WO2019068298A2

WO2019068298A2 - System with a robot on a wire, method of its operation, operation site with such system, and use thereof

Info

Publication number: WO2019068298A2
Application number: PCT/DK2018/050245
Authority: WO
Inventors: Hans Laurberg; Martin Huus Bjerge; Jens-Peter HOLMELUND; Kristian GRØNBÆK
Original assignee: Rope Robotics Aps
Current assignee: Rope Robotics Aps
Priority date: 2017-10-02
Filing date: 2018-10-02
Publication date: 2019-04-11
Anticipated expiration: 2020-04-02
Also published as: WO2019068298A3; DK179917B1; DK201770745A1

Abstract

System with a robot on a wire, method of its operation, operation site with such system, and use thereof A system is provided comprising a robot (8) on a wire, especially for cleaning or re- pairing a wind turbine blade. The robot (8) comprises a tool for inspecting and work- ing the surface of the turbine blade. Electricity or fluids for the operation of the robot are provided from a base station (11) through a cable or fluid tube (12A), which ex- tends over a pulley (43) above the robot (8) in order for the cable or fluid tube ap- proaching the robot (8) from above.

Description

System with a robot on a wire, method of its operation, operation site with such system, and use thereof

FIELD OF THE INVENTION

The present invention relates to a system with a robot hanging on a wire, especially used for cleaning and repair of vertical surface or inclined surface, in particular of a wind turbine, and a method of its operation. It also relates to use of the system and an operation site with such system.

BACKGROUND OF THE INVENTION

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 WO2004/092577 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 EP2281770 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 KR20130114913, KR20140001412, KR20140001444, KR20120067128, KR20140000370, and KR20140000383, Korean patent KR101324974B 1, as well as US patent application US2011318496A. 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 US2011318496A has the additional problem of a tube extending from the apparatus 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 WO2013/032166 equivalent to US2015/135459, US patent application US2010132137 and equivalent European patent application EP2752621, or Chinese utility model CN205129861U. Maintenance of an aircraft wing by a crawling robot is disclosed in US2013/0289766.

Another type of climbing robots for horizontal or vertical walls is disclosed in US5551525. 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 WO00/75000 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 US20140519169. The robot comprises a base with multiple vacuum suction cups that move relatively to each other alternatingly.

International patent application WO2012/158042 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 applica- tion US2011/0138937. 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 vehice 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 US7762362 and German patent application DE201510101290. Micro-structured dry adhesives are generally described and discussed in US2008/169003, US2014272272, and US8882996, referring to electrostatic and Van der Waals forces. In US2014272272, 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.

DESCRIPTION / SUMMARY OF THE INVENTION

It is an objective of the invention to provide an improvement in the art. In particular, it is an objective to provide a system which is simple to use, especially for cleaning and repair of surfaces, especially surfaces from wind turbine blades, and which requires low cost in fabrication and which has a high level of versatility and adaptivity. It should also be safe and prevent damage to the surface, in particular prevent damage to a wind turbine blade. This objective is achieved with a system for inspecting and/or working a surface with a robot below an anchor location at an operation site as ex- plained in more detail 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 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 and at least one wire, for example two or three wires. When the 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.

Optionally, the robot is attached to the at least one wire, in which case the at least one wire is dimensioned for carrying the weight of the robot. 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.

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 for 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 is also a support when moving the robot sideways without necessarily raising or lowering the robot.

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.

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.

Advantageously, in order to provide the line from above to the robot, a support unit, for example a pulley, is configured for attachment to the at least one wire, wherein the support unit is dimensioned for supporting the line between the base station and the robot. The support unit, for example pulley, comprises a support, for example a roller or sliding support surface, configured for movement of the line over the support. For example, when adjusting an elevation level of the robot, the line is kept stretched between the robot and the support unit during distance changes between the robot and the support, for example by moving the line over the support at a similar rate as the adjustment of the elevation level of the robot.

Advantageously, the system comprises a mechanism for changing the level of the support unit. In some embodiment, the support unit comprises a motor for moving along the at least one wire. For example, the motor is connected to a dragging unit that drags the support unit along the wire. Optionally, a hoist is used as a mechanism for the level adjustment of the support unit. Alternatively or in addition, such hoist can be used for the robot.

Optionally, the wires or wires for holding the support unit and the wire or wires for holding the robot are the same. However, this need not be the case, and different wires can be used. As a further alternative, only the support unit is provided on at least one wire, whereas none of the wires from the anchor location are used for the robot.

Especially, for the event that the base station is provided at a level below the robot, the support unit, for example a pulley, has been found advantageous for guiding the cable to a location above the robot before extending to the base station.

