Patent Description:
For cleaning or painting or maintenance of wind turbines blades, the prior art discloses a number of systems for servicing outer components of wind turbines.

International patent application <CIT> discloses a movable work platform for workers. The platform is hanging on a cable from at hoist in the nacelle and is attached to an arm that engages with the tower for gripping the tower or for sliding along the outside of the tower when lifting or lowering the platform. The distance between the tower and the platform can be adjusted by extending the arm.

In order to avoid personnel, automated devices have been proposed. An example is disclosed in European patent application <CIT> in which multiple unmanned climbing vehicles are provided around the tower and pressed against the tower surface by wires around the tower and the vehicles. A friction pad on an arm of each vehicle is repeatedly extended from the respective vehicle and pressed against the tower surface below the vehicles for pushing the vehicles upwards. A maintenance tool is provided below the vehicles, for example for cleaning and painting.

Other systems, which are unmanned, are provided on wires fastened to the nacelle or the rotor. Examples are Korean patent applications <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>, Korean patent <CIT>, as well as US patent application <CIT>. The latter system comprises a fluid sprayer which is connected by a tube to a tank on a ground based lorry for providing the fluid to the sprayer. These systems are relatively expensive in production due to their size and also expensive to transport to the site. The system in <CIT> has the additional problem of a tube extending from the robot downwards.

Smaller systems include robots that are sliding or crawling along the turbine blades while in horizontal orientation, for example as disclosed in International patent application <CIT> equivalent to <CIT>, US patent application <CIT> and equivalent European patent application <CIT>, or Chinese utility model <CIT>. Maintenance of an aircraft wing by a crawling robot is disclosed in <CIT>.

Another type of climbing robots for horizontal or vertical walls is disclosed in <CIT>. Two similar arms with suction cups are connected to each other by a hinge, and one arm is fastened to a location while the other is moved and vice versa. A further type of climbing robot is disclosed in international patent application <CIT> in which a vehicle comprises an endless belt track with suction chambers for sucking the track against a surface. Optionally, a movable arm with a suction cup at its remote end is attached to the vehicle. When the arm is properly attached to the surface, it is capable of lifting the vehicle over obstacles.

None of these systems have been commercially successful. It appears that the market is still awaiting a small scale technical solution which is versatile, involves low-cost production, and is easy to transport from site to site.

For wind turbines among others, a vacuum stepper robot is disclosed in US patent application <CIT>. The robot comprises a base with multiple vacuum suction cups that move relatively to each other alternatingly.

International patent application <CIT> discloses a cleaning vehicle constructed as a caterpillar with magnetic tracks for crawling up on a metallic tower of the wind turbine. A security line is used as a safety feature. Such robot is not useful for wind turbine wings, as there is no metal on which the magnetic feet are working.

A climbing and inspection device for turbine blades is disclosed in US patent application <CIT>. A caterpillar traction system comprising a vacuum suction system is used for holding the vehicle to the tower, optionally assisted by a wire system. The vehicle is moved along the tower with a camera up along the tower for inspection of the blade when it is oriented in parallel with the tower.

For robots in general, relatively recent developments focus on synthetic dry adhesive in an attempt to mimic the feet of geckos, seeing that geckoes can crawl along vertical walls as well as upside down on ceilings. Examples of dry adhesives are disclosed in <CIT> and German patent application <CIT>. Micro-structured dry adhesives are generally described and discussed in <CIT>, <CIT>, and <CIT>, referring to electrostatic and Van der Waals forces. In <CIT>, it is explained with reference to gecko feet that dry adhesives commonly use asymmetric micro-structured hairs that create a high area of contact when loaded in a preferred direction. When the load is reversed, the adhesives release from the surface with near zero force.

For gripping elements by an industrial robot, European patent <CIT> discloses a gripper that comprises a fin-ray element. Ray-fin elements are also disclosed for windscreen wipers, for examples as disclosed in US patent application <CIT> and European patent application <CIT>. A similar constructional principle is disclosed in <CIT>.

For dispensing viscous material, prior art systems are disclosed in general, for example as disclosed in <CIT>. <CIT> discloses an unmanned robot with an arm holding a spreader tool for spreading viscous material on the surface of a curved section of a wind turbine blade, wherein the spreader tool comprising a bendable spreader wing. However, the spreader tool is not adjustable to various curvatures of the curved section.

A manually operated spreader tool is disclosed in <CIT>, where the spreader tool comprises a small motor connected to a spreader blade. The motor is operated via buttons near the handle to adjust the curvature of the spreader blade. However, this spreader tool has a limited adjustment range since it is specially designed for wall decorations.

Another spreader tool is disclosed in <CIT> which has a fixed, non-adjustable profile.

For wind turbines in particular, there is a steady need for improvements with respect to servicing, inspection and repair of turbine blades.

It is an objective of the invention to provide an improvement in the art. In particular, it is an objective to provide a system according to claim <NUM> which is simple to use for repair of surfaces, especially surfaces of wind turbine blades, and which requires low cost in fabrication and which has a high level of versatility and adaptivity. This objective is achieved with a spreader tool for working a surface according to claim <NUM> as explained in more details in the following. As it will appear in the following, further advantages include reliability of the system, robustness, and low weight. The objective is also achieved by an operation site with such system according to claim <NUM> as well as a method of operating the system according to claim <NUM> as explained below. It is a further objective to provide methods for operating of the systems as well as advantageous use of such a system, especially of the various embodiments described.

The system comprises an unmanned robot. The robot has a base and an arm extending from the base. The robot can be of various type, for example with various legs or arms crawling on surfaces or according to other principles in the prior art. An example of a robot on a wire is explained in more detail below.

The term "an arm" is used with the meaning of "at least one arm". Multiple arms can be used for similar function, or multiple arms can have multiple functions. In the case of multiple arms, typically, the arms have different functions. For example, the different arms are used for holding and operating different tools. In cases where multiple arms are used with different functions, it is expressed as "an arm" and "a further arm"; in this case, the term "an arm" comprises one or more arms with the specific function described for this particular arm, and the term "further arm" comprises one or more further arms with the specific function of this particular "further arm".

