Cargo alignment control system and method therefor

Abstract

The present invention relates to a control system and method for controlling the alignment of a load suspended from a crane with a target. The method includes determining the motion of the load in at least one degree of freedom, generating a compensation signal indicative of the motion of the load, and generating a control signal for a crane and / or a load motion compensation system (LMCS) for controlling a reference pose of the load in a reference coordinate system provided by a first reference sensor in response to at least one compensation signal. The method further includes receiving, from a feature detection system, a relative motion signal indicative of relative motion between the target and the load, generating an alignment signal in response to the relative motion signal, and generating a control signal for controlling the crane and / or the LMCS to move the load in alignment with the target in response to the alignment signal.

Description

Technical Field

[0001]

[0001] The present invention relates to a control system for controlling the alignment of a load suspended from a crane with a target. In particular, the present invention relates to a load motion compensation system extended with a load alignment system. The present invention further relates to a method for controlling the alignment of a load suspended from a crane with a target.

Background Art

[0002]

[0002] The installation of an offshore wind turbine is a complex problem. For one thing, components such as nacelles and turbine blades must be lifted by a crane or other lifting device from the deck of an installation vessel to a great height, for example, 150 meters or more. Further, the components must be assembled with high precision at that height while being suspended from the crane. The installation can be further complicated by offshore conditions such as wind and waves that can impose disturbing motions on the installation vessel, on the components suspended in the air and lifted by the crane, and / or on the target structure on which the installation needs to be carried out.

[0003]

[0003] To isolate the installation vessel from the influence of ocean currents and waves, a jack-up vessel can be used. However, jack-up vessels have limited operating areas and limited usability in different water areas due to the height limitation of the jack-up legs that can lift the vessel. The influence of waves and wind on the installation vessel can be reduced by jacking up the vessel, but the wind and / or wave forces on all elements can still move the components suspended from the crane.

[0004]

[0004] As an alternative to jack-up vessels and conventional cranes, motion-compensated cranes or stabilization platforms can be used on floating vessels. Such cranes are configured such that, since the base of the crane is rigidly attached to the vessel with at least some degrees of freedom, the load suspended from the crane is kept substantially in the same position and orientation while the base of the crane moves with the motion of the vessel caused by wind and waves. However, such motion-compensated cranes can be heavy, require a lot of energy to operate, and / or have a limited operating range or loading capacity, particularly in the vertical range.

[0005]

[0005] An alternative motion compensation system is known from WO2021 / 002749A1, which discloses a load motion compensation system (LMCS) consisting of a crane having a hoist, such as a cable hoist or a hydraulic gripper, and several actuators, namely a combination of cables and winches controlled to compensate for motions due to wind and water. The position of the hoist and the suspended load can be represented as three-dimensional coordinates in a Cartesian coordinate system with three orthogonal translational axes. The orientation of the hoist can be represented as a set of three angles, which indicate the amount of rotation about the translational axes. Any other notation can be used for positions, orientations, or combinations thereof, such as angular axis coordinates, homogeneous coordinates, etc. Collectively, the position and orientation are called the pose of the object. Several force sensors are configured to provide sensor signals indicating the tension of one or more of the cables. The sensor tension signals are received by a control system configured to control the winches based on the received signals. Therefore, the system disclosed in WO2021 / 002749A1 compensates for the load against motions caused by wind and water or induced by any other factor and preferably enables the maintenance of the pose of the load within a (geo)reference coordinate system based on the Global Positioning System (GPS) or any other geolocation information.

[0006] When installed on a ship, regardless of whether the ship is a floating type or a jack-up type, the cargo motion compensation system reduces the task of installing a cargo such as a wind turbine blade towards a target such as the nacelle or rotor of a wind turbine. When using such a motion compensation system on a jack-up, it becomes possible to install at higher wind speeds than when such a compensation system is not used, and it also becomes possible to install the cargo even when the target (e.g., the nacelle) exhibits motion.

Summary of the Invention

[0007]

[0007] An object of the present invention is to facilitate the alignment of the cargo with the target. In addition, in a first aspect, the present disclosure relates to a computer-implemented method for controlling the alignment of a cargo suspended from a crane with a target. The method includes determining the motion of the cargo in at least one degree of freedom, generating at least one compensation signal indicative of the motion of the cargo, and generating a control signal for a crane and / or a load motion compensation system (LMCS) for controlling a reference pose of the cargo in a reference coordinate system provided by a first reference sensor in response to the at least one compensation signal. The method further includes receiving, from a feature detection system, a relative motion signal indicative of the relative motion between the target and the cargo, and generating a control signal for controlling the crane and / or the LMCS for the displacement of the cargo towards the target in response to the relative signal.

[0008]

[0008] According to another aspect, there is a control box for controlling the alignment of a cargo suspended from a crane with a target.

[0009]

[0009] According to another aspect, there is provided a control system for controlling the alignment of a cargo suspended from a crane with a target.

[0010] According to another aspect, a method is provided for controlling the alignment of a load suspended from a crane with a target.

[0011] According to another aspect, a crane is provided that includes a control system as disclosed.

[0012] According to another aspect, a ship is provided that includes a crane and a control system as disclosed.

[0013] Specific embodiments of the invention are set forth in the dependent claims.

[0014] Further objects, aspects, effects, and details of specific embodiments of the invention are described in the following modes for carrying out the invention of some illustrative embodiments with reference to the drawings.

[0015] By way of example only, embodiments of the present disclosure are described with reference to the accompanying drawings.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

[0017] Examples of various mounting devices for a target are schematically illustrated.

Figure 3

[0018] An example of a control system for controlling the alignment of a load with a target according to the present invention is schematically illustrated.

Figure 4

[0019] An example of a sensor device for a crane installed on a ship according to the present invention is schematically illustrated.

Figure 5

[0020] Examples of features and feature detection systems according to the present invention are schematically illustrated.

Figure 6

[0021] The perspective of the feature detection system of FIG. 5 is schematically illustrated.

Figure 7

[0022] An example of a method for controlling the alignment of a load with a target according to the present invention is schematically illustrated.

Figure 8

[0023] An example of a control scheme of a control system according to the present invention is schematically illustrated.

Figure 9

[0024] Another example of a feature, a feature detection system, and a feature plate according to the present invention is schematically illustrated.

Figure 10

[0025] An example of a feature plate mounted on a bolt of a load according to the present invention is schematically illustrated.

Figure 11

[0026] Another example of a method for controlling the alignment of a load with a target according to the present invention is schematically illustrated.

Embodiments for Carrying Out the Invention

[0017]

[0027] Referring to FIG. 1, a wind turbine generator 1 during installation is shown. A nacelle 2 having a rotor 3 is mounted on top of a tower 4. The tower 4 is mounted on a foundation 5 that can be provided in various ways. For example, as shown in FIG. 2, the foundation 5 can be provided by a so-called monopile via the seabed 6, there can be a floating foundation 7, or there can be a fixed jacket 8 or any other suitable foundation type. The floating foundation 7 can be fixed to the seabed by a cable or a chain. The fixed jacket 8 can be placed on the seabed or can be mounted on the seabed by piles.

