GB2548801A

GB2548801A - A system for machining a surface

Info

Publication number: GB2548801A
Application number: GB1604743.3A
Authority: GB
Inventors: Reece Alun
Original assignee: Loop Tech Ltd
Current assignee: Loop Tech Ltd
Priority date: 2016-03-21
Filing date: 2016-03-21
Publication date: 2017-10-04
Anticipated expiration: 2036-03-21
Also published as: GB2548801B; GB201604743D0

Abstract

An automated system comprising; a machining tool, e.g. a milling spindle 600 and a rotary cutter 610, for machining a surface; a robotic arm 400 for manipulating the machining tool; an imaging system 700 for determining the geometry of the surface to be machined. The system may be temporarily mounted to the damaged surface using mount 500. The system may determine the desired geometry of the surface, and direct the machining tool to reshape the surface as such; this may include machining recesses for prefabricated modules to be inserted, such that they reshape the surface to the desired geometry. The desired geometry may be determined by a CAD (computer aided design) model. The embodiment is directed towards a portable system for machining the damaged surfaces of wind turbine blades, aircraft wings, fuselages, or boat hulls, prior to their repair.

Description

A System for Machining a Surface

Field of the Invention

The invention relates to a system for machining a surface, for example machining a damaged surface prior to its repair. More particularly, but not exclusively, the invention relates to a system that may be used to machine a surface, for example of a relatively large structure, such as a wind turbine blade, an aircraft wing, a fuselage or a boat hull. In a particularly preferred embodiment the system may be adapted to be portable and is used to repair damaged surfaces on the aforesaid structures in situ.

Background

Wind turbine blades are typically subject to significant wear and tear during use, with the leading edge being especially prone to damage. The blades may be damaged by bird strikes, lightning strikes, rain, hail, insects, and by wind born salt, sand and debris. Even small amounts of damage to the blades may lead to surface roughness which can cause a decrease in the aerodynamic efficiency of the blades and therefore the reduce efficiency of the turbines.

Wind turbine blades are typically repaired in situ by specialised personnel who use a grinder and a resin and fibreglass kit while suspended from the turbine blade. Repairs made in this manner have limited precision due to the difficulty of working in this environment and are expensive. Although mention has been made to wind turbine blades, it is understood that the system may be used to repair any structure whose surface needs repairing.

Where a structure includes composite materials which required repair, it was previously standard practice to remove or disassemble the structure and transport it to a remote specialised workshop where repair or testing was carried out in a strictly controlled environment. Often this was carried out as any machining on the structure could only be achieved with large scale machining equipment. For example, where an aircraft fuselage or wing section had suffered impact from a ground vehicle.

The present invention provides a system to facilitate the repair of wind turbine blades and/or other surfaces that overcomes the aforementioned disadvantages.

Summary of the Invention

According to a first aspect of the present invention there is provided an automated system for machining a surface comprising: a machining tool, a robotic arm for manipulating the machining tool; and an imaging system for determining the geometry of the surface to be machined.

Preferably, the imaging system determines the geometry of the surface and compares the geometry of the surface with a desired geometry; the system determines an arrangement of machining stages and directs the machining tool to reshape the surface such that the surface has a geometry that substantially conforms to the desired geometry.

The system may be used to facilitate the repair of damaged surfaces. In use the system may machine recesses in a surface and material may be inserted into the recesses so as to achieve a desired shape and structure for the surface. Preferably the system machines one or more recesses in a surface into which material is inserted so as to reshape the surface such that it has a desired geometry.

Ideally repairs may be carried out either by inserting prefabricated modules or patches of material into the recesses, or by forming new material directly into the recesses. For instance, in order to repair a carbon composite structure, a prefabricated repair module or patch could be inserted into a recess machined by the system, or new fabric could be laid into a recess machined by the system a layer at a time.

Preferably one or more of the recesses are dimensioned to receive prefabricated repair modules.

Optionally repair may be performed by using a 3-D printer which prints new material directly into the recesses.

Ideally, layers of new fabric which are formed directly into a recess are applied with fibre angles which match those of the original construction of the surface. Preferably the imaging tool is capable of determining the fibre angle of material, so that a check may be made that the material laid in a repair layer has been oriented in the correct manner. The imaging tool ideally automatically checks that new material has been introduced with the correct orientation.

The imaging tool may also be used after the initial machining of a surface, to determine the size, location and shape of recesses that have been machined by system and to generate precise boundary and machining parameters for the construction of repair patches. This is particularly useful if initial estimates of dimensions of apertures to be machined and/or patches to be used are subsequently found to be too small or too large, for example if after machining damage is observed as being greater than originally anticipated, and larger or differently shaped repair modules are required.

Preferably the system compares the geometry of the surface to a desired geometry; and determines an arrangement of prefabricated modules that when incorporated in the surface, reshape the surface such that the surface has a geometry that substantially conforms to the desired geometry.

In use the machining tool may machine recesses in the damaged surfaces where repairs are necessary and repair modules may be inserted into and received by the recesses in order incorporate the modules into the surface and to effect repairs.

Multiple repair modules or patches may be inserted into a single recess in order to effect a repair. For example, repair patches may be layered on top of each other within the recess until a desired surface is achieved. A scarf repair technique may be used.

The machining of recesses by the system may remove damaged, weakened or otherwise undesirable material from a structure or surface. Repair material may then be inserted into the recesses so as to repair or improve the structural integrity and/or a geometric property and/or an aerodynamic property of the structure or surface.

The machining of recesses may also allow repair material to be inserted into a surface so as to replace material that has been lost from the surface due to damage, wear and tear or erosion. For example, if a region of the surface has been worn down or otherwise damaged such that the surface no longer conforms to its original desired geometry, a recess may be machined in, adjacent to, or enclosing the worn region. A repair module may then be inserted into the surface such that combined exterior of the repair module and the surface conform to the desired geometry of the surface.