A further arm can be used for holding and operating various tools. However, in some cases, in order to minimize weight and reduce production cost, only a single arm is used on the base.

The arm comprises a remote end, typically with a coupling for attachment of a tool for inspecting and/or working the surface. The arm is configured for movement of the remote end relatively to the base in order to adjust the location and orientation of the tool at the remote end.

The arm is moveable relatively to the base and, thus, has at least one degree of freedom relatively to the base. Typically, however, the arm has multiple degrees of freedom for movement relatively to the base, for example <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, degrees of freedom with respect to movement relatively to the base. For example, this is achieved by a corresponding number of rotational actuators with one degree of freedom each. However, a single actuator can be provided with more than one degree of freedom, for example when provided as cooperating half spheres.

The robot is provided with at least one tool configured for at least one of inspecting and working the surface. Working potentially includes cleaning, repairing, or painting.

For repairing the surface of a turbine blade, especially the edge of a turbine blade, it is a useful procedure to dispense filler material to the surface, which is subsequently spread over and along the surface, for example the edge.

For this purpose, a dispenser tool is provided for dispensing the filler material. The dispenser tool can also be used to dispense other viscous materials, for example glue or paint onto the surface.

For example, for working, the dispenser tool is attached to the remote end of the arm, for example permanently attached to the arm, or attached to the remote end of the arm via a coupling for easy attachment and removal.

In a practical embodiment not part of the claimed invention, the dispenser tool is holding multiple cartridges containing viscous material, each cartridge comprising a respective nozzle. For example, the cartridges are of the type comprising a tubular wall and a nozzle at one end of the tubular wall and an and cap remote from the nozzle arranged slidable inside the tubular wall and configured for push of the slidable cap towards the nozzle for expelling viscous material from inside the cartridge and out of the cartridge through the nozzle when the end cap is pushed towards the nozzle.

The dispenser tool comprises at least one dispenser actuator for dispensing viscous material from the cartridge. For example, in the case of the specific cartridge type described above, the actuator is driving a dispenser rod against the end cap and the dispenser rod moving with the end cap for pushing the end cap towards the nozzle under control of the dispenser actuator. Optionally, such dispenser rod is part of a spindle which is driven by a motor in the actuator.

For example, in operation, the arm is bringing the nozzle of the selected cartridge into the vicinity of the surface and orienting the dispenser tool relatively to the surface such that the nozzle of the corresponding selected cartridge is at the surface, for example closer to the surface than the nozzles of the other cartridges in the dispenser tool. Then, the dispenser is activated and viscous material is provided onto the surface of the blade from the selected cartridge while moving the nozzle along the surface.

In some embodiments not part of the claimed invention, the system dispenses from a single nozzle at a time. In other embodiments not part of the claimed invention, the system is configured for dispensing from more than one nozzle at a time. The latter can be useful when dispensing viscous material over larger surfaces.

For example, the actuator is of the type that is driven by an electrical motor. Optionally, electricity for an electrical motor in the dispenser tool is provided through an electrical connector of the dispenser tool. Alternatively, the dispenser tool comprises a battery.

However, it is, in principle, also possible to use a hydraulic or pneumatic drive as an actuator.

In some embodiments not part of the claimed invention, the dispenser tool comprises a cartridge housing in which the cartridges are arranged, for example arranged with the respective nozzles side-by-side. The robot is thus configured for at least one active dispensing orientation of the dispenser tool relatively to the surface for any selected cartridge, in which active dispensing orientation the nozzle of the selected cartridge is at the surface, for example closer to the surface than the nozzles of the other cartridges in the dispenser tool.

For example, in this non-claimed embodiment in operation, after selection of a cartridge, the dispenser tool is oriented relatively to the surface such that the nozzle of the corresponding selected cartridge is at the surface, for example closer to the surface than the nozzles of the other cartridges, in the dispenser tool and then activating the dispenser actuator and driving the end cap towards the nozzle of the selected cartridge. Alternatively, the end caps from more than one cartridge are driven in order to dispense from more than one cartridge simultaneously.

Optionally, the cartridges are arranged stationary in the dispenser, and the dispenser comprises a dispenser actuator for each cartridge and is configured for selectively driving the particular dispenser actuator for the selected cartridge while the other dispenser actuators are not activated. For example, in this non-claimed embodiment in operation, only one of the dispenser actuators is activated after selection of the corresponding cartridge and expelling viscous material only from the selected cartridge onto the surface.

Alternatively, the dispenser tool comprises a moving mechanism for moving the selected cartridge in the dispenser from an inactive position to an active position, wherein the dispenser is prevented from dispensing viscous material from the selected cartridge in the inactive position, and wherein the selected cartridge is aligned with the dispenser actuator only in the active position for dispensing viscous material from the selected cartridge. For example, in this non-claimed embodiment in operation, after selection of a cartridge that is in an inactive position the selected cartridge is moved from the inactive position to the active position, and then the dispenser actuator is activated for dispensing viscous material from the selected cartridge. An example is a revolver-type arrangement of the cartridges, where a drum magazine that holds the cartridges rotates the cartridges into the active position where a cartridge is aligned with a dispenser actuator.

In order to spread the filler or other viscous material properly over the surface of the blade, a spreader tool is provided for spreading viscous material on the curved surface, for example an edge, of a wind turbine blade. For working, the spreader tool is attached to the remote end of the arm, for example permanently attached to the arm, or attached to the remote end of the arm via a coupling for easy attachment and removal. It comprises a bendable spreader wing and a bending mechanism that comprises an actuator for deforming the spreader wing into a variable curved structure. By the actuator, the bending curve of the spreader wing is adjusted to the curvature of the curved section.

The term "a bendable spreading wing" is to be understood as "at least one bendable spreading wing", and an embodiment will be explained below with two bendable spreader wings.

