Mooring system with active control

Abstract

A vessel mooring system which includes at least two mooring robots secured to a terminal, each robot includes an attractive force attachment element eg. a vacuum cup and a base structure fixed relative to the terminal. The attachment element is able to be engaged with a vertically extending side vessel surface and to exert an attractive force normal to the vessel surface at where it is to be attached. Each robot can measure the attractive force between the attachment element and the vessel to provide an “attractive force capacity reading”. Also provided is capability to measure the force between the attachment element and the fixed structure of the mooring robot to provide a “normal force reading”. From monitoring of the relationship between the attractive force capacity reading and the normal force a control of the mooring robot can be provided such that if there is a tending to separate the attachment elements from said vessel the attractive force may be increased and/or alarm is sounded.

1 . A method of controlling a vessel mooring system, said system including at least one mooring robot for releasably fastening a vessel floating at the surface of a body of water to a terminal, the mooring robot including an attractive force attachment element displaceably engaged to a base structure of said mooring robot, said base structure being affixed to said terminal, said attractive force attachment element being releasably engagable with a vessel surface for making fast the vessel with said terminal, the mooring robot providing active translational movement of the attractive force attachment element relative to the base structure to allow thereby the movement of a vessel in a direction selected from any one or more of
 (i) an athwartship direction,   (ii) a longitudinal direction, and   (iii) a vertical direction   wherein said method, after the associating of the vessel with the mooring system by allowing the vessel surface to be engaged by the attractive force attachment element and the establishing of an attractive force between said vessel and said mooring robot, comprises;   (a) measuring the attractive force between the vessel surface and the attractive force attachment element, for the purposes of determining the holding capacity in a direction selected from at least one of
 (i) a direction generally parallel to the attractive force direction, 
 (ii) a direction generally normal to the attractive force direction and horizontally, and 
 (iii) a direction generally normal to the attractive force direction and vertically; 
   (b) measuring the force between the attractive force attachment element and the base structure of the mooring robot in a direction selected from any one or more of
 (i) the direction generally parallel to the attractive force direction, 
 (ii) the direction generally normal to the attractive force direction and horizontally, and 
 (iii) the direction generally normal to the attractive force direction and vertically; and 
   (c) monitoring the relationship between the attractive force and the force(s) measured in (b), wherein an alarm is triggered when any one or more of the forces measured in (b), in a direction to tend toward allowing relative movement between the attractive force attachment element and the said vessel, approaches an attractive force dependent holding capacity in the direction to tend towards allowing relative movement of the attractive force attachment element with said vessel.   
   
   
       2 . The method of  claim 1 , wherein the attractive force attachment element comprises a variable attractive force attachment element, and wherein the method further includes, when any one or more of the forces measured in (b) reach a predefined limit tending toward allowing relative movement between the variable force attractive element and the said vessel in a direction parallel to such force(s) measured, the controlling to vary the attractive force between the vessel surface and the variable attractive force attachment element in response to the force(s) measured in (b). 
   
   
       3 . The method of  claim 1 , wherein the attractive force attachment element comprises a variable attractive force attachment element, and wherein the method further includes, when any one or more of the forces measured in (b) reach a predefined limit tending toward allowing relative movement between the variable force attractive element and the said vessel in a direction parallel to such force(s) measured, the controlling to vary the attractive force between the vessel surface and the variable attractive force attachment element proportional to the force(s) measured in (b). 
   
   
       4 . The method of  claim 1 , wherein the attractive force attachment element comprises a variable attractive force attachment element, and wherein the method further includes, when any one or more of the forces measured in (b) reach a predefined limit tending toward allowing relative movement between the variable force attractive element and the said vessel in a direction generally parallel to such force(s) measured, the controlling by varying of the attractive force between the vessel surface and the variable attractive force attachment element when the force(s) measured in (b) reaches a maximum limit of a predetermined range. 
   
