Pile gripper positioning system, dynamic positioning system, single pile installation ship and corresponding method

Abstract

The present invention relates to a pile gripper positioning system for a pile gripper configured to be disposed on a vessel to engage with a single pile during a single pile installation process, where the pile gripper positioning system comprises:-an actuator system for applying a force to the pile gripper to position the pile gripper relative to the vessel,-a measurement system for measuring the position of the pile gripper relative to the vessel, the present invention relates to a pile gripper comprising:-an actuator system for determining a position of a single pile in the pile gripper relative to a vessel, and-a pile gripper control unit for driving the actuator system as a function of a desired position of the single pile and an actual position of the single pile measured by a measurement system, where the pile gripper control unit is configured to receive a signal representative of the position of the vessel, during at least a portion of the single pile installation process, the pile gripper control unit is configured to determine a drive signal for the actuator system to compensate for at most a portion of the deviation of the position of the vessel from the desired position of the vessel, and wherein during at least a portion of the single pile installation process, the actuator system is configured to actuate the actuator system. A pile gripper control unit for driving the actuator system is configured to drive the actuator system according to a desired position of the single pile and an actual position of the single pile measured by the measurement system, and to compensate for at most a portion of the deviation of the position of the vessel from the desired position of the vessel with the drive signal.

Description

Technical Field

[0001] The present invention relates to the installation of a monopile as part of the installation process of a wind turbine, in particular an offshore wind turbine. In known methods for installing an offshore wind turbine, a foundation in the form of a monopile is first installed by driving the monopile into the seabed, and then the wind turbine is installed on the monopile, either by installing the wind turbine as a whole at once or by assembling the wind turbine partially on the monopile. Background Art

[0002] There is a trend towards larger wind turbines, and it is expected that offshore wind turbines will be installed at greater depths than currently encountered. Both of these situations result in larger and heavier foundations. Therefore, it is expected that monopiles greater than 100 meters will soon need to be installed, perhaps 120 meters or more. The weight of such monopiles may be greater than 1000 mt, perhaps 1300 mt or more.

[0003] In order to save time during the installation process, it is preferred to use a floating vessel rather than a jack-up vessel. Such a floating vessel typically includes a lifting crane for suspending the monopile therefrom and a pile gripper for engaging the monopile, wherein the lifting crane and the pile gripper cooperate to lower the monopile into the sea using a pile gripper positioning system or the like. Typically, the vessel also includes a dynamic positioning system to position the vessel during the lowering of the monopile.

[0004] When the dynamic positioning system and the pile gripper positioning system function independently of each other, stability problems may arise wherein the dynamic positioning system becomes unstable.

[0005] In order to solve these and other problems, it has been proposed in the international patent publication WO2020 / 145825 to interconnect the control systems of different actuators of the vessel, such as the dynamic positioning system and the pile gripper positioning system. One of the disclosed interconnections is to use instructions for dynamic actions, i.e. signals sent directly or indirectly by the pile gripper positioning system to the actuators, to determine the forces intended to be applied to the vessel, subsequently determine the compensating actions, and control the dynamic positioning system to apply the compensating actions. This is also known as feedforward control.

[0006] However, applicants have found that this type of feed-forward control is not sufficient to provide stability under all desired operating conditions. Summary of the invention

[0007] In view of the above, an object of the present invention is to improve the stability of a monopile installation process using a floating vessel having a dynamic positioning system and a pile gripper positioning system.

[0008] According to a first aspect of the present invention, there is provided a pile gripper positioning system for a pile gripper configured to be disposed on a vessel to engage with a monopile during a monopile installation process, wherein the pile gripper positioning system comprises:

[0009] - an actuator system for applying a force to the pile gripper to position the pile gripper relative to the vessel,

[0010] - a measuring system to determine the position of the monopile in the gripper relative to the vessel, and

[0011] - a pile gripper control unit for driving the actuator system according to the desired position of the monopile and the actual position of the monopile measured by the measuring system,

[0012] wherein the pile gripper control unit is configured to receive a signal representing the position of the vessel,

[0013] wherein during at least a portion of the monopile installation process the pile gripper control unit is configured to determine a drive signal for the actuator system to compensate for at most a portion of a deviation of the vessel's position from a desired position of the vessel,

[0014] and wherein, at least during said part of the monopile installation process, the pile gripper control unit for driving the actuator system is configured to drive the actuator system in dependence on a desired position of the monopile and an actual position of the monopile measured by the measuring system and to compensate with the drive signal at most a part of a deviation of the position of the vessel from the desired position of the vessel.

[0015] According to a first aspect of the invention, the invention is based on the recognition that when a pile gripper and a corresponding pile gripper positioning system are configured to fully compensate for vessel motion, stability problems may arise since full compensation may apply relatively large forces to the vessel, thereby forcing the vessel away from its desired position, thus requiring more compensation. This may result in unstable behavior during at least some parts of the monopile installation process. By only partially compensating for vessel motion, and thus allowing the position of the monopile to deviate from its desired position, the forces applied by the pile gripper to the vessel may be limited to prevent unstable behavior.

[0016] Thus, by only partially compensating for the motion of the vessel, the set point for the pile gripper (and thus the monopile) is intentionally changed from the desired position to the adjusted position, and the pile gripper control unit is then configured to control the actuator system using this changed set point. However, there is always some type of set point, and the pile gripper control unit always forces the actual position to be the same as the position represented by the set point, whether the position is the desired position or is deliberately selected to be different from the desired position. Those skilled in the art will recognize that this intentional change of the set point is not related to any undesirable deviations or tolerances that may be inherent in the control system, nor to measures to reduce the applied force and prevent damage. These measures can be applied as a supplement to the present invention, but do not change the fact that the control system has a different set point for the position of the pile gripper and attempts to meet this set point rather than the original desired set point within the boundaries that may have been set by the force limiting circuit. The present invention is also independent of the uncontrolled state when the pile gripper is within a certain desired position range.

[0017] It should be explicitly pointed out that the position of a monopile in a pile gripper may alternatively or additionally refer to the position of a part of the monopile and / or the orientation of the monopile or a part thereof.

[0018] It should also be pointed out here that the position of a ship may alternatively or additionally refer to the position of a part of the ship and / or the orientation of the ship or a part thereof.

[0019] It should also be explicitly pointed out that determining the drive signal for the actuator system to compensate for at most a portion of the deviation of the vessel's position from the desired position of the vessel means that at least a non-zero portion of the deviation of the vessel's position from the desired position is ignored or discarded, directly or indirectly, by multiplying by a factor less than 1 or by subtracting a non-zero value.

[0020] The monopile installation process mentioned may include multiple stages, including but not limited to:

[0021] - the suspension phase, in which the monopile is suspended above the horizontal plane on a lifting crane and engaged by a pile gripper,

[0022] - the lowering phase, in which the monopile is suspended from the lifting crane and engaged by the pile grippers, and the lower end of the monopile is in the water but above the seabed,

[0023] - the seabed penetration phase, in which the monopile is suspended from a lifting crane and engaged by a pile gripper, and the lower end of the monopile has been driven into the seabed,

[0024] - The driving phase, in which the monopile is engaged by a pile gripper and driven into the seabed using a hammer or the like.

[0025] In one embodiment, at least part of the monopile installation process includes at least part of a seabed penetration phase.

[0026] In one embodiment, at least part of the monopile installation process includes at least part of a descent phase, such as the part of the descent phase just before the seabed penetration phase, wherein the lower end of the monopile is just above the seabed for penetration into the seabed.

[0027] In one embodiment, a ratio is defined between the compensated portion of the deviation of the vessel's position from the desired position of the vessel and the deviation of the vessel's position from the desired position of the vessel (ie the total deviation of the vessel's position from the desired position of the vessel).

[0028] In one embodiment, the ratio or the non-zero value to be subtracted depends on one or more of the following parameters:

[0029] - weight of a single pile,

[0030] - length of the single pile,

[0031] - the inclination of the pile with respect to the vertical,

[0032] - the length of the hoisting cable between the lifting crane and the monopile,

[0033] - Orientation of the hoisting cables between the lifting crane and the monopile,

[0034] - the length of the pile below the gripper,

[0035] - the length of the pile above the gripper,

[0036] - the length of the pile between the gripper and the seabed,

[0037] - water depth, i.e. the distance between the sea bottom and the water surface,

[0038] - the distance between the point where the lifting rope leaves the lifting crane and the pile gripper,

[0039] - the distance between the lower end of the monopile and the seabed,

[0040] - the distance between the point where the lifting rope leaves the lifting crane and the seabed,

[0041] - the distance between the pile gripper and the seabed,

[0042] - the ratio between the length of the monopile below the gripper and the length of the monopile above the gripper,

[0043] - the ratio between the length of the monopile above the gripper and the length of the monopile between the gripper and the seabed,

[0044] - the location of the pile's centre of gravity, and

[0045] - The tension in the hoisting cables between the lifting crane and the monopile.