The advantage of such support unit, for example pulley, is as follows. Due to the distance between the robot and the base station, the line has a substantial weight, espe- cially if the line is very long, for example if the base station is located at the base of a wind turbine while the robot is operating at the blade. Such weight implies a risk of downwards and sideways pulling of the robot, which is disadvantageous. By guiding the line over a roller of a pulley or a sliding surface of the support unit at a level above the position of the robot, the line is approaching the robot from above, which eliminates downwards and sideways drag on the robot caused by the line. In case of use of the robot for wind turbine blade inspection and/or repair, this support unit, for example pulley, also minimizes risks of the line causing damage to the edge of the blade, especially the trailing edge of the blade, which can be provided with a sensitive toothed structure.

However, in some cases, the base station is provided above the robot, for example at the nacelle or near the nacelle, and the line extends downwards from the location of the base station. In this case, the line is hanging down from the base station into a loop, extends upwards again over the support of the support unit and then from the support unit down to the robot. In this case, as well, the weight of the cable and/or fluid tube of the line keeps the line straightened upwards from the robot.

Advantageously, the support unit, for example pulley, is configured for attachment to at least one of the wires that are hanging down from the anchor location. For example, the same wire or wires are used that carry the robot.

Optionally, the support unit comprises a lock-mechanism for locking the support unit stationary to such wire or wires when the lock mechanism is activated. Advantageous- ly, the lock-mechanism is also configured for unlocking the support unit from the wire for sliding of the support unit along the wire when the lock-mechanism is deactivated.

An example of the lock mechanism is a friction brake. Another potential mechanisms is a clamp lock by which the wire is held against moving by a clamp.

In a concrete embodiment, the lock-mechanism comprises at least one of a movable handle and a bracket configured for de-activating the lock-mechanism when moved. For example, the system is configured for moving the robot upwards, for example along the wire, to the support unit, for example pulley, and moving at least one of the handle and bracket by the robot for de-activating the lock-mechanism. The robot may de-activate the lock mechanism and move the support unit, and optionally activate the lock-mechanism again at a different level of the support unit on the wire. For such moving action of the support unit by the robot, the robot is configured for supporting the support unit and moving the support unit along the wire to a different level. For example, the robot is moved upwards until it establishes supporting contact with the support unit, after which the lock-mechanism of the support unit is de-activated, and the support unit rest on the robot and moves with the robot to a different level along the wire.

For example, the lock-mechanism is configured for de-activation by upwards push of the bracket by the robot, and the system is configured for moving the robot to the support unit, for example along the wire. Optionally, a re-activation of the lock mecha- nism is also made by the robot, for example by operating the handle.

A possible sequence for initiating operation is as follows:

attaching the at least one wire to the anchor location;

locating the base station at a first level, typically below the anchor location; - providing the robot attached to the at least one the wire at a second level below the anchor location, the second level being different from the first level;

providing the support unit, for example pulley, attached to at least one the wire at a third level between the anchor location and the second level of the robot; providing the line with one end connected to the robot, for example to the base of the robot, and an opposite end connected to the base station, the line extending from the robot upwards to the support unit and over the support and from the support to the base station;

providing electricity through the cable or fluid through the fluid tube from the base station to the robot;

- adjusting an elevation level of the robot by adjusting the length of the wire between the robot and the anchor location by the length adjustment mechanism; and advantageously keeping the line stretched between the robot and the support uni during distance changes between the robot and the support by moving the line over the support at a similar rate as the adjustment of the elevation level of the robot;

and inspecting or working the surface with the at least one tool by the robot. The system as described above is advantageously part of the operation site for at least one of inspecting and working a surface below an anchor location at an operation site, wherein the operation site is a wind turbine with a wind turbine blade, and the surface is a surface of the wind turbine blade; wherein the operation site with the system comprises

- an unmanned robot in contact with the surface and comprising at least one tool configured for at least one of inspecting and working the surface;

at least one wire attached with one end to the anchor location at a level above the robot and carrying the robot while extending downwards from the anchor location to the robot;

- a length adjustment mechanism for adjusting the length of the at least one wire between the robot and the anchor location when adjusting an elevation level of the robot;

a base station and a line with one end connected to the base station and an opposite end connected to the robot, the line comprising at least one of an electri- cal cable and a fluid tube for providing electricity through the cable or fluid through the fluid tube from the base station to the robot;

a support unit attached to the wire and supporting the line between the base station and the robot, wherein the support unit comprises a support configured for movement of the line over the support, wherein the line extends from the robot upwards to the support unit and over the support and from the support to the base station.