[0018]

[0028] Figure 1 further shows a ship 9 in the sea 10 that supports a crane 11 from which a load 12, such as a wind turbine blade, is suspended. The crane 11 is configured to provide various degrees of freedom and can move and articulate in various forms. The crane 11 is further equipped with a hoist system 13 having a tool 14 for supporting the load 12, such as a cable hoist, a winch hook, a hydraulic gripper, or other types of devices for holding the load. The actuator 15 of the hoist system 13 controls the pose of the tool 14, i.e., the position and orientation, and thereby also controls the pose of the load 12. The load 12 is preferably rigidly connected to the tool 14 to ensure that operating the pose of the tool 14 directly affects the pose of the load 12. In some embodiments, some form of mechanical or controlled compliance may exist between the tool 14 and the load 12. In some embodiments, the tool may be suitable for directly gripping and supporting the load 12 while holding it with a rigid grip. In some examples, the load may include a dedicated structure that surrounds the element to be lifted and displaced. In this example, with respect to the installation of a wind turbine, the load is aligned with the target, in this case the nacelle 2, and relates to the wind turbine blade to be installed thereon. Alternatively, any other component, such as a monopile, a transition piece, a tower or tower section, a nacelle, a rotor, or any other part requiring assembly, may be considered as the load. Each of the components shown in Figure 1, including the load, i.e., the blade 12, and the target, i.e., the nacelle 2 and the tower 4, may experience or cause motion due to waves and wind.

[0019]

[0029] Generally, in the present disclosure, the crane can be any device suitable for lifting and displacing a load. It can include, for example, several articulated arms on a rotating platform. It can include a certain type of articulated tower. Or, it can include, for example, one or more towers having sliders and / or girders. Further, it can include, for example, a number of winches and hoists in combination with an articulated tower. It can combine the crane with another series or parallel structure and form a closed-loop or open-loop mechanism that can act on the load at one or more points. It can consist of a series or parallel mechanism that directly holds the load.

[0020]

[0030] Referring to FIG. 3, a control system 30 for controlling the alignment of a load with a target is shown. The control system 30 includes a control box 38 having at least one controller, in this example, an operator or a human machine interface (HMI) 31, a plurality of sensors 32, and a main controller 34 to which various elements providing input signals such as a manual control unit 33 are connected. Next, the main controller 34 provides output signals to various elements such as a load motion compensation system (LMCS) 35 and / or the crane 11. And, the control system 30 can include a load alignment system, here represented as part of the various sensors 32.

[0021]

[0031] At least one controller 34 of the control box 38 may be configured to generate an alignment signal in response to a relative movement signal. Then, by controlling the LMCS 35 and / or the crane, a control signal is generated in response to the alignment signal to control the displacement of the load towards the target. The relative movement signal indicates the relative movement between the target and the load. The relative movement signal may be received from a detection system including a sensor or a plurality of sensors, as will be described in more detail below. The alignment signal is generated, for example, to provide one or more target setpoints to the control system to control various actuators. In a simpler case, the alignment signal may be the same as the relative movement signal. Depending on the setup or configuration of the control system, the alignment signal may be represented in various other forms or formats. In a first aspect, the alignment signal is intended to enable the load to move in synchronization with the target, even if an offset remains. In a second aspect, the alignment signal may be intended to reduce the offset. And, more preferably, it may be intended for the load and the target to have corresponding structural features to face each other and / or engage with each other. The alignment signal may be derived, for example, by feedback control such as applicable during visual servoing and may directly drive the LMCS.

[0022]

[0032] As will be appreciated, the main controller may perform all of these functions or may include additional dedicated controllers. For example, the control box 38 may include a load motion compensation system LMCS controller 39 for generating an LMCS control signal. The control box 38 may include an offset calculator 37 for generating an alignment signal. And it may include a crane controller 36 for generating a crane control signal. In an alternative embodiment, each of the components of the control box may be arranged in a distributed setup, which may mean that at least one or more of the controllers and / or calculators are provided remotely and may be connected to the main controller via cables or wirelessly.

[0023]

[0033] Generally, signal generation can be performed sequentially or in parallel, or signals can be combined. This can depend on the computational resources applied and the type of algorithm. Further, signal generation can be continuous, resulting in a time-varying signal. Therefore, the generation of one signal can trigger the generation of additional signals in response while still continuously generating one signal. For example, when a control signal is generated in response to an alignment signal, this can be interpreted as generating the control signal in response to the generated alignment signal, or in other words, the control signal is generated in relation to the generated alignment signal. For example, the control signal can be directly generated based on a relative motion signal by applying a feedback control law such as that used in visual servoing well known to those skilled in the art. In this case, the relative motion signal and the alignment signal can be combined, and the control signal can also be combined. In such a case, a compensation signal can also be combined with the control signal, and the processing may not involve representing the compensation signal in an absolute reference but may involve directly applying a relative reference in response to the relative motion signal.

[0024]

[0034] The operator or human-machine interface HMI31 can take any form, such as a joystick, touch screen, display with a SCADA system, buttons, graphical user interface, or any other form that can enable the operator to provide an input to the main controller 34. Alternatively, the HMI31 can also provide an input directly to the LMCS controller 39 or the crane controller 36. In addition, the operator can provide an input manually via the manual control unit 33. The manual control unit 33 can include one or more joysticks, control sticks, push buttons, rotary knobs, space mice, mice, micromanipulators, or any other manual input device for humans. Each input from the HMI31 and the manual control unit 33 can be used by the main controller 34 to generate a setpoint. The setpoint can be output to the crane controller 36 to move the load suspended from the crane. And / or, it can be output to the LMCS 35 to control the pose of the load 12. The crane controller 36 is configured to control the movement and articulation of the crane 11 according to the setpoint, if provided, depending on the type of crane.

[0025]

[0035] The LMCS35 is configured to control the reference pose of the load, preferably the absolute reference pose. The reference pose, including position and orientation, can be a setpoint received from the main controller 34. It can also be configured to be interpreted as either the relative pose or the absolute pose with respect to the target, which can be represented either with respect to the Earth coordinate reference system or with respect to the reference coordinate reference system. Such an Earth coordinate reference system can be derived via the Global Positioning System (GPS), Beidou, GLONASS, Galileo, or any other currently known global navigation satellite system (GNSS). The LMCS35 can include at least one motion sensor configured to determine the movement of the load in at least one, preferably two degrees of freedom. The at least one motion sensor is further configured to generate at least one compensation signal indicative of the motion of the load. The LMCS35 further includes at least one motion compensation actuator configured to control the pose of the load in response to the at least one compensation signal. The load motion compensation system can be further configured to process the compensation signal and activate the motion compensation actuator, preferably to control the pose of the load in an absolute reference pose. Or, alternatively, directly with respect to the target.

