WO2019190314A2 - Offshore crane - Google Patents
Offshore crane Download PDFInfo
- Publication number
- WO2019190314A2 WO2019190314A2 PCT/NL2019/050184 NL2019050184W WO2019190314A2 WO 2019190314 A2 WO2019190314 A2 WO 2019190314A2 NL 2019050184 W NL2019050184 W NL 2019050184W WO 2019190314 A2 WO2019190314 A2 WO 2019190314A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- axis
- actuator
- luffing
- gripper
- slewing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
- B66C23/18—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes specially adapted for use in particular purposes
- B66C23/36—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes specially adapted for use in particular purposes mounted on road or rail vehicles; Manually-movable jib-cranes for use in workshops; Floating cranes
- B66C23/52—Floating cranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C13/00—Other constructional features or details
- B66C13/02—Devices for facilitating retrieval of floating objects, e.g. for recovering crafts from water
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B27/00—Arrangement of ship-based loading or unloading equipment for cargo or passengers
- B63B27/10—Arrangement of ship-based loading or unloading equipment for cargo or passengers of cranes
Definitions
- WO2010/114359 Also this simplified platform is kept motionless with respect to the fixed world (whilst the vessel is moving underneath the motionless platform). Although this platform is capable of keeping a crane almost fully motionless with a simple control, the platform is still large and heavy. According to WO2014/123414, the footprint is - with respect to WO2010/114359 - considerably reduced by a pedestal like construction of the carrying platform. This construction of WO2014/123414 still has a kind of carrying platform integrated in/with the pedestal. This construction is still large in height and heavy. Further in WO2014/123414 the power used for controlling the actuators of the carrying platform is still considerable because the entire crane on top of the pedestal is to be kept stationary.
- the sensor system may equally well be arranged on the vessel. It is even conceivable that a sensor system already present on the vessel is used. Further it is to be noted that the sensor system may also be provided on a moving part of the crane, such as on the boom structure of the crane.
- the sensor system is further configured for generating sensor signals representing said sensed movements of the substructure.
- the control system is adapted to generate control signals for driving the actuator system in response to the sensor signals such that the position of the gripper is compensated for said sensed movements.
- This simplification of the control is based on the insight that the cable carrying the load does not transfer x-axis, y- axis and z-axis rotation of the vessel to the load in case the free end of the boom structure is kept vertically above the load and that the vertical height of the load can be kept stationary by manipulating the vertical height of the free end of the boom structure and/or manipulating the heave device. Further, x-axis, y-axis and z-axis rotation experienced by the free end of the boom structure in practise turn out to be negligibly small.
- the actuator system further comprises a knuckle actuator configured for actuating the first and second boom member to rotate with respect to each other around the knuckle axis; and wherein the control system is adapted to generate a knuckle control signal for driving the knuckle actuator.
- the boom structure is a single boom comprising a first boom member 5.
- the sensor system 21 may be provided on the vessel, on the substructure of the crane, or on any part of the superstructure of the crane.
- the sensor system is by way of example provided on the substructure 3 of the crane.
- the sensor system 21 is by way of example provided on the vessel 1. Similar applies for the control system 22.
- the control system 22 may be provided on the vessel, on the substructure of the crane, or on any part of the superstructure of the crane.
- the control system 22 is in the first and second embodiment shown in figures 1-7 provided on the vessel.
- control system is adapted to determine from the sensor signals an x-, y- and z-translation experienced by the free end of the boom structure due to the sensed movements of the vessel or substructure or any other part of the crane, depending on where the sensor system is arranged.
- the sensed movements consist of an x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement. These movements represent the movement to which the vessel is subjected at a moment in time by the water motion.
- the y-translational movement caused by the water can be fully neutralized by only actuating the luffing actuator 16 and knuckle actuator 20.
- the winch actuator may be required to be actuated as well because the boom structure alone is unable to eliminate the x-, y- and z-translation experienced by the gripper 9.
- Figure 7 shows the case that the vessel and crane of figure 5 are subjected to only an y- translational movement caused by the water.
- the first position - solid lines - of the vessel is to the left of the second position - dashed lines - of the vessel.
- the gripper 9 is at the same position with respect to the fixed world. This is achieved by, starting from the first position shown in solid lines, simultaneously operating the luffing actuator 16 and winch actuator 17 to move the boom structure 5 to the second position shown in dashed lines.
- the y-translational movement caused by the water can be fully neutralized by only actuating the luffing actuator 16 and winch actuator 17.
- the superstructure comprises:
- heave device comprising a winch, a hoisting cable, and a gripper configured for carrying a load; wherein the crane comprises a slewing actuator and a luffing actuator;
- the slewing actuator configured for actuating the base to rotate around the slewing axis
- control system is adapted to generate a slewing control signal for driving the slewing actuator
- the actuator system further comprises a knuckle actuator configured for actuating the first and second boom member to rotate with respect to each other around the knuckle axis;
- control system is adapted to generate a heave control signal for driving the heave actuator.
- Assembly comprising an offshore crane according to one of the clauses 1-8 and a vessel, wherein the substructure of the crane is mounted on the vessel such that it is immobile with respect to the vessel.
- the offshore crane has a substructure and a superstructure, the superstructure comprising:
- boom structure has a fixed end supported by the base and a free end;
- control system is adapted
- the position of the gripper is kept stationary by controlling at least the slewing actuator and the luffing actuator.
- further actuators may be controlled by the controller.
- the superstructure comprises:
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Control And Safety Of Cranes (AREA)
- Jib Cranes (AREA)
Abstract
The invention relates to an offshore crane compensated for local water movement. The crane has a substructure, a boom, and a heave device comprising a winch, a hoisting cable, and a gripper for carrying a load. The boom has a fixed end supported by the substructure and a free end. The hoisting cable extends from the winch, along the boom to the free end of the boom, and suspends from the free end of the boom freely to the gripper. At the fixed end, the boom is configured for slewing with respect to the substructure around a slewing axis and for luffing with respect to the substructure around a luffing axis, the luffing axis being perpendicular to the slewing axis. In order to compensate for local water movement, an x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement are measured; on the basis of these measurements an x-, y-, and z-translation, experienced by the free end of the boom due to movement of the substructure, are determined; and these determined x-, y-, and z-translations are neutralized by correspondingly actuating the actuator system such that the position of the gripper is kept motionless. The invention further relates to a method for compensating such crane for local water movement.
Description
Title: Offshore crane
The present invention relates to an offshore crane.
When transferring loads from a vessel to another vessel or to some other construction, which may be movable or unmovable relative to the ground, problems arise due to movement of the water on which the vessel floats. Motion of the water subjects the crane, and consequently the load to be transferred, to similar movements. In case the load is carried by a hoisting cable, the water motion will cause swinging of the cable and load.
Similar problems arise when a crane is to deliver a load on the vessel of the crane (i.e. the vessel onto which the crane itself is mounted). In general, movement of the water causes the vessel to move, which in turn causes movement of the crane, movement of the location on the vessel which is to receive the load, and swinging of the cable and load.