[0046] In one embodiment, during at least part of the seabed penetration phase, the pile gripper control unit is configured such that the ratio increases with increasing penetration depth of the lower end of the monopile, or the non-zero value to be subtracted decreases with increasing penetration depth of the lower end of the monopile.

[0047] In one embodiment, during at least a part of the seabed penetration phase, the pile gripper control unit is configured such that the ratio is linearly related to the penetration depth of the lower end of the monopile.

[0048] In one embodiment, during at least part of the lowering phase, the pile gripper control unit is configured such that the ratio is set to the distance between the position where the hoisting rope leaves the lifting crane divided by the distance between the position where the hoisting rope leaves the lifting crane and the seabed.

[0049] According to a second aspect of the invention there is provided a dynamic positioning system for a vessel, wherein the vessel comprises a pile gripper for engaging with a monopile during a monopile installation process, wherein the dynamic positioning system comprises:

[0050] - an actuator system for applying forces to the boat to position the boat,

[0051] - a surveying system to measure the ship's position, and

[0052] - a dynamic positioning control unit for driving the actuator system according to the desired position of the vessel and the actual position of the vessel measured by the measurement system,

[0053] wherein the dynamic positioning control unit is configured to determine a signal representing a difference between a desired position of the vessel and an actual position of the vessel,

[0054] And wherein, during at least a portion of the monopile installation process, the dynamic positioning control unit is configured to output a signal representative of at most a portion of the difference.

[0055] It should be explicitly pointed out here that said difference between the desired position and the actual position of the ship may alternatively be referred to as a deviation of the position of the ship from the desired position of the ship.

[0056] It should also be pointed out here that the position of a ship may alternatively or additionally refer to the position of a part of the ship and / or the orientation of the ship or a part thereof.

[0057] It should also be explicitly pointed out that a portion of the difference between the desired position of the ship and the actual position of the ship means that at least a non-zero portion of said difference is ignored or discarded directly or indirectly by multiplying by a factor less than 1 or by subtracting a non-zero value.

[0058] The monopile installation process mentioned may include multiple stages, including but not limited to:

[0059] - the suspension phase, in which the monopile is suspended above the horizontal plane on a lifting crane and engaged by a pile gripper,

[0060] - the lowering phase, in which the monopile is suspended from the lifting crane and engaged by the pile grippers, and the lower end of the monopile is in the water but above the seabed,

[0061] - the seabed penetration phase, in which the monopile is suspended from a lifting crane and engaged by a pile gripper, and the lower end of the monopile has been driven into the seabed,

[0062] - The driving phase, in which the monopile is engaged by a pile gripper and driven into the seabed using a hammer or the like.

[0063] In one embodiment, at least part of the monopile installation process includes at least part of a seabed penetration phase.

[0064] In one embodiment, at least part of the monopile installation process includes at least part of a descent phase, such as the part of the descent phase just before the seabed penetration phase, wherein the lower end of the monopile is just above the seabed for penetration into the seabed.

[0065] In one embodiment, a ratio is defined between the outputted difference and the total difference between the desired position and the actual position of the vessel.

[0066] In one embodiment, the ratio or the non-zero value to be subtracted depends on one or more of the following parameters:

[0067] - weight of a single pile,

[0068] - length of the single pile,

[0069] - the inclination of the pile with respect to the vertical,

[0070] - the length of the hoisting cable between the lifting crane and the monopile,

[0071] - Orientation of the hoisting cables between the lifting crane and the monopile,

[0072] - the length of the pile below the gripper,

[0073] - the length of the pile above the gripper,

[0074] - the length of the pile between the gripper and the seabed,

[0075] - water depth, i.e. the distance between the sea bottom and the water surface,

[0076] - the distance between the point where the lifting rope leaves the lifting crane and the pile gripper,

[0077] - the distance between the lower end of the monopile and the seabed,

[0078] - the distance between the point where the lifting rope leaves the lifting crane and the seabed,

[0079] - the distance between the pile gripper and the seabed,

[0080] - the ratio between the length of the monopile below the gripper and the length of the monopile above the gripper,

[0081] - the ratio between the length of the monopile above the gripper and the length of the monopile between the gripper and the seabed,

[0082] - the location of the pile's centre of gravity, and

[0083] - The tension in the hoisting cables between the lifting crane and the monopile.

[0084] In one embodiment, during at least part of the seabed penetration phase, the dynamic positioning control unit is configured such that the ratio increases with increasing penetration depth of the lower end of the monopile, or the non-zero value to be subtracted decreases with increasing penetration depth of the lower end of the monopile.

[0085] In one embodiment, during at least a part of the seabed penetration phase, the dynamic positioning control unit is configured such that the ratio is linearly related to the penetration depth of the lower end of the monopile.

[0086] In one embodiment, during at least part of the descent phase, the dynamic positioning control unit is configured such that the ratio is set to the distance between the location where the hoisting rope leaves the lifting crane divided by the distance between the location where the hoisting rope leaves the lifting crane and the seabed.

[0087] According to a third aspect of the present invention, there is provided a vessel for performing a monopile installation process, the vessel comprising:

[0088] - Hull,

[0089] - Pile grippers, arranged on the hull for engaging monopiles,

[0090] - Dynamic Positioning Systems, used to locate the vessel, and

[0091] - Pile gripper positioning system, used to position a monopile using a pile gripper,

[0092] wherein the dynamic positioning system is configured to determine the position of the vessel,

[0093] And wherein, during at least a portion of the monopile installation process, the vessel is configured to operate the pile gripper positioning system to at most partially compensate for a deviation of the determined position of the vessel from a desired position of the vessel.

[0094] In one embodiment, the dynamic positioning system is configured to provide the determined position of the vessel to a pile gripper positioning system, wherein the pile gripper positioning system is a pile gripper positioning system according to the first aspect of the invention.

[0095] In one embodiment the dynamic positioning control unit is a dynamic positioning control unit according to the second aspect of the invention, wherein the pile gripper positioning system is configured to receive a signal representative of at most a part of said difference to at most partially compensate for a deviation of the determined position of the vessel from the desired position of the vessel.

[0096] In one embodiment, the vessel comprises an overall control unit, wherein the pile gripper positioning system is configured to receive a signal representing the position of the vessel from the dynamic positioning system to determine a drive signal for the actuator system to compensate for at most a portion of a deviation of the position of the vessel from a desired position of the vessel, and to output the drive signal to the pile gripper positioning system to compensate at most a portion of a deviation of the determined position of the vessel from the desired position of the vessel.

[0097] According to a fourth aspect of the invention there is provided a method for installing a monopile, wherein the method utilizes a vessel, the vessel comprising a dynamic positioning system for positioning the vessel and a pile gripper for engaging the monopile, and wherein the method comprises the following steps:

[0098] a. lowering the monopile towards the seabed or into the seabed while the monopile is engaged with the pile gripper,

[0099] b. determine the deviation of the ship's position from the ship's desired position, and

[0100] c. Using pile grippers to at most partially compensate for the deviation.

[0101] In one embodiment, the vessel comprises a lifting crane to suspend the monopile from the lifting crane.

[0102] In one embodiment, the method is performed while the monopile is suspended by a lifting crane.

[0103] In one embodiment, the method is performed during a portion of a monopile installation process.

[0104] In one embodiment, the method is performed during at least part of a seabed penetration phase in which the monopile is suspended from a lifting crane and engaged by a pile gripper, and the lower end of the monopile has penetrated the seabed.

[0105] In one embodiment, the method is performed during at least a portion of a lowering phase in which the monopile is suspended from a lifting crane and engaged by a pile gripper, with the lower end of the monopile in the water but above the seabed.

[0106] According to a fifth aspect of the present invention, there is provided a dynamic positioning system for a vessel, wherein the vessel comprises a lifting crane for lifting a monopile and a pile gripper for engaging with the monopile, the lifting crane and the pile gripper being configured to cooperate in lowering the monopile into the sea, wherein the dynamic positioning system comprises:

[0107] - an actuator system for applying forces to the boat to position the boat,

[0108] - measurement systems to measure the position of the ship,

[0109] - a dynamic positioning control unit for driving the actuator system according to the desired position of the vessel and the actual position of the vessel measured by the measurement system,

[0110] Wherein the dynamic positioning control unit is configured to receive a signal representing a force applied by the pile gripper to the vessel, and wherein the dynamic positioning control unit is configured to use a portion of said signal as a feed-forward signal to drive the actuator system.

[0111] The invention according to the fifth aspect is based on the recognition that the apparent improvement over WO2020 / 145825 by using the actual force applied to the vessel by the pile grippers rather than the expected force to be applied by the pile grippers is not sufficient to improve stability in all circumstances, but that stability is indeed improved by using a portion of the actual force applied by the pile grippers as a feed-forward signal.

[0112] It should be explicitly pointed out here that the position of a ship may alternatively or additionally refer to the position of a part of the ship and / or the orientation of the ship or a part of the ship.