[0026]

[0036] Referring to FIG. 5, the load alignment system includes a feature 51 that can be disposed on the load 12 or on the target 2, and a feature detection system 50 disposed on the target 2 and on the load 12, respectively. Thus, depending on which component, load, or target the feature 51 is disposed on, the feature detection system 50 will be disposed on the other component, target, or load. The feature detection system 50 is configured to detect the feature 51, track the movement of the feature 51, and generate a relative movement signal indicative of the relative movement between the target and the load.

[0027]

[0037] The cargo alignment system may further include an offset calculator 37 for generating an alignment signal in response to a relative motion signal. The offset calculator may be a dedicated computing resource as in the embodiment of FIG. 3, or may be provided as part of the main controller 34. In either case, it can provide the function of an offset calculator for generating an alignment signal in response to a relative motion signal. The generated alignment signal may be transmitted by the main controller 34 to the crane controller 36. Or, when generated by the dedicated offset calculator 37, via the main controller 34. Or, it may be transmitted directly by the dedicated offset calculator 37 to the crane controller 36, as shown by the dotted line in FIG. 3. The crane controller 36 is configured to control the crane 11 for the displacement of the cargo towards the target in response to the alignment signal. Alternatively or additionally, the generated alignment signal may be transmitted by the main controller 34 to the LMCS controller 39. Or, when generated by the dedicated offset calculator 37, via the main controller 34. Or, it may be transmitted directly by the dedicated offset calculator 37 to the LMCS controller 39 (not shown). The LMCS controller 39 may be configured to control the LMCS 35 for the displacement of the cargo towards the target in response to the alignment signal, alternatively or additionally. The main controller 34, the LMCS controller 39, the crane controller 36, and / or the offset calculator 37 may all be combined and may include at least one or more feedback controllers based on the inputs of the HMI 31, the sensor 32, and / or the manual control unit 33.

[0028]

[0038] The control box 38 having at least one controller 34 is configured to generate an alignment signal in response to a relative motion signal. And by controlling the load motion compensation system LMCS and / or the crane, a control signal for controlling the displacement of the cargo towards the target is generated in response to the alignment signal.

[0029]

[0039] Referring to FIG. 1, the actuator 15 of the LMCS may include a set of control lines or tag lines installed on the tool 14 that holds the load 12. The control lines are arranged such that the tool and the load can be moved in at least one, preferably at least two degrees of freedom, such as at least one of pitch, roll, yaw, heave, sway, and / or surge, as mentioned in the nautical field. By applying different tensions to these control lines, the position and orientation of the tool 14, and along with it the position and orientation of the load 12, can be controlled in the arranged degrees of freedom. The method of representing the degrees of freedom can take any form and is not limited to an orthogonal system, as it can include a right-handed coordinate system, a left-handed coordinate system, a quaternion or axis-angle representation of position and orientation, or any other representation.

[0030]

[0040] As an alternative to the cable-based system, the LMCS can be provided differently, for example, by being arranged as mechanical equipment having one or more towers that provide several degrees of freedom. For example, the LMCS can be arranged on a tower having a rotating base on the ship deck, several linear actuators, and / or additional rotating joints for moving the load relative to the ship. In practice, any kinematic chain that is suitable and can be contemplated by those skilled in the art can be used, as long as the LMCS is capable of causing a controlled motion of the load.

[0031]

[0041] Referring to FIGS. 4 and 5, a plurality of sensors 32 of the control system 30 as shown in FIG. 3 are described in more detail. In the following description, each sensor "nn" can define a local coordinate reference represented by {Snn}, and "Snn" is the name of the coordinate reference.

[0032]

[0042] In FIG. 4, a first reference sensor 41 is disposed on the tool 14 and provides a reference coordinate system {S41}. The second reference sensor 42 may be disposed on the crane 11 additionally or alternatively and provides a second reference coordinate system {S42}. When the reference sensor 42 is disposed as an alternative to the reference sensor 41, the sensor 42 may be regarded as the first reference sensor. The first reference sensor 41 may further be capable of providing pose measurement values of the tool in absolute world coordinates or geolocation {W} by utilizing global navigation satellite sensor signals in combination with, for example, an inertial measurement device generally called a GNSS / INS device. Additionally, correction services such as PPP or RTK, or any other available corrections, may be used to increase the accuracy of the pose measurement values. The second reference sensor 42 provides remote sensing measurements of the tool and / or the load and may convert the pose information of the tool and / or the load such that the pose of the load 12 can be represented in world coordinates {W}. In such a case, the sensor 42 may remotely sense the tool or the load via one or more cameras, lidars, or radars, or may measure feedback from active or passive markers, reflectors, or any other active or passive system to determine the relative pose between the sensor 42 and the tool 14 and / or the load 12.

[0033]

[0043] Therefore, when using the GNSS / INS device, the first reference sensor 41 can directly measure the pose of the tool 14 and / or the payload 12 in the world coordinates {W}. Alternatively, the pose and orientation of the tool 14 and / or the payload 12 can be measured indirectly, with the help of the first reference sensor 41 that acts as, for example, an active or passive marker or a wireless beacon and then converts these measurements into world coordinates, by utilizing remote sensing measurements of any feature as described above by a second reference sensor 42. The remote sensing measurements can be made, for example, by utilizing a GNSS / INS combination in the second reference sensor 42 and using a camera, lidar, radar, or other remote sensing techniques to infer the relative position of the first reference sensor 41 with respect to the second reference sensor 42 or the relative position of any feature of the tool 14 and / or the payload 12 and / or any marker device.

[0034]

[0044] Therefore, the pose of {S41} can be measured in {S42} in a relative form, and when {S42} utilizes a GNSS / INS system, the pose of {S41} in the world coordinates {W} will be easily derivable. As can be understood, the arrangement of the first and second reference sensors 41, 42 can be reversed while achieving the same result. Additionally, they can be used individually or in combination. Further, additional sensors can be provided, each defining a further reference coordinate system {Snn}. When using multiple reference sensors, these are preferably arranged such that each sensor has a pose that can be represented in the coordinate system of at least one other reference sensor. It is possible for at least one of the reference sensors to provide the world coordinates {W}, and as long as each sensor can associate its pose with at least one other reference sensor, all sensor and payload pose measurements can be represented in the world coordinates {W} by either remote sensing or inference. Further, motion techniques such as using Denavit Hartenberg parameters and homogeneous transformations can be used in combination with some rotational measurements derivable from encoders, for example, in a serial robotic arm. Since the pose of each sensor can be inferred and represented in the reference coordinate system of another sensor, a kinematic chain can be defined. Similarly, pose measurements of other elements such as the crane 11, the hoist 13, and / or the ship 9, i.e., position and orientation, can be performed by inference or directly represented in the world coordinates {W}.

[0035]

[0045] For example, in the embodiment of FIG. 4, a third sensor 43 can be installed on the ship 9, providing a third reference coordinate system {S43}, and the poses of the first reference sensor 41 and / or the second reference sensor 42 can be represented. If a GNSS / INS device is provided on the third reference sensor 43, the other reference sensors may be sufficient without such a device and can still obtain their locations represented in the world coordinates {W} through motion propagation.

