WO2018030897A1

WO2018030897A1 - Motion compensating crane system

Info

Publication number: WO2018030897A1
Application number: PCT/NO2017/050200
Authority: WO
Inventors: Mark CALLAWAY
Original assignee: Rolls-Royce Marine As
Priority date: 2016-08-10
Filing date: 2017-08-03
Publication date: 2018-02-15
Also published as: NO20161285A1; NO341050B1

Abstract

A method of controlling a crane (101) and a vessel (102) comprising a crane, for transferring equipment to a second vessel (2009, comprising a crane controller controlling the motion of the crane, a first motion reference unit (102) in communication with the crane controller, a second motion reference unit (103) in communication with the crane controller, wherein the crane controller is adapted to transfer the second motion reference unit to the second vessel, receive motion information from the first motion reference unit and the second motion reference unit, determine a relative motion between the vessel and the second vessel based on the received motion information and dynamically adjust the position of the crane to compensate for the relative motion between the vessel and the second vessel.

Description

Motion compensating crane system

INTRODUCTION

The present invention relates to a vessel comprising a crane for transfer of goods, provisions or ropes to another vessel.

BACKGROUND

Performing operations between two floating bodies, i.e. vessels, are often difficult because they are moving independently of each other in 6 degrees of freedom. The environment of wind, waves, and current act differently on the hulls of the different vessels and produce different motions. According to known systems to transfer goods and provisions with a crane from a first vessel to an offshore platform, the vessel and the offshore platform are both equipped with motion reference units that allows a control system to determine the relative motion between the vessel and the offshore platform. The crane is provided with a motion compensating manipulator that compensates for the determined relative motion between the vessel and the offshore platform. In the case the relative motion exceeds the compensation capabilities of the motion compensating manipulator, the control system will also control the crane motions to compensate for the excessive relative motion.

A tug, or tugboat, is a powerful, highly maneuverable boat or ship that is used for towing and pushing vessels. By towing and pushing the vessel, one or more tugs may maneuver the vessel during difficult maneuvering operations, such as in a harbor, in a narrow canal or during rescue operations of vessels in distress. During towing operations, the tug maneuvers the vessel by pulling a towline connected between a winch on the tug and the vessel. The towline is connected to the vessel by a series of manual operations. First, a crew member of the vessel throws a line towards the tug, the line is picked up by a crew member of the tug and attached to the towline. Then the crew of the vessel needs to pull the towline from the tug to the vessel and connect the towline to the vessel. This is a time consuming and cumbersome method. SUMMARY OF THE INVENTION

According to a first aspect, the invention provides a vessel comprising a crane for transferring equipment to a second vessel, comprising a crane controller controlling the motion of the crane, a first motion reference unit in communication with the crane controller, a second motion reference unit in communication with the crane controller, wherein the crane controller is adapted to transfer the second motion reference unit to the second vessel, receive motion information from the first motion reference unit and the second motion reference unit, determine a relative motion between the vessel and the second vessel based on the received motion information and dynamically adjust the position of the crane to compensate for the relative motion between the vessel and the second vessel. The vessel may further comprise a dynamic positioning system in communication with the crane controller, wherein the crane controller is further adapted to dynamically adjust the position of the vessel to compensate for the relative motion between the vessel and the second vessel. The crane controller may further be adapted to

dynamically adjust the position of the vessel by controlling a distal end of the crane. The crane may be provided with a rope handling device adapted to deploy a rope on the second vessel. The vessel is may be adapted to tow the second vessel using the rope deployed on the second vessel. The second motion reference unit may be provided with a transceiver to communicate with the crane controller. The second motion reference unit may be adapted to be magnetically attached to the second vessel, clamped to the second vessel or fixed to the second vessel by an adhesive.

According to a second aspect, the invention provides a method of controlling a crane on a first vessel for transferring equipment to a second vessel, using a crane controller in communication with a first motion reference unit and a second motion reference unit, comprising controlling the motion of the crane to transfer the second motion reference unit to the second vessel, receive motion information from the first motion reference unit and the second motion reference unit, determine a relative motion between the vessel and the second vessel based on the received motion information, and dynamically adjust the position of the crane to compensate for the relative motion between the vessel and the second vessel. The vessel may further comprises a dynamic positioning system in communication with the crane controller, wherein the method further comprises dynamically adjusting the position of the vessel to compensate for the relative motion between the vessel and the second vessel. The method may further comprise dynamically adjusting the position of the vessel by controlling a distal end of the crane. The crane may be provided with a rope handling device, wherein the method further comprises deploying a rope on the second vessel by using the rope handling device.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention will now be described with reference to the followings drawings, where:

Fig. 1 illustrates a vessel transferring a motion reference unit according to an embodiment of the present invention.