Optionally the system may also be used during the manufacturing process to machine a surface with a view to inserting a stronger surface layer thereon. A recess machined by the system may be dimensioned so as to receive a prefabricated repair module as an interference fit, or alternatively, a recess may be dimensioned so as to receive both the module and filler or adhesive with which the module is secured in the recesses.

Alternatively, recesses may be machines with shapes that facilitate the laying of new material directly into the recesses in situ. For example, the recesses may be machined with faces onto which layers of composite material may be formed arranged substantially parallel to a desired exterior surface such that during repairs the layers are built up until the desired shape for the surface is achieved.

The system may be used to repair surfaces constructed from composite materials such as resin, glass fibre or carbon fibre based materials. The prefabricated repair modules may be constructed from the same materials as the surface into which they are to be inserted, thereby replacing removed or damaged material and restoring the surface to its original form.

Alternatively, the recesses may receive prefabricated repair modules formed from some other materials which may provide a superior repair material or may overcome some disadvantage in the original surface. For example, the material may be stronger, cheaper, more resilient to wear and tear, lighter or be adapted to be more securely received by the recesses than the same material as the surface.

In preferred embodiments of the system: the imaging system determines the geometry of the surface; the system compares the geometry of the surface with a desired geometry for the surface; and the system determines an arrangement of prefabricated repair modules that when incorporated in the surface in order to reshape the surface, such that the surface has a geometry that substantially conforms to the desired geometry for the surface.

Determining an arrangement of prefabricated repair modules comprises determining which prefabricated repair modules to use for a repair, how many prefabricated repair modules to use and in what positions and with which orientations they are to be installed in the surface.

Alternatively, or additionally, the vision system scans the surface and calculates a machining path which optimises the recess geometry for a selected repair material, which may include prefabricated modules of material, layered materials laid directly into the surface or may involve another repair method, such as for example laser or ultra-sonic welding. A plurality of differently sized, shaped or dimensioned prefabricated repair modules may be available and when determining an arrangement of modules, the system may determine which module, combination of modules of the same type, or combination of modules of different types are best suited for the repairs or modifications being made to a surface.

The prefabricated repair modules may have differently shaped exteriors, for example different modules may have outer faces with different curvatures. Ideally the system may determine which module or combination of modules that when installed in the surface, will result in a geometry that most closely conforms to the desired geometry for the surface.

It may be advantageous to remove as little material from the surface as possible so as to preserve the structural integrity of the surface, in this case the system may determine which of the modules or combinations of modules that would achieve the desired geometry when inserted into the surface will necessitate the removal of the least amount of original material as possible.

In preferred embodiments the system compares the geometry of the surface to a CAD model of the desired geometry of the surface; the system uses CAD models of prefabricated repair modules to determine an arrangement of prefabricated repair modules and an associated arrangement of recess such that that when the recesses are machined in the surface and the modules are received by the recesses, the surface has a geometry that substantially conforms to the desired geometry of the surface.

The geometry of the surface is determined by the imaging system and a CAD (Computer Aided Design) model of the ideal desired geometry for the surface is provided to the system. The system may then compare the two geometries in order to identify discrepancies between the current geometry of the surface and the desired geometry of the surface so that prefabricated repair modules may be inserted into the surface so as to correct any discrepancies.

By examining the geometries of the current surface and the desired surface in the region where a discrepancy has been identified the system may determine whether a prefabricated repair module should be installed in the surface at this region. If one should, then the system may determine which type of prefabricated repair module should be installed and in what exact position and orientation it should be inserted into the surface. For example, the system may determine which of a selection of prefabricated repair modules has an exterior that best conforms to the desired geometry in the region with the discrepancy, and then determine the exact orientation and location with which it would have to be inserted into the surface for the exterior to conform to the desired surface.

Three dimensional CAD models of the prefabricated repair modules may allow the system to determine how the installation of a specific type of prefabricated repair module in a specific position in the surface with a specific orientation will affect the geometry of the surface after the module has been installed.

The system may determine an arrangement of prefabricated repair modules that when installed in the surface will have exteriors that are flush with the exterior of the surface so as to present a uniform external shape.

The system may have different parameters for determining the optimum arrangement of prefabricated repair modules. For example, the system may determine the arrangement of prefabricated repair modules that substantially conforms to the desired three dimensional surface while minimising the volume of material removed from the surface.

Alternatively, some dimensions and shapes of prefabricated repair modules may be preferred and the system may determine the arrangement of prefabricated repair modules that substantially conforms to the desired three dimensional surface and that uses the highest proportion of preferred modules. The system may have some predetermined tolerance to determine the preferred allowable degree of difference between the actual geometry of the three dimensional surface and the desired geometry of the three dimensional surface.

If a region of the surface has a discrepancy which exceeds said tolerance the system would determine an arrangement that installs a module so as to correct the discrepancy, whereas if the discrepancy does not exceed said tolerance, no module will be installed in this location and the present exterior of the surface will be left intact.

Determining an optimum arrangement of prefabricated modules allows the system to determine a corresponding arrangement of recesses dimensioned and located so as to receive the arrangement of modules in the surface such that the desired final three dimensional surface is achieved.

In preferred embodiments the imaging system recognises material in a surface that is weakened and/or damaged.

The imaging system may recognise features on the exterior of a surface that are known to correspond to material that has been weakened or damaged. For example, the imaging system may be adapted to recognise cracks, scratches or other features that correspond to damaged areas of the surface without actually altering the geometry of the exterior of the surface. This allows the system to identify weakened or damaged areas that reduce the structural integrity of a surface, negatively impact the performance of a surface, or present a risk for greater future damage to the surface.