Also when the weather conditions are very calm, the above mentioned problems due to local water movement are present. In this respect it is to be noted that although evidently the water is brought into motion strongly by wind, the effects of wind can lag for weeks in water and have influence on water at large distance away from the location of the wind. Even the water may look like very calm, but still being in motion due to wind weeks ago and/or far away. The effect of this on for example marine building operations is that one has to wait for the water to be almost motionless, in case for example a crane with hoisting cable is to be used safely.
With respect to the motions to which a vessel on water is subjected, it is to be noted that a vessel is in fact subject to 6 degrees of freedom of movement, three translational movements and three rotational movements. Using a mathematical approach based on a carthesian coordinate system having an imaginary set of three orthogonal axes - an x-axis, y-axis and z-axis - these 6 movements can be called x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement. It is to be noted, that from a
mathematical point of view there are also other equivalent manners to define the 6-degrees of movement in a space, for example the 3 axes used may not be orthogonal with respect to each other or a so called spherical coordinate system may be used. It is just a matter of mathematical calculation to transfer one definition of 6 degrees of freedom of movement into another definition of 6 degrees of freedom of movement. Using the so called carthesian
coordinate system and defining the z-axis as extending vertically, the x-axis as extending in longitudinal direction of a vessel and the y-axis as extending in transverse direction of a vessel,
the x-axis translational movement is in practise called surge
the y-axis translational movement is in practise called sway
the z-axis translational movement is in practise called heave
the x-axis rotational movement is in practise called roll
the y-axis rotational movement is in practise called pitch
the z-axis rotational movement is in practise called yaw.
With offshore cranes it is desired to compensate for movement of the vessel, caused by local water movement, in order reduce the impact of movement of the vessel onto the load.
Possibly the eldest manner of compensation is the so called‘heave compensation’. With heave compensation only the hoisting cable is used for compensation. The principle of heave compensation is that the cable of the hoisting system is extended or shortened in order to maintain the load on a vertical height. Swinging of the cable and load is not prevented.
Another manner of compensation is using a so called Stewart platform carrying the crane. A Stewart platform is a triangular platform supported by three pairs of two hydraulic actuators which are capable of controlling all 6 degrees of freedom of movement of the platform. Theoretically this allows for a control which can keep the platform completely motionless with respect to the fixed world (whilst the vessel is moving underneath the motionless platform). When the platform is kept motionless, also the crane carried by the platform is kept motionless. Stewart platforms are large, heavy, complex and require very high power for operating the platform. Not only the Stewart platform is complex, also its control is complex.
A further disadvantage of such a platform is that the platform is so to say an additional unit to be placed on the vessel between the vessel and the crane.
A simplified platform for compensating a crane for water motion is known from
WO2010/114359. Also this simplified platform is kept motionless with respect to the fixed world (whilst the vessel is moving underneath the motionless platform). Although this platform is capable of keeping a crane almost fully motionless with a simple control, the platform is still large and heavy.
According to WO2014/123414, the footprint is - with respect to WO2010/114359 - considerably reduced by a pedestal like construction of the carrying platform. This construction of WO2014/123414 still has a kind of carrying platform integrated in/with the pedestal. This construction is still large in height and heavy. Further in WO2014/123414 the power used for controlling the actuators of the carrying platform is still considerable because the entire crane on top of the pedestal is to be kept stationary.
Further, WO 2017/103139 shows a knuckle boom crane which is provided with an additional accessory carried by the free end of the knuckle boom. The knuckle boom crane itself is not compensated for any motion due to movement of the vessel caused by water movement, but the accessory is controlled by a motion compensation system in order to keep the load carried by a hook on a hoisting cable stationary. For this purpose, the accessory has a telescopic boom, which is rotatably mounted to the free end of the knuckle boom crane for rotation around two mutually perpendicular rotation axes and which is provided with a heave device comprising a winch, a hoisting cable and a crane hook. To keep the crane hook stationary, the telescopic boom is operated for i) rotation around said two mutually perpendicular rotation axes and ii) extended or shortened, and additionally the heave device is operated. This accessory is heavy and introduces additional large momentums and forces to be carried by the knuckle boom crane on top of the load.
The present invention has as its object to provide an alternative offshore crane with motion compensation, which crane preferably overcomes one or more of the drawback of the above prior art.
This object is according to the invention achieved by providing an offshore crane according to claim 1. This crane comprises a substructure and a superstructure. The superstructure comprises a base, a boom structure, and a heave device. The boom structure has a fixed end supported by the base and a free end. The heave device comprises a winch, a hoisting cable, and a gripper configured for carrying a load. The winch can for example be mounted on the base, but it is also very well conceivable that the winch is provided on the boom, like on the free end of the boom or at a distance from the free end of the boom. The hoisting cable extends from the winch to the gripper and suspends from the free end of the boom structure freely to the gripper. This part of the hoisting cable between the free end of the boom structure and the gripper, is the part, hanging freely downwards under the influence of gravity, which is in practise subject to swinging motions due to movement of the vessel. In other words, this part of the cable suspends freely from the free end of the gripper to the gripper. The gripper may be a simple crane hook, but can - depending from circumstances
and requirements - also be of more complicated structure. The crane comprises a slewing actuator and a luffing actuator. The slewing actuator is configured for slewing the base with respect to the substructure around a slewing axis. At the fixed end of the boom structure the luffing actuator is provided which luffing actuator is configured for luffing the boom structure with respect to the base around a luffing axis, the luffing axis being perpendicular to the slewing axis. Assuming the substructure of the crane is oriented in its neutral position (i.e. not tilted due to for example movement of the vessel or water), the slewing axis will extend essentially vertical.
According to the invention the substructure of the crane will be immovably mounted on the vessel, i.e. the substructure is immovable with respect to the vessel.
In order to describe the crane according to the invention further, an imaginary set of orthogonal axes is defined, comprising an x-axis, an y-axis and a z-axis, wherein the z-axis extends vertically. This imaginary set of orthogonal axes may be defined with respect to the vessel or the substructure of the crane or any part of the superstructure of the crane, like the boom structure of the crane.
In order to compensate for local water movement, the crane according to the invention furthermore includes a motion compensation system. This motion compensation system comprises a sensor system, an actuator system and a control system.
The sensor system is configured for sensing x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement. These movements may be sensed with respect to a reference point. This reference point can for example be the fixed world (which does not move), but the reference point can also be some other point, for example another vessel. But a reference point is not required when the motion compensation system senses the changes in x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement.
It is practical to arrange the sensor system on the substructure of the crane. But taking into account that the substructure of the crane will be immovable with respect to the vessel, the sensor system may equally well be arranged on the vessel. It is even conceivable that a sensor system already present on the vessel is used. Further it is to be noted that the
sensor system may also be provided on a moving part of the crane, such as on the boom structure of the crane.
The sensor system is further configured for generating sensor signals representing said sensed movements of the substructure.
The actuator system is configured for manipulating the position of the gripper.
The control system is adapted to generate control signals for driving the actuator system in response to the sensor signals such that the position of the gripper is compensated for said sensed movements.