Fig. 2a, 2b and 2c illustrate a vessel controlling a crane according to an

embodiment of the present invention.

Fig. 3 illustrates an exemplary embodiment of a control system of the present invention.

Fig. 4 illustrates an exemplary dynamic positioning control system. DETAILED DESCRIPTION

The present invention will be described with reference to the drawings.

Fig. 1 illustrates a first vessel 100 comprising a crane 101 for transferring equipment to a second vessel. The first vessel 100 comprises a crane controller controlling the motion of the crane 101 , a first motion reference unit 102 in communication with the crane controller and a second motion reference unit 103 in communication with the crane controller. The motion reference units 102, 103 may comprise any type of motion sensor, preferably providing six-degree of freedom motion information. The first motion reference unit 102 is positioned in or on the hull of the first vessel 100. The second motion reference unit 103 is here shown at a distal end of the crane 101 . The crane controller is adapted to transfer the second motion reference unit 103 to the second vessel. The second motion reference unit may be connected to the second vessel without aid from any crew personnel. The transfer of the second motion reference unit 103 may be a soft- touch transfer. The second motion reference unit may be adapted to be

magnetically attached to the second vessel or be fixed to the second vessel by use of an adhesive. Alternatively, the transfer of the second reference unit 103 may be adapted to be clamped to the second vessel. A camera 106 may be positioned on the crane 101 , e.g. near the second motion reference unit 103. The camera 106 may provide visual feedback to a crane operator for positioning of the second motion reference unit 103 on the second vessel. When the second motion reference unit is connected to the second vessel, the crane controller receives motion information from both the first motion reference unit 102 and the second motion reference unit 103. The second motion reference unit 103 may be provided with a transceiver to communicate with the crane controller. Alternatively, the second motion reference unit 103 may be provided with a transmitter for one-way communication to the crane controller. The crane controller determines a relative motion between the first vessel and the second vessel based on the received motion information from both the first motion reference unit 102 and the second motion reference unit 103. The crane controller then dynamically adjust the position of the crane 101 to compensate for the relative motion between the first vessel 100 and the second vessel.

The first vessel 100 may further comprise a dynamic positioning system in communication with the crane controller. A dynamic positioning (DP) system is a computer-controlled system to automatically maintain the first vessel's position and heading by using its own propellers and thruster based on a plurality of input parameters. The DP-system may work in unison with steering input from the captain of the first vessel, such that the captain can cede the control of the propellers and thrusters to the DP-system, while the captain focuses on the maneuvering, surface traffic etc. In this manner is the control of the propellers and thrusters carried out semi-autonomously by the DP-system. The crane controller in communication with the dynamic positioning system may be further adapted to, not only dynamically adjust the position of the crane to compensate for the relative motion between the first vessel and the second vessel, but also dynamically adjust the position of the first vessel 100 to compensate for the relative motion between the first vessel 100 and the second vessel. The crane controller 102 may further be adapted to dynamically adjust the position of the first vessel 100 by controlling the distal end of the crane 101. This allows the captain of the first vessel to cede the control of the vessel to the crane controller. The captain will then only drive the distal end crane, such that e.g. an approach towards the second vessel will be controlled by a crane control input only. The crane controller in combination with the dynamic positioning system then handles the movement of the first vessel and the crane movement to allow dynamic positioning movement of the distal end of the crane.

Fig. 1 illustrates an exemplary embodiment of the present invention, where the crane 101 is provided with a rope handling device 104 adapted to deploy a rope 105 on the second vessel. The rope 105 may e.g. be deployed on a pollard on the second vessel. The first vessel 100, e.g. a tug, may further be adapted to tow the second vessel using the rope 105 deployed on the second vessel.

According to embodiments, there is provide a method of controlling a crane 101 on a first vessel 100 for transferring equipment to a second vessel, using a crane controller in communication with a first motion reference unit 102 and a second motion reference unit 103 as described above. The method comprises controlling the motion of the crane 101 to transfer the second motion reference unit 103 to the second vessel, receive motion information from the first motion reference unit 102 and the second motion reference unit 103, determine a relative motion between the first vessel 100 and the second vessel based on the received motion information, and dynamically adjust the position of the crane 101 to compensate for the relative motion between the first vessel 100 and the second vessel.