This may enable a system to identify regions that no longer have the desired structural integrity or are weakened such that they are likely to wear down in the future.

Recognising damaged material in a surface may include recognising changes to the texture of the surface exterior that will negatively impact the performance of the surface. For example, the imaging system may identify areas with increased surface roughness as damaged.

In further preferred embodiments: the imaging system identifies weakened and/or damaged material in a surface; and the system determines an arrangement of prefabricated repair modules that when incorporated in the surface replace any weakened and/or damaged material identified in the surface and have exterior faces flush with the exterior of the surface.

This may allow the system to replace damaged or weakened material in the surface without altering the geometry of the surface and thereby affecting its performance.

In preferred embodiments: the imaging system identifies weakened and/or damaged material in a surface and determines the geometry of the surface; the system compares the geometry of the surface with the desired geometry for the surface; and the system determines an arrangement of prefabricated repair modules that when incorporated in the surface replace any damaged and/or weakened material identified in the surface and reshape the surface to have a geometry that substantially conforms to the desired geometry for the surface.

This embodiment of the system may correct discrepancies between the geometry of the surface and replace weakened and/or damaged material within the surface simultaneously. Alternatively, a system may first determine an arrangement of prefabricated repair modules such that when the arrangement of modules is installed in the surface, the modules will replace any weakened and/or damaged material identified in the surface and the exterior of the modules will be flush with the exterior of a desired geometry for the surface, and then the system may determine a second arrangement of modules such that when the arrangement of modules is installed in the surface, the surface will have a geometry that substantially conforms to the desired geometry for the surface.

In preferred embodiments, after determining an arrangement of prefabricated repair modules the system determines an arrangement of recesses dimensioned and located so as to receive the arrangement of prefabricated repair modules in the surface.

Determining an arrangement of recesses comprises, determining the number of recesses necessary to receive the arrangement of prefabricated repair modules in the surface and determining the exact dimensions and shapes necessary to receive the modules such that their exteriors are in the correct location.

This allows the modules to be inserted into the surface such that their exteriors conform to the desired geometry of the surface and such that the final combination of surface and modules affects the repairs desired by a user.

The number of recesses may equal the number of repair modules in the arrangement of prefabricated repair modules, or multiple modules may be arranged adjacent to each other so as to be inserted into the same recess.

In preferred embodiments the system manipulates and operates the machining tool and machines an arrangement of recesses in the surface that are dimensioned and located so as to receive a specific corresponding arrangement of prefabricated repair modules.

Preferably the system determines a series of machining stages and directs the machining tool in order to machine the arrangement of recesses.

In order to machine the recesses, the robotic arm manipulates the machining tool such that it removes material from the recess locations determined by the system.

During the machining of recesses, the imaging system may be used to determine the arrangement of the system with respect to the surface. For example, the imaging system may track the location of the machining tool or other components so as to ensure that they do not unintentionally contact or collide with the surface.

The robotic arm may be an industrial robotic arm with six degrees of freedom so as to enable the machining of a wide variety of different recesses with different dimensions and shapes.

Optionally a self-propelled tractor may transport a machining head. The tractor may be adapted to ‘crawl’ along the structure (turbine blade) using a gimbal mounts in order to present the machining head at a preferred orientation to the surface to be machined.

In some embodiments the system may machine recesses in a surface which are dimensioned such that a corresponding prefabricated repair module that is inserted into the recess will extend beyond the desired geometry of the surface and will not conform to the desired final geometry of the surface. In this case, after the module is installed the machining tool may be used to machine down the protruding module such that it conforms to the desired geometry of the surface. This may be useful when the surface lacks the depth to receive a specific prefabricated repair module or when no prefabricated repair module is available that adequately conforms to the desired geometry of the surface.

An additional means may be provided to displace material that is removed from the surface by the machining tool; this means may be a vacuum system to remove the material to a remote location. A safety means may be provided to determine if the robotic arm or machining tool has been blocked. Sensors may be provided to determine if greater than expected resistance is experienced by the movement of the robotic arm and which may automatically stop the machining tool and the robotic arm.

The system may be adapted to automatically stop the machining of recesses if the imaging system detects relative movement between the surface and the system which would affect the accuracy with which recesses may be machined in the surface. An optional step that may be performed after scanning by the imaging system, and prior to machining, is to use the imaging system in order to validate a generated or a pre-programmed machining path. Ideally this is performed whilst the tractor or the system moves the imaging system in accordance with a predefined path albeit with a modified tool centre point (TCP). The surface prescribed by the TCP is then compared with the surface and repair module so as to ensure the desired result is generated. This method verifies that a machining path produces the desired recess.

The imaging system may comprise at least one line scan camera, and at least one area scan camera or a 3D scanner or a combination of the aforesaid devices.

The imaging system may create a point cloud that corresponding to the geometry of the surface. The system may use polynomial analysis of the data gathered by the imaging system to remove noise from the data produced by the imaging system and/or to populate absent data.

The imaging system may be supported on the robotic arm. This may allow the robotic arm to move the imaging system while it is observing the surface; this may allow the imaging system to view a larger area of the surface without the system in its entirety being moved. Moving the imaging system on the robotic arm may enable the imaging system to more accurately determine the geometry of the surface by viewing the surface from multiple different locations and angles.

When the imaging system is being manipulated by the robot arm, the robot arm may act to keep the imaging system at some optimal distance and orientation with respect to the surface. The system may use the data gathered by the imaging system to determine the relative location and orientation of the imaging system, with respect to the surface, and to ensure that the robot arm moves the imaging system as desired.

The system also has the ability to combine positional data generated by the robot with that of the imaging system to produce a normalised surface in the event it is not possible to achieve an optimal location of the imager relative to the surface along an optimum path.