[0113] It should also be explicitly pointed out that using a portion of the signal representative of the force applied by the pile gripper to the vessel means that at least non-zero portions of the signal are ignored or discarded by multiplying by a factor smaller than 1 or by subtracting non-zero values.

[0114] In one embodiment, the ratio between the portion of the signal used as feed-forward signal and the total signal received is between 0.4 and 0.9, preferably between 0.5 and 0.7, such as 0.6.

[0115] The monopile installation process can include multiple stages, including but not limited to:

[0116] - the suspension phase, in which the monopile is suspended above the horizontal plane on a lifting crane and engaged by a pile gripper,

[0117] - the lowering phase, in which the monopile is suspended from the lifting crane and engaged by the pile grippers, and the lower end of the monopile is in the water but above the seabed,

[0118] - the seabed penetration phase, in which the monopile is suspended from a lifting crane and engaged by a pile gripper, and the lower end of the monopile has been driven into the seabed,

[0119] - The driving phase, in which the monopile is engaged by a pile gripper and driven into the seabed using a hammer or the like.

[0120] In one embodiment, the ratio between the portion of the signal used as feed-forward signal and the total signal received or the non-zero value to be subtracted depends on the stage of the monopile installation process.

[0121] In one embodiment, the use of only a portion of the signal representing the force applied by the pile gripper to the vessel (eg a ratio below 1) or a non-zero value to be subtracted is applied only during the descent phase and / or the seabed penetration phase.

[0122] In one embodiment, the ratio between the portion of the signal used as feedforward signal and the total signal received, or the non-zero value to be subtracted, depends on one or more of the following parameters:

[0123] - weight of a single pile,

[0124] - length of the single pile,

[0125] - the inclination of the pile with respect to the vertical,

[0126] - the length of the hoisting cable between the lifting crane and the monopile,

[0127] - Orientation of the hoisting cables between the lifting crane and the monopile,

[0128] - the length of the pile below the gripper,

[0129] - the length of the pile above the gripper,

[0130] - the length of the pile between the gripper and the seabed,

[0131] - the ratio between the length of the monopile below the gripper and the length of the monopile above the gripper,

[0132] - the ratio between the length of the monopile above the gripper and the length of the monopile between the gripper and the seabed,

[0133] - the location of the pile's centre of gravity, and

[0134] - The tension in the hoisting cables between the lifting crane and the monopile.

[0135] In one embodiment, the ratio between the portion of the signal used as feedforward signal and the total signal received depends on the length of the monopile below the gripper or the length of the monopile between the gripper and the seafloor and on the length of the monopile above the gripper. In one embodiment, this dependency may apply only during the seabed penetration phase.

[0136] In one embodiment, during the seabed penetration phase, the dynamic positioning system is configured to determine the ratio α between the portion of the signal used as feedforward signal and the total signal received using the following equation:

[0137] α = a / (a ​​+ b)

[0138] Where a is the length of the monopile above the gripper and b is the length of the monopile below the gripper, or the length of the monopile between the gripper and the seabed.

[0139] In one embodiment, the dynamic positioning system is configured to receive input that allows the determination of parameters a and b. This input may include one or more of the following information:

[0140] - a measurement signal representing parameter a,

[0141] - the measurement signal representing parameter b,

[0142] - the total length of the treated pile,

[0143] - a measurement signal representing the (vertical) position of the hook from which the monopile is suspended, and

[0144] - (Average) water depth.

[0145] According to a sixth aspect of the present invention, there is provided a pile gripper positioning system for a pile gripper configured to be disposed on a vessel to engage a monopile suspended by a lifting crane of the vessel, wherein the pile gripper positioning system comprises:

[0146] - an actuator system for applying a force to the pile gripper to position the pile gripper relative to the vessel,

[0147] - a measuring system to determine the position of the monopile in the pile gripper,

[0148] - a pile gripper control unit for driving the actuator system according to the desired position of the monopile and the actual position of the monopile measured by the measuring system,

[0149] wherein the measuring system is further configured to determine the force applied by the pile gripper to the vessel,

[0150] And wherein the pile gripper control unit is configured to output a signal representative of a portion of the force applied by the pile gripper to the vessel as measured by the measurement system.

[0151] It should be clearly pointed out here that the position of a pile clamp may alternatively or additionally refer to the position of a part of the pile clamp and / or the orientation of the pile clamp or a part thereof. Furthermore, the position of a monopile in a pile clamp may alternatively or additionally refer to the position of a part of the monopile and / or the orientation of a part thereof.

[0152] It should also be explicitly pointed out that outputting a portion of the signal representative of the force applied by the pile gripper to the vessel means that at least a non-zero portion of said signal is ignored or discarded by multiplying by a factor less than 1 or by subtracting a non-zero value.

[0153] In one embodiment, the ratio between the output signal and the signal representing the force applied by the pile gripper to the vessel as measured by the measurement system is between 0.4 and 0.9, preferably between 0.5 and 0.7, such as 0.6.

[0154] In one embodiment the ratio between the output signal and the signal representing the force applied by the pile gripper to the vessel as measured by the measurement system or the non-zero value to be subtracted depends on the stage of the monopile installation process as described above for the fifth aspect of the invention.

[0155] In one embodiment outputting only a portion (eg a ratio below 1) of the signal representing the force applied by the pile gripper to the vessel measured by the measurement system or a non-zero value to be subtracted is applied only during the descent phase and / or the seabed penetration phase.

[0156] In one embodiment, the ratio between the output signal and the signal representing the force applied by the pile gripper to the vessel as measured by the measurement system, or the non-zero value to be subtracted, depends on one or more of the following parameters:

[0157] - weight of a single pile,

[0158] - length of the single pile,

[0159] - the inclination of the pile with respect to the vertical,

[0160] - the length of the hoisting cable between the lifting crane and the monopile,

[0161] - Orientation of the hoisting cables between the lifting crane and the monopile,

[0162] - the length of the pile below the gripper,

[0163] - the length of the pile above the gripper,

[0164] - the length of the pile between the gripper and the seabed,

[0165] - the ratio between the length of the monopile below the gripper and the length of the monopile above the gripper,

[0166] - the ratio between the length of the monopile above the gripper and the length of the monopile between the gripper and the seabed,

[0167] - the location of the pile's centre of gravity, and

[0168] - The tension in the hoisting cables between the lifting crane and the monopile.

[0169] In one embodiment, the ratio between the output signal and the signal representing the force applied by the pile gripper to the vessel as measured by the measuring system, or the non-zero value to be subtracted, depends on the length of the monopile below the pile gripper or the length of the monopile between the pile gripper and the seabed, and on the length of the monopile above the pile gripper. In one embodiment, this dependency may apply only during the seabed penetration phase.

[0170] In one embodiment, during the seabed penetration phase, the dynamic positioning system is configured to determine a ratio α between the output signal and a signal representing the force applied by the pile gripper to the vessel as measured by the measurement system using the following equation:

[0171] α = a / (a ​​+ b)

[0172] Where a is the length of the monopile above the gripper and b is the length of the monopile below the gripper, or the length of the monopile between the gripper and the seabed.

[0173] In one embodiment, the dynamic positioning system is configured to receive input that allows the determination of parameters a and b. This input may include one or more of the following information:

[0174] - a measurement signal representing parameter a,

[0175] - the measurement signal representing parameter b,

[0176] - the total length of the treated pile,

[0177] - a measurement signal representing the (vertical) position of the hook from which the monopile is suspended, and

[0178] - (Average) water depth.

[0179] According to a seventh aspect of the present invention, there is provided a vessel for installing a monopile, comprising:

[0180] - Hull,

[0181] - a lifting crane, arranged on said hull, for hanging the monopile on said hull,

[0182] - Pile grippers, for engaging monopiles,

[0183] - Dynamic Positioning System, used to position the vessel,

[0184] - Pile gripper positioning system, used to position a monopile using a pile gripper,

[0185] wherein the pile gripper positioning system is configured to determine a force applied by the pile gripper to the vessel,

[0186] Therein, the vessel is configured to utilize a portion of the determined forces as a feedforward signal to a dynamic positioning system to position the vessel.

[0187] It should be clearly pointed out here that the position of a ship may alternatively or additionally refer to the position of a part of the ship and / or the orientation of the ship or a part thereof. Furthermore, the position of a monopile may alternatively or additionally refer to the position of a part of the monopile and / or the orientation of a monopile or a part thereof.

[0188] In one embodiment the pile gripper positioning system is configured to provide a signal representative of the force applied by the pile grippers to the vessel to a dynamic positioning system, and the dynamic positioning system is a dynamic positioning system according to the fifth aspect of the invention.

[0189] In one embodiment the pile gripper positioning system is a pile gripper positioning system according to the sixth aspect of the invention and the pile gripper positioning system provides to the dynamic positioning system a signal representing a portion of the force applied by the pile gripper to the vessel as determined by the pile gripper positioning system.