   
       5 . The method of  claim 1 , wherein the force(s) measured in (b) between the attractive force attachment element and the base structure is continuously monitored and determined from a signal responsive to a transducer, and wherein said signal responsive to said transducer is displayed on a control system visually, to indicate the force (s) between vessel and said base structure of said mooring robot. 
   
   
       6 . The method of  claim 1 , wherein said system included a plurality of spaced apart mooring robots, each presenting an attractive force attachment element to engage to a surface of said vessel, and wherein the force(s) as measured in (b) between the attractive force attachment element and the base structure of each mooring robot is continuously monitored and determined from a signal responsive to a transducer,
 wherein said signal responsive to said transducer is displayed on a control system visually, to indicate the force (s) between vessel and said base structure of said mooring robot.   
   
   
       7 . The method of  claim 1 , wherein said system included a plurality of spaced apart mooring robots, each presenting an attractive force attachment element to engage to a surface of said vessel, and wherein said method further includes, when any one or more of the forces measured in (b) of one of said mooring robots tends toward allowing relative movement between the attractive force attachment element and the said vessel in a direction parallel to such force(s) measured by such approaching a holding capacity of the attractive force attachment element in any such direction, at least one of the other mooring robots is controlled for movement of its' attractive force attachment element relative to said base structure in a direction to vary the force between its attractive force attachment element and its base structure in a direction opposite to such said direction to thereby reduce the force in such said direction between the attractive force attachment element and its said base structure of said one mooring robot. 
   
   
       8 . The method of  claim 1 , wherein said system includes a plurality of spaced apart mooring robots, each presenting a variable attractive force attachment element to engage to a surface of said vessel, and wherein said method further includes, when any one or more of the forces measured in (b) of one of said mooring robots tends toward allowing relative movement between the variable force attractive element and the said vessel in a direction generally parallel to such force(s) measured by such approaching a holding capacity of the attractive force attachment element in any such direction, at least one of the other mooring robots is controlled to vary its attractive force. 
   
   
       9 . The method of  claim 1 , wherein the attractive force between each attractive force attachment element and the vessel surface is measured and a signal corresponding to the measured attractive force is transmitted for the purpose of display on a control system. 
   
   
       10 . The method of  claim 1 , wherein the attractive force between said attractive force attachment element and the vessel surface is measured, and a signal corresponding to the measured attractive force is transmitted for the purpose of comparison with the measured force(s) of (b), and wherein an alarm is triggered when any one or more of the forces measured in (b) reaches a proportion of a force (the “holding force”) required to result in relative movement between said attractive force attachment element and said vessel, which holding force is dependent on attractive force measured. 
   
   
       11 . The method of  claim 1 , wherein the attractive force between said attractive force attachment element and the vessel surface is measured and a signal corresponding to the measured attractive force is transmitted for the purpose of comparison with the measured force(s) of (b), and wherein the attractive force is varied when any one or more of the forces measured in (b) reaches a limit corresponding to a force required to result in relative movement between said attractive force attachment element and said vessel, which holding force is dependent on the measured attractive force. 
   
   
       12 . The method of  claim 1 , wherein the attractive force attachment element is of a kind to be engaged with a planar surface of said vessel with its attractive force acting normal only to said planar surface, and wherein the attractive force between each attractive force attachment element and the planar surface is measured and a signal corresponding to the measured attractive force is transmitted for the purpose of comparison with the force measured in (b) (ii), and wherein an alarm is triggered when such force in a direction to tend toward resulting in a relative movement of said attractive force attachment element and said vessel in the direction parallel to the force measured in (b) (ii), approaches the holding capacity of said attractive force attachment element with said vessel as determined from the measured attractive force. 
   