The system may further comprise a light or torch to illuminate a surface during use. This allows the system to be used in lower light environments and may increase the accuracy with which the imaging system determines the geometry of the surface and/or the relative locations of the surface and the machining tool. The light or torch may be located on the robotic arm and/or adjacent the imaging system.

The surface may be illuminated using a laser line or may be illuminated using projected structured light patterns or any other form of scanner.

The imaging system may be adapted to identify when its view of the surface is blocked or partially obscured by an object that is not part of the system or part of the surface. The system may raise an alarm to alert an operator or user in the event that this occurs.

The system may use the surface geometry data produced by the imaging system to optimise the path of the machining tool and robotic arm during the machining of the recesses. For example, the system may determine the path for the machining tool that machines a predetermined arrangement of recesses into a surface in the shortest possible time for the given system.

Preferably the system comprises a mount for temporarily affixing the system to the surface.

In use, the system may be affixed to the surface that is to be repaired, the imaging system then identifies where on the surface repairs are necessary and determines an arrangement of repair modules suitable to repair the surface. The system then machines an arrangement of recesses to receive the arrangement of repair modules. The repair modules may be installed while the system is still affixed to the surface, or alternatively the system may be removed from the surface first, or moved to a different location on either the same surface or some other surface.

The imaging system and machining tool may identify and affect repairs to a region of the surface that is within reach of the robotic arm of the system. In order to repair a larger area of a surface, the system may be detached from the surface after machining recesses in a first area surrounding a first affixing location, and then moved to a second affixing location where it machines repair recesses in a second area that surrounds the second affixing location.

If the system machines recesses in a first area, and then is moved to a second area before prefabricated repair modules are installed in the recesses machined in the first area, the imaging system may be adapted to identify the recesses in the first area such that it does not misidentify them as damage to the surface in the event that there is any overlap between the first and second areas. The geometry of the first or preceding recess can be used by the imaging system to act as a datum reference to assist in determining the orientation of the system when moved to a second or subsequent location.

Affixing the system to the surface that is being repaired may eliminate any possibility of relative movement between the system and the surface, this increases the accuracy with which the imagining system may observe and analyse the surface and the accuracy with which the machining tool and the robotic arm may be used to machine recesses into the surface.

Alternatively, while repairing a surface, the system may be supported on some secondary surface adjacent to the surface that is being repaired. As this introduces the possibility of relative movement between the system and surface being repaired (especially if the damaged surface and the secondary surface are not rigidly connected), the imaging system may be adapted to identify when the surface is moving relative to the system. A secondary imaging system or a different sensor form, such as a series of laser displacement sensors, may be used to achieve this.

The system may then be configured to suspend the repairs until the surface is no longer moving relative to the system, or alternatively the imaging system may track the relative movement of the surface and may compensate for said movement during repairs by moving the robotic arm in response to said relative movement.

Ideally, the system may be small and light, so as to be easily portable. This allows the system to be transported to a damaged surface such that repairs may be made to the surface in situ, without having to transport a damaged surface to a workshop where repairs may be carried out. For example, the system may be designed to be easily and safely carried by a single user, and the mount may be configured such that the system may also be affixed to a surface by a single user.

In one embodiment the mount is adapted to affix the system to substantially vertical surfaces. In order to affix the system to a substantially vertical surface, the mount may exert an attractive and frictional force between the surface and the mount that is strong enough to counteract any gravitational force acting on the system in a downwards direction substantially parallel to the surface. A system with a mount adapted to affix to substantially vertical surfaces may be used to repair vertical surfaces in situ. Typically, repairs of vertical surfaces may necessitate the damaged section of said vertical surface being removed from its location and transported either to a location where it can be repaired in a horizontal orientation or simply repaired at a lower height. Removing a damaged surface to some other repair location is typically time consuming and expensive and may have adverse effects on the structure from which a damaged surface is removed. For example, temporarily removing a damaged portion of surface may expose some vulnerable area below the surface. Furthermore, some damaged surfaces may not be removable for repairs to be carried out.

Alternatively, vertical surfaces may be repaired in situ. Typically, this involves constructing a scaffold, in order to provide a work platform adjacent and proximate to the damaged portion of a surface. Specialised personnel may then use the work platform to repair the damaged portion surface. Working on such a work platform is often more difficult than working in a workshop as limited space is available for workers, and additional safety considerations may have to be considered, especially if the damaged portion of a surface is at a significant height. Alternatively, repair personnel equipment may be suspended from a point higher on the surface and may undertake repairs without a work platform to support them. Therefore, repairing vertical surfaces in situ may often make precision repairs more difficult. Furthermore, if a surface is easily damaged it may not be possible to rigidly connect a scaffold to a surface, increasing the difficulties of making repairs.

Using an automated repair system that affixed to a vertical surface simplifies the process of repairing a damaged portion of a vertical surface. A user only needs to construct a scaffold or be suspended to reach a point where they can affix the system such that the robotic arm is within reach of the damage to be repaired. They do not need to machine the surface themselves while supported adjacent the vertical surface as the system will be rigidly affixed to the surface and will automatically undertake the process of machining appropriate recesses in the surface. The user may then install prefabricated repair modules into the recesses, or this may be done at a later point in time.

Utilising a system that is affixed to a damaged surface may be advantageous when repairing outdoor vertical structures that are prone to moving due to the force of the wind. When the system is attached to the vertical surface, there will be no relative motion between the system and the damaged surface, thereby increasing the precision with which repairs may be undertaken. A one or more lifting eyes may be provided on the system such that the system may be additionally secured to some point on the surface, or a nearby structure. This may provide an aid when lifting the system to a desired height on a vertical surface and may also provide an additional safety feature in the event the system becomes detached from the surface.