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 pro- vides secured stationary contact with the surface when activated. This base attachment device is de-activated when the robot is raised and lowered on the wire, 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. Optionally, an arm is extending from the base. 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".

Although, a further arm can be used for holding and operating various tools, 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 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 2, 3, 4, 5, 6, 7, or 8, 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.

For example, the base is configured for attachment to the at least one wire in order to change the elevation level of the base. The 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 KR20140000383 by Samsung Heavy Ind. 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 ex- ample 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. If the robot is provided with a roller for rolling up the wire in or on the base, or the robot comprises a dragging unit for dragging the robot along the wire, the robot can move up and down the wire while the support unit, for example pulley, is hanging on the same wire. Alternatively, different wires are used for the support unit and the robot. In the latter case, a hoist can be used for the level adjustment of the support unit and the robot, respectively.

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.

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 de- vices that function similarly as gecko feet, for example comprising artificial nano- sized structures as disclosed in US7762362, US8882996, US8398909, US2014/272272, US2014/227473. It is pointed out that the base and arm attachment devices need not be of identical type but can be different. The system is configured for a sequence of operations comprising,

- adjusting the elevation level of the robot by the length adjustment mechanism;

- then securing the base stationary to the surface by the base attachment device;

- while the base is in contact with the surface and secured stationary to the surface, moving the remote end of the arm to an attachment point on the surface, the attach- ment point being distant from the secured stationary base, and securing the remote end of the arm to the surface at the attachment point,

- while the remote end of the arm is still secured stationary at the attachment point on the surface, detaching the base attachment device from its stationary position on the surface and moving the base relatively to the attachment point 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.

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.

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. 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 mentioned, 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.

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.

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. As it appears from the above, in short, a system is provided comprising a robot on a wire, for example for cleaning or repairing a wind turbine blade. The robot comprises a base and an arm that extends from the base and which comprises a remote end for holding and operating tools. Electricity or fluids for the operation of the robot are provided from a base station through a cable or fluid tube, which extends over a support unit, for example pulley, above the robot in order for the cable or fluid tube approaching the robot from above.

The robot is unmanned and especially useful for wind turbines, for example remotely controlled or fully automatic. SHORT DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail with reference to the drawing, where FIG. 1 is a sketch of an embodiment of the invention on a wind turbine with a base station a) on the ground and b) on a platform above the robot;

FIG. 2 a-c illustrate a) mounting of the wire, b) mounting of the robot to the wire, lifting of the robot along the wire;

FIG. 3 illustrates the robot with a grinding tool on the leading edge of the blade; FIG. 4 illustrates an embodiment of the robot in greater detail with an attachment device on the blade;

FIG. 5 a-b illustrates a robot a) without and b) with an attachment device on the arm; FIG. 6 is an example of couplings for coupling tools to the base;

FIG. 7 illustrates a remote control station;

FIG. 8 illustrates a dragging unit,

FIG. 9 exemplifies a pulley as a) photo and b) partial technical drawing.

DETAILED DESCRIPTION / PREFERRED EMBODEVIENT

FIG. la is an illustrative embodiment of the invention. A wind turbine 1 comprises a tower 2 and a nacelle 3 onto which a rotor 4 is rotationally coupled. The rotor 4 comprises a plurality of rotor blades 5 secured to a centre 6 of the rotor 4. A system 7 comprises a robot 8 and a wire 9 to which the robot 8 is attached. The wire 9 is secured to the rotor 4, for example centre 6 of the rotor 4, and/or to the nacelle 3 and extends downwards towards the base region 10 of the wind turbine 1.

On the base region 10 of the wind turbine 1, a base station 11 is provided for assisting the operation of the robot 8. For example, the base station 11 provides electricity in case that the robot 8 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 11 is connected to the robot 8 by a line 12A com- prising 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 11 is wired by this first cable to the robot 8 and by a second cable 12B through a port 13 in the tower 2 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 1 is an offshore installation where no sufficient wireless data connection is available.

Due to the relatively long distance between the robot 8 and the base station 11, the line 12A has a substantial weight. Such weight implies a risk of downwards and sideways pulling of the robot 8, which is disadvantageous. For this reason, the line 12A is led over a support 42 of a support unit 43, for example over a roller 42 of a pulley 43, which is attached to the wire 9 at a level above the position of the robot 8. It ensures that the line 12A has a section 12C which is approaching the robot 8 from above. This pulley principle also minimizes risk of the line 12A causing damage to the edge of the blade 5, especially the trailing edge of the blade 5, which can be provided with a sen- sitive toothed structure.