In order to transfer signals between the sensor system, the control system and actuator system, the control system is connected to the sensor system for receiving the sensor signals from the sensor system and the control system is connected to the actuator system for sending the control signals to the actuator system. These connections may be wired connections but may also be wireless.
The control system is according to the invention adapted to determine from the sensor signals an x-, y-, and z-translation experienced by the free end of the boom structure or gripper due to said sensed movements. In general these sensed movements will be the movements sensed by the substructure. The control system is further adapted to generate, on the basis of these determined x-, y-, and z-translations, control signals for driving the actuator system such that the position of the gripper is kept stationary, i.e. the position of the gripper does not change essentially, with respect to a predetermined target location. This predetermined target location can be a location on the fixed world, a location on the vessel carrying the crane or a location on another vessel.
According to the invention the substructure of the crane is mounted directly on the vessel and immovable with respect to vessel. Here,‘mounted directly on the vessel’ means that there is no intermediate construction allowing substantial movement of a part of the substructure with respect to the vessel. Instead of using an intermediate construction, like a Stewart platform or a platform according to WO-2010/114359 or WO-2014/123414, for keeping the crane motionless, the control system according to the invention does not neutralize movement of the crane due to movement of the vessel but it neutralizes only x-, y- and z-translations which the free end of the boom structure or the gripper would experience due to movement of the vessel. These x-, y-, and z-translations which the free end of the
boom structure would experience (in absence of compensation) are caused by a) x-axis translation, y-axis translation and z-axis translation of the vessel and by b) x-axis rotation, y- axis rotation and z-axis rotation of the vessel. So the control system according to the invention calculates, from these x-, y-, and z-translations of the vessel and the x-, y-, z- rotations of the vessel, the x-, y- and z-translation which the gripper/free end of the boom structure would, in case of absence of motion compensation, experience due to the x-, y-, and z-translations of the vessel and the x-, y-, z-rotations of the vessel. Subsequently, the control system according to the invention generates control signals for driving the actuators such that only x-, y- and z-translation felt by the gripper or free end of the boom structure are neutralized.
Doing so considerable less power for the actuators is required because only the mass of the boom structure and load is to be moved instead of - as is the case in the prior art - the mass of the entire crane (including its substructure) and a platform carrying the crane. Further, the control is very much simplified because rotations of the vessel as such are not compensated but only the translations caused by these rotations are compensated. This simplification of the control is based on the insight that the cable carrying the load does not transfer x-axis, y- axis and z-axis rotation of the vessel to the load in case the free end of the boom structure is kept vertically above the load and that the vertical height of the load can be kept stationary by manipulating the vertical height of the free end of the boom structure and/or manipulating the heave device. Further, x-axis, y-axis and z-axis rotation experienced by the free end of the boom structure in practise turn out to be negligibly small.
With respect to the prior art, like WO2010/114359, WO2014/123414 and WO 2017/103139, it is noted that none of these prior art documents describe or suggest to determine from the sensor signals— which sense the x-, y- and z-translational movement and x-, y- and z- rotational movement of the vessel— the x-, y- and z-translational movement experienced by the free end of the boom structure and to generate, on the basis of these determined values, the control signals for driving the actuator system. According to these prior art documents control signals for movement compensation are generated also on basis of rotational movements of the vessel or other parts.
Taking into account that according to the invention the freedoms of movement of the crane itself, i.e. the movements of the boom structure and optionally the movement of the load under influence of the heave device, can be used for neutralizing the effects of movement of the vessel. The actuator system thus may comprises the slewing actuator configured for slewing the base with respect to the substructure around the slewing axis and the luffing
actuator configured for luffing the boom structure with respect to the base around the luffing axis. Supplementary, the actuator system may further comprise a heave actuator configured for paying out or hauling in the hoisting cable.
According to a further embodiment of the crane according to the invention, the actuator system comprises a slewing actuator configured for actuating the base to rotate around the slewing axis with respect to the substructure, and a luffing actuator configured for actuation the boom structure to rotate around the luffing axis with respect to the base; wherein the control system is adapted to generate a slewing control signal for driving the slewing actuator; and wherein the control system is adapted to generate a luffing control signal for driving the luffing actuator.
According to another further embodiment of the crane according to the invention, the boom structure is a knuckle boom having a first boom member and a second boom member;
wherein the first and second boom member are connected to each other by a knuckle hinge configured for knuckling the first and second boom member with respect to each other around a knuckle axis, the knuckle axis being parallel to the luffing axis. A knuckle boom allows for a large range in which z-translations and y- or x-translations can be neutralized.
According to another further embodiment of the crane according to the invention with knuckle boom, the actuator system further comprises a knuckle actuator configured for actuating the first and second boom member to rotate with respect to each other around the knuckle axis; and wherein the control system is adapted to generate a knuckle control signal for driving the knuckle actuator.
In case of a knuckle boom, the position of the gripper can be kept stationary by keeping the position of the free end of the boom structure stationary. So in case the boom structure is a knuckle boom, the control system may be adapted to determine from the sensor signals an X-, y-, and z-translation experienced by the free end of the boom structure due to said sensed movements, and to generate, on the basise of these determined x-, y-, and z- translations, control signals for driving the actuator system such that the position of the free end of the boom structure is kept stationary with respect to a predetermined target location.
According to another further embodiment of the crane according to the invention, the actuator system further comprises a heave actuator configured for paying out or hauling in the cable; wherein the control system is adapted to generate a heave control signal for driving the heave actuator. Using the heave actuator allows for a large range in which z-
translations can be neutralized. The heave actuator may actuate the winch to pay out or haul in the cable, but it also conceivable that the heave actuator acts on different manner on the cable in order to pay out or haul in the cable. For example, the hoisting cable may have a first cable part run from the winch to the gripper and a second cable part returning from the gripper to an attachment point where the end of the second cable part is attached to the crane, wherein the heave actuator acts on the attachment point for moving this attachment point and consequently hauling in or paying out the hoisting cable.
According to a second aspect, the invention relates to an assembly comprising an offshore crane according to the invention and a vessel, wherein the substructure of the crane is mounted on the vessel such that it is immobile with respect to the vessel.
According to a third aspect, the invention relates to a method for compensating an offshore crane for local movement, wherein the offshore crane has a substructure and a
superstructure, the superstructure comprising a base, a boom structure, and a heave device having a winch, a hoisting cable, and a gripper configured for carrying a load. The boom structure has a fixed end supported by the base and a free end. The hoisting cable extends from the winch, along the boom structure to the free end of the boom structure, and from the free end of the boom structure freely to the gripper. The base is configured for slewing with respect to the substructure around a slewing axis. At the fixed end, the boom structure is configured for luffing with respect to the base around a luffing axis, the luffing axis being perpendicular to the slewing axis. An x-axis, an y-axis and z-axis define an imaginary set of orthogonal axes, the z-axis extending vertically. The method according to the third aspect comprises the following steps:
- measuring an x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement;
- determining -- on the basis of the measured x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement -- an x-, y-, and z- translation experienced by the gripper or by the free end of the boom structure due to movement of the substructure, and
- neutralizing these determined x-, y-, and z-translations by correspondingly actuating the actuator system such that the position of the gripper is kept motionless with respect to a predetermined target location, like a location on the fixed world, a location on the vessel carrying the crane or a location on another vessel.