In practice, the robot is located at the curved section, and viscous material is provided onto the curved section, for example with a dispenser as described above. Then, the spreader tool is oriented relatively to the curved section by the arm, and the spreader wing is adjusted to the curvature of the curved section by the actuator. By moving the spreader tool along the curved section by the arm keeping the proper orientation of the spreader tool, the viscous material is dragged along the curved section and the viscous material spread on the curved section.

For example, adjustment of the orientation and/or curvature of the spreader wing or wings to the curvature of the curved section is made during the spreading. This is especially useful if the direction and/or curvature changes along the moving path of the spreader tool.

The dispenser tool and the spreader tool are potentially operated by the same robot. For example two different arms are sued for the two tools. Alternatively, the same arm is used and the dispenser is detached from the arm and the spreader tool attached to the arm, for example attached to the coupling at the remote end of the arm. In an alternative embodiment, one robot is operating the dispenser tool and another robot is operating the spreader tool.

In some embodiments, a flat flexible band is attached to the spreader wing for abutting the curved section and for dragging viscous material along the curved section during movement of the spreader tool along the curved section by the arm.

For example, the spreader wing is constructed according to a fin-ray principle with a first strut and a second strut. The two struts constitute two long sides with an acute angle between the struts. A plurality of support beams connect the first strut with the second strut in rotational connections; wherein the second strut is connected to the actuator. In practice, the fin-ray structure is forced into a bending configuration by moving the second strut relatively to the first strut by the actuator.

In some concrete embodiments, the struts are formed by a first and a second chain, respectively, and the actuator is connected to the second chain, which is moved by the actuator relatively to the first chain, forcing the first chains into a bending shape similarly to the shape of the blade at the curved section. For example, the first chain attains a shape similarly to the shape of the blade at the edge. Optionally, the rotational connections for the support beams are combined with the rotational connections of the chain links.

For the embodiment with the flexible band, this band would be attached to the first chain and be forced into a bending shape in combination with the first chain similarly to the shape the curved section, for example the shape of the blade at the edge.

In some embodiments, the spreader tool comprises a second spreader wing. For example, the two spreader wings are extending from a centre region in opposite directions; wherein each of the two the spreader wings are connected to the bending mechanism for adjusting the bending curve of the combination of the two spreader wings to the curvature of the curved section. In practice, the method comprises orienting the spreader tool relatively to the curved section and adjusting the curvature of the spreader wings in combination to the curvature of the curved section.

For example, if the curved section is an edge of the blade, the following embodiment is useful. In this case, the two bendable spreader wings are configured for facing each other when the centre region is positioned at the edge of the turbine blade while the two spreader wings are facing the surface of the turbine blade on either side of the edge for abutting the turbine blade when the spreader wings are bent around the blade edge by the bending mechanism.

In this case in practice, the spreader tool is oriented by the arm relatively to the edge, and adjusted to a bent configuration with the two spreader wings on either side of the edge adjusted to the curvature of the turbine blade around the blade edge. In this configuration, the spreader tool is moved along the edge and is dragging the viscous material along the surface, optionally with a flexible band that functions similarly to a squeegee. This way, the viscous material is spread properly on the edge.

The spreader tool has been developed especially for spreading viscous material onto bent surface sections of the blade, for example around edges of the blade, and is capable of bending correspondingly. However, in some embodiments, the wings of the spreader tool are adjustable not only into a bent configuration but can also be straight. This implies that the spreader tool can shift between abutment of the edge of the blade and abutment of the quasi-plane surface at the flat side of the blade.

In some concrete embodiments, the robot has a base that comprises a base attachment device for securing the base stationary to the surface. The base attachment device provides secured stationary contact with the surface when activated. This base attachment device is de-activated when the robot is raised and lowered or when the robot is moved sideways. During working of the surface, the base attachment device is activated to secure the robot stationary in place relatively to the surface.

For the concrete embodiment of the robot with the base and the arm, the method may include the further steps of securing the base stationary at a stationary position on the surface by the base attachment device and providing the remote end of the arm with a tool and inspecting or working the surface with the tool while the base is in contact with the surface and secured stationary to the surface. The dispenser tool and the spreader tool are two examples of such tool.

In order to provide electricity to the robot or for providing fluids, for example water, compressed air, or hydraulic fluids, a line with at least one of an electrical cable and a fluid tube is provided for connection to the robot from a base station. For example, such base station is provided at the base foundation of the operation site, or alternatively on a suitable platform, typically below the level of the robot, although this is not strictly necessary. A further alternative, especially in case of offshore installation, such as offshore wind turbines, the base station is provided on a vessel, for example a ship, or on or at the transition piece.

Optionally, the combination of base and arm of the robot are used for moving the robot along the surface of the operation site. This mechanism is explained in more detail in the following. For this case, the remote end of the at least one arm comprises an arm attachment device for securing the remote end stationary to a surface of an operation site. For being stationary secured, the arm attachment device is in contact with the surface. Similarly, as already mentioned above, the base comprises a base attachment device, which is different from the arm attachment device, for securing the base stationary to the surface.

Examples of attachment devices are a suction cup, a dry adhesive pad, an electromagnetic pad, or an electrostatic pad, Velcro® pads, or sticky or high-friction pads. The term dry adhesive pad is here used for devices that exhibit adhesive behaviour as explained in the introduction above without using a liquid adhesive. Examples are devices that function similarly as gecko feet, for example comprising artificial nano-sized structures as disclosed in <CIT>, <CIT>, <CIT>, <CIT>, <CIT>. It is pointed out that the base and arm attachment devices need not be of identical type but can be different.

In these embodiments, the system is configured for a sequence of operations comprising,.

By this movement, the robot is always attached to the surface, either by the base being in contact with the surface and stationary secured to the surface or by the remote end of the arm being in contact with the surface and stationary secured to the surface.

