Patent Description:
As wind turbine blades become longer, it is advantageous to divide such blades into a plurality of blade parts which are individually molded, for example by different manufacturers, and subsequently assembled. When the blade parts are assembled, it is important that the blade resulting structure is as much as possible identical to a blade which is casted in one piece.

Since different blade parts may come from different molds, correct assembly of the blade parts may become difficult due to an insufficient match and/or quality of a connection area of a blade part.

For example, when blade parts are assembled, it is important that the tip of a blade is placed correctly with respect to the root and that the twist of the blade is as designed. If this is not the case, then loads throughout the wind turbine may change and the annual energy production may change. In a worst-case scenario, the wind turbine blade may even strike the tower of the wind turbine.

<CIT> discloses a method for manufacturing a rotor blade for a wind turbine, in which at least two rotor blade elements are arranged one behind the other in the longitudinal direction of the rotor blade and are bonded to one another via at least one, preferably at least two, connecting elements bridging a separating gap between the rotor blade elements.

It is one object of the present invention to provide a way of ensuring that independently manufactured blade parts can be assembled in a manner such that the assembled blade comes as close as possible to a single-casted blade.

Accordingly, a method for assembling blade parts of a wind turbine blade is provided. The method comprises obtaining information about a connection area of a blade part, selecting, customizing and/or manufacturing an adaptor piece depending on the obtained information about the connection area of the blade part, wherein the adaptor piece serves to connect the blade part with at least another blade part, and connecting the blade part to the adaptor piece.

By for example identifying the geometry of the connection area of the blade part, the adaptor piece for connecting multiple blade parts can be provided in an improved manner. The size of the connection can be determined such that the adaptor piece does not have to be adjusted in the mold, i.e. when connecting the blade part and the adaptor piece. The presented solution rather allows an "offline kitting" for connecting multiple blade parts.

The step of obtaining information about the connection area of the blade part further allows to determine the quality of the connection area and to provide information about the same to a manufacturer of the blade part. Since the manufacturer can use this quality control feedback to enhance a material placement of parts to be assembled, a manufacturing process can be improved.

Moreover, it can be determined if different blade parts would match and whether they should be assembled or not. Accordingly, the structural performance of the assembled blade is optimized since only the best fitting parts may be selected for being connected to each other.

The blade part, other blade part (as mentioned hereinafter) and/or the adaptor piece may be provided as a fiber lay-up with or without resin. The resin may be cured, partially cured or uncured. Examples of fibers include glass fibers or carbon fibers. The resin may include a thermoplastic or duroplastic material, for example. Also, the lay-up(s) may include wood such as balsa wood.

"Selecting an adaptor piece" includes choosing one adaptor piece from multiple adaptor pieces previously manufactured, i.e. prior to the step of choosing the one adaptor piece.

"Customizing an adaptor piece" includes changing the geometry of an existing (previously manufactured) adaptor. This may include machining the adaptor piece, adding or removing fiber layers etc..

"Manufacturing an adaptor piece" includes producing a fiber lay-up (from scratch). The fiber lay-up may include a resin. The resin may be cured, partially cured or uncured.

The step of obtaining information about the connection area comprises placing tracker markers on the blade part and recording positions of the placed tracker markers.

This allows a simple and cost-effective way of obtaining information about the connection area.

According to a further embodiment, the tracker markers are placed at predefined geometric details and/or layup details in the connection area of the blade part.

According to a further embodiment, the tracker markers are casted in the blade part.

This is particularly advantageous since the tracker markers may be automatically integrated into the blade part during manufacturing of the same and hence, a manual placement of tracker markers after the manufacturing is not required anymore.

According to a further embodiment, the step of obtaining the information about the connection area of the blade part comprises performing a Digital Image Correlation (DIC) using a stereoscopic camera device.

This has the advantage that the blade part does neither have to be manipulated during manufacturing nor after manufacturing since the DIC allows to obtain the information about the connection area solely based on recorded image data. Instead of DIC, laser scanners, radar, trackers etc. could be used for obtaining the information about the connection area of the blade part, i.e. for surface recognition. In principle one may use any equipment/method which can return a 3D surface.

According to a further embodiment, the step of selecting, customizing and/or manufacturing the adaptor piece comprises providing the obtained information to the adaptor piece by projecting optical lines onto the adaptor piece.

According to a further embodiment, the optical lines represent a geometry which the adaptor piece should have to provide correct dimensions for connecting the blade part to the adaptor piece.

This may comprise projecting laser lines on a mold of the adaptor piece, wherein the laser lines can be either flattened or curved.

According to a further embodiment, the adaptor piece is selected, customized and/or manufactured depending on the obtained information about the connection area of the blade part and/or the other blade part.