In this application the term‘adapted to’ is used, especially in relation to the control system, with the meaning‘configured for’.
The present invention will be explained further with reference to the drawings. In these drawings:
- Figure 1 shows highly schematically a first embodiment of the invention;
- Figure 2 shows schematically compensation of a z-translation of the gripper of the crane according to figure 1 ;
- Figure 3 shows schematically compensation of an y-translation of the gripper of the crane according to figure 1 ;
- Figure 4 shows schematically compensation of an x-translation of the gripper of the crane according to figure 1 ;
- Figure 5 shows highly schematically a second embodiment of the invention;
- Figure 6 shows schematically compensation of a z-translation of the gripper of the crane according to figure 2; and
- Figure 3 shows schematically compensation of an y-translation of the gripper of the crane according to figure 2.
As indicated with the orthogonal set of axes in the drawings, the z-direction is - in these drawings - defined as the vertical direction, the y-direction is - in these drawings - defined as the horizontal direction transverse to the length direction of the vessel and the x-direction is - in these drawings - defined as the horizontal direction parallel to the vessel.
The Figures 1-7 show a vessel 1 provided with a crane 2 according to the invention. In the two examples of figures 1-7, the crane is a pedestal crane 2, but the crane can also be of another type. The crane 2 has a substructure 3 carrying a base 27. The base 27 in turn carries an operator cabin 4, a boom structure 5, 6, and a heave device 7, 8, 9. In case of a pedestal crane, the substructure is also called‘pedestal’.
The boom structure 5, 6 has a fixed end 10 supported by the base 27 and a free end 11.
The heave device comprises a winch 7, a hoisting cable 8 and a gripper 9. The gripper may be a crane hook 9 as shown in the figures 1-7, but depending on the load 28 to be carried by the gripper any another type of gripper is very well conceivable. In case the load 28 is for example a sea container, the gripper may comprise a frame provided with four corner casting locks to be locked to the four upper corners of the sea container. In the shown examples, the winch 7 is mounted on the base 27 and the hoisting cable 8 extends from the
winch 7 along the boom structure 5, 6 to the free end 11 of the boom. At the free end 11 , the part 12 of the cable suspends downwards from the free end 11 and carries the gripper 9. However the winch 7 may also be mounted on the free end 11 of the boom structure or at any other place of the boom structure.
The base 27 is configured for slewing - see arrow S - with respect to the substructure 3 around slewing axis 13. In neutral position, as shown in the figures 1-7, the slewing axis 13 extends vertically, parallel to the z-direction. But when the vessel is subjected to roll - i.e. rotational movement around the x-axis - and/or subjected to pitch - i.e. rotational movement around the y-axis - the slewing axis will assume a slanting position with respect to the vertical. In order to slew the base 27 with respect to the substructure 3 a slewing actuator 14 is provided. This slewing actuator 14 may for example be an electric or hydraulic drive provided in the substructure 3 and configured to rotate the base 27 with respect to the substructure 3 around the slewing axis 13.
At the fixed end 11 , the boom structure 5, 6 is configured for luffing with respect to the base 27 around luffing axis 15. In neutral position, as shown in the figures 1-7, the luffing axis 15 extends horizontally. In figures 1 , 2, 3, 5, 6 and 7 the luffing axis extends perpendicular to the sheet of paper. But when the vessel is subjected to pitch - i.e. rotational movement around the y-axis - the luffing axis 15 will assume a slanting position with respect to the horizontal. In order to luff the boom structure 5, 6 with respect to the base 27 a luffing actuator 16 is provided. This luffing actuator 16 may for example be an hydraulic cylinder- piston assembly extending between the base 27 and the first boom member 5 of the boom structure and configured to rotate the first boom member 5 with respect to the base 27 around the luffing axis 15 by extending or retracting the piston-cylinder-assembly in the direction of double arrow L.
The winch 7 is provided with a winch actuator 17 configured for actuating the winch for hauling in or paying out the cable 8 in order to raise or lower the gripper 9.
The figures 1-7 show a first embodiment of the crane according to the invention - see figures 1-4 - and a second embodiment of the crane according to the invention - see figures 5-7. The difference between these two embodiments is essentially in the boom structure.
In the first embodiment of the crane according to the invention as shown in figures 1-4, the boom structure is a knuckle boom comprising a first boom member 5, also known as the
main boom, and a second boom member 6, also known as jib. The first boom member 5 and second boom member 6 are connected to each other by a knuckle hinge 18 for knuckling the first boom member 5 and second boom member 6 around a knuckle axis 19 with respect to each other. In neutral position, as shown in the figures 1-7, the knuckle axis 19 extends horizontally. In figures 1 , 2, 3, 5, 6 and 7 the knuckle axis 19 extends perpendicular to the sheet of paper. But when the vessel is subjected to pitch - i.e. rotational movement around the y-axis - the knuckle axis 19 will assume a slanting position with respect to the horizontal. In order to knuckle the second boom member 6 with respect to the first boom member 5 a knuckle actuator 20 is provided. This knuckle actuator 20 may for example be an hydraulic cylinder-piston assembly extending between the first boom member 5 and the second boom member 6 and configured to rotate the second boom member 6 with respect to the first boom member 5 around the knuckle axis 19 by extending or retracting the piston-cylinder- assembly in the direction of double arrow K.
In the second embodiment of the crane according to the invention as shown in figures 5-7, the boom structure is a single boom comprising a first boom member 5.
Now returning to the embodiments according to figures 1-7 in general, the crane according to the invention comprises a sensor system 21 and a control system 22. The slewing actuator 14, the luffing actuator 16, the optional knuckle actuator 20, the optional winch actuator 17 and optionally further actuators form together an actuator system configured for manipulating the position of the gripper 9. The sensor system 21 , the actuator system 14,
16, 17, 20, and the control system 22 together form a motion compensation system.
The sensor system 21 may be provided on the vessel, on the substructure of the crane, or on any part of the superstructure of the crane. In the first embodiment shown in figures 1-4, the sensor system is by way of example provided on the substructure 3 of the crane. In the second embodiment shown in figures 5-7, the sensor system 21 is by way of example provided on the vessel 1. Similar applies for the control system 22. Also the control system 22 may be provided on the vessel, on the substructure of the crane, or on any part of the superstructure of the crane. For ease of drawing, the control system 22 is in the first and second embodiment shown in figures 1-7 provided on the vessel.
The sensor system is configured for sensing movement in the x-direction, y-direction and z- direction (x-axis translational movement, y-axis translational movement and z-axis translational movement, respectively), and rotation around the x-axis, y-axis and z-axis (x- axis rotational movement, y-axis rotational movement and z-axis rotational movement,
respectively) and for generating sensor signals representing said sensed
movements/rotations. By means of connection 23 the sensor system 21 is connected to the control system 22 in order to transfer the sensor signals from the sensor system to the control system. This connection may be wired, wireless or by any other means allowing transfer of sensor signals from the sensor system 21 to the control system.