The first vessel may further comprise a dynamic positioning system as described above, and the method may further comprises dynamically adjusting the position of the first vessel 100 to compensate for the relative motion between the first vessel 100 and the second vessel. The method may further comprise dynamically adjusting the position of the vessel by controlling a distal end of the crane. The crane 101 may be provided with a rope handling device 104 as described above, and the method may further comprise deploying a rope 105 on the second vessel by using the rope handling device 104.

Fig. 2a to 2d illustrates illustrates a vessel controlling a crane according to an exemplary embodiment of the present invention. In Fig. 2a, the second motion reference 103 is transferred from the crane 101 of the first vessel 100 to a second vessel 200. The second motion reference unit 103 may be connected to the steel hull of the second vessel 200 using magnets. The crane 101 then back off, as shown in Fig. 2b, and waits for the crane controller to receive motion information from the second motion reference unit 103 and determine the relative motion between the first vessel 100 and the second vessel 200. The crane controller dynamically adjust the position of the crane 101 to compensate for the relative motion between the first vessel 100 and the second vessel 200, such that the crane operator may, as shown in Fig. 2c, transfer equipment, e.g. a rope 105, to the second vessel 200 by controlling the distal end of the crane 101 , which is now only moving in reference to the second vessel 200.

Fig. 3 illustrates an exemplary embodiment of a control system 300 of the present invention. The crane controller 301 is, as described above, connected to the dynamic positioning system 302. The dynamic positioning system 302

automatically controls the position and heading of the first vessel 100 by using its own propellers and thruster based on a plurality of input parameters. One of the inputs being the input from the crane controller 301 , and vice versa.

The first vessel 100 is acted on by wind, waves and sea current. In addition, the first vessel may operate under difficult maneuvering operations, such as in a harbor or in a narrow canal, where the first vessel 100 may face other hazards such as other surface traffic, land, rocks and other fixed hazards. The DP-system may therefore receive additional input parameters from sensors 303 and navigational systems 304. Based on the plurality of input parameters the DP control system 302 is controlling the position, heading and amount of thrust of the first vessel 100. The DP control system 302 determines when, where and how the first vessel should be moved. When the DP control system 302 determines that the first vessel should move, the DP control system 302 outputs movement instructions including speed and direction to a propulsion control unit.

Fig. 4 illustrates an exemplary arrangement 400 for the dynamic positioning control system 302. The DP control system checks current operating instructions 401. The DP control system 400 may check parameters relating meteorological input parameters 402, environmental input parameters 403, movement of the first vessel 404 and crane movement related parameters 407. If the first vessel has drifted away, or is likely to drift away, from the second vessel, or the position of the first vessel relative to the second vessel has changed, the DP control system outputs movement instructions to counteract the drift or change in position. The DP control system 400 may also check parameters relating to the actual position of the first vessel relative to land, rocks and other fixed hazards 405. If the DP control system 400 determines that the first vessel is too close to any fixed hazards, the DP control system outputs movement instructions to move the first vessel safely away from the fixed hazards. The DP control system 400 may also check parameters relating to the position of the vessel relative to other surface traffic 406, evaluates the surface traffic parameters in view of relevant navigational rules. If the DP control system 400 determines that the first vessel should move away from other surface traffic, the DP control system outputs movement instructions to move the first vessel accordingly.

Wind, waves and sea currents acting on first vessel causes the first vessel to move from the desired location or path, thus also changing the parameters relating to crane movement. The DP control system may calculate the movement from the desired location or path, e.g. the drift, based on meteorological parameters and environmental input parameters such as wind direction, wind strength, water temperature, air temperature, barometric pressure, wave height etc. The input parameters are provided by relevant sensors connected to DP control system such as a wind meter, thermometer, barometer etc. When the DP-control system has calculated the drift, the system output movement instructions to counteract the drift. Other input parameters to calculate the drift may include data from movement sensors such as a gyro, an accelerometer, a gyrocompass and a turn-rate indicator. Movement of the first vessel may also be calculated from actual position

parameters of the first vessel relative to the desired location. The actual position parameters may be obtained from navigation systems connected to the DP control system. The navigation system may be a ground based radio navigation system, such as DECCA, LORAN, GEE and Omega, or a satellite navigation systems, such as GPS, GLONASS, Galileo and BeiDou. In the case of satellite navigation systems, the accuracy of the actual location may be improved by input to the CP control system from a Differential Global Positioning System (DGPS).

