbine blade (24) at a 9 o’clock position.

6. The method of any preceding claim, wherein following wrapping the rope (46), the method further comprises: releasing each end portion of the rope (46) so that the rope (46) hangs under gravity from the wind turbine blade (24).

7. The method of any preceding claim, wherein positioning the repair vehicle assembly (38) includes placing the repair vehicle assembly (38) at or near the ground.

8. The method of any preceding claim, wherein positioning the repair vehicle assembly (38) includes orienting the repair vehicle assembly (38) upside down.

9. The method of any preceding claim, wherein operably coupling the rope (46) to each of the at least two winches (44) includes securing a second weight (50) on the rope (46) before operably coupling the rope (46) to at least one winch (44) of the at least two winches (44).

10. The method of any preceding claim, wherein operating at least the first winch (44) includes operating the at least two winches (44) to wind in the rope (46).11 . The method of any preceding claim, wherein following operating of at least one of the at least two winches (44) to wind in the rope (46), the repair vehicle assembly (38) is located adjacent a leading edge (32) of the wind turbine blade (24).

12. The method of any preceding claim, wherein following operating one of the first winch (44) and the second winch (44) of the at least two winches (44) to wind in the rope (46) while operating the other one of the first winch (44) and the second winch (44) of the at least two winches (44) to let out the rope (46), the method further comprises: pitching the wind turbine blade (24) to a 0° position whereby the repair vehicle assembly (38) rests on the wind turbine blade (24) under gravity.

13. The method of any preceding claim, wherein following operating one of the first winch (44) and a second winch (44) of the at least two winches (44) to wind in the rope (46) while operating the other one of the first winch (44) and the second winch (44) of the at least two winches (44) to let out the rope (46), the method further comprises: repairing the wind turbine blade (24).

14. The method of any of claims 1 -13, wherein the repair vehicle assembly (38) further comprises the robotic maintenance device (36) and wherein following operating the at least the first winch (44), the method further comprises: repairing the wind turbine blade (24) with the robotic maintenance device (36).

15. The method of claim 14, wherein repairing the wind turbine blade (24) includes moving the robotic maintenance device (36) off the tool platform (42) and on to the wind turbine blade (24).

16. The method of claim 14, wherein the repair vehicle assembly (38) further comprises a drive coupled to the tool platform (42), the drive being configured to move the repair vehicle assembly (38), and wherein repairing the wind turbine blade (24) includes operating the drive to move the repair vehicle assembly (38) along the wind turbine blade (24).

17. A wind turbine blade (24) repair vehicle hoisting system (10), comprising: a tool platform (42) configured to receive a robotic maintenance device (36) capable of repairing a wind turbine blade (24); a rope (46) configured to be wrapped around a wind turbine blade (24); two weights (50) being movably coupled to the rope (46); and at least two winches (44) secured to the tool platform (42), the at least two winches (44) operably receiving the rope (46).

18. The wind turbine blade (24) repair vehicle hoisting system (10) of claim 17, wherein the at least two winches (44) are arranged on the tool platform (42) so that during operation counter rotation of the winches (44) winds in the rope (46).

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