The control system 23 generates control signals for driving the actuator system in response to the sensor signals such that the position of the gripper is compensated for the
movements sensed by the sensor system. By means of connections 24-27 the control system 22 is connected to actuator system 14, 16, 17, 20 in order to transfer the control signals from the sensor system to (the actuators of) the actuator system. These connections may be wired, wireless or by any other means allowing transfer of control signals from the control system 22 to (the actuators of) the actuator system. Connection 24 connects the control system 22 with the slewing actuator, connection 25 connects the control system 22 with the winch actuator, connection 26 connects the control system with the luffing actuator and connection 27 connects the control system with the knuckle actuator.
With respect to figures 2-4 it is noted that the sensor system, the control system and the connections 23-27 are not shown in order to avoid these drawings from getting clouded with too many lines, but in figure 1 these are all shown. With respect to figures 6-7 it is noted that the sensor system, the control system and the connections 23-26 are not shown in order to avoid these drawings from getting clouded with too many lines, but in figure 5 these are all shown.
According to the invention the control system is adapted to determine from the sensor signals an x-, y- and z-translation experienced by the free end of the boom structure due to the sensed movements of the vessel or substructure or any other part of the crane, depending on where the sensor system is arranged. The sensed movements consist of an x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement. These movements represent the movement to which the vessel is subjected at a moment in time by the water motion. Depending on the movement to which the vessel is being subjected, one or more of the x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement may be zero or have any other value. In absence of any movement compensation and other movement action of the crane, the movements sensed by the sensor system would result in an x-, y- and z-translation experienced by the free end
of the gripper. These x-, y- and z- translations that the free end of the gripper would experience in absence of any movement compensation or other movement action of the crane, can be calculated from the movements sensed by the sensor system. The control system is programmed to make this calculation, more in general the control system is adapted to determine the x-, y-, z- translation experienced by the free end of the gripper.
The control system subsequently uses these determined x-, y- and z-translations as input for a control algorithm that generates control signals for driving the actuators of the actuator system to keep the position of the gripper stationary. Stationary here means that the position of the gripper with respect to a reference point, like the fixed world or a position on deck of the vessel, does essentially not change. For this purpose the free end of the boom is kept vertically above the load 28, i.e. the x- and y-position of the free end of the gripper with respect to the reference point is kept stationary, on the one hand, and the vertical height of the gripper with respect to the reference point is kept stationary, on the other hand. So instead of saying, as is the case in claim 1 , that“the control system is adapted to generate, on the basis of these determined x-, y-, and z-translations, control signals for driving the actuator system to keep the position of the gripper stationary with respect to a
predetermined target location", one can say that“the control system is adapted to generate, on the basis of these determined x-, y-, and z-translations, control signals for driving the actuator system to keep the x- and y-position of free end of the boom structure stationary with respect to a predetermined target location, on the one hand, and to keep b) the z- position of the gripper stationary with respect to said predetermined target location, on the other hand”.
The control system will now be further illustrated with reference to specifically the figures 2-4 and 5-6. In these figures the vessel and crane are shown in two different position (in case of figure 4, three different positions), a first position shown in solid lines and a second - and in case of figure 4 a third - position shown in dashed lines.
Figure 2 shows the case that the vessel and knuckle boom crane of figure 1 are subjected to only a z-translational movement caused by the water. In the first position - solid lines - the level of the water is higher than in the second position - dashed lines -. In both positions, the gripper 9 is at the same position with respect to the fixed world. This is achieved by, starting from the first position shown in solid lines, operating the luffing actuator 16 and knuckle actuator 20 to move the boom structure 5, 6 to the second position shown in dashed lines and/or by operating the winch actuator to adjust the winch so that the z-position of the gripper is kept stationary. In the example of figure 2, the z-translational movement caused
by the water is relatively small so that the winch actuator does not need to be actuated. In case of a larger z-translational movement caused by the water, the winch actuator may be required to be actuated as well because the boom structure alone is unable to eliminate the X-, y- and z-translation experienced by the gripper 9.
Figure 3 shows the case that the vessel and knuckle boom crane of figure 1 are subjected to only an y-translational movement caused by the water. The first position - solid lines - of the vessel is to the right of the second position - dashed lines - of the vessel. In both positions, the gripper 9 is at the same position with respect to the fixed world. This is achieved by, starting from the first position shown in solid lines, operating the luffing actuator 16 and knuckle actuator 20 to move the boom structure 5, 6 to the second position shown in dashed lines and/or by operating the winch actuator to adjust the winch so that the z-position of the gripper is kept stationary. In the example of figure 3, the y-translational movement caused by the water can be fully neutralized by only actuating the luffing actuator 16 and knuckle actuator 20. In other circumstances, the winch actuator may be required to be actuated as well because the boom structure alone is unable to eliminate the x-, y- and z-translation experienced by the gripper 9.
Figure 4 shows the case that the vessel and knuckle boom crane of figure 1 are subjected to only an x-translational movement caused by the water. The first position - in solid lines - of the vessel is midway between the second and third position- both in dashed lines - of the vessel. In the second position on the right, the vessel has moved in forward direction, and, in the third position the vessel has moved in backward direction. In all positions, the gripper 9 is at the same position with respect to the fixed world. This is achieved by, starting from the first position shown in solid lines, operating the slewing actuator 14 to rotate the base 27 with respect to the substructure 3 and simultaneously operating the luffing actuator 16 and knuckle actuator 20 to move the boom structure 5, 6 with respect to the base 27 to the second or third position shown in dashed lines and/or by operating the winch actuator to adjust the winch so that the z-position of the gripper is kept stationary. In the example of figure 4, the x-translational movement caused by the water can be fully neutralized by only actuating slewing actuator 14, the luffing actuator 16 and knuckle actuator 20. In other circumstances, the winch actuator may be required to be actuated as well because the boom structure alone is unable to eliminate the x-, y- and z-translation experienced by the gripper 9.
In the case of a knuckle boom crane as shown in figures 1-4, the gripper can be kept stationary by keeping the free end of the boom structure stationary. So in case of a knuckle
boom crane, the end of claim 1 can be worded as follows '‘the control system is adapted to generate, on the basis of these determined x-, y-, and z-translations, control signals for driving the actuator system such that the position of the free end of the boom structure is kept stationary with respect to a predetermined target location.’’
Figure 6 shows the case that the vessel and crane of figure 5 are subjected to only a z- translational movement caused by the water. In the first position - solid lines - the level of the water is lower than in the second position - dashed lines In both positions, the gripper 9 is at the same position with respect to the fixed world. This is achieved by, starting from the first position shown in solid lines, operating the winch actuator 20 to pay out the cable 8 in order to increase the length of the cable part 12 suspending freely from the free end 11 of the boom member 5.
Figure 7 shows the case that the vessel and crane of figure 5 are subjected to only an y- translational movement caused by the water. The first position - solid lines - of the vessel is to the left of the second position - dashed lines - of the vessel. In both positions, the gripper 9 is at the same position with respect to the fixed world. This is achieved by, starting from the first position shown in solid lines, simultaneously operating the luffing actuator 16 and winch actuator 17 to move the boom structure 5 to the second position shown in dashed lines. In the example of figure 7, the y-translational movement caused by the water can be fully neutralized by only actuating the luffing actuator 16 and winch actuator 17.