[0190] In one embodiment, the vessel comprises an overall control unit, wherein the pile gripper positioning system is configured to provide a signal representative of the force applied by the pile gripper to the vessel to the overall control unit, and wherein the overall control unit is configured to utilize a portion of the signal received from the pile gripper positioning system to determine a feedforward signal to be provided by the overall control unit to the dynamic positioning system.

[0191] It is explicitly noted that utilizing a portion of the signal representative of the force applied by the pile gripper to the vessel means that the overall control unit is configured to ignore or discard at least the non-zero portion of the signal by multiplying by a factor less than 1 or subtracting a non-zero value.

[0192] According to an eighth aspect of the present invention, there is provided a method for installing a monopile, wherein the method uses a vessel, the vessel comprising: a dynamic positioning system for positioning the vessel; a lifting crane for suspending the monopile on the lifting crane; and a pile gripper for engaging the monopile during lowering of the monopile, and wherein the method comprises the following steps:

[0193] a. lowering the monopile towards the seabed or into the seabed while the monopile is engaged with the pile gripper,

[0194] b. determine the forces applied to the vessel by the pile grippers during lowering, and

[0195] c. Utilize a portion of the determined forces as a feed-forward signal to the dynamic positioning system to position the vessel.

[0196] In one embodiment, the method is performed while the monopile is suspended by a lifting crane.

[0197] It is explicitly mentioned herein that embodiments and / or features described in relation to one aspect of the invention may readily be applied to other aspects of the invention where appropriate.

[0198] As an example, the pile gripper positioning system according to the first aspect of the present invention may be combined with the pile gripper positioning system according to the sixth aspect of the present invention:

[0199] A pile gripper positioning system for a pile gripper configured to be disposed on a vessel to engage with a monopile during a monopile installation process, wherein the pile gripper positioning system comprises:

[0200] - an actuator system for applying a force to the pile gripper to position the pile gripper relative to the vessel,

[0201] - a measuring system to determine the position of the monopile in the gripper relative to the vessel, and

[0202] - a pile gripper control unit for driving the actuator system according to the desired position of the monopile and the actual position of the monopile measured by the measuring system,

[0203] wherein the pile gripper control unit is configured to receive a signal representing the position of the vessel,

[0204] wherein during at least a portion of the monopile installation process the pile gripper control unit is configured to determine a drive signal for the actuator system to compensate for at most a portion of a deviation of the vessel's position from a desired position of the vessel,

[0205] and wherein, during said at least part of the monopile installation process, the pile gripper control unit for driving the actuator system is configured to drive the actuator system in dependence on the desired position of the monopile and the actual position of the monopile measured by the measurement system, and to use the drive signal to compensate for at most a part of the deviation of the position of the vessel from the desired position of the vessel,

[0206] wherein the measuring system is further configured to determine the force applied by the pile gripper to the vessel,

[0207] And wherein the pile gripper control unit is configured to output a signal representative of a portion of the force applied by the pile gripper to the vessel as measured by the measurement system.

[0208] As another example, the dynamic positioning system according to the second aspect of the present invention may be combined with the dynamic positioning system according to the fifth aspect of the present invention:

[0209] A dynamic positioning system for a vessel, wherein the vessel comprises a lifting crane for lifting a monopile and a pile gripper for engaging with the monopile, the lifting crane and the pile gripper being configured to cooperate in lowering the monopile into the sea during a monopile installation process, wherein the dynamic positioning system comprises:

[0210] - an actuator system for applying forces to the boat to position the boat,

[0211] - a surveying system to measure the ship's position, and

[0212] - a dynamic positioning control unit for driving the actuator system according to the desired position of the vessel and the actual position of the vessel measured by the measurement system,

[0213] wherein the dynamic positioning control unit is configured to determine a signal representing a difference between a desired position of the vessel and an actual position of the vessel,

[0214] and wherein, during at least a portion of the monopile installation process, the dynamic positioning control unit is configured to output a signal representative of at most a portion of said difference,

[0215] wherein the dynamic positioning control unit is configured to receive a signal representative of a force applied to the vessel by the pile gripper,

[0216] And wherein the dynamic positioning control unit is configured to use a portion of the signal as a feed-forward signal to drive the actuator system.

[0217] As another example, the ship according to the third aspect of the invention may be combined with the ship according to the seventh aspect of the invention:

[0218] A vessel for performing a monopile installation process, comprising:

[0219] - Hull,

[0220] - Pile grippers, arranged on the hull for engaging monopiles,

[0221] - Dynamic Positioning Systems, used to locate the vessel, and

[0222] - Pile gripper positioning system, used to position a monopile using a pile gripper,

[0223] wherein the pile gripper positioning system is configured to determine a force applied by the pile gripper to the vessel,

[0224] wherein the vessel is configured to utilize a portion of the determined forces as a feedforward signal for a dynamic positioning system to position the vessel,

[0225] wherein the dynamic positioning system is configured to determine the position of the vessel,

[0226] And wherein, during at least a portion of the monopile installation process, the vessel is configured to operate the pile gripper positioning system to at most partially compensate for a deviation of the determined position of the vessel from a desired position of the vessel.

[0227] Alternatively, a ship can be described as:

[0228] A vessel for performing a monopile installation process, comprising:

[0229] - Hull,

[0230] - Pile grippers, arranged on the hull for engaging monopiles,

[0231] - Dynamic Positioning Systems, used to locate the vessel, and

[0232] - Pile gripper positioning system, used to position a monopile using a pile gripper,

[0233] wherein the dynamic positioning system is the dynamic positioning system according to the second aspect of the present invention, and the pile gripper positioning system is the pile gripper positioning system according to the sixth aspect of the present invention,

[0234] And / or wherein the dynamic positioning system is the dynamic positioning system according to the fifth aspect of the invention and the pile gripper positioning system is the pile gripper positioning system according to the first aspect of the invention.

[0235] As another example, the method according to the fourth aspect of the present invention may be combined with the method according to the eighth aspect of the present invention:

[0236] A method for installing a monopile, wherein the method uses a vessel comprising a dynamic positioning system for positioning the vessel and a pile gripper for engaging the monopile, and wherein the method comprises the following steps:

[0237] a. lowering the monopile towards the seabed or into the seabed while the monopile is engaged with the pile gripper,

[0238] b. determine the deviation of the ship's position from the ship's desired position,

[0239] c. using a pile gripper to at most partially compensate for the deviation,

[0240] d. determine the forces applied to the vessel by the pile grippers during lowering, and

[0241] e. Use a portion of the determined forces as a feed-forward signal to the dynamic positioning system to position the vessel.

[0242] It is explicitly mentioned here that throughout the specification, a signal may refer to its signal value where appropriate. Therefore, throughout this specification, the term "signal" may be replaced by the term "signal value". BRIEF DESCRIPTION OF THE DRAWINGS

[0243] The invention will now be described in a non-limiting manner with reference to the accompanying drawings, in which like parts are indicated by like reference numerals, and in which:

[0244] Figure 1 schematically depicts a ship according to an embodiment of the invention,

[0245] Figure 2 Schematic depiction of the inversion of a monopile Figure 1 part of the ship,

[0246] Figure 3 Schematically depicts a control scheme for a ship according to one embodiment of the present invention,

[0247] Figure 4 A control scheme for a ship according to another embodiment of the present invention is schematically depicted,

[0248] Figure 5 A control scheme for a ship according to yet another embodiment of the present invention is schematically depicted.

[0249] Figure 6 Schematically depicting a monopile during the seabed penetration phase of the monopile installation process,

[0250] Figure 7 Schematically depicting a vessel lowering a monopile during the lowering phase of the monopile installation process,

[0251] Figure 8 Schematically depicts a control scheme for a ship according to one embodiment of the present invention,

[0252] Fig. 9 schematically depicts a control scheme for a ship according to another embodiment of the present invention, and

[0253] Fig.10 A control scheme for a ship according to yet another embodiment of the present invention is schematically depicted. DETAILED DESCRIPTION

[0254] Figure 1 and Figure 2 A vessel 200 according to one embodiment of the invention is schematically depicted. The vessel 200 comprises a deck 201. The deck 201 provides sufficient space to store five monopiles 202 in this case in a horizontal orientation. The monopiles 202 are stored such that their longitudinal axis is parallel to the longitudinal axis of the vessel 200.

[0255] In this embodiment, the vessel 200 is a monohull, but alternatively the vessel could be semi-submersible.

[0256] A lifting crane 203 is provided at the stern of the ship 200. The lifting crane 203 is arranged at the center of the deck 201 as viewed in the transverse direction of the ship 200 to be aligned with the center of gravity of the ship 200. A pile gripper 1 is arranged on one side of the lifting crane, and a pile driving mechanism 205, or pile hammer, is arranged at a corresponding storage position on the opposite side of the lifting crane 203.