Optionally, the base station 11 comprises a transceiver, wired or wireless, for data communication with the robot 8. In case of wireless communication, the robot 8 comprises a corresponding wireless data transceiver 41, as illustrated in FIG. 3

As an alternative, the base station 11 is not provided at the base region 10 of the tower 2 but on a platform 19 of the tower 2, where the platform 19 is provided at a higher level than the base region 10 of the tower 2. Such an example is illustrated in FIG. 2c. A further option is illustrated in FIG. lb, in which the platform 19 with the base station 11 is at a level above the robot 8. In this case, the pulley 43 assist in keeping the line 12A stretched between the pulley 43 and the robot 8 due to the weight of the line 12A hanging downwards between the pulley 12A and the base station 11. As a further option, the base station 11 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. 2a. A person or a team of persons, in the following for simplicity called the installer 14, installs the two wires 9 at the turbine top and lets the wires 9 hang down while one of the blades 5 is oriented vertically downwards. As illustrates in FIG. 2b, the installer 14 mounts the robot 8 onto the wires 9. The robot 8 is provided with dragging units through which the wires 9 extend and in which they are held in place. The dragging units are configured for running along the wires 4 and thereby drag the robot 8 along the wires 9 in an upwards or downwards direction as illustrated in FIG. 2c. Thereby, the dragging unit provide a length adjustment mechanism for adjusting the length of the at least one wire 9 between the robot 8 and the anchor location for thereby lifting or lowering the robot 8. An example of a dragging unit is illustrated in FIG. 8.

FIG. 3 illustrates a robot 8 in operation. The robot 8 comprises a base 15 from which an arm 16 extends. The arm 16 comprises seven rotational couplings 17a-g as illustrated best in FIG. 5a, giving the arm seven degrees of freedom for motion relatively to the base 15. The illustrated number of actuators is exemplary and could be different from seven. The base 15 is secured to the blade 5 while the arm 16 is provided with a grinding tool 18 for grinding the leading edge 5" of the blade 5. Such grinding is used prior to filling possible damages with adequate filler as part of the repair of the blade surface 5' . In addition, the arm 16 comprises a video camera 40 for inspecting the site and for controlling the actions.

The robot in FIG. 3 and FIG. lb is slightly modified as compared to the robot in FIG. 2c in that the wires 9 are rolled onto rollers (not shown) which are part of the base 15 and located inside the base 15. In this case, the wires 9 do not hang further down than the robot 8. Such exemplary embodiment with rollers that roll up the wires is also il- lustrated in FIG. 4. As a further alternative, the robot 8 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. 3 and FIG. 4 as the rollers are provided inside the base. As illustrated on FIG. 4, a base attachment device 20 is provided, for example a plurality of base suction cups, as part of the base 15 for securing the base 15 to the blade 5 surface 5' . The base suction cups are exemplary and the base attachment device 20 could be provided by other means as mentioned in the description above.

In this particular illustration, the arm 16 is provided with an arm attachment device 21, for example an arm suction cup, for securing the remote end 22 of the arm 16 to an attachment point 23 on the blade surface 5' . The arm suction cup is exemplary and the arm attachment device 20 could be provided by other means as mentioned in the description above.

When the base attachment device 20 is released from the blade surface 5', the arm 16 can drag the base 15 towards the attachment point 23. For sake of illustration on FIG. 4, the arm 16 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 15 would be placed more sideways relatively to the base 16 such that the vertical adjustment of the position against gravity is determined by inter- action with the wire 9, whereas the sideways movement is determined by drag from the arm 16 on the base 15.

FIG. 5a and 5b illustrate the robot 8 in further detail, where FIG. 5a illustrated the arm 16 without tool and FIG. 5b illustrates an arm attachment device 21 coupled to the remote end 22. The base 15 comprises a magazine 24 for a plurality of tools, for example in particular for working the surface. The magazine 24 comprises a plurality of magazine couplings 25 for coupling of tools to the magazine couplings 25, 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. 6. The coupling counterparts 26A, 26B are operated electrically through a connector 27 such that after mating, electrical power activates a locking mechanism 28, in this case a recess 29 into which an expandable ring of balls 30 is secured. As illustrated in FIG. 1, optionally, the base station 11 is wired for data transfer through a data transfer cable 12B. Such cable is useful for offshore wind turbines 1 as wireless data networks are typically inadequate offshore. However, wind turbines 1 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. 7. In the remote control station 31, an operator 32 is remotely operating the offshore located robot 8, for example by watching display screens 33 and operating a control panel 34. The operation of the control panel 34 causes transmission of operational command data to the control unit 35 of the offshore-located robot 8, the control unit 35 illustrated in FIG. 3. With reference to FIG. 7, the display screens 33 can be used to watch the video sequence recorded by a video camera on the arm.