Referring to the figures 1-7, it is noted that, although these figures 1-7 all show a crane according to the invention arranged at a longitudinal of the vessel, it will be clear that the crane according to the invention can equally well be arranged at the stern or bow of the vessel.
The above and additional embodiments of the invention may be described as well in the next following clauses:
1] Offshore crane comprising a substructure and a superstructure,
wherein the superstructure comprises:
- a base,
- a boom structure, and
- a heave device comprising a winch, a hoisting cable, and a gripper configured for carrying a load;
wherein the crane comprises a slewing actuator and a luffing actuator;
wherein the boom structure has a fixed end supported by the base and a free end;
wherein the hoisting cable extends from the winch to the gripper and suspends from the free end of the boom structure freely to the gripper;
wherein the slewing actuator is configured for slewing the base with respect to the substructure around a slewing axis;
wherein, at the fixed end of the boom structure, the luffing actuator is provided which is configured for luffing the boom structure with respect to the base around a luffing axis, the luffing axis being perpendicular to the slewing axis;
wherein an x-axis, an y-axis and a z-axis define an imaginary set of orthogonal axes, the z- axis extending vertically;
wherein the crane furthermore includes a motion compensation system comprising:
- a sensor system configured
o for sensing x-axis translational movement, y-axis translational movement, z- axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement, and
o for generating sensor signals representing said sensed movements,
- an actuator system configured for manipulating the position of the gripper, and
- a control system generating control signals for driving the actuator system in
response to the sensor signals such that the position of the gripper is compensated for said sensed movements;
wherein the control system is connected to the sensor system for receiving the sensor signals from the sensor system;
wherein the control system is connected to the actuator system for sending the control signals to the actuator system;
wherein the control system is adapted
- to determine from the sensor signals an x-, y-, and z-translation experienced by the free end of the boom structure due to said sensed movements, and
- to generate, on the basis of these determined x-, y-, and z-translations, control
signals for driving the actuator system such that the position of the gripper or the position of the free end of the boom structure is kept stationary with respect to a predetermined target location.
2] Offshore crane comprising a substructure and a superstructure,
wherein the superstructure comprises:
- a base,
- a boom structure, and
- a heave device comprising a winch, a hoisting cable, and a gripper configured for carrying a load;
wherein the crane comprises a slewing actuator and a luffing actuator;
wherein the boom structure has a fixed end supported by the base and a free end;
wherein the hoisting cable extends from the winch to the gripper and suspends from the free end of the boom structure freely to the gripper;
wherein the slewing actuator is configured for slewing the base with respect to the substructure around a slewing axis;
wherein, at the fixed end of the boom structure, the luffing actuator is provided which is configured for luffing the boom structure with respect to the base around a luffing axis, the luffing axis being perpendicular to the slewing axis;
wherein an x-axis, an y-axis and a z-axis define an imaginary set of orthogonal axes, the z- axis extending vertically;
wherein the crane furthermore includes a motion compensation system comprising:
- a sensor system configured
o for sensing x-axis translational movement, y-axis translational movement, z- axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement, and
o for generating sensor signals representing said sensed movements,
- an actuator system configured for manipulating the position of the gripper, and
- a control system generating control signals for driving the actuator system in
response to the sensor signals such that the position of the gripper is compensated for said sensed movements;
wherein the control system is connected to the sensor system for receiving the sensor signals from the sensor system;
wherein the control system is connected to the actuator system for sending the control signals to the actuator system;
wherein the control system is adapted
- to determine from the sensor signals an x-, y-, and z-translation experienced by the free end of the boom structure due to said sensed movements, and
- to generate, on the basis of these determined x-, y-, and z-translations, control
signals for driving the actuator system to keep i) the x- and y- position of the free end of the boom stationary with respect to a predetermined target location, and to keep ii) z-position of the gripper stationary with respect to said predetermined target position.
3] Offshore crane according to clause 1 or 2, wherein the actuator system comprises the movement actuators of the crane.
4] Offshore crane according to one of clauses 1-2, wherein the actuator system comprises the slewing actuator and the luffing actuator.
5] Offshore crane according to one of clauses 1-4,
wherein the actuator system comprises:
- the slewing actuator configured for actuating the base to rotate around the slewing axis, and
- the luffing actuator configured for actuating the boom structure to rotate around the luffing axis; and
wherein the control system is adapted to generate a slewing control signal for driving the slewing actuator; and
wherein the control system is adapted to generate a luffing control signal for driving the luffing actuator.
6] Offshore crane according to one of the clauses 1-5,
wherein the boom structure is a knuckle boom having a first boom member and a second boom member;
wherein the first and second boom member are connected to each other by a knuckle hinge configured for knuckling the first and second boom member with respect to each other around a knuckle axis, the knuckle axis being parallel to the luffing axis.
7] Offshore crane according to clause 6,
wherein the actuator system further comprises a knuckle actuator configured for actuating the first and second boom member to rotate with respect to each other around the knuckle axis; and
wherein the control system is adapted to generate a knuckle control signal for driving the knuckle actuator.
8] Offshore crane according to one of the clause 1-7,
wherein the actuator system further comprises a heave actuator configured for paying out or hauling in the cable; and
wherein the control system is adapted to generate a heave control signal for driving the heave actuator.
9] Assembly comprising an offshore crane according to one of the clauses 1-8 and a vessel, wherein the substructure of the crane is mounted on the vessel such that it is immobile with respect to the vessel.
10] Assembly comprising an offshore crane according to one of the clauses 1-8 and a vessel, wherein the substructure of the crane is directly mounted on the vessel such that it is immobile with respect to the vessel.
11] Method for compensating an offshore crane for local water movement,
wherein the offshore crane has a substructure and a superstructure, the superstructure comprising:
- a base,
- a boom structure, and
- a heave device comprising a winch, a hoisting cable, and a gripper configured for carrying a load;
wherein the boom structure has a fixed end supported by the base and a free end;
wherein the hoisting cable extends from the winch to the gripper and suspends from the free end of the boom structure freely to the gripper;
wherein the base is configured for slewing with respect to the substructure around a slewing axis;
wherein, at the fixed end, the boom structure is configured for luffing with respect to the base around a luffing axis, the luffing axis being perpendicular to the slewing axis;
wherein an x-axis, an y-axis and z-axis define an imaginary set of orthogonal axes, the z- axis extending vertically;
wherein the method comprises the following steps:
- measuring an x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement;
- determining -- on the basis of the measured x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement -- an x-, y-, and z- translation experienced by the free end of the boom structure due to movement of the substructure, and
neutralizing these determined x-, y-, and z-translations by correspondingly actuating the actuator system such that the position of the gripper or the position of the free end of the boom structure is kept stationary with respect to a predetermined target location.
12] Method according to clause 11 , wherein the actuator system comprises the slewing actuator and the luffing actuator.