Preferably the mount is adapted to be able to affix the system to non-planar surfaces. A system that is able to attach to non-planar surface may be used to repair a wider variety of more complex differently shaped and dimensioned surfaces. Non planar surfaces, especially vertical non planar surfaces, are typically more difficult to repair in situ as a more complicated and precisely shaped final geometry is required. A system that is able to attach to non-planar surfaces may also be used to repair a surface that is intended to be substantially planar but has been damaged and deformed such that it’s exterior is no longer planar.

Specially dimensioned prefabricated repair modules may be provided that are shaped to conform to the exterior of a non-planar surface to be repaired, and the system may be adapted to machine specially dimensioned recesses to receive these modules into the damaged non planar surface.

Preferably the mount comprises a frame and a plurality of connectors supported on the frame.

The frame may be dimensioned so as to provide a larger footprint for the base of the system and/or the robotic arm, therefore increasing the stability of the system. During the use of the system to repair a damaged surface the robotic arm will move to a variety of different positions and configurations, therefore a mount that provides a frame with a larger footprint prevents the system from toppling and allows it to machine recesses in a greater area of a surface.

The plurality of connectors may be distributed across the area of the frame such that they connect to different areas on a surface to which the system is affixed. This allows the system to be more rigidly affixed to a system and reduces the risk of the system moving, sliding or rotating about a single connector on a base. This allows the system to more reliably machine recesses in a damaged surface.

Having a plurality of connectors may also ensure the system remains affixed to the surface in the event that some proportion of the connectors do not connect tightly to a surface, such as if they have poor purchase on a certain area of the surface.

Alternatively, the mount may comprise a clamp.

Preferably the frame is triangular and a leg is supported at each vertex of the frame such that the foot of each leg is rigidly located a distance below the frame.

The frame may be a triangular prism, with a triangular base below which the feet are located, a triangular upper surface upon which the robotic arm is supported and three side faces that join corresponding sides of the triangular upper and base surfaces.

The feet of the legs may be connectors. The aspects of each connector that affixes to a surface may be rigidly located a distance below the frame. Alternatively, the feet may be rubber feet which do not affix to the surface and only support the frame.

The three legs located at the vertices of the frame are arranged such that their feet define the vertices of a triangle below the body of the triangular frame. A triangular shape is advantageous as the vertices of a triangle can conform to non-planar surfaces. Therefore, the three legs can support the triangular frame upon a wide variety of differently shaped and dimensioned surfaces as the three feet can be placed in contact with the surface and the body of the frame can be supported above peaks on the surface that are higher than the points of contact of the affixing aspects.

The distance below the frame at which the feet of the three legs are located may be variable by a user so as to enable the system to be used on a wide variety of different surfaces with different degrees of curvature. For example, the feet may each be located on the end of a threaded pillar which may be screwed up and down through an aperture in the frame.

Alternatively, the frame may be circular, for example in the form of a substantially flat cylinder with a circular base upon which legs and/or connectors are supported, a circular upper surface upon which the robotic arm is supported and a side wall which connects the base and the upper surface. An advantage of a circular base is that moment exerted on the system due to forces acting on the robotic arm is independent of the direction of a machining location from the frame of the mount. A plurality of legs may be supported on the circumference of the circular frame such that the foot of each leg is rigidly located a distance below the frame. These legs may be distributed evenly around the perimeter of the circular base, the distance below the frame at which the feet are located may be variable by a user and the feet of the legs may be connectors.

Preferably a plurality of connectors is supported on the underside of the frame and the aspects of the connectors that affix to a surface are displaceable with respect to the frame.

The plurality of displaceable affixing aspects will conform to the shape of a non-planar surface that they are brought into contact with, thereby allowing the system to be affixed to non-planar surfaces.

The affixing aspects of the connectors may be freely displaceable such that they may conform to the shape of a surface that they are brought into contact with. This allows the mount to affix the system to a variety of differently shaped surfaces.

Alternatively, the connectors may be lockable such that the aspects that affix to a surface are not displaceable, or the displacement of the aspects may be controlled by a user or be varied automatically by the system in response to the surface to be repaired.

The degree to which the affixing aspects of the connectors are displaceable may depend upon the curvature of the surface upon which the system is intended to be supported.

Preferably, the mount may comprise a triangular frame; a connector supported at each vertex of the frame with an aspect that affixes to the surface rigidly located a distance below the frame; and an array of connectors supported on the underside of the frame with aspects that affix to the surface that are displaceable with respect to the frame.

This mount provides a large number of connectors to ensure the mount is rigidly supported upon a surface to be repaired and distributes the connectors over the underside of the frame so as to provide even adherence over the base of the system and prevent the system from tipping or rotating when supported upon a substantially vertical surface and minimises distortion of a supporting surface. A connector may be a clamp, a suction or a vacuum connector. The mount may comprise an array of suction or vacuum connectors supported on the frame.

Suction or vacuum connectors are ideal because they adhere well to a wide variety of different materials and differently shaped surfaces. Furthermore, they are unlikely to damage a surface to which they are affixed so they may be used to repair a damage surface without risking further compromising the surface itself.

The affixing aspect of a suction or vacuum connector is the sealing face provided at the end of a vacuum or suction cup, through which air is drawn and which seals onto a surface, creating a region of low pressure and exerting an attractive force on the surface.

The sealing faces of the suction or vacuum connectors may be displaceable with respect to the frame of the mount and the system as a whole. For example, the vacuum or suction connectors may be compliant vacuum or suction cups with folding compressible bodies formed as bellows. A plurality of compliant suction or vacuum cups may be provided in an array. When such an array is brought into contact with a surface, the sealing faces of the cups will be displaced such that they conform to the shape of surface. Therefore, a plurality of suction or vacuum connectors may simultaneously exert an attractive force on areas of a surface that are located at different distances from the frame of the mount.