[0036]

[0046] As another example of suitable sensor means, still referring to FIG. 4, the fourth sensor 44 may include a set of rotary and linear encoders and / or position measurement devices, which, together with the geometric characteristics of the crane and information about its pose with respect to the ship, may be used to infer the position of the second reference sensor 42 in a third reference coordinate system {S43} or alternatively in a ship reference coordinate system {V} provided by the ship structure itself. Any further and / or other combination of sensors suitable for measuring the pose may be contemplated, which may also include parameters such as the speed, acceleration, and / or jerk of the load. Here, while all poses are represented in the absolute world frame {W}, the method described herein may be equally applicable when no conversion to the world reference is performed, but a direct relative conversion between the load and the target is measured and controlled by utilizing relative motion signals and / or alignment signals.

[0037]

[0047] Depending on the type of the load, for example, when extending in the longitudinal direction, it may be preferable to define one point of the load as the center of the load, such as the center of gravity, and one point as the load tip. The center of the load can then be regarded as the reference center, and the position of the load tip can be described with reference to the center of the load, which can help to describe the pose of the load. Both the center of the load and the load tip can be defined as the origin, providing corresponding coordinate reference systems {LC} and / or {LE}. These can be used interchangeably as the origin. When the load is considered to be a relatively rigid object, the load tip will move following the movement of the center of the load. In particular, in the case of a wind turbine blade, which is a rigid longitudinal object, as shown in FIG. 4, the blade center 16 as the center of the load {LC} and the blade root 17 as the load tip {LE} can be defined. Each of the blade center and the blade root again defines coordinate reference systems {BC} and {BR} respectively. As understood, using various sensor reference coordinates, the position of the load tip can be represented in the world coordinates {W} or with respect to the world coordinates {W}, or with respect to any other arbitrarily selected position on the crane or the ship or the load compensation system. Alternatively, the load tip can also be directly measured from a sensor 45 attached to the tool, or directly measured by a sensor 46 attached close to the load tip. The measurement via the sensor 45 from the tool 14 may be preferable for non-rigid objects where the motion of the load tip may not be easily determined from the motion of the center of the load, or when the detailed geometric shape of the load is not known. In such cases, the sensor 45 can be configured to measure the pose of the load end with respect to the sensor coordinate reference {45}, and then, through conversion via a GNSS / INS device, or inference or motion propagation through other sensors, and coordinate reference through to a sensor incorporating a GNSS / INS device capable of representing its own coordinates in world reference, represent this pose in world coordinates via one of the methods described above. The sensor 45 can be configured to remotely detect certain geometric features of the load and determine their relative pose with respect to {45}.This can be done, for example, by one or more cameras, lidars, or radars, or by any combination thereof, or by any other known method for determining the pose of a structure relative to a reference. Alternatively, the payload end pose can be directly measured by sensor 46 in a coordinate reference {46}, which can then be directly converted back to a world reference either via a dedicated GNSS / INS device as part of sensor 46 or via inference and / or motion propagation towards another sensor incorporating such a device as described above.

[0038]

[0048] Referring to FIG. 5, an example of a feature detection system 50 and features 51 present on the payload 12 is shown. The feature detection system 50 is configured to detect the features 51, track the movement of the features 51, and generate a relative movement signal indicative of the relative movement between the target, in this example the nacelle 2 and the payload 12. The feature detection system 50 includes a vision detector 52, in this embodiment a camera, and processing means 53 such as a PC, PLC, or other general-purpose processor, FPGA, or microprocessor. Instead of a camera such as a CCD or CMOS camera, the vision detection means may use one or more LIDAR sensors or one or more RADAR sensors or any combination thereof, or any other type of analog or computer-compatible vision means. The processing means 53 is configured to process the signals from the vision detector 52, perform the processing required to track the features 51, and generate a relative movement signal that can also be directly applied as an input to a compensation signal. The feature detection system 50 further includes a communication module 54, such as a WiFi device or a general cable network interface (router, switch, etc.), for transmitting signals and / or exchanging signals with at least one other component of the control system.

[0039]

[0049] The feature detection system 50 is positioned at the target 2, inside or above or near the nacelle 2 of FIG. 1 in this example. The camera 52 is mounted on a tripod 57 and positioned at a stable position on the inner floor 58 or other structural elements of the nacelle 2, and is directed such that the camera has an outward view towards the payload to be aligned with the target 2. Precise mounting and mounting devices are not relevant and can be carried out differently.

[0040]

[0050] Referring to FIG. 6, the perspective of the feature detection system 50 of FIG. 5 is shown, more specifically the perspective of the vision detector 52, looking outside the opening 59 formed by the mounting ring 60 of the nacelle where the blade is to be aligned and mounted. During the lifting operation, when the payload 12 is moved by the crane 11 or the LMCS for alignment with the target nacelle 2, the feature 51 presented on the payload blade 12 is detected by the camera 52 and the movement of the feature 51 will be tracked. During the hoisting operation, the LMCS or the crane will compensate for the motion of the payload due to wind, etc., as described above. Also, the target, in this example, the tower and / or the nacelle, may still experience motion due to wind, etc. As a result, the feature 51 may appear to move in front of the vision detector 52 regardless of whether the source of the movement is the payload or the target or both, and the vision detector will track the relative movement of the feature with respect to the target.

[0041]

[0051] Therefore, the movement of the feature 51 tracked by the feature detection system 50 represents the relative movement between the payload 12 and the target 2. This relative movement can then be directly applied as an input for controlling the pose of the payload, for example, via feedback control (visual servo), through the crane or the LMCS. However, since the absolute reference point of the payload can also be known from the reference sensor device 32, this relative movement can be represented in the world coordinates {W}. As a result, it can be used as a target setpoint for the control system 30. This enables the control system 30 to move the payload 12 in synchronization with the target 2.

[0042]

[0052] Still referring to FIG. 6, feature 51 is shown in more detail. In this example, it is a type ArUco or Charuco marker that enables the vision detector 52 to track the relative movement of the feature and, along with it, the relative movement of the load 12. The features on the load can include any set of geometric shapes on the load, any marker, decal or print, or visual identification thereon, or any other characteristic feature that can be recognized by computer vision and / or LIDAR or RADAR sensors. Additionally, the feature can be a structure or structural feature or characteristic of the load or a part thereof, or can even include a specific color and / or light intensity of the paint, surface treatment, surface roughness, or can even consist of them, or can be created and / or modulated by any other material or surface or geometric property in the backscatter information, and can be that of a structural element of the load, a specific passive or active marker, or any combination thereof.

[0043]

[0053] As can be understood, a setup opposite to FIG. 5 is also contemplated, where the feature is provided on the target and the feature detection system is provided on the load.