[0257] When the vessel 200 has sailed to the offshore installation site where the monopile 202 needs to be installed into the seabed, the monopile 202 is positioned in the pile frame 50 of the pile gripper 1. In this embodiment, the pile frame 50 can be oriented vertically and as shown in FIG. Figure 1 The pile frame 50 is pivotable between the horizontal orientation shown, in which the pile frame can receive the monopile in the horizontal orientation, and in which the pile frame can guide the monopile towards or into the seabed to be lowered into the sea. In this embodiment, the monopile is positioned in the pile frame 50 of the pile gripper 1 when the pile frame 50 is in the vertical position.

[0258] The arms 57, 58 of the pile holder 50 are movable between an open position, in which the monopile 202 is allowed to pass through the arms 57, 58 and thereby receive the monopile, and a closed position, in which the pile holder 50 (and hence the pile gripper 1) engages the monopile 202 to restrict movement in a direction perpendicular to the longitudinal axis of the monopile 202.

[0259] The pile frame 50 may be provided with a pile support 77 configured to engage with the lower end of the monopile 202. The monopile 202 may be engaged by first placing the pile support 77 in the desired position and then translating the monopile along its longitudinal axis until the lower end of the monopile engages with the pile support 77. The pile support 77 serves to limit movement of the monopile 202 in a direction parallel to the longitudinal axis of the monopile 202, which is advantageous during inversion of the monopile 202.

[0260] Then, with the lower end of the monopile 202 located in the pile frame 50, the upper end of the monopile 202 is lifted using the lifting crane 203, thereby rotating the monopile 202 from the horizontal orientation to the vertical orientation. Figure 2 The monopile is shown in an intermediate inclined orientation between the horizontal and vertical orientations.

[0261] After the rotation, the pile frame 50 is in a horizontal position, which may alternatively be referred to as a lowered position, and the monopile 202 is located outside the outline of the vessel 202 (i.e., outside the vessel) as seen from above, to be lowered into the water, as may be seen in FIG. Figure 1 Seen in.

[0262] Before the monopile 202 is lowered into the water, the lower end of the monopile 202 needs to be detached from the pile support 77. In this case the monopile 202 is first lifted using a lifting crane 203, after which the pile support 77 can be removed. The monopile 202 can then be lowered into the water.

[0263] During the above operation, the vessel 200 is in a floating state, and the pile frame 50 compensates for the wave induced motion of the vessel 200 by operating the pile gripper positioning system of the pile gripper 1 in a wave induced motion compensation mode to maintain a predetermined XY position independent of the wave induced motion of the vessel 200, which will be described below with reference to Figures 3 to 10 Explain in more detail.

[0264] In order to allow the pile gripper 1 to maintain a predetermined XY position, the vessel 200 must maintain its position within the working boundaries of the pile gripper 1. Therefore, the vessel 200 is provided with a dynamic positioning system to position the vessel 200, including maintaining or adjusting the position or orientation of the vessel 200. The dynamic positioning system comprises an actuator system including, for example, a plurality of propulsion modules 220 for applying forces to the vessel 200, preferably enabling the vessel 200 to translate at least in a horizontal XY plane and to rotate the vessel 200 about a Z axis.

[0265] When the monopile 202 is lowered into the water and suspended from the lifting crane 203, the lifting crane 203 may be operated in a wave induced motion compensation mode so that the monopile 202 is compensated for the wave induced motion of the vessel 200 to maintain a predetermined Z position regardless of the wave induced motion of the vessel 200. This may also be referred to as heave compensation.

[0266] In order to lift the upper end of the monopile 202 so as to rotate the monopile 202 from a horizontal orientation to a vertical orientation, the lifting crane 203 may be provided with a pile clamping device 210 comprising a clamping portion 211 for clamping the upper end of the monopile 202 and a connecting portion 212 allowing the pile clamping device to be connected to a load connector 213 of the lifting crane 203. During lifting of the upper end, i.e. during rotation of the monopile 202, the connecting portion 212 can freely rotate relative to the clamping portion 211.

[0267] Figure 3 A control scheme for a vessel 200 according to an embodiment of the present invention is schematically depicted. Figure 3 The control scheme can be used to control Figure 1 of boats 200.

[0268] Figure 3Schematically depicted is a vessel 200 and a dynamic positioning system 100 for positioning the vessel 200, and a pile gripper 1 with a pile gripper positioning system 150 for positioning a monopile using the pile gripper 1. Although the pile gripper 1 is shown as part of the pile gripper positioning system 150, it is explicitly mentioned here that the pile gripper 1 is not part of the pile gripper positioning system 150. The pile gripper 1 comprises construction elements and the pile gripper positioning system 150 comprises all other components configured to position the construction elements of the pile gripper 1.

[0269] The dynamic positioning system 100 includes an actuator system 220 for applying a force F1 to the ship 200 to position the ship 200. The dynamic positioning system 100 also includes a measurement system 105 for measuring the position of the ship 200 and a dynamic positioning control unit 110 for driving the actuator system 220 according to the desired position 111 and the actual position 112 measured by the measurement system 105.

[0270] The pile gripper positioning system 150 comprises an actuator system 170 for applying a force F2 to the pile gripper 1 to position the pile gripper 1 relative to the vessel 200. The pile gripper positioning system 150 further comprises: a measuring system 155 for determining the position of the monopile in the pile gripper 1; and a pile gripper control unit 160 for driving the actuator system 170 using a driving signal 164 according to a desired position 161 of the monopile and an actual position 162 of the monopile measured by the measuring system 155.

[0271] The dynamic positioning system 100 is configured to output a signal 112a representing the position of the vessel 200. The signal 112a is provided to the pile gripper positioning system 150, wherein the pile gripper control unit 160 is configured to receive the signal 112a representing the position of the vessel 200.

[0272] In this embodiment, during at least a portion of the monopile installation process, the pile gripper control unit 160 is configured to determine a drive signal 163 for the actuator system 170 to compensate for at most a portion of a deviation of the position of the vessel 200 from a desired position of the vessel 200 .

[0273] The signal 112a output by the dynamic positioning system 100 may be equal to the actual position 112 measured by the measurement system 105. The deviation of the position of the vessel 200 from the desired position of the vessel 200 may then be determined by providing the desired position 111 of the vessel 200 via the dashed line 111b and allowing the gripper control unit 160 to compare the actual position 112 with the desired position 111.

[0274] Alternatively, the deviation of the position of vessel 200 from the desired position 111 of vessel 200 may be determined in a dynamic positioning system, for example by comparing signal 112 with signal 111a and outputting the comparison result as signal 112a, which now represents the deviation of the position of vessel 200 from the desired position 111 of the vessel.

[0275] Alternatively, the position output by the measurement system 105 may already be a relative measurement indicating the deviation of the position of the vessel 200 from the vessel's desired position 111, so that no desired position needs to be additionally provided. Dashed lines are used to represent the signals 111a and 111b for a number of possible reasons.

[0276] During said at least part of the monopile installation process, the pile gripper control unit 160 is further configured to drive the actuator system 170 with a drive signal 164 according to a desired position 161 of the monopile and an actual position 162 of the monopile measured by the measurement system 155, and to compensate at most a part of the deviation of the position of the vessel from the desired position of the vessel with a drive signal 163.

[0277] In this embodiment, compensation for at most a portion of the deviation of the vessel 200 from the expected position of the vessel is achieved by applying a factor α to the received signal 112a, and possibly also to the received signal 111b (if present), with the factor α < 1. Alternatively, a non-zero value may be subtracted from the received signal.

[0278] Figure 4 A control scheme for a vessel 200 according to another embodiment of the present invention is schematically depicted. Figure 4 The control scheme can be used to control Figure 1 of boats 200.

[0279] Figure 4 Schematically depicted is a vessel 200 and a dynamic positioning system 100 for positioning the vessel 200, and a pile gripper 1 with a pile gripper positioning system 150 for positioning a monopile using the pile gripper 1. Although the pile gripper 1 is shown as part of the pile gripper positioning system 150, it is explicitly mentioned here that the pile gripper 1 is not part of the pile gripper positioning system 150. The pile gripper 1 comprises construction elements and the pile gripper positioning system 150 comprises all other components configured to position the construction elements of the pile gripper 1.

[0280] The dynamic positioning system 100 includes an actuator system 220 for applying a force F1 to the ship 200 to position the ship 200. The dynamic positioning system 100 also includes a measurement system 105 for measuring the position of the ship 200 and a dynamic positioning control unit 110 for driving the actuator system 220 according to the desired position 111 and the actual position 112 measured by the measurement system 105.

[0281] The pile gripper positioning system 150 comprises an actuator system 170 for applying a force F2 to the pile gripper 1 to position the pile gripper 1 relative to the vessel 200. The pile gripper positioning system 150 further comprises: a measuring system 155 for determining the position of the monopile in the pile gripper 1; and a pile gripper control unit 160 for driving the actuator system 170 using a driving signal 164 according to a desired position 161 of the monopile and an actual position 162 of the monopile measured by the measuring system 155.