Therein, the selection may be either done by a computer algorithm or manually. Since the obtained information about the connection area of the blade part or the other blade part is taken into consideration, an adaptor piece requiring a minimum customization effort can be selected.

According to a further embodiment, the blade part is manufactured using a first mold and the adaptor piece is manufactured using a second mold which is different from the first mold.

According to a further embodiment, the step of connecting the blade part to the adaptor piece comprises aligning the blade part and the adaptor piece with respect to each other, laying fibers across the blade part and the adaptor piece to build a fiber layup, infusing the fibers with a resin, and curing the resin.

This process allows a solid bond between the blade part and the adaptor piece which provides a structure which is similar to the structure of a single-casted blade.

According to a further embodiment, the connection area of the blade part comprises a recess and the adaptor piece comprises a protrusion which corresponds to the recess.

Providing a recess at the blade part and a protrusion at the adaptor piece allows a simple but stable connection.

According to a further embodiment, the step of obtaining the information about the connection area of the blade part comprises measuring the recess.

According to a further embodiment, the step of selecting, customizing and/or manufacturing the adaptor piece and/or the step of connecting the blade part, other blade part and/or the adaptor piece comprises using a resin infusion process, in particular a vacuum infusion process.

According to a further embodiment, the method comprises obtaining information about a connection area of the other blade part, selecting, customizing and/or manufacturing the adaptor piece depending on the obtained information about the connection area of the other blade part, and connecting the other blade part to the adaptor piece.

According to a further aspect, the invention relates to a system for assembling blade parts of a wind turbine blade comprising (first) means configured to obtain information about a connection area of a blade part, (second) means configured to select, customize and/or manufacture an adaptor piece depending on the obtained information about the connection area of the blade part, wherein the adaptor piece serves to connect the blade part with at least another blade part, and (third) means configured to connect the blade part to the adaptor piece.

The first means may include a camera, the second means a projector device, and the third means a resin infusion device, an autoclave etc..

The embodiments and features described with reference to the method of the present invention apply mutatis mutandis to the system of the present invention.

<FIG> shows a flowchart illustrating a method for assembling a blade part <NUM> (see Fig. <NUM>) of a wind turbine blade <NUM> with another blade part <NUM> using an adaptor piece <NUM>. The blade parts <NUM>, <NUM> and the adaptor piece <NUM> are made from a lay-up of fibers, respectively, and may include a cured, partially cured or uncured resin.

In step S1, information about a connection area <NUM> (see <FIG>) of the blade part <NUM> arranged on a mold <NUM> is obtained. This may be done by placing tracker markers <NUM> on the blade part <NUM> and recording positions of the placed tracker markers <NUM> with a capturing device such as a camera <NUM>, for example a conventional 2D camera. Therein, the tracker markers <NUM> are placed at predefined geometric details and/or layup details in the connection area <NUM> of the blade part <NUM>.

The tracker markers <NUM> may either be placed in the connection area <NUM> after manufacturing the blade part <NUM> or may be casted in the blade part <NUM> during manufacturing. The step of manufacturing may include building a fiber lay-up and, optionally, infusing said lay-up with a resin. The resin may or may not be in a cured state. Curing is done in an autoclave, preferably.

As an alternative to using tracker markers <NUM>, the step of obtaining the information about the connection area <NUM> of the blade part <NUM> may comprise performing a Digital Image Correlation (DIC) using a stereoscopic camera device <NUM>. Step S1 serves to identify exact dimensions (geometries) of the connection area <NUM> which are subsequently used to provide the adaptor piece <NUM>.

In step S2, the adaptor piece <NUM> is selected, customized and/or manufactured depending on the obtained information about the connection area <NUM> of the blade part <NUM>. The adaptor piece <NUM> serves to connect the blade part <NUM> with at least another blade part <NUM>.

According to a first alternative, the adaptor piece <NUM> is selected (from multiple adaptor pieces <NUM> previously manufactured) and the adaptor piece <NUM> is customized based on the information obtained from the connection area <NUM> of the blade part <NUM>. Customizing the adaptor piece <NUM> may comprise changing its geometry by adding or removing fiber layers, for example. The adaptor piece <NUM> may not be completely cured such that a further customizing of the adaptor piece <NUM> is still possible.

By projecting optical lines <NUM>, such as laser lines, onto the pre-manufactured adaptor piece <NUM> which has been selected, the information obtained from the blade part <NUM> is provided to the adaptor piece <NUM>. The optical lines <NUM> represent a geometry which the adaptor piece <NUM> should have to provide correct dimensions for connecting the blade part <NUM> to the adaptor piece <NUM> and hence, a customization of the adaptor piece <NUM> is possible in a simple manner.

According to a second alternative, the information obtained from the connection area <NUM> of the blade part <NUM> may be used to manufacture the adaptor piece <NUM>, rather than merely customizing or selecting the adaptor piece <NUM>. Manufacturing the adaptor piece <NUM> may include forming a lay-up of fibers.