[0044]

[0054] Referring to FIG. 7, an example of a computer-implemented method for controlling the alignment of a load suspended from a crane with a target is illustrated. The method includes determining 701 the motion of the load in at least one degree of freedom and generating 702 at least one compensation signal indicative of the motion of the load. In response to the at least one compensation signal, a control signal is generated 703 for a crane and / or load motion compensation system LMCS to control the preferably absolute reference pose of the load within a reference coordinate system provided by a first reference sensor, e.g., the first, second, or third reference sensors 41, 42, or 43. The reference coordinate system can be the world coordinates {W} directly or by inference as described above. In some embodiments, depending on the configuration of the control system, e.g., if there is no separate dedicated controller and only one main controller, the compensation signal 702 can be directly obtained / processed as the control signal 703. For example, in other embodiments where the compensation signal is received directly by the main controller from a remote sensor, the generation 703 of the control signal requires additional processing. In still other embodiments, the main controller can receive data indicative of the motion of the load and generate the compensation signal as a target setpoint and as an input for generating 703 the control signal.

[0045]

[0055] This method further includes receiving 704, from a feature detection system such as feature detection system 50, a relative motion signal indicative of relative motion between a target and a load. The feature detection system detects features such as feature 51 and generates a relative motion signal by tracking the motion of the features relative to the feature detection system. Generally, the method further includes generating 706 a control signal for controlling a crane and / or a load motion compensation system LMCS to align and move the load in response to the relative motion signal. As can be understood, the generation of the control signals in steps 702 and 706 can be superimposed or combined, thereby providing a superposition of signals. Therefore, the order of execution is not necessarily fixed sequentially, and any combination of signals can be merged into a single signal. In this example, the method also includes generating 705 an alignment signal in response to the relative motion signal, and generating 706 a control signal for controlling the crane and / or the load motion compensation system LMCS is responsive to the alignment signal.

[0046]

[0056] Using the devices and methods as described heretofore, the load can even be aligned with the target, enabling the crane and / or the LMCS to move the load towards the target. Basically, the systems and methods described present the load and the target as being in a fixed alignment with each other, which means that relative motions such as rotation or translation of the target are mimicked through the control system such that the target maintains the same relative pose with respect to the target. This enables the operator to focus on the task of displacing the load towards the target by means of the manual control. The offset between the load and the target appears to the operator as "static" or "fixed". And the operator no longer needs to consider interfering motions of the target. Therefore, the operator can use the manual control to provide a displacement command to move the load towards the target.

[0047]

[0057] During operation, the moment and position at which the feature detection system detects a target and starts tracking provide relative movement from the moment of detection, and there may be an offset for alignment. In one embodiment, to close the offset during the step of moving the load to the target and starting installation, the control system includes a manual control unit 33 for the operator. This will enable the operator to close any remaining gaps due to the offset.

[0048]

[0058] Furthermore, the control system may include a human machine interface (HMI) for providing visual feedback of the alignment operation. The HMI will then be configured to display views or images captured by the feature detection system or, alternatively, for example, by one or more cameras. The operator can use the visual feedback during the final step to close the gap due to the offset. Alternatively, such feedback can be provided virtually by a 3D visualization or virtual or augmented reality display that can be combined with the camera feedback signal.

[0049]

[0059] In another embodiment, the control system may apply a pattern classification system to the view or image captured by the feature detection system to identify whether the load is at a position overlapping the target installation point.

[0050]

[0060] Referring to FIG. 8, an example of a control scheme of the expansion control system is illustrated. The initial set point Xdes is input at point 80 and corrected with respect to the ship position of the reference sensor 82 that senses the position of the ship 81. The input 80 is used by the main controller 83 to control the LMCS actuator 84 that moves the blade 85 to bring about a change in the blade position Xbl. Alternatively, the main controller 83 can control the crane to move the blade 85, or can do both. As an alternative to using S3 82, here, the relative motion signal of the feature detection system 52 can be directly used, for example, in a feedback control method such as visual servo. Alternatively, the offset calculator 88 processes the relative motion signal of the feature detection system 87, calculates a new set point, and corrects the blade position Xbl to a new position Xbl' having that set point, in the same manner as described in relation to FIG. 5. Also, in such an embodiment, then, the operator input from the manual control unit 89 can still be applied to correct the set point to Xbl'' to minimize the offset. The set point is then applied, for example, as a control signal to the LMCS actuator. They can be summed at the input 80 of a main controller (not shown).

[0051]

[0061] Referring to FIG. 9, which shows the same elements as those shown in FIG. 6, the load alignment system can additionally include a second feature 61 in addition to the feature 51 on the load. In FIG. 9, the second feature, which is the feature plate 61, is located within the view 63 or line of sight of the feature detection system, which in this embodiment is the visual detector 52. The feature plate 61 forms part of the load alignment system and is arranged within the nacelle 2, where the feature detection system is provided. The feature plate 61 is further arranged such that the feature detection system 52 detects the second feature 61 as a target reference point or as a lead towards a structural target reference point. In the example of FIG. 9, bolts 91 are provided on the blade instead of the holes 71.

[0052]

[0062] To achieve a complete alignment, the installation position of the load is positioned facing the corresponding target installation position, such as a bolt in a hole, and further movement may be required. This is for performing the assembly. In addition, here, the first feature 51, which is also embodied as a feature plate, and the second feature plate 61 require that certain conditions be met because the feature detection system 52 needs to be able to determine the geometric relationship between both the load and the structural parts of the target.

[0053]

[0063] Referring to FIG. 10, a load, in this example a part of the circular edge 90 of a wind turbine blade, having a bolt 91 extending from an edge 90 and engaging a hole in a corresponding circular edge of a target, in this example a nacelle of a wind turbine, is shown. In this example, the feature plate 51 is mounted on the bolt 91 by a clamp 92, and the clamp 92 enables easy mounting and disassembly before and / or after the merger of the blade and the nacelle. However, other means for mounting the feature plate 51 on the bolt 91 may be contemplated. Other structural elements on which the feature plate 51 may be mounted may be contemplated as long as the geometric relationship between the structural element and the feature plate is known or derivable or may be known or derivable. Or these may be inferred, for example, from CAD and design data of the load, the target, and / or the feature plate. Alternatively, the feature plate may be defined as one or more directly detectable visual features, such as holes or bolts detected by, for example, computer vision algorithms, lidar, radar, or other methods. Similarly, this also applies to the feature plate 61 to be mounted on the target. In other examples, for example, as in the example of FIG. 6, when both the load and the target include holes and the bolt is to be pushed through the holes of both the load and the target, the feature plates 51, 61 may be mounted on or near the holes 62, 71 in a fixed inferable geometric relationship. As an example of a geometric relationship, the structural relationship of the bolt and / or the hole may be used. This may be extracted, for example, from CAD data, drawings, design information, or other 2D, 3D, or dimensionless model data, so that it can be compared with the feature detection measurements.

[0054]

[0064] Regardless of the specific details of how the feature plates 51, 61 are installed, the locations and / or poses at which the feature plates are installed on the load or target, i.e., the positions and orientations, need to be known or at least inferable from the design. This is to understand the geometric relationship between the feature plates and the corresponding installation positions of the load and target. For example, the blade needs to be installed on the nacelle at a predetermined position and / or orientation.