For example, when the remote end of the arm is secured stationary on the surface at an attachment point on the surface, the arm is used to drag the base, typically along the surface, towards the attachment point or to push it away. Alternatively, the remote end of the arm is secured stationary to the surface at the attachment point, and the base is moved by the length adjustment mechanism. A combination of the two functions is also possible, where the remote end of the arm is secured stationary to the surface at the attachment point, and the base is moved by the length adjustment mechanism as well as by movement of the arm. Typically, the dragging or pushing by the arm is used for sideways movements, which optionally are combined with level adjustment by the length adjustment mechanism.

Optionally, the base comprises a magazine with at least one tool, the magazine comprising a magazine coupling and the tool, for example dispenser tool and/or spreader tool, comprises a first tool coupling configured for cooperation with the magazine coupling for securing the tool in the magazine. The remote end of the arm, or a remote end of a further arm, comprises an arm coupling, and the tool comprises a second tool coupling for cooperation with the arm coupling and securing the tool to the remote end of the respective arm. In operation, the remote end of the respective arm is moved to the magazine, and the arm coupling is adjusted to an orientation and position where the arm coupling and the second tool coupling are in a mating orientation. Then, the arm coupling is locked to the tool coupling, and the first tool coupling is released from the magazine coupling for removing the tool from the magazine by the respective arm. Once the tool is secured to the respective arm, the tool can be operated by it.

For example, tools are provided for grinding the surface, optionally a wind turbine blade, a dispenser tool for filling filler into cracks and ground areas, as well as a spreader tool for smoothing the filler in order to obtain a repaired surface. As a further alternative, a screwing tool is provided for tightening bolts that hold blade parts together or that hold blades to the rotor centre of a wind turbine. Such operation of a tool, such as screwing tool, is potentially driven electrically, pneumatically or hydraulically. For example the tool is provided with electrical power from the arm. Alternatively, for hydraulic or pneumatic tools, correspondingly, compressed air or hydraulic fluid is provided through tubing in or along the arm. Typically, as already described above, the electrical power, water, compressed air or hydraulic fluid is provided to the respective arm from a base station.

In some useful embodiments, the base comprises a magazine with a tool or a plurality of tools. For example, the tools are different for various work steps in a sequence of work steps, for example various working steps for inspecting, cleaning, repairing and/or painting sequence. Repair examples also include exchange of lightning receptors, bolt tightening, or gluing various aerodynamic add-ons onto the blade, for example vortex generators.

However, it is also possible to use the magazine with plural identical tools; this embodiment is useful if the tools have a short lifetime for a given process. For example, in case that a large surface has to be cleaned, ground, repaired or painted, a single tool may not be functional for the entire surface, and has to be exchanged to a properly working tool when the capabilities are not sufficient any more after some time of use of the tool. The dispenser with multiple cartridges, one-time-use cartridges, for example of the type as explained above, is useful in such situation, as the only the cartridges need to be changed and not the entire tool.

In some embodiments, especially if the robot comprises only one arm, the attachment device is detachable from the arm. In this case, it is automatically detached and stored in the tool magazine. For this reason, it advantageously comprises couplings identical to the first and second tool coupling. In order to detach the attachment device from the arm, the remote end of the arm is moved to the magazine and the attachment device is transferred to the magazine before the tool from the magazine is coupled to the arm.

Typically, the robot comprises a control unit for electronically controlling the operation of the at least one arm. The electronic control unit activates the necessary actuators, for example electrical actuators by corresponding electrical switches or pneumatic or hydraulic actuators by corresponding valves.

In some embodiments, the control unit comprises a computer that is programmed for autonomously video-inspecting the site and evaluating the video signal and thereupon autonomously running a treatment program with the available tools, optionally after modification and adaptation of the treatment program in dependence on the evaluation. The treatment program potentially involves steps of cleaning, repairing and/or painting. Alternatively or in addition to a video signal, signals of other sensors can be used as well, for example tactile sensors or infrared sensors or laser scanners.

Alternatively, the control unit is connected by a data transfer line to a control station, for example remotely located. For inspection, the robot comprises an inspection tool, and the operation site is inspected by the inspection tool, for example imaged by a video camera, and the inspection signals are transmitted from the inspection tool to the remote control station and at the remote control station evaluated for remote operating the at least one arm. Remarkably, in this advantageous operation model, the robot is transported to an operation site without the expert operator being needed present on site, due to the possibility of remote inspection, evaluation and operation. The latter has the advantage of the control station having the possibility of handling multiple robots at different sites with the need of only relatively few expert operators, as the expert operators do not need to be moved to the various sites with the robot but can stay in the remote control station.

In principle, the data connection line for the data communication between the remote control station and the control unit of the robot can be a wireless data line using satellite transmission or a wireless data network. However, especially for offshore wind turbines, wireless data transmission lines, typically, are not satisfactory for the purpose, why a wired connection is preferred. As offshore wind turbines are equipped with not only offshore-onshore power cables but also data transmission cables on the bottom of the sea, these cables can also be used for transmitting the data between the remote control station and the control unit of the robot for the operation of the robot. Optionally, for this reason, the control unit has a signal cable socket for connection to a signal cable, through which it receives operative control signals from the remote control station. This way, the operation of the at least one arm is controlled by wired data signals.

For example, the remote end of the arm is moved to the magazine, if present, and then coupled to the tool, and the tool is released from the magazine. Once, the tool is on the arm, it can be operated by the at least one arm while the base is secured to the blade surface.

Optionally, a tool kit is provided for a robot system as described above, the tool kit comprising a grinding tool for grinding a surface, a dispenser tool for dispensing filling material to the surface, and a spreader tool for shaping the filling material on the surface.

Although the use of the robot system is exemplified herein with reference to a wind turbine, in particular for servicing outer components of wind turbines, the invention is of more general character, and the robot system is advantageously used for cleaning, painting or repairing a surface, optionally vertical surface or inclined surface, for example a wall of a building.