As a further option, the robot 8 can be operated using virtual reality tools, similar to those used for corresponding computer games. For example, the operator 32 is provided with special an operational unit, the movement of which by the operator's arm causes the arm 16 to move correspondingly.

FIG. 8 illustrates an example of a dragging unit 36 for the base 8. The wire 9 runs through pairs of rollers 37 which squeeze the wire 9 in between them such that rolling of the pairs of rollers 37 drags the dragging unit 36 along the wire 9, even in lifting action against gravity. The wire 9 also move around a brake roller 28, which in squeezing cooperation with a brake shoe 39 secures the wire at a predetermined position. This way, the robot 8 is secured against falling. Alternatively, the robot 8 comprises rollers for winding up the wires inside or on the base.

FIG. 9a and FIG. 9b illustrate an example of a pulley 43 with a roller 42 over which the line 12A is running such that one section 12C of the line 12A is approaching the robot 8 from above. The pulley 43 comprises two additional rollers 42A and 42B on a transverse bar 49 for smooth guidance of the line 12 A. By way of example, the pulley 43 comprises a frame 44 with throughput opening 45 in the frame 44 for the wire 9. The frame 44 also comprises a lock-mechanism 48 by which the pulley 43 can be locked temporarily to the wire 9. A movable bracket 46 is provided which upon push from below by the robot 8 unlocks the frame 44 on the wire 9 by de-activating the lock-mechanism 48. Accordingly, in order for the frame 44 to be unlocked from the wire 9, the robot 8 is driven upwards from below along the wire 9 until it hits the movable bracket 46 from below and pushes it upwards. This upwards movement de-activates the lock-mechanism 48 and makes the pulley 43 free to slide on the wire 9.

In one embodiment, after release of the locked state by the robot 8 moving upwards against the movable bracket 46 from below, the lock-mechanism 48 is de-activated, and the pulley 43 can slide freely on the wire and does follow the robot on its way down along the wire, for example for final demounting from the operational site.

In order for the lock-mechanism 48 to be ready for activation initially or again after release, the handle 47 is tilted, for example by press from the operator or by the robot arm 16. In this ready -for-activati on state of the lock-mechanism, the frame can slide freely upwards on the wire 9 as long as it is pushed by the robot 8 on its way upwards. When the robot 8 stops its upwards movement and the upwards push against the movable bracket 46 is halted and the robot 8 starts moving downwards, the lock- mechanism 48 is automatically activated with a return-tilt of the handle and the frame 44 is locked to the wire 9. Potentially, a friction brake in cooperation with the movable bracket 46 is used to activate the lock-mechanism 48 for preventing the pulley 43 from moving downwards together with the robot 8. Only, once the robot 8 pushes against the movable bracket 46 again later, the lock-mechanism 48 is de-activated for free downwards sliding of the pulley 43 along the wire 9.

In an alternative embodiment, after release of the locked state by the robot 8 moving upwards while pushing against the movable bracket 46 from below, the frame 44 can slide in an upwards movement but locks itself to the wire 9 when the robot 8 moves downwards again. The downwards motion of the robot 8 also leads to downwards moving of the movable bracket 46, which in turn causes the lock-mechanism 48 to be activated into a locking state against the wire. Potentially, a friction brake in coopera- tion with the movable bracket 46 is used to activate the lock-mechanism 48 for preventing the pulley 43 from moving downwards together with the robot 8.

In this embodiment, the robot 8 can push the pulley step-wise or all the way upwards along the wire 9 and leave the pulley at a higher level while the robot 8 is moving downwards again. In order to move the pulley 43 downwards, the robot 8 can deactivate the lock-mechanism 48 by pressing the handle 47 with the arm 16 so that it can slide freely down together with the robot 8 for final demounting from the operation site.

As illustrated on FIG. 9b, the transverse bar 49 comprises mounting brackets 52 for the additional rollers 42A and 42B. As illustrated in FIG. 9, end parts 50 of the transverse bar 49 are offset in the direction towards the blade surface 5' by bent sections 53 of the transverse bar 49 and are provided with cushions 51 on the end parts 50 in or- der to prevent scratching and other type of damage on the blade surface 5'.

Although, the robot 8 has been explained in detail in relation to a wind turbine 1 and its blade 5 because of the special advantages at such type of operation site, the principles apply equally well when the robot 8 is used at other types of operation sites, for example other types of vertical or inclined walls, for example of buildings.