[0055]

[0065] Using a load alignment system extended and arranged as described using a second feature, the offset calculator can be configured to use the target reference point and geometric relationships to determine the aligned pose of the load. It is the pose of the load 12 that allows the installation of the load on the target without further offset to be compensated. For example, in the example of FIG. 6, the mounting ring 60 is provided with bolt holes 62 that should be aligned with the bolt holes 71 on the mounting ring 70 of the blade 12. The aligned pose indicates that the bolt holes of the load and the target are aligned and will, for example, allow a through bolt to be guided through the holes. Thus, once the aligned pose of the load is determined, this can be applied, for example, stepwise when generating an alignment signal in response to a relative movement signal. The alignment signal may involve a trajectory planner and / or a trajectory controller and may calculate the alignment trajectory continuously in one step or for each calculation step.

[0056]

[0066] In this extended load alignment system of FIG. 9 including the second feature, the manual control unit 89 of FIG. 8 can instead be replaced by a trajectory controller configured to receive any input from the system. Alternatively, the trajectory controller can be used to “guide” a manual motion along a predetermined trajectory or a trajectory path calculated online. The trajectory controller obtains the output of an offset calculator and generates a trajectory to displace the load in a direction that engages the target. The trajectory controller outputs from the alignment system 50 that generates a path or one or more set points for the crane or the LMCS or both by generating an alignment signal in consideration of the aligned pose.

[0057]

[0067] Referring again to FIG. 9, a third feature 64 or feature plate may be provided to further strengthen the determination of the geometric relationship between the first feature 51 and the feature plate 61 and the feature detection system 52. A photograph showing the second feature 61 and the third feature 64 in a single view enables the determination of the pose offset of the feature detection system 52 relative to the target 2, or at least the relevant installation position of the target indicated by the pose inferable via the feature plate 61. In the example of FIG. 9 where the feature detection system 52 is positioned inside the wind turbine nacelle, the operator can simply take a photograph and digitally upload or provide it to the control system 30 by any means. Or alternatively, for the operator or computational means extracting relevant offsets from the photograph, such as the offset of {S64} relative to {S61}, by additional calculations known to those skilled in the art. Using the available photographs, and / or by knowing the relative offset between the local coordinate systems of both feature plates 61, 64, and by knowing the offset from the bolt hole 62 to the sensor location of the feature detection system 52, the relative offset from the camera or sensor frame of the feature detection system 52 to the structurally relevant location can be more accurately established. Photographs showing both features 61, 64 present on the target can be taken before performing the alignment process. Alternatively, they can be obtained or processed opportunistically. Additionally, in other embodiments, the relevant parameters can be input into the control system manually or by a secondary system.

[0058]

[0068] Referring to FIG. 11, another example of a method for controlling the alignment of a load suspended from a crane with a target is illustrated. The method includes providing a reference coordinate system 901 by a first sensor. The reference coordinate system can be the world coordinates {W}, either directly or by inference as described above. The method further includes providing a feature 902, such as a feature 51, on either the load 12 or the target 2, and providing a feature detection system 50 on the target 2 or the load 12, respectively. The method includes controlling, preferably the absolute reference pose of the load, within the reference coordinate system 904, and controlling the reference pose of the load 904 responds to at least one compensation signal. As will be appreciated, these steps of controlling the reference pose are performed in a continuous iterative manner. The method includes a feature detection system that detects features, tracks the movement of the features, and generates a relative movement signal indicating the relative movement between the target and the load 907. The method further includes generating an alignment signal 909 in response to the relative movement signal, and controlling the crane and / or the load motion compensation system to move the load in alignment with the target 910 in response to the alignment signal.

[0059]

[0069] As seen in FIG. 9, the step 904 of controlling the reference pose can include two further steps or sub-processes, namely, determining 905 the motion of the load in at least one, and preferably at least two, or more preferably at least three degrees of freedom, and generating 906 at least one compensation signal indicative of the motion of the load.

[0060]

[0070] Still referring to FIG. 9, an example of the enhanced method is illustrated. In addition, the method includes providing a second feature and preferably a third feature, such as second feature 61 and third feature 64. The second feature is provided at a location such that the feature detection system detects the second feature as a target reference point. Preferably, the third feature should also be detected as a target reference point or at least used to derive or infer related transformations. The method further includes calculating a load offset based on the target reference point and applying the calculated offset when generating an alignment signal. In the enhanced example, the method further includes generating a displacement signal in response to the calculated offset and / or an input from a manual control unit, and generating a control signal for controlling a crane and / or an LMCS for displacement of the load towards the target in response to the displacement signal.

[0061]

[0071] A control system having an extended load alignment system including a second and preferably a third feature, and a method for alignment corresponding to such a control system, can provide the benefit that it is possible to perform alignment of the load with the target while taking into account the offset, if any, from the moment the feature detection system detects the feature. This is due to the second feature and / or the third feature, for which world coordinates can be inferred from the position relative to other reference sensors, which makes it possible to determine the exact geometric relationship between all sensors, features, and structural elements of the load and the target. World coordinate system reference can be provided directly, for example, when a GNSS / INS device is provided to the feature detection system, as described above in connection with FIGS. 4 and 5.

[0062]

[0072] The present invention has been described above with reference to specific embodiments, but is not intended to be limited to the specific forms described herein. Rather, the present invention is limited only by the appended claims, and embodiments other than the above specific embodiments are equally possible within the scope of these appended claims.

[0063]

[0073] Furthermore, although exemplary embodiments have been described above in terms of some exemplary combinations of components and / or functions, it should be recognized that alternative embodiments may be provided by different combinations of members and / or functions without departing from the scope of the present disclosure. For example, the load motion compensation system may take a form different from that disclosed in, for example, WO2021002749A1. Additionally, it is particularly contemplated that specific features described either individually or as part of one of the embodiments can be combined with other individually described features or parts of other embodiments.

[0064]

[0074] The present disclosure further relates to embodiments reflected in the following clauses.

[0065] c1. A computer-implemented method for controlling the alignment of a load suspended from a crane with a target, the method comprising: determining (701) the motion of the load in at least one degree of freedom; generating (702) at least one compensation signal indicative of the motion of the load; generating (703) a control signal for a crane and / or a load motion compensation system (LMCS) to control a reference pose of the load in a reference coordinate system provided by a first reference sensor in response to the at least one compensation signal; receiving (704) from a feature detection system a relative motion signal indicative of a relative motion between the target and the load; generating (706) a control signal for controlling the crane and / or the load motion compensation system (LMCS) to move the load in alignment with the target in response to the relative motion signal; and a computer-implemented method.

[0066] c2. generating (705) an alignment signal in response to the relative motion signal Further comprising generating a control signal for controlling a crane and / or a load motion compensation system (LMCS) (706), which is a computer-implemented method according to clause c1, responsive to an alignment signal.

[0067] c3. A feature detection system that detects features provided on a load and generates a relative motion signal by tracking the motion of the features The computer-implemented method according to clause c1 or c2, further comprising.

[0068] c4. Generating a displacement signal in response to a calculated offset and / or an input from a manual control unit, and Generating a control signal for controlling a crane and / or an LMCS for displacement of a load relative to a target in response to the displacement signal The computer-implemented method according to any one of clauses c1 to c3, further comprising.