It is pointed out that the arm can have further functions. For example, the arm can be used to lift devices from a remote location to the vicinity of the base. In addition, the arm can be used to assist another similar robot to move to the operation site, for example by lifting the other robot up from the ground, while the base is secured to the surface.

In the following, a system is described that comprises an unmanned robot and at least one wire, for example two or three wires, to which the robot is attached, and wherein the at least one wire is dimensioned for carrying the weight of the robot by the at least one wire. If only one wire is used, it is dimensioned to carry the entire weight of the robot. If more than one wire is used, for example two or three wires, it is sufficient that the wires are dimensioned to hold the weight in common. Typically, however, for safety reasons, even in the case of multiple wires, each wire would be dimensioned to hold the entire weight.

When this exemplified system is in in operation, the at least one wire is attached to an anchor location and extends downwards, as the anchor location is at a level above the robot.

In some embodiments, the at least one wire is not necessarily carrying the robot at all times but used as a safety line in order to prevent accidents, for example if the robot is of the type that is holding itself to the surface and accidentally should slide off or down the surface. Examples include attachment of robots by vacuum suction to the surface or by a multi-arm grabbing mechanism.

In other embodiment, the at least one wire is used for carrying the robot and the adjusting the elevation of the robot by lifting or lowering the robot on the wire. In such embodiment, a length adjustment mechanism is provided for adjusting the length of the at least one wire between the robot and the anchor location. This length adjustment can be used for thereby raising or lowering the robot or for length adjustment of the wire when the robot is moved sideways and thereby changes the distance from the base to the anchoring location. Thus, the at least one wire can also be sued as a support when moving the robot sideways without necessarily raising or lowering the robot. Advantageously, the base is configured for attachment to the at least one wire in order to change the elevation level of the base, and the at least one wire secures the robot against gravity at desired heights.

In some embodiment, for the length adjustment mechanism, the base is provided with a dragging unit by which the base is dragged along the wire, for example selectively in an upwards or downwards direction. An example of a dragging unit with rollers between which the wire kept under pressure is disclosed in Korean patent application <CIT>.

As an alternative, the at least one wire is rolled onto at least one roller which is part of the base. In this case, typically, the at least one wire does not hang further down than the robot. As a further alternative, the robot is secured to the at least one wire, for example to the end of the at least one wire, and the length adjustment mechanism comprises a wire hoist at elevated level above the robot, for example at the top of a wind turbine, which is used to lift the robot up and down as desired by winding up or rolling out the wire or wires.

In some practical procedures for operating the system, the following steps are used. The at least one wire is attached to the anchor location, and the robot attached thereto below the anchor location. The elevation level of the robot is adjusted by adjusting the length of the wire by the length adjustment mechanism and locating the robot at the surface of the blade, for example near the edge of the blade.

In this operational model, the at least one wire is attached at an elevated level at the operation site, for example at an anchor location on the nacelle or the rotor of a wind turbine. The robot is attached to the wire or wires for moving it up to an elevated level. In order to operate the robot from the remote control station, a data connection line is established between the control unit of the robot and a remote control station, and operation signals are transmitted from the remote control station to the control unit. This way, the arm can be remotely operated by operation signals from the remote control station without the need of operation experts on site. This is important because transport to and from the operation site requires relatively long time, and due to the remote operation, the experts can operate optimally.

As already pointed out, although the robot can be used in various operation sites, in principle, one particularly interesting operational example is where the operation site is a wind turbine with a wind turbine blade. The wire is attached to an anchoring location on the nacelle or on the central part of the rotor, and the wire extends downwards therefrom. The base is moved along the wire by remote control of the dragging unit from the control station or by lifting the base with a remotely controlled hoist, thereby increasing the elevation of the robot until the robot is abutting the wind turbine blade. By the base attachment device, the base is secured to the blade surface. While the base is secured to the blade surface and maintained stationary on the blade surface, the arm is extended, typically extended sideways, from the base, and the remote end of the arm is secured by the arm attachment device, for example arm suction cup or the arm dry adhesive pad, for remaining stationary secured to the blade surface at the attachment point. The base attachment device is released from the blade surface and moved relatively to the attachment point of the remote end of the arm by moving the arm relatively to the base or by changing the elevation level of the base by the length adjustment mechanism or by a combination thereof. For example, the base is dragged along the blade surface relatively to the attachment point or pushed away therefrom. After moving the base relatively to the remote end of the arm, the base is again secured to the blade surface by activating the base attachment device. While the base is stationary relatively to the blade surface, the arm attachment device at the remote end of the arm is than again released from the blade surface for the next action.

The invention will be explained in more detail with reference to the drawing, where.

<FIG> is an illustrative embodiment of the invention. A wind turbine <NUM> comprises a tower <NUM> and a nacelle <NUM> onto which a rotor <NUM> is rotationally coupled. The rotor <NUM> comprises a plurality of rotor blades <NUM> secured to a centre <NUM> of the rotor <NUM>. A system <NUM> comprises a robot <NUM> and a wire <NUM> to which the robot <NUM> is attached. The wire <NUM> is secured to the rotor <NUM>, for example the centre <NUM> of the rotor <NUM>, and/or to the nacelle <NUM> and extends downwards towards the base region <NUM> of the wind turbine <NUM>.

On the base region <NUM> of the wind turbine <NUM>, a base station <NUM> is provided for assisting the operation of the robot <NUM>. For example, the base station <NUM> provides electricity in case that the robot <NUM> is not provided with a battery system. In addition or alternatively, it provides at least one of the following: water, cleaning liquid, compressed air for cleaning and/or for pneumatic driving of tools, hydraulic fluid, and/or paint for painting. For this reason, the base station <NUM> is connected to the robot <NUM> by a line 12A comprising at least one cable and/or at least one flexible tube for a fluid. Optionally, the line 12A is a hose, also called an umbilical, inside which there is provided a plurality of fluid tubes or at least one cable and at least one fluid tube.