The suction or vacuum connectors may use the Venturi effect to increase the attractive force they may exert upon a surface.

One or more pressure probes may be provided to monitor the vacuum pressure of the connector or connectors and may alert a user when the vacuum pressure falls below some threshold level. Therefore, the user can ensure that the system is properly and securely affixed to a damaged surface before beginning repairs.

The vacuum cups may have a circular or a triangular footprint in order to maximise surface area covered by the cups and so increase overall suction force.

Alternatively, the connectors may comprise at least one of: mechanical grippers, needle attachment means, cryogenic attachment means, electrostatic attachment means, a mechanical gripper or electromagnetic attachment means.

The mount may comprise one or more stabilisation leg. The stabilisation leg may extend from the mount or from elsewhere on the system and may be arranged so as to increase the effective footprint of the system in order to increase its stability. A connector may be supported upon the end of one or more of the stabilisation legs such that the leg may be affixed to the surface. This ensures that a leg remains correctly positioned during use and helps to affix the system to a surface during use.

Alternatively, feet may be supported on the ends of the stabilisation legs. These feet may be rubber.

The orientation and position of the stabilisation leg with respect to the system may be varied by a user, therefore the user may arrange any stabilisation legs so as to best support the system on a given surface. A user may also position the stabilisation legs such that they do not block the system from accessing any damaged areas of the surface to be repaired. The stabilisation legs may be extendable, foldable, hinged or may branch such that they have multiple ends.

The stabilisation legs may be adapted to be removed and reattached to the system or mount.

The system may have a mount that is adapted to travel across a surface to which the mount is affixed.

This may allow the system to machine recesses across a greater area of a surface without having to be removed from a surface and reaffixed elsewhere by a user. Ideally this may enable the system to be repair an entire damaged surface without having to remove and reaffix the system. This may be useful if areas of the surface are difficult for a user to reach, for example in the case of a vertical surface the system may be affixed to a lower portion of the surface which is easily reached by a user, the system may then travel across the surface, machining recesses where necessary, before returning to the user at the lower portion of the surface.

The system may undertake repairs as it travels, with the imaging system identifying locations to machine a recess over the area of the surface, and the system travelling to within the robotic arm’s reach of the locations on the surface and then machining recesses in the surface.

Alternatively, the system may travel to a first location, the determine where to machine recesses within a robotic arms reach of the first location, then machine recesses in this area, then travel to a second location and conduct repairs within reach of the second location. This may be repeated until a desired area has been repaired or the entire surface has been repaired.

Preferably the machining tool comprises a milling spindle. A plurality of different rotary cutters may be available for the milling spindle, depending upon the surface to be repaired. The milling spindle may be configured so as to facilitate the easy replacement of the milling spindle.

Alternatively, he machining tool may comprise a laser, a grinder, a router, an abrasive belt or a waterjet system.

The milling spindle may be located at a first end of the robotic arm and a mount may be connected to a second end of the robotic arm.

The machining tool may protrude substantially beyond the robotic arm so as to enable the machining tool to be inserted into recesses in the surface that are narrower than the robotic arm but wider than the machining tool. A retractable shroud may be provided that fits around the cutter of the milling spindle or about the component of another machining tool. Unless in contact with the surface the shroud protrudes beyond the length of the machining tool so that a user does not accidentally injure themselves using the machining tool.

Preferably the system may be ruggedised for outdoor use.

Surfaces located outdoors are subject to significantly greater wear and tear than those located indoors primarily due to the effects of the weather. Therefore, ruggedising the system for outdoor use adapts the system to better repair those surfaces that most need repairs.

In order to ruggedize the system for outdoor use, the system may be adapted to be resistant to vibration, impacts and the ingress of liquids, or fine particles such as dust, sand and mud. The components of the system that are vulnerable to damage may be contained within waterproof enclosures, these may prevent any liquids, such as rain, or any fine particles, such as dust, salt or sand, from damaging the system. The system may further be adapted to be resistant to and/or to operate while vibrating, such as when the surface upon which the system is mounted vibrates in the wind. The system may be further adapted to provide resistance to impacts or shocks from wind born debris or potential mishandling by a user.

The system may be further adapted to be suitable to operate in wide range of temperatures.

Components of the system that are difficult to protect from outside factors because they must be exposed during use, such as a milling spindle or vacuum connector, may be configured to be easily and quickly replaced in the event that they become damaged or worn down during use.

Preferably the surface may be the surface of a wind turbine blade.

The system may be specially adapted to machine repair module receiving recesses in a damaged turbine blade.

Wind turbine blades that are typically manufactured from a composite of a polyester resin, a vinyl resin and/or an epoxy thermosetting matrix resin and glass and/or carbon fibres, the machining tool may be designed to as to optimally operate on these materials.

The system may have a mount adapted to affix to the vertical non-planar surface of a wind turbine blade, for example the mount may be adapted to affix to a surface with curvature equal to the known curvature of a wind turbine blade.

The imaging system may be adapted to recognise specific features of a wind turbine blade. For example, the imaging system may recognise the tip or a wind turbine blade or the lightning conductors of a wind turbine blade, and the system may use these identified features to accurately determine the location of the system with respect to the blade and to accurately compare the geometry of the damaged wind turbine blade to the desired geometry of a wind turbine blade. Additionally, or alternatively, the imaging system may be adapted to recognise any damage to a wind turbine blade that will have a negative impact on the performance of the associated wind turbine, for example surface roughness due to the effect of weather on the wind turbine blade.

The system may be adapted to consider the effect of the repairs on the turbine blade in when determining where to machine recesses, for example it may be advantageous for the recesses to be machined with no faces substantially parallel to the prevailing wind direction in order to reduce the risk ingress of water or material into the cracks between inserted repair modules and the edges of the recesses.