[0282] The dynamic positioning system 100 is configured to output a signal 112a representing the position of the vessel 200. The signal 112a is provided to the pile gripper positioning system 150, in which a pile gripper control unit 160 is configured to receive the signal 112a representing the position of the vessel 200.

[0283] The dynamic positioning system 100 is configured to output a signal 112a representing a majority of the difference between the desired position 111a and the actual position 112 of the vessel 200 during at least a portion of the performed installation method. The signal 112a is provided to the pile gripper positioning system 150, in which the pile gripper control unit 160 is configured to receive the signal 112a representing a portion of the deviation in the position of the vessel 200.

[0284] Alternatively, the signal output by the measurement system 105 may already be a relative measurement indicative of a deviation of the position of the vessel 200 from the desired position 111a or 111 of the vessel 202, so that the signal 111a may be omitted.

[0285] The pile gripper control unit 160 is further configured to drive the actuator system 170 with a drive signal 164 according to a desired position 161 of the monopile and an actual position 162 of the monopile measured by the measurement system 155, at least during said part of the monopile installation process, and to compensate at most a part of said difference with a signal 112a representing the difference between the desired position and the actual position of the vessel 200.

[0286] In this embodiment, compensation for at most a portion of the difference between the desired position and the actual position of the vessel 200 is achieved by applying a factor α < 1 to the difference. Alternatively, a non-zero value may be subtracted from the difference.

[0287] Figure 5 A control scheme of a ship 200 according to yet another embodiment of the present invention is schematically depicted. Figure 5 The control scheme can be used to control Figure 1 of boats 200.

[0288] Figure 5Schematically depicted is a vessel 200 and a dynamic positioning system 100 for positioning the vessel 200, and a pile gripper 1 with a pile gripper positioning system 150 for positioning a monopile using the pile gripper 1. Although the pile gripper 1 is shown as part of the pile gripper positioning system 150, it is explicitly mentioned here that the pile gripper 1 is not part of the pile gripper positioning system 150. The pile gripper 1 comprises construction elements and the pile gripper positioning system 150 comprises all other components configured to position the construction elements of the pile gripper 1.

[0289] The dynamic positioning system 100 includes an actuator system 220 for applying a force F1 to the ship 200 to position the ship 200. The dynamic positioning system 100 also includes a measurement system 105 for measuring the position of the ship 200 and a dynamic positioning control unit 110 for driving the actuator system 220 according to the desired position 111 and the actual position 112 measured by the measurement system 105.

[0290] The pile gripper positioning system 150 comprises an actuator system 170 for applying a force F2 to the pile gripper 1 to position the pile gripper 1 relative to the vessel 200. The pile gripper positioning system 150 further comprises: a measuring system 155 for determining the position of the monopile in the pile gripper 1; and a pile gripper control unit 160 for driving the actuator system 170 using a driving signal 164 according to a desired position 161 of the monopile and an actual position 162 of the monopile measured by the measuring system 155.

[0291] Input signals 111 and 161 are provided to the dynamic positioning control unit 110 and the pile gripper control unit 160, respectively, via the overall control unit 180. The overall control unit 180 is configured to receive one or more inputs and output signals 111 and 161 based on these one or more inputs, thereby allowing information from different systems to be used when driving the dynamic positioning system 100 and the pile gripper positioning system 150. Two examples of one or more inputs to the overall control unit 180 are given, namely user input 181 and measurement signal 112 from the measurement system 155.

[0292] The measurement signal 112 provided to the overall control unit 180 therefore represents the actual position of the vessel 200. The overall control unit 180 is configured to compare this actual position of the vessel 200 with the desired position 111a of the vessel 200 and to use only a part of the comparison result in the unit 190 to determine the drive signal 163 in order to at most partially compensate for the deviation of the determined position of the vessel from the desired position of the vessel. The drive signal 163 may be combined with other signals to determine the input signal 161 to be provided to the pile gripper control unit 160.

[0293] In order to at most partially compensate for the deviation of the determined position of the ship from the expected position of the ship, a factor α is applied to the signals 112 and 111a. Alternatively, a non-zero value may be subtracted from the received signal.

[0294] By reference Figures 1 to 5 , a part of the monopile installation process has been described. In more detail, the monopile installation process may include multiple stages, including but not limited to:

[0295] - Suspension phase, in which the monopile is suspended from a lifting crane above the horizontal plane and, after the monopile is fully rotated to a vertical orientation, the monopile is lifted by e.g. Figure 2 The pile gripper engagement shown,

[0296] - a descent phase, wherein the monopile is suspended from a lifting crane and engaged by a pile gripper, and the lower end of the monopile is in the water but above the seabed (referred to alternatively throughout this specification as the seabed),

[0297] - the seabed penetration phase, in which the monopile is suspended from a lifting crane and engaged by a pile gripper, and the lower end of the monopile has been penetrated into the seabed, and

[0298] - The driving phase, in which the monopile is engaged by a pile gripper and driven into the seabed using a hammer or the like.

[0299] Figure 6 A monopile 202 is schematically depicted during the seabed penetration phase of the monopile installation process. The monopile 202 is suspended from a lifting crane using a pile clamping device 210, which comprises a clamping portion 211 for clamping the upper end of the monopile 202 and a connecting portion 212 allowing the pile clamping device 210 to be connected to a load connector of the lifting crane. The connecting portion 212 is able to rotate freely relative to the clamping portion 211 about a rotation axis 251, thereby providing a suspension point. Alternatively, the clamping device 210 may only comprise a clamping portion 211 configured to be directly connected to the load connector of the lifting crane, thereby providing a suspension point 251 allowing some rotation of the clamping portion 211 relative to the load connector. The connecting portion 212 may then be a hoisting cable and a load connector, indicated using reference numeral 250, to clearly distinguish between the two alternative suspension types.

[0300] During the seabed penetration phase, the lower end of the monopile 202 has penetrated the seabed SB and the monopile 202 is engaged by a pile gripper to apply a force FG to the monopile using, for example, a pile gripper positioning system as described above.

[0301] Different parameters can be defined:

[0302] a is the length of the pile above the pile gripper,

[0303] a' is the distance between the pile gripper and the suspension point,

[0304] b is the length of the pile below the gripper, and

[0305] b' is the length of the monopile between the gripper and the seabed.

[0306] Alternatively or additionally, the following parameters may be defined:

[0307] c = a + b', the length of the monopile above the seabed, and

[0308] c' = a' + b', the distance between the seabed and the suspension point.

[0309] The above about Figures 3 to 5 The described ratio α can be determined during the seabed penetration phase using the following equation or its equivalent:

[0310]

[0311] Where L is equal to the length of the monopile and l1 is the predetermined length of the monopile above the seabed, i.e. L-l1 is the predetermined length of the monopile that has penetrated into the seabed, also called the penetration depth, corresponding to the case where the control of the monopile is sufficiently stable to fully compensate the deviation of the actual position of the vessel from the desired position of the vessel using the gripper positioning system. Thus, during the duration of the seabed penetration phase when the parameter c is between L and L-l1, at most a portion of said deviation is compensated by the gripper positioning system.

[0312] By compensating only part of the deviation, the stability of the monopile is improved, but a loss of position of the monopile may result. However, at this stage of the monopile installation process, the position of the monopile can still be corrected and large compensating forces due to deviations in the position of the vessel are avoided. When the penetration depth increases, the stability of the monopile increases and a larger force can be applied between the monopile and the vessel, allowing the position of the monopile to be corrected and thus fully compensated for deviations in the position of the vessel.

[0313] Although the above equations show a linear relationship, it is expressly noted that other relationships (quadratic, hyperbolic, non-linear, etc.) may also be used.

[0314] Figure 7 The vessel 200 is schematically depicted during the lowering phase of a monopile installation process such as described above. The vessel comprises a lifting crane 203 for suspending a monopile 202 therefrom using a lifting rope 215. The vessel 200 also comprises a pile gripper 10 for engaging with the monopile.

[0315] Figure 7It comprises a vessel 200 and a monopile 202 shown in solid and dashed lines. The solid version corresponds to the situation where the monopile 202 is in a vertical orientation above a position LO where the monopile 202 should be installed in the seabed SB and the vessel 200 is in the desired position.

[0316] The dashed version corresponds to a situation where the vessel 200 has drifted away and therefore there is a deviation Δx between the position of the vessel 200 and the expected position of the vessel 200 (solid line).

[0317] Due to the deviation Δx in the position of the vessel 200 , the hoisting rope 215 has also drifted away from the position of the lifting crane 203 , thereby in principle taking the monopile 202 along with it, thus moving the monopile 202 away from the position LO.

[0318] In one embodiment, for example, Figures 3 to 5 The pile gripper 10 is operated by one of the control systems of the vessel 200 to compensate only a portion α*Δx of the deviation Δx of the position of the vessel 200 from the desired position of the vessel 200, where α is defined by the ratio D1 / (D1+D2), where D1 is the distance between the position where the lifting rope 215 leaves the lifting crane 203 and the pile gripper 10, D2 is the distance between the pile gripper 10 and the seabed SB, and thus D1+D2 is the distance between the position where the lifting rope 215 leaves the lifting crane 203 and the seabed SB.