13] Offshore crane comprising a substructure and a superstructure,
wherein the superstructure comprises:
- a base,
- a boom structure, and
- a heave device comprising a winch, a hoisting cable, and a gripper configured for carrying a load;
wherein the crane comprises a slewing actuator and a luffing actuator;
wherein the boom structure has a fixed end supported by the base and a free end;
wherein the hoisting cable extends from the winch to the gripper and suspends from the free end of the boom structure freely to the gripper;
wherein the slewing actuator is configured for slewing the base with respect to the substructure around a slewing axis;
wherein, at the fixed end of the boom structure, the luffing actuator is provided which is configured for luffing the boom structure with respect to the base around a luffing axis, the luffing axis being perpendicular to the slewing axis;
wherein an x-axis, an y-axis and a z-axis define an imaginary set of orthogonal axes, the z- axis extending vertically;
wherein the crane furthermore includes a motion compensation system comprising:
- a sensor system configured
o for sensing x-axis translational movement, y-axis translational movement, z- axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement, and
o for generating sensor signals representing said sensed movements,
- an actuator system configured for manipulating the position of the gripper, and
- a control system generating control signals for driving the actuator system in
response to the sensor signals such that the position of the gripper is compensated for said sensed movements;
wherein the control system is connected to the sensor system for receiving the sensor signals from the sensor system;
wherein the control system is connected to the actuator system for sending the control signals to the actuator system;
wherein the actuator system comprises the slewing actuator and the luffing actuator, or in other words wherein the slewing actuator and luffing actuator are part of the actuator system controlled by control signals from the control system;
wherein the control system is adapted
- to determine from the sensor signals an x-, y-, and z-translation experienced by the free end of the boom structure due to said sensed movements, and
- to generate, on the basis of these determined x-, y-, and z-translations, control signals for driving the actuator system such that the position of the gripper or the position of the free end of the boom structure is kept stationary with respect to a predetermined target location.
In other words the position of the gripper is kept stationary by controlling at least the slewing actuator and the luffing actuator. In addition also further actuators may be controlled by the controller.
14] Offshore crane comprising a substructure and a superstructure,
wherein the superstructure comprises:
- a base,
- a boom structure, and
- a heave device comprising a winch, a hoisting cable, and a gripper configured for carrying a load;
wherein the crane comprises a slewing actuator and a luffing actuator;
wherein the boom structure has a fixed end supported by the base and a free end;
wherein the hoisting cable extends from the winch to the gripper and suspends from the free end of the boom structure freely to the gripper;
wherein the slewing actuator is configured for slewing the base with respect to the substructure around a slewing axis;
wherein, at the fixed end of the boom structure, the luffing actuator is provided which is configured for luffing the boom structure with respect to the base around a luffing axis, the luffing axis being perpendicular to the slewing axis;
wherein an x-axis, an y-axis and a z-axis define an imaginary set of orthogonal axes, the z- axis extending vertically;
wherein the crane furthermore includes a motion compensation system comprising:
- a sensor system configured
o for sensing x-axis translational movement, y-axis translational movement, z- axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement, and
o for generating sensor signals representing said sensed movements,
- an actuator system configured for manipulating the position of the gripper, and
- a control system generating control signals for driving the actuator system in
response to the sensor signals such that the position of the gripper is compensated for said sensed movements;
wherein the control system is connected to the sensor system for receiving the sensor signals from the sensor system;
wherein the control system is connected to the actuator system for sending the control signals to the actuator system;
wherein the actuator system comprises the slewing actuator and the luffing actuator, or in other words wherein the slewing actuator and luffing actuator are part of the actuator system controlled by control signals from the control system;
wherein the control system is adapted
- to determine from the sensor signals an x-, y-, and z-translation experienced by the free end of the boom structure due to said sensed movements, and
- to generate, on the basis of these determined x-, y-, and z-translations, control
signals for driving the actuator system such that i) the x- and y- position of the free end of the boom are kept stationary with respect to a predetermined target location,
and such that ii) the z-position of the gripper is kept stationary with respect to said predetermined target position.
In other words the position of the gripper is kept stationary by controlling at least the slewing actuator and the luffing actuator. In addition also further actuators may be controlled by the controller.
15] Offshore crane according to clause 13 or clause 14 in combination with one or more of clauses 3-8.
16] Assembly comprising an offshore crane according to one of the clauses 13-15 and a vessel, wherein the substructure of the crane is mounted on the vessel such that it is immobile with respect to the vessel.
17] Assembly comprising an offshore crane according to one of the clauses 13-15 and a vessel, wherein the substructure of the crane is directly mounted on the vessel such that it is immobile with respect to the vessel.
Claims
1] Offshore crane comprising a substructure and a superstructure,
wherein the superstructure comprises:
- a base,
- a boom structure, and
- a heave device comprising a winch, a hoisting cable, and a gripper configured for carrying a load;
wherein the crane comprises a slewing actuator and a luffing actuator;
wherein the boom structure has a fixed end supported by the base and a free end;
wherein the hoisting cable extends from the winch to the gripper and suspends from the free end of the boom structure freely to the gripper;
wherein the slewing actuator is configured for slewing the base with respect to the substructure around a slewing axis;
wherein, at the fixed end of the boom structure, the luffing actuator is provided which is configured for luffing the boom structure with respect to the base around a luffing axis, the luffing axis being perpendicular to the slewing axis;
wherein an x-axis, an y-axis and a z-axis define an imaginary set of orthogonal axes, the z- axis extending vertically;
wherein the crane furthermore includes a motion compensation system comprising:
- a sensor system configured
o for sensing x-axis translational movement, y-axis translational movement, z- axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement, and
o for generating sensor signals representing said sensed movements,
- an actuator system configured for manipulating the position of the gripper, and
- a control system generating control signals for driving the actuator system in
response to the sensor signals such that the position of the gripper is compensated for said sensed movements;
wherein the control system is connected to the sensor system for receiving the sensor signals from the sensor system;
wherein the control system is connected to the actuator system for sending the control signals to the actuator system;
wherein the control system is adapted
- to determine from the sensor signals an x-, y-, and z-translation experienced by the free end of the boom structure due to said sensed movements, and
- to generate, on the basis of these determined x-, y-, and z-translations, control signals for driving the actuator system such that the position of the gripper or the position of the free end of the boom structure is kept stationary with respect to a predetermined target location.