The system may be further specially adapted to perform repairs on the leading edges of wind turbine blades.

The system may relay usage data to a remote location. This usage data may include the duration of time that the system is in operation for, when the system is in operation, where the system is in operation and information relating to whether the system needs or may soon need repairs or maintenance. The system may comprise a GPS device and/or a satellite uplink device in order to enable the relaying of this information.

According to a second aspect of the invention there is provided a method of utilising a system as described in any preceding claim wherein the system is mounted on or adjacent to a damaged surface; the imaging system locates damaged regions of the surface and the machining tool machines recesses in the surface that are dimensioned to receive prefabricated repair modules.

Brief Description of the Figures

Figure 1 is an overall view of an automated system pertaining to a first embodiment of the present invention, which does not show the milling spindle or the imaging system;

Figure 2 is a detailed view of the connectors supported on the underside of the mount;

Figure 3 is a detailed view of a stabilisation leg; and

Figure 4 is an overall view of the system showing all components.

Detailed Description of the Figures

Referring to the figures generally there is shown an automated system pertaining to a first embodiment of the present invention comprising: a milling spindle 600; an imaging system 700; a robotic arm 400; and a mount 500. The milling spindle and imaging system are supported on and manipulated by the robotic arm 400, and the robotic arm 400 is supported on and affixed to a surface by the mount 500.

Figure 4 shows an overall view of the system with all components, and figure 1 shows an overall view without the imaging system 700 and the milling spindle 600.

In use the system is affixed to a damaged surface using the mount 500, the imaging system 700 determines the geometry of the surface, determines the relative arrangement of the system and the surface, and identifies regions of the surface in need of repairs. The system then determines an arrangement of prefabricated repair modules that, when installed in the surface, will restore the surface to some desired geometry and structure. The robotic arm 400 then manipulates the milling spindle 600 in order to machine recesses dimensioned and located so as to receive the arrangement of prefabricated repair modules.

The milling spindle 600 comprises a rotary cutter 610 driven by a motor. The milling spindle is supported on a flange 450 located at a first end of the robotic arm 400. Therefore, by controlling and varying the movement and arrangement of the robotic arm 400, the location and orientation of the milling spindle 600 is controlled by the system. In use the system defines a path for the milling spindle 600 such that the rotary cutter 610 of the milling spindle 600 removes material from the surface so as to mill a desired recess in the surface.

The imaging system 700 comprises a 3D scanner that uses an area scan camera and structured light (laser line) in order to generate a 3D profile of the surface. It is supported on the robotic arm 400. The robotic arm 400 manipulates and orients the line scan camera such that it can scan an area of a surface that is to be repaired. The data gathered by the line scan camera is used in real time to ensure that an optimum distance and orientation for scanning is maintained between the imaging system and the surface.

The data gathered by the imaging system is used to determine where to make repairs in a surface and also to determine the relative location and orientation of the various components of the system to the surface. The advantage of the system is that an indication of the characteristics of a repair module are provided via a computer aided design (CAD) model which is then used to generate a cutting path in a virtual coordinate frame and subsequently to map that frame to the structure based on information generated by the vision system.

The scanning creates a point cloud corresponding to the three dimensional geometry of the surface. The system then uses polynomial analysis of slices of the point cloud to remove noise and to populate absent spline data.

The robotic arm 400 is an industrial robotic arm with six degrees of freedom. The milling spindle is supported on a flange 450 at a first end of the robotic arm, and the second end of the robotic arm is rigidly supported on the mount 500. The robotic arm has a rotating waist 410, a bowing shoulder 420, a bowing elbow 430, a bowing and rotating wrist 440 and a rotating flange 450 upon which the milling spindle is supported.

The mount 500 comprises a rigid triangular prism shaped frame 510 upon which a plurality of connectors 520, 530 and stabilisation legs 540 are supported. The mount provides a stable platform upon which the robotic arm is supported and which may be affixed to a surface that is to be repaired. The mount 500 is constructed from a rigid, strong lightweight material such as aluminium so as to provide a reliable, sturdy and rigid base for the system without excessively increasing its weight.

The frame 510 has a triangular upper surface, a triangular lower surface, upon which the feet 520, the connectors 530 and the robotic arm 400 are supported and three side faces that join corresponding sides of the upper and lower triangular faces. The upper and side faces of the frame and depth and therefore rigidity to the structure.

One foot 520 is located or supported underneath each corner of a lower triangular face of the frame 510. An array of vacuum cups 530 are supported underneath the lower face of the frame 510.

The three feet 520 are located a fixed distance below the lower face of the mount such that they define a triangle below the lower face of the mount frame 510. A triangular shape is ideal because it can be arranged so that the three vertices of the triangle are located on any plane that is large enough such that they can all be brought into contact with it simultaneously.

Therefore, these three feet 520 can conform to a wide variety of different surfaces to be repaired.

The vacuum cups 530 have sealing faces that are compliant such that the sealing faces are displaceable away from and towards the lower face of the mount frame. Therefore, when the array of vacuum cups 530 are brought into contact with a non-planar surface the sealing faces of the cups will be displaced such that they conform to the shape of the surface.

Therefore, separate cups of the array may simultaneously seal onto, and exert a force acting towards the mount on, separate portions of the surface that are different distances from the lower face of the array. Therefore, the array of compliant vacuum cups 530 may all simultaneously adhere to and exert a vacuum force on a variety of differently shaped irregular non-planar surfaces. A detailed view of a portion of the array of the vacuum cups 530 is shown in Figure 2.

The compliance of the suction cups 530 is provided by folding compressible cup bodies with articulated edges formed as bellows.