For example, the line 12A comprises a first cable, and the base station <NUM> is wired by this first cable to the robot <NUM> and by a second cable 12B through a port <NUM> in the tower <NUM> in order to receive electrical power and/or to communicate with a remote control station through a wired data transfer cable connection. The latter is particularly advantageous in case where the wind turbine <NUM> is an offshore installation where no sufficient wireless data connection is available.

Optionally, the base station <NUM> comprises a transceiver, wired or wireless, for data communication with the robot <NUM>. In case of wireless communication, the robot <NUM> comprises a corresponding wireless data transceiver <NUM>, as illustrated in <FIG>.

As an alternative, the base station <NUM> is not provided at the base region <NUM> of the tower <NUM> but on a platform <NUM> of the tower <NUM>, where the platform <NUM> is provided at a higher level than the base region <NUM> of the tower <NUM>. As a further option, the base station <NUM> is provided on a vessel in case of offshore installations, such as offshore wind turbines.

An example of a method for installation is illustrated in <FIG>. A person or a team of persons, in the following for simplicity called the installer <NUM>, installs the two wires <NUM> at the turbine top and lets the wires <NUM> hang down while one of the blades <NUM> is oriented vertically downwards. As illustrates in <FIG>, the installer <NUM> mounts the robot <NUM> onto the wires <NUM>. It is pointed out that in this illustrated example, that the robot <NUM> is mounted onto the wires on a platform <NUM>, however, it can also be mounted to the wire at the base <NUM> of the wind turbine.

For example, the robot <NUM> is provided with dragging units through which the wires <NUM> extend and in which they are held in place. The dragging units are configured for running along the wires <NUM> and thereby drag the robot <NUM> along the wires <NUM> in an upwards or downwards direction as illustrated in <FIG>. Thereby, the dragging unit provide a length adjustment mechanism for adjusting the length of the at least one wire <NUM> between the robot <NUM> and the anchor location for thereby lifting or lowering the robot <NUM>. An example of a dragging unit is illustrated in <FIG>.

<FIG> illustrates a robot <NUM> in operation. The robot <NUM> comprises a base <NUM> from which an arm <NUM> extends. The arm <NUM> comprises seven rotational couplings 17a-g as illustrated best in <FIG>, giving the arm seven degrees of freedom for motion relatively to the base <NUM>. The illustrated number of actuators is exemplary and could be different from seven. The base <NUM> is secured to the blade <NUM> while the arm <NUM> is provided with a grinding tool <NUM> for grinding the leading edge <NUM>" of the blade <NUM>. Such grinding is used prior to filling possible damages with adequate filler as part of the repair of the blade surface <NUM>'. In addition, the arm <NUM> comprises a video camera <NUM> for inspecting the site and for controlling the actions.

As an alternative to the illustrated embodiment, the wires <NUM> are rolled onto rollers (not shown) which are part of the base <NUM> and located inside the base <NUM>. In this case, the wires <NUM> do not hang further down than the robot <NUM>. Such exemplary embodiment with rollers that roll up the wires is also illustrated in <FIG>. As a further alternative, the robot <NUM> is secured to the wires, for example to the end of the wires, and a hoist is provided at the top of the wind turbine which is used to lift the robot up and down. Such exemplary embodiments are similar in appearance as the embodiments that are illustrated in <FIG> as the rollers are provided inside the base.

As illustrated on <FIG>, a base attachment device <NUM> is provided, for example a plurality of base suction cups, as part of the base <NUM> for securing the base <NUM> to the blade <NUM> surface <NUM>'. The base suction cups are exemplary and the base attachment device <NUM> could be provided by other means as mentioned in the description above.

In this particular illustration, the arm <NUM> is provided with an arm attachment device <NUM>, for example an arm suction cup, for securing the remote end <NUM> of the arm <NUM> to an attachment point <NUM> on the blade surface <NUM>'. The arm suction cup is exemplary and the arm attachment device <NUM> could be provided by other means as mentioned in the description above.

When the base attachment device <NUM> is released from the blade surface <NUM>', the arm <NUM> can drag the base <NUM> towards the attachment point <NUM>. For sake of illustration on <FIG>, the arm <NUM> is directed partly downwards and partly to the side such that a drag would be skew downwards. Such movement of the arm would typically be assisted in change of the length of the wire by the length adjustment mechanism. In many situations, however, the arm <NUM> would be placed more sideways relatively to the base <NUM> such that the vertical adjustment of the position against gravity is determined by interaction with the wire <NUM>, whereas the sideways movement is determined by drag from the arm <NUM> on the base <NUM>.

<FIG> illustrate the robot <NUM> in further detail, where <FIG> illustrated the arm <NUM> without tool and <FIG> illustrates an arm attachment device <NUM> coupled to the remote end <NUM>. The base <NUM> comprises a magazine <NUM> for a plurality of tools, for example in particular for working the surface. The magazine <NUM> comprises a plurality of magazine couplings <NUM> for coupling of tools to the magazine couplings <NUM>, in the present illustration three magazine couplings, although the number can be different depending on the requirements.

An example of a coupling with two coupling counterparts 26A, 26B is illustrated in <FIG>. The coupling counterparts 26A, 26B are operated electrically through a connector <NUM> such that after mating, electrical power activates a locking mechanism <NUM>, in this case a recess <NUM> into which an expandable ring of balls <NUM> is secured.

As illustrated in <FIG>, optionally, the base station <NUM> is wired for data transfer through a data transfer cable 12B. Such cable is useful for offshore wind turbines <NUM> as wireless data networks are typically inadequate offshore. However, wind turbines <NUM> are typically connected by electrical cables for transport of electrical power as well as connected by data transfer cables to onshore stations. Such data cables are advantageously extended for transferring data between the robot and an onshore control station as illustrated in <FIG>. In the remote control station <NUM>, an operator <NUM> is remotely operating the offshore located robot <NUM>, for example by watching display screens <NUM> and operating a control panel <NUM>. The operation of the control panel <NUM> causes transmission of operational command data to the control unit <NUM> of the offshore-located robot <NUM>, the control unit <NUM> illustrated in <FIG>. With reference to <FIG>, the display screens <NUM> can be used to watch the video sequence recorded by a video camera on the arm or the base.