[0319] The advantage of defining α as the ratio D1 / (D1+D2) is that the monopile 202 remains oriented towards the intended installation position LO regardless of the motion of the vessel, so that the monopile can be easily landed on the seabed SB at the position LO without any stability problems. After landing on the seabed, the seabed penetration phase begins and can be applied Figure 6 situation.

[0320] In one embodiment, regarding Figure 6 The equation for α described can be applied to the seabed penetration phase, except that according to Figure 7 The implementation scheme of always applies the minimum ratio defined by D1 / (D1+D2).

[0321] Figure 8 A control scheme for a vessel 200 according to an embodiment of the present invention is schematically depicted. Figure 8 The control scheme can be used to control Figure 1 of boats 200.

[0322] Figure 8Schematically depicted is a vessel 200 and a dynamic positioning system 100 for positioning the vessel 200, and a pile gripper 1 with a pile gripper positioning system 150 for positioning a monopile using the pile gripper 1. Although the pile gripper 1 is shown as part of the pile gripper positioning system 150, it is explicitly mentioned here that the pile gripper 1 is not part of the pile gripper positioning system 150. The pile gripper 1 comprises construction elements and the pile gripper positioning system 150 comprises all other components configured to position the construction elements of the pile gripper 1.

[0323] The dynamic positioning system 100 includes an actuator system 220 for applying a force F1 to the ship 200 to position the ship 200. The dynamic positioning system 100 also includes a measurement system 105 for measuring the position of the ship 200 and a dynamic positioning control unit 110 for driving the actuator system 220 according to the desired position 111 and the actual position 112 measured by the measurement system 105.

[0324] The pile gripper positioning system 150 comprises an actuator system 170 for applying a force F2 to the pile gripper 1 to position the pile gripper 1 relative to the vessel 200. The pile gripper positioning system 150 further comprises: a measuring system 155 for determining the position of the monopile in the pile gripper 1; and a pile gripper control unit 160 for driving the actuator system 170 according to a desired position 161 of the monopile and an actual position 162 of the monopile measured by the measuring system 155.

[0325] The measurement system 155 is further configured to determine the force F3 applied by the pile gripper 1 to the vessel 200. The pile gripper positioning system 150 is further configured to output a signal representative of the measured force F3 and provide the signal to the dynamic positioning system 100.

[0326] The dynamic positioning system 100 is configured to use only a portion of the signal provided by the gripper positioning system 150 as a feedforward signal to the dynamic positioning control unit 110, in this embodiment by applying a factor α to the received signal, the factor α < 1. Alternatively, a non-zero value may be subtracted from the received signal.

[0327] Fig. 9 A control scheme for a vessel 200 according to another embodiment of the present invention is schematically depicted. Fig. 9 The control scheme can be used to control Figure 1 of boats 200.

[0328] Fig. 9Schematically depicted is a vessel 200 and a dynamic positioning system 100 for positioning the vessel 200, and a pile gripper 1 with a pile gripper positioning system 150 for positioning a monopile using the pile gripper 1. Although the pile gripper 1 is shown as part of the pile gripper positioning system 150, it is explicitly mentioned here that the pile gripper 1 is not part of the pile gripper positioning system 150. The pile gripper 1 comprises construction elements and the pile gripper positioning system 150 comprises all other components configured to position the construction elements of the pile gripper 1.

[0329] The dynamic positioning system 100 includes an actuator system 220 for applying a force F1 to the ship 200 to position the ship 200. The dynamic positioning system 100 also includes a measurement system 105 for measuring the position of the ship 200 and a dynamic positioning control unit 110 for driving the actuator system 220 according to the desired position 111 and the actual position 112 measured by the measurement system 105.

[0330] The pile gripper positioning system 150 comprises an actuator system 170 for applying a force F2 to the pile gripper 1 to position the pile gripper 1 relative to the vessel 200. The pile gripper positioning system 150 further comprises: a measuring system 155 for determining the position of the monopile in the pile gripper 1; and a pile gripper control unit 160 for driving the actuator system 170 according to a desired position 161 of the monopile and an actual position 162 of the monopile measured by the measuring system 155.

[0331] The measurement system 155 is further configured to determine the force F3 applied by the pile gripper 1 to the vessel 200. The pile gripper positioning system 150 is further configured to output a signal representing a portion of the measured force F3 (in the present embodiment, by applying a factor α to the measured signal, the factor α <1), and to provide this reduced signal to the dynamic positioning system 100. Alternatively, a non-zero value may be subtracted from the measured signal to obtain the reduced signal.

[0332] The dynamic positioning system 100 is configured to use the reduced signal provided by the gripper positioning system 150 as a feed-forward signal to the dynamic positioning control unit 110 .

[0333] Fig.10 A control scheme of a ship 200 according to yet another embodiment of the present invention is schematically depicted. Fig.10 The control scheme can be used to control Figure 1 of boats 200.

[0334] Fig.10Schematically depicted is a vessel 200 and a dynamic positioning system 100 for positioning the vessel 200, and a pile gripper 1 with a pile gripper positioning system 150 for positioning a monopile using the pile gripper 1. Although the pile gripper 1 is shown as part of the pile gripper positioning system 150, it is explicitly mentioned here that the pile gripper 1 is not part of the pile gripper positioning system 150. The pile gripper 1 comprises construction elements and the pile gripper positioning system 150 comprises all other components configured to position the construction elements of the pile gripper 1.

[0335] The dynamic positioning system 100 includes an actuator system 220 for applying a force F1 to the ship 200 to position the ship 200. The dynamic positioning system 100 also includes a measurement system 105 for measuring the position of the ship 200 and a dynamic positioning control unit 110 for driving the actuator system 220 according to the desired position 111 and the actual position 112 measured by the measurement system 105.

[0336] The pile gripper positioning system 150 comprises an actuator system 170 for applying a force F2 to the pile gripper 1 to position the pile gripper 1 relative to the vessel 200. The pile gripper positioning system 150 further comprises: a measurement system 155 for determining the position of the monopile in the pile gripper 1; and a pile gripper control unit 160 for driving the actuator system 170 according to an input signal 161 and an actual position 162 of the monopile measured by the measurement system 155.

[0337] Input signals 111 and 161 are provided to the dynamic positioning control unit 110 and the pile gripper control unit 160, respectively, by the overall control unit 180. The overall control unit 180 is configured to receive one or more inputs and output signals 111 and 161 based on these one or more inputs, thereby allowing information from different systems to be used when driving the dynamic positioning system 100 and the pile gripper positioning system 150. Two examples of one or more inputs to the overall control unit 180 are given, namely user input 181 and a measurement signal from the measurement system 155.

[0338] The measurement system 155 is also configured to determine the force F3 applied by the pile gripper 1 to the vessel 200. Thus, the signal provided to the overall control unit represents the force F3. The overall control unit uses only a portion of this signal to determine a corresponding drive signal in the unit 190, possibly combining this drive signal with other signals to determine the input signal 111 to be provided to the dynamic positioning control unit 110. In this way, a portion of the force F3 can be used as a feedforward signal to drive the dynamic position system 100. Alternatively, the drive signal used as a feedforward signal is provided to the dynamic positioning control unit 110 from the overall control unit 180 as a separate input immediately after the input signal 111. This can make it easier to use the separate inputs differently.

[0339] In order to use only a portion of the determined force F3 , a factor α is applied to the signal received by the overall control unit, the factor α < 1. Alternatively, a non-zero value may be subtracted from the received signal.

[0340] Reference again Figure 6 , the above about Figures 8 to 10 The described ratio α can be determined during the seabed penetration phase using the following equation:

[0341] α = a / (a ​​+ b)

[0342] In one embodiment, a may be replaced by a' and / or b may be replaced by b'. When a (or a') is between b (or b') and 1.5 times b (or b') during the seabed penetration phase, α will be between 0.5 and 0.6.

Claims

1. A pile gripper positioning system for a pile gripper configured to be disposed on a vessel to engage a monopile during a monopile installation process, wherein: The pile gripper positioning system comprises: - an actuator system for applying a force to the pile gripper to position the pile gripper relative to the vessel, - a measuring system for determining the position of the monopile in the pile gripper relative to the vessel, and - a pile gripper control unit for driving the actuator system as a function of a desired position of the monopile and an actual position of the monopile measured by the measuring system, wherein the pile gripper control unit is configured to receive a signal representing the position of the vessel, wherein, during at least a portion of the monopile installation process, the pile gripper control unit is configured to determine a drive signal for the actuator system to compensate for at most a portion of a deviation of the position of the vessel from a desired position of the vessel, and wherein, during said at least part of the monopile installation process, the pile gripper control unit for driving the actuator system is configured to drive the actuator system in dependence on a desired position of the monopile and an actual position of the monopile measured by the measurement system, and the pile gripper control unit uses the drive signal to compensate for at most a part of a deviation of the position of the vessel from the desired position of the vessel.