Reference numbers

1 wind turbine

2 tower

3 nacelle

4 rotor

5 blades

5' blade surface

5" blade leading edge

6 centre of rotor 4

7 system

8 robot

9 wire

10 base region of the wind turbine 1 11 base station

12A first cable between base station 11 and robot 8

12B second cable between base station and first cable to a remote control station 31 12C vertical part of first cable between pulley 42 and robot 8

13 port in the tower 2 for the second cable 12B

14 installer

15 base

16 arm

17 a-g rotational actuators on arm 16

18 grinding tool

19 platform

20 base attachment device

21 arm attachment device

22 remote end of the arm 16

23 attachment point on the blade surface 5'

24 magazine for tool

25 magazine coupling

26A, 26B coupling counterparts

27 electrical connector of coupling counterparts 26A, 26B

28 locking mechanism of coupling counterparts 26A, 26B

29 recess of coupling counterparts 26A, 26B

30 expandable ring of balls of coupling counterparts 26 A, 26B

31 remote control station

32 operator

33 display screens

34 control panel

35 control unit of robot 8

36 dragging unit

37 pairs of rollers

38 brake roller

39 brake shoe interacting with brake roller

40 video camera

41 wireless transceiver in base 15

42 support/roller for first cable 12A between station 11 and robot 8 42A, 42B additional rollers

43 support unit/pulley attached to wire 9

44 frame of pulley 43

45 throughput openings in frame 44 for wire 9

46 movable bracket for lock and release mechanism 48

47 handle for lock and release mechanism 48

48 lock-mechanism

49 transverse bar

50 offset end part of traverse bar 49

51 cushions on offset end part 50

52 mounting brackets for additional rollers 42A and 42B

53 bent section of transverse bar 49

Claims

1. A method of operating a system (7) at an operation site (1), the operation site (1) comprising an anchor location and a surface (5') below the anchor location; wherein the operation site is a wind turbine (1) with a wind turbine blade (5), and the surface

(5') is a surface of the wind turbine blade (5);

wherein the system comprises

an unmanned robot (8) comprising at least one tool configured for at least one of inspecting and working the surface (5');

- at least one wire (9) for attachment to the anchor location at a level above the robot (8) and for extending downwards from the anchor location;

a line (12A) comprising at least one of an electrical cable and a fluid tube and configured for connection to the robot (8);

a base station (11) connectable to the robot (8) by the line (12A) and config- ured for providing at least one of electricity and fluid through the cable or the fluid tube, respectively, to the robot (8);

a support unit (43) configured for attachment to the at least one wire (9), the support unit (43) being dimensioned for supporting the line (12A) between the base station (11) and the robot (8), wherein the support unit comprises a sup- port (42) configured for movement of the line (12 A) over the support (42); wherein method comprises

attaching the at least one wire (9) to the anchor location;

locating the base station (11) at a first level;

providing the robot (8) at a second level below the anchor location, the second level being different from the first level;

providing the support unit (43) attached to the at least one wire (9) at a third level between the anchor location and the second level;

providing the line (12A) with one end connected to the robot (8) and an opposite end connected to the base station (11), the line (12A) extending from the robot (8) upwards to the support unit (43) and over the support (42) and from the support (42) to the base station (11);

providing electricity through the cable or fluid through the fluid tube from the base station to the robot (8); adjusting an elevation level of the robot (8) and keeping the line (12C) stretched between the robot (8) and the support unit (43) during distance changes between the robot (8) and the support (43);

and inspecting or working the surface (5') with the at least one tool by the ro- bot (8).

2. Method according to claim 1, wherein the system comprises a mechanism for changing the level of the support unit (43) on the at least one wire (9), and wherein the method comprises changing the level of the support unit (43) while keeping it on the wire above the second level of the robot (8).

3. Method according to claim 2, wherein the support unit (43) comprises a lock- mechanism (48) for locking the support unit (43) stationary to the wire (9) when the lock mechanism (48) is activated and for unlocking the support unit (43) from the wire (9) for sliding of the support unit (43) along the wire (9) when the lock- mechanism (48) is de-activated, wherein the method comprises activating the lock mechanism (48) when the support unit (43) is at the third level and maintaining the support unit at the third level during working of the surface by the robot (8) below and remote from the support unit (43).

4. Method according to any preceding claim, wherein the support unit (43) comprises a motor for moving the support unit (43) along the wire (9) and wherein the method comprises moving the support unit (43) along the wire (9) with the motor to the third level.