As a further option, the robot <NUM> can be operated using virtual reality tools, similar to those used for corresponding computer games. For example, the operator <NUM> is provided with special an operational unit, the movement of which by the operator's arm causes the arm <NUM> to move correspondingly.

<FIG> illustrates an example of a dragging unit <NUM> for the base <NUM>. The wire <NUM> runs through pairs of rollers <NUM> which squeeze the wire <NUM> in between them such that rolling of the pairs of rollers <NUM> drags the dragging unit <NUM> along the wire <NUM>, even in lifting action against gravity. The wire <NUM> also move around a brake roller <NUM>, which in squeezing cooperation with a brake shoe <NUM> secures the wire at a predetermined position. This way, the robot <NUM> is secured against falling. Alternatively, the robot <NUM> comprises rollers for winding up the wires inside or on the base.

<FIG> shows a dispenser tool <NUM> not part of the claimed invention. Inside a housing <NUM>, dispenser cartridges <NUM> are provided from which material, for example filler material or glue, is provided through corresponding nozzles <NUM>. An access door <NUM> gives access to the cartridges <NUM> for exchange thereof. On a bracket <NUM>, a coupling counterpart 26A is provided for receiving electricity for driving the tool and/or fluids as part of a pneumatic or hydraulic driving system for the dispensing action.

<FIG> is a detailed drawing of an example of such dispenser tool <NUM> where part of the housing <NUM> has been removed. The dispensers cartridges <NUM> or of the type with a nozzle <NUM> is screwed onto the cartridge <NUM>, and the cartridge <NUM> comprises an end cap that is sliding inside the cartridge <NUM> wall such that pressing of the sliding end cap towards the nozzle <NUM> causes expelling of the content of the cartridge <NUM> out of the nozzle <NUM>. This type of cartridge <NUM> is standard for glues and filler materials and optionally for one-time-use. The end cap (nor shown) is driven by a dispenser actuator <NUM> in which a spindle <NUM> is driven by an electrical motor <NUM> against the end cap inside the cartridge <NUM> housing <NUM>. As illustrated, four dispenser actuators <NUM> with corresponding motors <NUM> and spindles <NUM> are provided for the four cartridges <NUM>, however, the number can be different. Electricity for the motors <NUM> is provided through the coupling 26A. Proper control of the actuators <NUM> is achieved with the electronic boards <NUM> connected thereto.

Typically, only one of the dispensers <NUM> is used at a time. In order to properly control the dispensing from the corresponding nozzle <NUM> to the surface <NUM>', the arm that is holding the dispenser tool <NUM> through the coupling 26A is angled into a fitting orientation where only the predetermined dispenser nozzle <NUM> is in contact with the surface <NUM>' or so close to the surface <NUM>' that the dispensed viscous material is dispensed onto the surface <NUM>'.

<FIG> illustrate an alternative embodiment not part of the claimed invention, in which the cartridges <NUM> are provided in a rotational drum magazine <NUM> of a revolver type dispenser tool <NUM>, where the rotational drum <NUM> is rotated by a motor <NUM> until one of the cartridges <NUM> is aligned with a dispenser actuator <NUM>, for example similar to the type as illustrated in <FIG> with a spindle <NUM> and a motor <NUM> that drives the spindle <NUM> which in turn pushes the end cap <NUM> towards the nozzle <NUM>. Due to the rotation with the drum <NUM>, the nozzle <NUM> of the cartridge <NUM> that is aligned with the dispenser actuator <NUM> always has the same position. For this reason, the orientation of the dispenser tool <NUM> relatively to the blade surface <NUM>" is the same independent of the cartridge <NUM> which is to be used for dispensing.

Once, the material from the cartridge <NUM>, such as glue or filler material, has been dispensed from the cartridge <NUM> through the respective nozzle <NUM> onto the surface <NUM>', a further tool is provided for properly spreading the dispensed viscous material on the surface <NUM>'.

In some cases, the edge <NUM>" or another curved section of the surface <NUM>' of the blade <NUM> is repaired by dispensing a viscous filler material on the surface <NUM>' and subsequently spreading it properly by a spreader tool. An example of such spreader tool is illustrated in <FIG>.

<FIG> shows a spreader tool <NUM> in operation. It has a flexible band <NUM> fastened to a bendable constructions <NUM> in order for the flexible band <NUM> to be used as a squeegee when abutting the surface <NUM>'. When the spreader tool <NUM> is abutting the edge <NUM>" of the blade <NUM>, the flexible band <NUM> is deformed into the shape of the blade <NUM> around the edge <NUM>" and abuts the surface <NUM>' tightly, which is illustrated in the enlarged drawing of FIG. Hydraulic or pneumatic spreader actuators <NUM> are used for a controlled deformation of the bendable construction <NUM>. The spreader actuators <NUM> are provided with corresponding hydraulic or pneumatic tube connectors <NUM>. Correspondingly, the flexible band <NUM> is deformed when spreading viscous material on other curved sections of the blade surface <NUM>'.

<FIG> illustrate the spreader tool <NUM> when its flexible band <NUM> is in straight condition, for example during storage or when used for spreading viscous material on straight sections of the surface <NUM>' of the blade <NUM>. The flexible band <NUM> has a flat side <NUM> directed away from the bendable construction <NUM> and is configured for contact with the blade surface <NUM>' and a blade edge <NUM> which is used for spreading the viscous material, for example filler, onto the surface.