The adaptor piece <NUM> may be provided to the assembly site after selecting the same, customized or manufactured on a mold <NUM>.

In each of the two alternatives, the connection area <NUM> of the blade part <NUM> may comprise a recess <NUM> and the adaptor piece <NUM> may comprise a protrusion <NUM> which corresponds to the recess <NUM>. In such case, the preceding step of obtaining the information about the connection area <NUM> of the blade part <NUM> comprises measuring the recess <NUM>.

In step S3, the blade part <NUM> is connected to the adaptor piece <NUM>. This may comprise aligning the blade part <NUM> and the adaptor piece <NUM> with respect to each other, laying fibers across the blade part <NUM> and the adaptor piece <NUM> to build a fiber layup, infusing the fibers with a resin (for example in a vacuum resin infusion process), and curing the resin (for example in an autoclave).

The drawing on the left side of <FIG> shows a step of placing tracker markers <NUM> on the blade part and recording positions of the placed tracker markers <NUM>. Therein, the tracker markers <NUM> are placed at predefined geometric details and/or layup details in the connection area <NUM> of the blade part <NUM>. The tracker markers <NUM> may be placed by means of a stick <NUM> which is configured to provide the tracker markers <NUM>. As an alternative, the tracker markers <NUM> may also be placed using a robotic arm or the like. After the tracker markers <NUM> have been placed, the positions of the placed tracker markers <NUM> are recorded. For this purpose, a capturing device such as camera <NUM> is arranged above the blade part <NUM>. The camera <NUM> records the positions of all tracker markers <NUM> and provides corresponding information to a processing device <NUM> such as a notebook computer or the like.

The drawing on the right side of <FIG> shows the step of selecting, customizing and/or manufacturing an adaptor piece <NUM> depending on the obtained information about the tracker markers <NUM>. For this purpose, the processing device <NUM> is connected to a projector device <NUM> which emits optical lines <NUM>, such as laser lines, based on obtained the information. The optical lines <NUM> indicate on an adaptor piece <NUM> that has been selected, for example depending on the obtained information about the connection area <NUM> of the blade part <NUM>, how the selected adaptor piece <NUM> should be customized. A customization of the adaptor piece <NUM> can be subsequently carried out as described above. Instead of selecting an adaptor piece <NUM> and customizing the same, a new adaptor piece <NUM> could be manufactured based on the obtained information by projecting optical lines <NUM> onto a mold.

As it is apparent from <FIG> in more detail, a plurality of tracker markers <NUM> is placed at predefined geometric details and/or layup details in the connection area <NUM> of the blade part <NUM>. The information about the positions of the tracker markers <NUM> is obtained using a capturing device such as a camera <NUM>, for example a conventional 2D camera. After the information has been obtained, it is provided to the processing device <NUM>. The information may also serve to check the quality of a connection area in terms of allowed tolerances, offsets and the like.

<FIG> shows a step of obtaining information about a connection area <NUM> by performing a Digital Image Correlation (DIC) using a stereoscopic camera device <NUM>, also known as a 3D camera. This makes the step of placing tracker markers <NUM> on the blade part <NUM> redundant. In order to position the stereoscopic camera device <NUM> in a simple manner, the same may be attached to a cart <NUM>. The cart <NUM> may also serve to hold the processing device <NUM> in form of a notebook computer in order to allow personnel to verify if information of the connection area <NUM> is properly obtained. As an alternative, the stereoscopic camera device <NUM> may also be operated by a robot arm or the like, thereby using image recognition technologies to verify a proper alignment of the stereoscopic camera device <NUM> with respect to the blade part <NUM>.

<FIG> shows the step of connecting the two blade parts <NUM>, <NUM> to an adaptor piece <NUM>. Prior to connecting the blade parts <NUM>, <NUM> to the adaptor piece <NUM>, the adaptor piece <NUM> has been customized based on information obtained about a connection area <NUM> of the first blade part <NUM> and about a connection area <NUM> of the second blade part <NUM>.

Claim 1:
A method for assembling blade parts (<NUM>) of a wind turbine blade (<NUM>), the method comprising the steps of:
obtaining information about a connection area (<NUM>) of a blade part (<NUM>),
selecting, customizing and/or manufacturing an adaptor piece (<NUM>) depending on the obtained information about the connection area (<NUM>) of the blade part (<NUM>), wherein the adaptor piece (<NUM>) serves to connect the blade part (<NUM>) with at least another blade part (<NUM>), and
connecting the blade part (<NUM>) to the adaptor piece (<NUM>),
characterized in that
the step of obtaining information about the connection area (<NUM>) comprises placing tracker markers (<NUM>) on the blade part (<NUM>) and recording positions of the placed tracker markers (<NUM>).