5. A method according to any preceding claim, wherein the at least one wire (9) is also holding the robot (8) such that the at least one wire for holding the support unit (43) and the robot (8) is the same. 6. Method according to claim 3 or claim 5 when dependent on claim 3, wherein the lock-mechanism (48) comprises at least one of a movable handle (47) and bracket (46) configured for de-activating the lock-mechanism (48) when moved; wherein the method comprises moving the robot (8) to the support unit (43) and moving at least one of the handle (47) and bracket (46) by the robot (8) for de-activating the lock- mechanism (48) and during support of the support unit (43) by the robot (8) moving the support unit (43) by the robot (8) along the wire (9) to a different level.

7. Method according to claim 6, wherein the lock-mechanism (48) is configured for de-activation by upwards push of the bracket (46); wherein the method comprises moving the robot (8) to the support unit (43) and by the robot (8) pushing the bracket (46) upwards and thereby de-activating the lock-mechanism (48).

8. Method according to any preceding claim, wherein the support is a sliding support surface, or wherein the support is a roller (42) and the support unit a pulley (43); and wherein the method comprises causing the line (12A) to slide over the sliding surface or roll over the roller (42) during adjustment of the elevation level of the robot (8). 9. Method according to any preceding claim, wherein the method comprises locating the base station (11) on the ground (10), on a platform (19), on a vehicle or on a vessel.

10. Method according to any preceding claim, wherein the robot comprises a base (15) and an arm (16) extending from the base (15), the arm comprising a remote end

(22) with a coupling for attachment of a tool for at least one of inspecting and working the surface (5'); the arm (16) being configured for movement of the remote end (22) relatively to the base (15); the base (15) comprising a base attachment device (20) for securing the base (15) stationary to the surface (5') by contact of the base at- tachment device (20) with the surface (5').

11. Method according to any preceding claim, wherein the at least one wire (9) is dimensioned to carry the weight of the robot (8) and wherein the robot (8) is configured for attachment to the at least one wire (9); wherein the system also comprises a length adjustment mechanism for adjusting the length of the at least one wire (9) between the robot (8) and the anchor location; wherein the method comprises providing the robot (8) attached to the at least one wire at the second level, adjusting an elevation level of the robot (8) by adjusting the length of the wire (9) by the length adjustment mechanism while keeping the line (12C) stretched between the robot (8) and the support unit (43) during distance changes between the robot (8) and the support (43).

12. Method according to any preceding claim, wherein the robot (8) comprises a vid- eo camera and wherein the tool (18) is a turbine blade surface repair tool; and wherein the method comprises imaging the surface (5') at the operation site by the video camera and the method comprises inspecting the blade surface with the video camera and evaluating the video signal for finding surface damage on the blade surface (5') and determining a possible necessary repair of the surface (5'); repairing the surface damage by operating the arm (16) with the surface repair tool.

13. A system for at least one of inspecting and working a surface (5') below an anchor location at an operation site (1), wherein the operation site is a wind turbine (1) with a wind turbine blade (5), and the surface (5') is a surface of the wind turbine blade (5);

wherein the system comprises

at least one wire (9) for attachment to the anchor location at a level above the robot (8) and for extending downwards from the anchor location to the robot

(8);

a base station (11) and a line (12A) with one end being connectable to the base station (11) and an opposite end being connectable to the robot (8), the line (12A) comprising at least one of an electrical cable and a fluid tube for provid- ing electricity through the cable or fluid through the fluid tube from the base station (11) to the robot (8);

a support unit (43) configured for attachment to the at least one wire (9), the support unit (43) being dimensioned for supporting the line (12A) between the base station (11) and the robot (8), wherein the support unit comprises a sup- port (42) configured for movement of the line (12A) over the support (42).

14. System according to claim 13, wherein the system comprises a mechanism for changing the level of the support unit (43) while on the at least one wire (9), and wherein the system is configured comprises changing the level of the support unit (43) while keeping it on the wire above the second level of the robot (8).

15. System according to claim 13 or 14, wherein the support unit (43) comprises at least one of a motor for moving the support unit (43) along the wire (9) and a lock- mechanism (48) for locking the support unit (43) stationary to the wire (9) when the lock mechanism (48) is activated and for unlocking the support unit (43) from the wire (9) for sliding of the support unit (43) along the wire (9) when the lock- mechanism (48) is de-activated.

16. A system according to claim 15, wherein the at least one wire (9) is also holding the robot (8) such that the at least one wire for holding the support unit (43) and the robot (8) is the same. 17. System according to any one of the claims 13-16, wherein the lock-mechanism

(48) comprises at least one of a movable handle (47) and bracket (46) configured for de-activating the lock-mechanism (48) when moved; wherein the system is configured for moving the robot (8) to the support unit (43) and moving at least one of the handle (47) and bracket (46) by the robot (8) for de-activating the lock-mechanism (48) and configured for supporting and moving the support unit (43) by the robot (8) along the wire (9) to a different level.