When the spreader tool <NUM> is held inclined relatively to the surface <NUM>', such that the flexible band <NUM> is not resting with its flat side <NUM> against the blade surface <NUM>' but only with the blade edge <NUM> of the flexible band <NUM>, the viscous material can be evenly spread by the spreader tool <NUM> over and along the edge <NUM>" surface <NUM>' when the spreader tool <NUM> is drawn along the edge <NUM>". This situation is illustrated in <FIG>, where it is readily recognised that there is a gap <NUM> between the surface <NUM>' and flat side <NUM> of the flexible band <NUM>, while the band's blade edge <NUM> is close to abutting the surface <NUM>' in order to drag the viscous material from inside the gap <NUM> along the edge <NUM>" while spreading it around the edge <NUM>".

The spreader tool <NUM> comprises two couplings 26A which gives two possibilities for attachment to the arm of the robot <NUM>. Alternatively, one is used for attachment of the spreader tool <NUM> to the arm of the robot <NUM> and another coupling 26A is used when the spreader tool <NUM> is stored in the toolbox, as it was explained in relation to <FIG>. As a further alternative, the spreader tool <NUM> comprises only one coupling 26A.

For example, the coupling 26A is connected to the connectors <NUM> of the pair of hydraulic or pneumatic actuators <NUM>. In this case, the provision of hydraulic or pneumatic fluid is provided through the robot arm.

When activated, the pair of actuators <NUM> bend the two sections 54A, 54B of the bendable construction <NUM>, together with the flexible band <NUM>, for example around the edge <NUM>", as illustrated.

As best illustrated in <FIG>, the bendable construction <NUM> comprises two spreader wings 54A, 54B which are arranged on either side of a centre region <NUM>, where the centre region in operation is positioned on the edge <NUM>" of the blade surface <NUM>', and the two spreader wings 54A, 54B extend in opposite directions and are bent into the profile of the blade's <NUM> edge <NUM>" onto opposite sides of the edge <NUM>".

The construction follows a fin-ray principle in which two flexible struts are inclined to each other and a plurality of support beams connect the struts at various locations along their lengths. When one strut is moved relatively to the other, the construction deforms into a curved structure.

In the exemplified embodiment of <FIG>, each spreader wing 54A, 54B comprises a double-chain structure <NUM> with two chains 60A, 60B as struts. Each chain can only bend in one plane, which is in a direction normal to the flat side <NUM> of the flexible band <NUM>. When the two chains 60A, 60B are straightened, as illustrated in <FIG>, the two chains 60A and 60B are inclined relatively to each other and form an acute angle, typically in the range of between <NUM> and <NUM> degrees. A centre region <NUM> forms the base of a triangle with the two struts, formed by the chains 60A and 60B.

In more detail, a plurality of chain links 61A of one of the two chains 60A is connected to a corresponding plurality of chain links 61B of the other chain 60B by a corresponding plurality of support beams <NUM> which extends largely laterally from the chains 60A, 60B and which are individually rotationally coupled with their two ends to either of the two chain links 61A, 61B which they individually connect. Due to the two chains 60A, 60B being inclined to each other when straight, the support beams <NUM> have different sizes and are increasing in length along the double chain <NUM>. The consequence of the triangular arrangement of the two chains 60A, 60B is a bending in a lateral direction, where the bending is not free but which is restricted to a smooth curve by the cooperation of the two chains 60A, 60B, which are linked to each other by the plurality of support beams <NUM>. Whereas one chain 60A is attached to the flexible band <NUM>, the two sections of the other chain 60B are covered by two covering bands <NUM>.

The actuators <NUM> comprise an actuator rod <NUM> which is fastened to an end of the outer chain 61B. When the actuators <NUM> are extended, the actuator rod <NUM> pushes the outer chain away 61B from the actuator <NUM> and forces the two spreader wings 54A, 54B to bent around the centre region <NUM>.

When the actuator <NUM> is retracted, the spreader wings 54A, 54B are extended into a straight configuration. Although, the spreader tool <NUM> has been developed especially for spreading viscous material around edges <NUM>" and is capable of bending correspondingly, the spreader wings 54A, 54B can also be used in straight configuration when filler, glue, or other viscous material is to be spread on the flat surface <NUM>' of the blade <NUM>. For versatility, it is a great advantage that the spreader tool <NUM> can easily and quickly shift between abutment of the edge of the blade <NUM> and abutment of the quasi-plane surface <NUM>'at the flat side of the blade <NUM>.

Although, two wings have been used for an exemplification that is suitable for the edge of the blade <NUM>, a spreader tool <NUM> with only a single spreader wing 54A is also an option, especially, when surface sections with less curvature are repaired.

Claim 1:
A method of operating a system (<NUM>) at an operation site (<NUM>), wherein the operation site is a wind turbine (<NUM>) with a wind turbine blade (<NUM>) having a surface (<NUM>'), wherein the system comprises
an unmanned robot (<NUM>), wherein the robot (<NUM>) comprises a base (<NUM>), an arm (<NUM>) extending from the base (<NUM>), the arm (<NUM>) comprising a remote end (<NUM>) configured for movement of the remote end (<NUM>) relatively to the base (<NUM>), and a control unit for electronically controlling the operation of the at least one arm, and
a spreader tool (<NUM>)
attached to the remote end (<NUM>) of the arm (<NUM>) and
configured for spreading a viscous material on the surface (<NUM>') of a curved section of the wind turbine blade (<NUM>),
the spreader tool (<NUM>) comprising a bendable spreader wing (54A) and
a bending mechanism, that comprises an actuator (<NUM>) for deforming the spreader wing (54A) into a variable curved structure and configured for adjusting the bending curve of the spreader wing (54A) to the curvature of the curved section, and
wherein the method comprises
locating the robot (<NUM>) at the curved section,
providing viscous material onto the curved section,
orienting the spreader tool (<NUM>) relatively to the curved section by the arm (<NUM>), adjusting the spreader wing (54A) to the curvature of the curved section by the actuator (<NUM>), and
moving the spreader tool (<NUM>) along the curved section by the arm (<NUM>), thereby dragging the viscous material along the curved section and spreading the viscous material on the curved section.