2. The pile gripper positioning system according to claim 1, wherein: At least part of the monopile installation process includes at least part of a seabed penetration phase in which the monopile is suspended from a lifting crane and engaged by the pile gripper and the lower end of the monopile is penetrated into the seabed.

3. The pile gripper positioning system according to claim 1 and 2, wherein: A ratio is defined between the portion of the deviation to be compensated and the total deviation of the position of the vessel from the desired position of the vessel, and wherein the pile gripper control unit is configured such that the ratio increases with increasing penetration depth of the lower end of the monopile.

4. The pile gripper positioning system according to claim 3, wherein: The pile gripper control unit is configured so that the ratio is linearly related to the penetration depth of the lower end of the monopile.

5. The pile gripper positioning system according to claim 1, wherein: At least part of the monopile installation process comprises at least part of a lowering phase in which the monopile is suspended from a lifting crane and engaged by the pile gripper with the lower end of the monopile in the water but above the seabed, wherein a ratio is defined between the portion of the deviation to be compensated and the total deviation of the position of the vessel from the desired position of the vessel, and wherein the pile gripper control unit is configured such that the ratio is set to the distance between the position where the lifting rope leaves the lifting crane divided by the distance between the position where the lifting rope leaves the lifting crane and the seabed.

6. A dynamic positioning system for a ship, wherein: The vessel comprises a pile gripper for engaging with a monopile during a monopile installation process, wherein the dynamic positioning system comprises: - an actuator system for applying a force to the vessel to position the vessel, - a measurement system for measuring the position of the vessel, and - a dynamic positioning control unit for driving the actuator system as a function of a desired position of the vessel and an actual position of the vessel measured by the measurement system, wherein the dynamic positioning control unit is configured to determine a signal representing a difference between the desired position and the actual position of the vessel, And wherein, during at least a portion of the monopile installation process, the dynamic positioning control unit is configured to output a signal representative of at most a portion of the difference.

7. The dynamic positioning system according to claim 6, wherein: At least part of the monopile installation process includes at least part of a seabed penetration phase in which the monopile is suspended from a lifting crane and engaged by the pile gripper and the lower end of the monopile is penetrated into the seabed.

8. A dynamic positioning system according to claims 6 and 7, wherein: A ratio is defined between the output deviation and the total deviation between the desired position of the vessel and the actual position of the vessel, and wherein the dynamic positioning control unit is configured such that the ratio increases with increasing penetration depth of the lower end of the monopile.

9. The dynamic positioning system according to claim 8, wherein: The dynamic positioning control unit is configured such that the ratio is linearly related to the penetration depth of the lower end of the monopile.

10. The dynamic positioning system according to claim 6, wherein: At least part of the monopile installation process comprises at least part of a lowering phase in which the monopile is suspended from a lifting crane and engaged by the pile gripper with the lower end of the monopile in the water but above the seabed, wherein a ratio is defined between the portion of the deviation to be compensated and the total deviation of the position of the vessel from the desired position of the vessel, and wherein the pile gripper control unit is configured such that the ratio is set to the distance between the position where the lifting rope leaves the lifting crane divided by the distance between the position where the lifting rope leaves the lifting crane and the seabed.

11. A vessel for performing a monopile installation process, comprising: - Hull, - a pile gripper arranged on the hull for engaging a monopile, - a dynamic positioning system for positioning the vessel, and - a pile gripper positioning system for positioning a monopile using said pile gripper, wherein the dynamic positioning system is configured to determine the position of the vessel, And wherein, during at least a portion of the monopile installation process, the vessel is configured to operate the pile gripper positioning system to at most partially compensate for a deviation of the determined position of the vessel from a desired position of the vessel.

12. The vessel of claim 11, wherein: The dynamic positioning system is configured to provide the determined position of the vessel to the pile gripper positioning system, and wherein the pile gripper positioning system is a pile gripper positioning system according to any one of claims 1 to 5.

13. The vessel of claim 11, wherein: The dynamic positioning control unit is a dynamic positioning control unit according to any one of claims 6 to 10 and wherein the pile gripper positioning system is configured to receive a signal representative of at most a part of the difference to at most partially compensate for a deviation of the determined position of the vessel from a desired position of the vessel.

14. The vessel of claim 11, wherein: The vessel comprises an overall control unit, wherein the pile gripper positioning system is configured to receive a signal representing the position of the vessel from the dynamic positioning system to determine a drive signal for the actuator system to compensate for at most a portion of a deviation of the position of the vessel from a desired position of the vessel, and to output the drive signal to the pile gripper positioning system to compensate at most a portion of a deviation of the determined position of the vessel from the desired position of the vessel.

15. A method for installing a monopile, wherein: The method utilizes a vessel comprising a dynamic positioning system for positioning the vessel and a pile gripper engaging the monopile, and wherein the method comprises the steps of: a. lowering the monopile toward the seabed or lowering the monopile into the seabed when the monopile engages with the pile gripper, b. determining the deviation of the position of the vessel from the expected position of the vessel, and c. Using the pile gripper to at most partially compensate for the deviation.

16. A dynamic positioning system for a ship, wherein: The vessel comprises a lifting crane for lifting a monopile and a pile gripper for engaging with the monopile, the lifting crane and the pile gripper being configured to cooperate in lowering the monopile into the sea, wherein the dynamic positioning system comprises: - an actuator system for applying a force to the vessel to position the vessel, - a measuring system for measuring the position of the vessel, - a dynamic positioning control unit for driving the actuator system as a function of a desired position of the vessel and an actual position of the vessel measured by the measurement system, wherein the dynamic positioning system is configured to receive a signal representative of a force applied to the vessel by the pile gripper, And wherein the dynamic positioning system is configured to use only a portion of the signal as a feed-forward signal to drive the actuator system.

17. The dynamic positioning system of claim 16, wherein: The ratio between the portion of the signal used as feedforward signal and the total signal received is between 0.4 and 0.

9.

18. A pile gripper positioning system for a pile gripper configured to be positioned on a vessel to engage a monopile suspended by a lifting crane of the vessel, wherein: The pile gripper positioning system comprises: - an actuator system for applying a force to the pile gripper to position the pile gripper relative to the vessel, - a measuring system for determining the position of the monopile in the pile gripper, - a pile gripper control unit for driving the actuator system as a function of a desired position of the monopile and an actual position of the monopile measured by the measuring system, wherein the measuring system is further configured to determine a force applied by the pile gripper to the vessel, And wherein the pile gripper control unit is configured to output a signal representing a portion of the force applied by the pile gripper to the vessel as measured by the measurement system.

19. The pile gripper positioning system according to claim 18, wherein: The ratio between the output signal and the signal representing the total force applied by the pile gripper to the vessel is between 0.4 and 0.

9.

20. A vessel for installing a monopile, comprising: - Hull, - a lifting crane, arranged on said hull, for hanging the monopile on said hull, - Pile grippers, for engaging monopiles, - a dynamic positioning system for positioning the vessel, - a pile gripper positioning system for positioning a monopile using said pile gripper, wherein the pile gripper positioning system is configured to determine a force applied by the pile gripper to the vessel, Wherein the vessel is configured to utilize a portion of the determined forces as a feedforward signal to the dynamic positioning system to position the vessel.

21. The vessel of claim 20, wherein: The pile gripper positioning system is configured to provide a signal representative of the force applied by the pile gripper to the vessel to the dynamic positioning system, and the dynamic positioning system is a dynamic positioning system according to any one of claims 16 to 17.

22. The vessel of claim 20, wherein: The pile gripper positioning system is a pile gripper positioning system according to any one of claims 18 to 19 and provides a signal to the dynamic positioning system representing a portion of the force applied by the pile gripper to the vessel.

23. The vessel of claim 20, wherein: The vessel comprises an overall control unit, wherein the pile gripper positioning system is configured to provide a signal representative of a force applied by the pile gripper to the vessel to the overall control unit, and wherein the overall control unit is configured to utilize a portion of the signal received from the pile gripper positioning system to determine a feed-forward signal provided by the overall control unit to the dynamic positioning system.

24. A method for installing a monopile, wherein: The method utilizes a vessel comprising: a dynamic positioning system for maintaining or adjusting the position or orientation of the vessel; a lifting crane for suspending a monopile from the lifting crane; and a pile gripper for engaging the monopile during lowering of the monopile, and wherein the method comprises the following steps: a. lowering the monopile toward the seabed or lowering the monopile into the seabed when the monopile engages with the pile gripper, b. determining the force applied by the pile grippers to the vessel during descent, and c. Using a portion of the determined forces as a feed-forward signal to the dynamic positioning system to position the vessel.

25. The method according to claim 24, wherein: The method is performed while the monopile is suspended by the lifting crane.

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