2] Offshore crane comprising a substructure and a superstructure,
wherein the superstructure comprises:
- a base,
- a boom structure, and
- a heave device comprising a winch, a hoisting cable, and a gripper configured for carrying a load;
wherein the crane comprises a slewing actuator and a luffing actuator;
wherein the boom structure has a fixed end supported by the base and a free end;
wherein the hoisting cable extends from the winch to the gripper and suspends from the free end of the boom structure freely to the gripper;
wherein the slewing actuator is configured for slewing the base with respect to the substructure around a slewing axis;
wherein, at the fixed end of the boom structure, the luffing actuator is provided which is configured for luffing the boom structure with respect to the base around a luffing axis, the luffing axis being perpendicular to the slewing axis;
wherein an x-axis, an y-axis and a z-axis define an imaginary set of orthogonal axes, the z- axis extending vertically;
wherein the crane furthermore includes a motion compensation system comprising:
- a sensor system configured
o for sensing x-axis translational movement, y-axis translational movement, z- axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement, and
o for generating sensor signals representing said sensed movements,
- an actuator system configured for manipulating the position of the gripper, and
- a control system generating control signals for driving the actuator system in
response to the sensor signals such that the position of the gripper is compensated for said sensed movements;
wherein the control system is connected to the sensor system for receiving the sensor signals from the sensor system;
wherein the control system is connected to the actuator system for sending the control signals to the actuator system;
wherein the control system is adapted
- to determine from the sensor signals an x-, y-, and z-translation experienced by the free end of the boom structure due to said sensed movements, and
- to generate, on the basis of these determined x-, y-, and z-translations, control
signals for driving the actuator system to keep i) the x- and y- position of the free end of the boom stationary with respect to a predetermined target location, and to keep ii) z-position of the gripper stationary with respect to said predetermined target position.
3] Offshore crane according to claim 1 or 2, wherein the actuator system comprises the slewing actuator and the luffing actuator.
4] Offshore crane according to one of claims 1-3,
wherein the actuator system comprises:
- the slewing actuator configured for actuating the base to rotate around the slewing axis, and
- the luffing actuator configured for actuating the boom structure to rotate around the luffing axis; and
wherein the control system is adapted to generate a slewing control signal for driving the slewing actuator; and
wherein the control system is adapted to generate a luffing control signal for driving the luffing actuator.
5] Offshore crane according to one of the claim 1-4,
wherein the boom structure is a knuckle boom having a first boom member and a second boom member;
wherein the first and second boom member are connected to each other by a knuckle hinge configured for knuckling the first and second boom member with respect to each other around a knuckle axis, the knuckle axis being parallel to the luffing axis.
6] Offshore crane according to claim 5,
wherein the actuator system further comprises a knuckle actuator configured for actuating the first and second boom member to rotate with respect to each other around the knuckle axis; and
wherein the control system is adapted to generate a knuckle control signal for driving the knuckle actuator.
7] Offshore crane according to one of the claims 1-6,
wherein the actuator system further comprises a heave actuator configured for paying out or hauling in the cable; and
wherein the control system is adapted to generate a heave control signal for driving the heave actuator.
8] Assembly comprising an offshore crane according to one of the claims 1-7 and a vessel, wherein the substructure of the crane is directly mounted on the vessel such that it is immobile with respect to the vessel.
9] Method for compensating an offshore crane for local water movement,
wherein the offshore crane has a substructure and a superstructure, the superstructure comprising:
- a base,
- a boom structure, and
- a heave device comprising a winch, a hoisting cable, and a gripper configured for carrying a load;
wherein the boom structure has a fixed end supported by the base and a free end;
wherein the hoisting cable extends from the winch to the gripper and suspends from the free end of the boom structure freely to the gripper;
wherein the base is configured for slewing with respect to the substructure around a slewing axis;
wherein, at the fixed end, the boom structure is configured for luffing with respect to the base around a luffing axis, the luffing axis being perpendicular to the slewing axis;
wherein an x-axis, an y-axis and z-axis define an imaginary set of orthogonal axes, the z- axis extending vertically;
wherein the method comprises the following steps:
- measuring an x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement;
- determining -- on the basis of the measured x-axis translational movement, y-axis translational movement, z-axis translational movement, x-axis rotational movement, y-axis rotational movement and z-axis rotational movement -- an x-, y-, and z- translation experienced by the free end of the boom structure due to movement of the substructure, and
- neutralizing these determined x-, y-, and z-translations by correspondingly actuating the actuator system such that the position of the gripper or the position of the free
end of the boom structure is kept stationary with respect to a predetermined target location.
10] Method according to claim 9, wherein the actuator system comprises the slewing actuator and the luffing actuator.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2020664A NL2020664B1 (en) | 2018-03-26 | 2018-03-26 | Offshore crane |
| NL2020664 | 2018-03-26 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2019190314A2 true WO2019190314A2 (en) | 2019-10-03 |
| WO2019190314A3 WO2019190314A3 (en) | 2020-04-02 |
Family
ID=62167866
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/NL2019/050184 Ceased WO2019190314A2 (en) | 2018-03-26 | 2019-03-25 | Offshore crane |
Country Status (2)
| Country | Link |
|---|---|
| NL (1) | NL2020664B1 (en) |
| WO (1) | WO2019190314A2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4008679A1 (en) * | 2020-12-03 | 2022-06-08 | Reel | Articulated boom crane, for offshore application |
| FR3117100A1 (en) * | 2020-12-03 | 2022-06-10 | Reel | Articulated jib crane, for offshore application |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010114359A1 (en) | 2009-04-03 | 2010-10-07 | Barge Master Ip B.V. | Motion compensation device for compensating a carrier frame on a vessel for water motion |
| WO2014123414A1 (en) | 2013-02-05 | 2014-08-14 | Barge Master Ip B.V. | Motion compensation device |
| WO2017103139A1 (en) | 2015-12-18 | 2017-06-22 | Van Aalst Group B.V. | 3d motion-compensated lifting assembly for cranes |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL2007761C2 (en) * | 2011-11-09 | 2013-05-13 | Ihc Holland Ie Bv | Vessel and crane with full dynamic compensation for vessel and wave motions. |
| MX357680B (en) * | 2012-06-06 | 2018-07-19 | Seaonics As | Hybrid crane. |
| WO2015199543A1 (en) * | 2014-06-23 | 2015-12-30 | Ulstein Idea Equipment Solutions Bv | Positioning system with distal end motion compensation |
-
2018
- 2018-03-26 NL NL2020664A patent/NL2020664B1/en active
-
2019
- 2019-03-25 WO PCT/NL2019/050184 patent/WO2019190314A2/en not_active Ceased
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010114359A1 (en) | 2009-04-03 | 2010-10-07 | Barge Master Ip B.V. | Motion compensation device for compensating a carrier frame on a vessel for water motion |
| WO2014123414A1 (en) | 2013-02-05 | 2014-08-14 | Barge Master Ip B.V. | Motion compensation device |
| WO2017103139A1 (en) | 2015-12-18 | 2017-06-22 | Van Aalst Group B.V. | 3d motion-compensated lifting assembly for cranes |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4008679A1 (en) * | 2020-12-03 | 2022-06-08 | Reel | Articulated boom crane, for offshore application |
| FR3117100A1 (en) * | 2020-12-03 | 2022-06-10 | Reel | Articulated jib crane, for offshore application |
| FR3117099A1 (en) * | 2020-12-03 | 2022-06-10 | Reel | Articulated jib crane, for offshore application |
| US11858783B2 (en) | 2020-12-03 | 2024-01-02 | Reel | Knuckle boom crane, for offshore application |
| EP4464648A3 (en) * | 2020-12-03 | 2025-01-15 | Reel | Articulated boom crane for offshore application |
Also Published As
| Publication number | Publication date |
|---|---|
| NL2020664B1 (en) | 2019-10-07 |
| WO2019190314A3 (en) | 2020-04-02 |
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