The DP-control system may also receive input parameters from electronic navigational charts. Combined with input parameters from the navigation systems, this allows the DP control system to determine movement instructions that safely controls the first vessel from colliding with land, rocks and other fixed hazards. For this purpose, the DP-control system may also receive input parameters from other sensors such as a sonar, marine radar, and/or an optical system using a camera. The sonar may provide information about underwater hazards such as land, rocks, underwater vessel etc. The marine radar and/or optical system may provide information about overwater hazards such as land and other surface vessels. The marine radar and/or optical system may also provide navigation information from sea marks such as beacons, buoys, racons, cairns and lighthouses.

The first vessel may have to comply with navigational rules for preventing collision with other ships or vessels. A database comprising the relevant navigational rules for an operation location of the first vessel may be included in the DP control system. In one embodiment, the DP control system receives input parameters relating to other surface traffic, evaluates the surface traffic parameters in view of the relevant navigational rules, when determining when and where the first vessel should be moved. The input parameters relating to surface traffic may be provided by sensors and systems connected to the vessel controller unit such as a marine radar, an Automatic Identification System (AIS) and an automatic radar plotting aid (ARPA). In one embodiment, the input parameters relating to surface traffic may be provided by optical sensors such as a camera. The optical sensors may observe and recognize other surface vessels and provide navigation information from sea marks such as beacons, buoys, cairns and lighthouses.

The crane controller and the dynamic positioning system may be implemented in a computer having at least one processor and at least one memory. An operating system runs on the at least one processor. Custom programs, controlled by the system, are moved into and out of memory. These programs include at least the crane controller unit and the dynamic positioning system as described above. The system may further contain a removable memory component for transferring images, maps, instructions or programs.

Having described preferred embodiments of the invention it will be apparent to those skilled in the art that other embodiments incorporating the concepts may be used. These and other examples of the invention illustrated above are intended by way of example only and the actual scope of the invention is to be determined from the following claims.

Claims

1 . Vessel comprising a crane for transferring equipment to a second vessel, comprising:

a crane controller controlling the motion of the crane;

a first motion reference unit in communication with the crane controller; a second motion reference unit in communication with the crane controller; wherein the crane controller is adapted to

transfer the second motion reference unit to the second vessel; receive motion information from the first motion reference unit and the second motion reference unit;

determine a relative motion between the vessel and the second vessel based on the received motion information;

dynamically adjust the position of the crane to compensate for the relative motion between the vessel and the second vessel.

2. Vessel according to claim 1 , wherein the vessel further comprises a dynamic positioning system in communication with the crane controller, wherein the crane controller is further adapted to dynamically adjust the position of the vessel to compensate for the relative motion between the vessel and the second vessel.

3. Vessel according to claim 2, wherein the crane controller is further adapted to dynamically adjust the position of the vessel by controlling a distal end of the crane.

4. Vessel according to any of the proceeding claims, wherein the crane is provided with a rope handling device adapted to deploy a rope on the second vessel.

5. Vessel according to claim 4, wherein the vessel is adapted to tow the second vessel using the rope deployed on the second vessel.

6. Vessel according to claim 1 , wherein the second motion reference unit is provided with a transceiver to communicate with the crane controller.

7. Vessel according to claim 1 , wherein the second motion reference unit is adapted to be magnetically attached to the second vessel.

8. Vessel according to claim 1 , wherein the second motion reference unit is adapted to be clamped to the second vessel.

9. Vessel according to claim 1 , wherein the second motion reference unit is adapted to be fixed to the second vessel by an adhesive.

10. Method of controlling a crane on a first vessel for transferring equipment to a second vessel, using a crane controller in communication with a first motion reference unit and a second motion reference unit, the method comprising:

controlling the motion of the crane to transfer the second motion reference unit to the second vessel;

receive motion information from the first motion reference unit and the second motion reference unit;

determine a relative motion between the vessel and the second vessel based on the received motion information; and

1 1 . Method according to claim 10, wherein the vessel further comprises a dynamic positioning system in communication with the crane controller, wherein the method further comprises dynamically adjusting the position of the vessel to compensate for the relative motion between the vessel and the second vessel.

12. Method according to claim 1 1 , wherein the method further comprises dynamically adjusting the position of the vessel by controlling a distal end of the crane.

13. Method according to any of claims 10 to 12, wherein the crane is provided with a rope handling device, wherein the method further comprises deploying a rope on the second vessel by using the rope handling device.