[0069] c5. A control box for controlling the alignment of a load suspended from a crane with a target, comprising At least one controller (34) configured to implement the computer-implemented method according to any one of clauses c1 to c4.

[0070] c6. A control system for controlling the alignment of a load suspended from a crane with a target, comprising At least one reference sensor (41, 42, 43) for providing a reference coordinate system ({S41}, {S42}, {S43}), and A load motion compensation system (LMCS) (35) for controlling a reference pose of a load (12) in the reference coordinate system ({S41}, {S42}, {S43}), where the LMCS (35) At least one motion sensor (41) configured to determine motion in at least one degree of freedom and generate at least one compensation signal indicating the motion of the load At least one motion compensation actuator (15) configured to control the pose of the load in response to at least one compensation signal, a load alignment system, where the load alignment system a first feature (51) disposed on the load (12) or on the target (2), a feature detection system (50) respectively disposed on the target (2) or on the load (12), configured to detect the feature (51), track the movement of the feature (51), and generate a relative movement signal indicating the relative movement between the target (2) and the load (12), at least one controller (34), where the at least one controller (34) generates an alignment signal in response to the relative movement signal, and generates a control signal for controlling the crane and / or the load motion compensation system (LMCS) to move the load in alignment with the target in response to the alignment signal, comprising a control system.

[0071] c7. The at least one controller generates a displacement signal in response to the calculated offset and / or an input from the manual control unit, and generates a control signal for controlling the crane and / or the load motion compensation system (LMCS) for the displacement of the load towards the target in response to the displacement signal, The control system according to clause c6, further configured to perform.

[0072] c8. The at least one controller a load motion compensation system (LMCS) controller (39) for generating an LMCS control signal, and / or an offset calculator (37, 88) for calculating an offset, and / or a crane controller (36) for generating a crane control signal, The control system according to clause c6 or c7, comprising.

[0073] c9. The control system includes a plurality of reference sensors, the plurality of reference sensors are arranged such that each sensor has a position represented in the coordinate system of at least one other reference sensor, at least one reference sensor provides world coordinates, The control system according to any one of clauses c6 to c8.

[0074] c10. The load motion compensation system (35) is configured to process a compensation signal and activate a motion compensation actuator for controlling the pose of the load at a reference pose, the control system according to any one of clauses c6 to c9.

[0075] c11. Further comprising a human machine interface (HMI), the human machine interface is configured to display a view captured by the feature detection system, and / or Further comprising a manual control unit for the operator, the control system according to any one of clauses c6 to c10.

[0076] c12. The load alignment system is a second feature arranged at the location where the feature detection system is provided such that the feature detection system detects the second feature as a target reference point, and a third feature preferably arranged on the feature detection system such that the second and third features can be captured in a single camera view and further comprising, at least one controller is configured to calculate an offset based on at least the first and second features, the control system according to any one of clauses c6 to c11.

[0077] c13. A method for controlling the alignment of a load suspended from a crane with a target, comprising providing a reference coordinate system by a first sensor (901), Providing features on the load or the target, and respectively providing a feature detection system on the target or the load (902); Controlling the reference pose of the load within the reference coordinate system (904); Here, the feature detection system detects features, tracks the movement of the features, and generates a relative movement signal indicating the relative movement between the target and the load (907); Generating an alignment signal in response to the relative movement signal (909); Controlling the crane and / or the load motion compensation system to move the load in alignment with the target in response to the alignment signal (910); A method comprising the above.

[0078] c14. Controlling the reference pose (704) includes: Determining the motion of the load in at least two degrees of freedom (905); Generating at least one compensation signal indicating the motion of the load (906); The method according to clause c13, wherein controlling the reference pose of the load responds to at least one compensation signal.

[0079] c15. Providing a second feature, and more preferably a third feature, so that the feature detection system (50) detects the second feature and preferably the third feature as the target reference point (903); The method according to clause c13 or c14, comprising the above.

[0080] c16. Generating a displacement signal in response to the calculated offset and / or an input from the manual control unit; Controlling the crane and / or the LMCS for the displacement of the load towards the target in response to the displacement signal; The method according to any one of clauses c13 to c15, further comprising the above.

[0081] c17. A crane comprising the control system according to any one of clauses c6 to c12.

[0082] A ship comprising a crane and a control system according to any one of clauses c6 to c12.

[0083] A computer program product comprising instructions which, when the program is executed by a computer, cause the computer to perform the method according to any one of clauses c1 to c4 or clauses c13 to c16.

[0084] A computer-readable data carrier storing the computer program product according to clause c19.

Claims

1. A control system for controlling motion compensation of a load (12) that is suspended from a crane (11) and moves relative to a fixed external reference system ({W}), and for simultaneously controlling the alignment of the load (12) with respect to a target (2), wherein the control system is: A cargo motion compensation system (LMCS) (35) for controlling the reference pose of the cargo (12) with respect to the external reference system ({W}), wherein the LMCS (35) is At least one motion sensor (41, 42, 43, 44, 45) is configured to determine the movement of the load (12) in at least one degree of freedom relative to the external reference system ({W}) and to generate at least one compensation signal (702) indicating the motion of the load, The system comprises the external reference system ({W}) and at least one LMCS actuator (15, 84) configured to control the pause of the load in response to at least one compensation signal (702), A cargo positioning system, and here, the cargo positioning system is The first feature (51) positioned on / in the cargo (12) or on / in the target (2), The system comprises a feature detection system (50) positioned on / inside the target (2) or on / inside the cargo (12), respectively, which is configured to detect and track the movement of the first feature (51) and to generate a relative motion signal (907) indicating the relative movement between the target (2) and the cargo (12), The control system is equipped with, The system generates an alignment signal (905) in response to the relative motion signal (907), and the alignment signal is different from the compensation signal (702). In response to the alignment signal (705), a control signal (706) is generated for controlling the crane and / or at least one of the LMCS actuators (84) to move the load in alignment with the target. A control system comprising at least one controller (34, 39) configured to perform the following.

2. At least one of the motion sensors (41, 42, 43, 44, 45) is configured to determine the absolute motion of a reference point ({BR}) on the load (12) relative to the fixed external reference system ({W}) and to generate the compensation signal (702) based on the absolute motion. The feature detection system (50) is configured to detect and track the first feature (51) located on the load (12) or the target (2), and to generate the relative motion signal (907) indicating the relative motion between the reference points ({BR}) on the load (12) with respect to a target reference frame ({S7}) associated with the target (2), and the control system is configured to derive the control signal (706) for controlling the crane and / or at least one of the LMCS actuators (84) used to move the load (12) in synchronization with the target (2), by representing the relative motion signal (907) in world coordinates based on the determined pose of the reference points ({BR}) with respect to the external reference system ({W}) and the measured relative pose between the reference points ({BR}) with respect to the local reference frame ({S7}).