The combination of the feet 520 and the vacuum connectors 530 act to keep the frame 510 of the body static with respect to the surface. The three feet 520 located at the corners of the frame act to define the orientation of the mount and system with respect to the frame by contacting the surface simultaneously. The array of compliant vacuum cups 530 is provided so as to provide an attractive force between the surface and the mount on a variety of differently shaped surfaces. This frame 510 of the mount 500 to remain rigidly fixed and steady when the robotic arm 400 moves during use of the system. A series of pressure sensitive probes are provided to monitor the array of vacuum cups 530. If the vacuum pressure falls below a desirable level the pressure probes alert the system indicating a lack or loss of adhesion.

Two stabilisation legs 540 are supported on the frame of the mount 510; they are individually attached to the frame of the mount by hinges located adjacent the corners of the triangular frame 510. Additional feet 520 are supported on the ends of the stabilisation legs and are used to support the legs on a surface upon which the system is supported. The orientation of the stabilisation legs may be varied so as to ensure that they have good purchase on the surface and do not obstruct the system from machining recesses in the surface. A detailed view of a stabilisation leg 540 is shown in Figure 3. Alternatively, the rubber feet 520 on the end of the legs 540 may be replaced with vacuum cups 530.

It will be appreciated that variation may be made to the aforementioned embodiments without departing form the scope of the invention as defined in the claims.

Claims

1. An automated system comprises: a machining tool for machining a surface; a robotic arm for manipulating the machining tool; and an imaging system for determining the geometry of the surface to be machined.

2. A system according to claim 1 wherein: the imaging system determines the geometry of the surface and compares the geometry of the surface with a desired geometry; the system determines an arrangement of machining stages and directs the machining tool to reshape the surface such that the surface has a geometry that substantially conforms to the desired geometry.

3. A system according to claim 1 or 2 wherein the system machines one or more recesses in a surface into which material is inserted so as to reshape the surface such that it has a desired geometry.

4. A system according to claim 3 wherein one or more of the recesses are dimensioned to receive prefabricated modules.

5. A system according to any preceding claim wherein the system compares the geometry of the surface to a desired geometry; and determines an arrangement of prefabricated modules that when incorporated in the surface, reshape the surface such that the surface has a geometry that substantially conforms to the desired geometry.

6. A system according to any preceding claim wherein: the system compares the geometry of the surface to a CAD model of the desired geometry of the surface; the system uses CAD models of prefabricated modules to determine an arrangement of prefabricated modules and an associated arrangement of recesses such that when the recesses are machined in the surface and the modules are received by the recesses, the surface conforms substantially to the desired geometry.

7. A system according to any preceding claim wherein the imaging system recognises material in a surface that is weakened and/or damaged.

8. A system according to claim 7 wherein: the imaging system identifies weakened and/or damaged material in a surface; and the system determines an arrangement of prefabricated modules that when incorporated in the surface replace any weakened and/or damaged material identified in the surface and have exterior faces flush with the exterior of the surface.

9. A system according to any preceding claim wherein: the imaging system identifies weakened and/or damaged material in a surface and determines the geometry of the surface; the system compares the geometry of the surface with the desired geometry for the surface; and the system determines an arrangement of prefabricated modules that when incorporated in the surface replace any damaged and/or weakened material identified in the surface and reshape the surface to have a geometry that substantially conforms to the desired geometry for the surface.

10. A system according to any of claims 5 to 9 wherein after determining an arrangement of prefabricated modules, the system determines an arrangement of recesses dimensioned and located so as to receive the arrangement of prefabricated modules in the surface.

11. A system according to any preceding claim wherein the system manipulates and operates the machining tool and machines an arrangement of recesses in a surface that are dimensioned and located so as to receive a corresponding arrangement of prefabricated modules.

12. A system according to claim 11 wherein the system determines a series of machining stages and directs the machining tool in order to machine the arrangement of recesses.

13. A system according to any preceding claim comprising a mount for temporarily affixing the system to the surface.

14. A system according to claim 13 wherein the mount is adapted to affix the system in a predetermined orientation with respect a surface.

15. A system according to claim 13 or 14 wherein the mount is adapted to affix the system to substantially non-planar surfaces.

16. A system according to claim 15 wherein the mount comprises a frame and a plurality of connectors supported on the frame.

17. A system according to any of claims 13, 14, 15 or 16 wherein the frame is triangular and a leg is supported at each vertex of the frame such that the foot of each leg is rigidly located a distance below the frame.

18. A system according to claim 16 or 17 wherein a plurality of connectors are supported on the underside of the frame and the aspects of the connectors that affix to a surface are displaceable with respect to the frame.

19. A system according to any preceding claim wherein the mount comprises a triangular frame; a leg supported at each vertex of the frame, each leg having a foot rigidly located a distance below the frame; and an array of connectors supported on the underside of the frame with aspects that affix to the surface that are displaceable with respect to the frame.

20. A system according to any of claims 16 to 19 wherein at least one connector is a suction or vacuum connector.

21. A system according to any of claims 13 to 20 wherein the mount comprises at least one stabilisation leg.

22. A system according to any of claims 13 to 21 wherein the mount is adapted to travel across a surface to which the mount is affixed.

23. A system according to any preceding claim wherein the machining tool comprises a milling spindle.

24. A system according to any preceding claim wherein the machining tool comprises a laser.

25. A system according to any preceding claim wherein the system is ruggedised for outdoor use.

26. A system according to any preceding claim wherein the surface is the surface of a wind turbine blade.

27. A system according to any preceding claim that relays usage data to a remote location.

28. A method of utilising a system as described in any preceding claim wherein the system is mounted on or adjacent to a damaged surface; the imaging system locates damaged regions of the surface and the machining tool machines recesses in the surface that are dimensioned to receive prefabricated modules.

29. A system substantially as herein described with reference to the Figures.