18. System according to claim 17, wherein the lock-mechanism (48) is configured for de-activation by upwards push of the bracket (46); wherein system is configured for moving the robot (8) to the support unit (43) and by the robot (8) pushing the bracket (46) upwards and thereby de-activating the lock-mechanism (48).

19. System according to any one of the claims 13-18, wherein the support is a sliding support surface; or wherein the support is a roller (42) and the support unit a pulley (43) configured for sliding of the line (12A) over the slider or rolling of the line

(12A) over the roller (42) during adjustment of the elevation level of the robot (8).

20. System according to any one of the claims 13-19, wherein the robot comprises a base (15) and an arm (16) extending from the base (15), the arm comprising a re- mote end (22) with a coupling for attachment of a tool for at least one of inspecting and working the surface (5'); the arm (16) being configured for movement of the remote end (22) relatively to the base (15); the base (15) comprising a base attachment device (20) for securing the base (15) stationary to the surface (5') by contact of the base attachment device (20) with the surface (5').

21. System according to any one of the claims 13-20, wherein the at least one wire (9) is dimensioned to carry the weight of the robot (8) and wherein the robot (8) is configured for attachment to the at least one wire (9); wherein the system also com- prises a length adjustment mechanism for adjusting the length of the at least one wire (9) between the robot (8) and the anchor location; wherein the system is configured for adjusting an elevation level of the robot (8) by adjusting the length of the wire (9) by the length adjustment mechanism while keeping the line (12C) stretched between the robot (8) and the support unit (43) during distance changes between the robot (8) and the support (43).

22. An operation site comprising a system for at least one of inspecting and working a surface (5') below an anchor location at the operation site (1), wherein the operation site is a wind turbine (1) with a wind turbine blade (5), and the surface (5') is a surface of the wind turbine blade (5);

wherein the operation site with the system comprises

an unmanned robot (8) in contact with the surface (5') and comprising at least one tool configured for at least one of inspecting and working the surface (5'); at least one wire (9) attached with one end to the anchor location at a level above the robot (8) while extending downwards from the anchor location; a base station (11) and a line (12 A) with one end connected to the base station (11) and an opposite end connected to the robot (8), the line (12 A) comprising at least one of an electrical cable and a fluid tube for providing electricity through the cable or fluid through the fluid tube from the base station (11) to the robot (8);

a support unit (43) attached to the wire (9) and supporting the line (12A) between the base station (11) and the robot (8), wherein the support unit (43) comprises a support (42) configured for movement of the line (12A) over the support (42), wherein the line (12 A) extends from the robot (8) upwards to the support unit (43) and over the support (42) and from the support (42) to the base station (11).

23. an operation site according to claim 22, wherein the system comprises a mecha- nism for changing the level of the support unit (43) while on the at least one wire (9), and wherein the system is configured comprises changing the level of the support unit (43) while keeping it on the wire above the second level of the robot (8).

24. An operation site according to claim 23, wherein the support unit (43) comprises at least one of a motor for moving the support unit (43) along the wire (9) and a lock-mechanism (48) for locking the support unit (43) stationary to the wire (9) when the lock mechanism (48) is activated and for unlocking the support unit (43) from the wire (9) for sliding of the support unit (43) along the wire (9) when the lock-mechanism (48) is de-activated.

25. An operation site according to anyone of the claims 22-24, wherein the at least one wire (9) is also holding the robot (8) such that the at least one wire for holding the support unit (43) and the robot (8) is the same. 26. An operation site according to claim anyone of the claims 22-25, wherein the support is a sliding support surface; or wherein the support is a roller (42) and the support unit a pulley (43) configured for sliding of the line (12A) over the slider or rolling of the line (12A) over the roller (42) during adjustment of the elevation level of the robot (8).

27. An operation site according to anyone of the claims 22-26, wherein the at least one wire (9) is carrying the robot (8) while extending downwards from the anchor location to the robot (8); wherein the system also comprises a length adjustment mechanism for adjusting the length of the at least one wire (9) between the robot (8) and the anchor location; wherein the system is configured for adjusting an elevation level of the robot (8) by adjusting the length of the wire (9) by the length adjustment mechanism while keeping the line (12C) stretched between the robot (8) and the support unit (43) during distance changes between the robot (8) and the support (43).

28. Use of a system according to anyone of the claims 23-21 for inspecting or working a surface on a wind turbine blade (7).