3. The control system according to claim 1, wherein the control system (30) is configured to combine the compensation signal (702) and the alignment signal (705) to produce a superimposed or merged signal (706) of the signals, and to control the crane (11) and / or at least one of the LMCS actuators (84) to hold the load (12) in alignment with the target by simulating relative rotation and translation between the load (12) and the target (2) through dynamically repositioning and holding the load (12) in essentially the same relative pose including a static offset with the target.

4. The feature detection system (50) is A visual detector (52) having a field of view (63) positioned on or in the target (2) and oriented toward the first feature (51) positioned on / in the load (12), To enable tracking of the first feature (51) and generation of the relative motion signal (907), a processor (53) is configured to process the detector signal received from the visual detector (52) and The control system according to claim 1, including the following:

5. The cargo is a wind turbine blade (12) suspended from the crane (11) installed on the ship (9), and the wind turbine blade (12) is movable relative to the external reference system ({W}). The aforementioned target is the nacelle (2) of the wind turbine generator (1), The control system according to claim 1, wherein the wind turbine blade (12) is elongated, has a blade root (17) defined at one distal end (90), and is associated with a blade root reference frame ({BR}).

6. The control system according to claim 5, wherein the feature detection system (50) has a visual detector (52) positioned inside the nacelle (2) in a fixed pose, mounted, for example, on a tripod (57) positioned on the floor inside the nacelle (2), the visual detector (52) has a field of view (63) directed outward through the mounting ring (60) of the nacelle (2), and looks toward the first feature (51) provided on the blade root (17) in a fixed position with respect to the blade root reference frame ({BR}), and optionally the first feature (51) is an ArUco marker, a ChArUco marker, or a plate having a plurality of structural features in a fixed geometric arrangement known to the control system.

7. The control system according to claim 6, wherein the cargo alignment system further includes a feature plate (61) located inside the nacelle (2) and within the field of view (63) of the visual detector (52), and the feature detection system (50) is configured to detect the feature plate (61) as a target reference point associated with the local reference system ({S7}) of the visual detector (52) located in a fixed pose inside the nacelle (2).

8. The wind turbine blade (12) includes a blade mounting member (91), such as a bolt, provided at the distal end (90), and the blade mounting member (91) is configured to be connected to a corresponding mounting member (62), such as a bolt hole, provided at the mounting position (60) in the nacelle (2). The control system according to claim 5, wherein the feature plate (51) is removably mounted on the blade mounting member (91) by a clamp (92) so as to allow the feature plate (51) to be removed after the wind turbine blade (12) has been fixed to the nacelle (2).

9. At least one of the controllers (34, 39) To generate a displacement signal in response to the calculated offset and / or input from the manual control unit (33), In response to the displacement signal, a control signal is generated for controlling the crane and / or the load motion compensation system (LMCS) for the displacement of the load toward the target. The control system according to claim 1, further configured to perform the following:

10. At least one of the controllers (34, 39) An LMCS controller (39) for generating LMCS control signals, and / or An offset calculator (37, 88) for calculating the offset, and / or, Crane controller (36) for generating crane control signals The control system according to claim 1, comprising:

11. The control system comprises a plurality of reference sensors (41, 42, 43, 44, 45), and the plurality of reference sensors are arranged such that each sensor has a position represented in the coordinate system of at least one other reference sensor. At least one reference sensor provides world coordinates. The control system according to claim 1.

12. The system further comprises a human-machine interface (HMI) (31), the human-machine interface being configured to display a view captured by the feature detection system, and / or The control system according to claim 1, further comprising a manual control unit for an operator.

13. The aforementioned cargo positioning system is The second feature (61) is located at the location where the feature detection system (50) is provided, so that the feature detection system detects the second feature as a target reference point. The control system according to claim 1, further comprising, wherein at least one of the controllers is configured to calculate an offset based on at least the first and second features.

14. The cargo positioning system is The second feature (61) is located at the location where the feature detection system (50) is provided, so that the feature detection system detects the second feature as a target reference point. The controller further comprises at least one of the controllers configured to calculate an offset based on at least the first and second features, The control system according to claim 6, wherein the feature detection system (50) comprises a third feature (64) positioned on the visual detector (52) at a location that enables the second feature (61) and the third feature (64) to be captured in a single image acquired by an operator located in or within the nacelle (2), and the control system (30) is configured to receive the image containing both the second feature (61) and the third feature (64) and to derive from the image the pose offset of the visual detector (52) relative to the nacelle (2) and the second feature (61).

15. A method for controlling the alignment of a load suspended from a crane with respect to a target, Determining the motion of the load in at least one degree of freedom (701), To generate at least one compensation signal indicating the motion of the cargo (702), In response to at least one of the compensation signals, generate a control signal for a crane and / or load motion compensation system (LMCS) for controlling the reference pose of the load in a reference coordinate system provided by a first reference sensor (703), The feature detection system receives a relative motion signal indicating the relative movement between the target and the cargo (704), (706) To generate a control signal for controlling the crane and / or load motion compensation system (LMCS) to move the load in alignment with the target in response to the relative motion signal. A method that includes [a certain feature].

16. (705) Generating an alignment signal in response to the relative motion signal. The method of claim 15, further comprising (706) generating the control signal for controlling the crane and / or load motion compensation system (LMCS) in response to the alignment signal.

17. The feature detection system detects features provided on the cargo and generates the relative motion signal by tracking the movement of the features. The method according to claim 15, further comprising:

18. To generate a displacement signal in response to the calculated offset and / or input from the manual control unit, In response to the displacement signal, a control signal is generated for controlling the crane and / or LMCS for the displacement of the load relative to the target. The method according to claim 15, further comprising:

19. A method for controlling the alignment of a load suspended from a crane with respect to a target, The first sensor provides a reference coordinate system (901), (902) Provide a feature on the cargo or on the target, and provide a feature detection system on the target or on the cargo, respectively. Controlling the reference pose of the cargo within the reference coordinate system (904), Here, the feature detection system detects the feature, tracks the movement of the feature, and generates a relative motion signal indicating the relative movement between the target and the cargo (907), (909) generating an alignment signal in response to the relative motion signal, (910) Control the crane and / or load motion compensation system to move the load in alignment with the target in response to the alignment signal. A method that includes [a certain feature].

20. Controlling the aforementioned reference pose (704) Determining the motion of the load in at least two degrees of freedom (905), The method according to claim 19, comprising generating (906) at least one compensation signal indicating the motion of the load, wherein controlling the reference pose of the load is in response to at least one of the compensation signals.

21. The feature detection system is provided on the second feature, and more preferably the third feature, so that the feature detection system can detect the second feature, and more preferably the third feature, as a target reference point (903) The method according to claim 19, comprising:

22. To generate a displacement signal in response to the calculated offset and / or input from the manual control unit, In response to the displacement signal, the crane and / or LMCS are controlled for the displacement of the load toward the target. The method according to claim 19, further comprising:

23. A crane comprising the control system described in any one of claims 1 to 14.

24. A ship comprising a crane and a control system according to any one of claims 1 to 14.

25. A computer program product comprising, when the program is executed by a computer, an instruction causing the computer to perform the method described in any one of claims 15 to 22.

26. A computer-readable data carrier storing the computer program product described in claim 25.

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