   
       13 . The method of  claim 1 , wherein the attractive force attachment element is configured to be engaged with a planar surface of said vessel with its attractive force acting normal only to said planar surface and comprises a variable attractive force attachment element,
 wherein the attractive force between each attractive force attachment element and the planar surface is measured and a signal corresponding to the measured attractive force is transmitted for the purpose of comparison with the force measured in (b) (ii), and wherein, when such force in a direction reaches a predefined limit tending toward resulting in a relative movement of said attractive force attachment element and said vessel in the direction generally parallel to the force measured in (b) (ii) approaches the holding capacity of said attractive force attachment element with said vessel, the attractive force is varied.   
   
   
       14 . The method of  claim 1 , wherein, when the force between the mooring robot and the vessel parallel to the direction of force measured in (b) (i) tends toward resulting in a separation of said attractive force attachment element from said vessel exceeds a first threshold, the mooring robot adopts a safe mode wherein the attractive force between the vessel surface and the attractive force attachment element changes to a maximum attractive force. 
   
   
       15 . A vessel mooring system, suitable for mooring a vessel to a terminal, which may be a fixed or floating terminal, which comprises
 at least two mooring robots secured to the terminal, each mooring robot including   a base structure fixed relative to the terminal, and   an attractive force attachment element moveably engaged to the base structure, said attractive force attachment element being releasably engageable with an adjacent vessel surface to secure the vessel to said terminal, said attractive force attachment element capable of exerting an attractive force normal to said vessel surface at which it is to be attached for counteracting external forces (“loading forces”) being exerted on the vessel; and   one or more controllers to establish the attractive force between said vessel and said attractive force attachment element;   wherein each mooring robot includes actuators to actuate movement of the attractive force attachment element relative to the base structure in at least a direction selected from any one or both of an athwartship direction and longitudinal direction; said system further including   (a) a measuring device to measure the attractive force between the attractive force attachment element of each mooring robot and the vessel in a direction generally parallel to said normal to provide an “attractive force capacity reading” and   (b) a measuring device to measure the force between said attractive force attachment element and the base structure of said mooring robot in at least a direction corresponding to any one or more of:
 i. a direction generally parallel to the said normal to provide a “normal force reading” 
 ii. a direction generally horizontal and perpendicular to said normal to provide a “horizontal shear force reading”, and 
 iii. a direction generally vertical and perpendicular to the normal to provide a “vertical shear force reading” 
   (c) a sensor to monitor the relationship between said attractive force capacity reading and any one or more of said normal force reading, horizontal shear force reading, and vertical shear force reading to provide a, or several, “mooring status reading(s)”   (d) a controller to control each mooring robot responsive to said mooring status reading (s) in a manner such that when any one or more of normal force reading, horizontal shear force reading reaches a predefined limit, and vertical shear force reading in a direction tending to allowing a relative movement between said vessel and said attractive force attachment element of a said mooring robot, of the capacity of said attractive force attachment element to hold the vessel in such direction, said controller initiates at least one or more selected from the following:
 i. said controller to establish said attractive force in a manner to vary said attractive force, 
 ii. an alarm, and 
 iii. a displacement of the attractive force attachment element of at least one other mooring robot relative to its base structure, in a direction opposite to a direction that tends towards allowing a relative movement between said vessel and said attractive force attachment element of said mooring robot, to increase the loading force on said at least one other mooring robot and reducing the loading force on the said mooring robot in said direction that tends towards allowing a relative movement between said vessel and said attractive force attachment element of said mooring robot. 
   
   
   
       16 . The vessel mooring system of  claim 15 , wherein said attractive force attachment element comprises a vacuum pad or cup, and
 said controllers to establish the attractive force between said vessel and said attractive force attachment element comprises a vacuum system in fluid communication with said vacuum cup and includes a vacuum generator.   
   
   
       17 . The vessel mooring system of  claim 15 , wherein at least two mooring robots (the “bow set”) are provided to be engaged proximate more to the bow of a said vessel, and wherein at least two mooring robots (the “stern set”) are provided to be engaged proximate more to the stern of said vessel, and wherein said controller can control the attractive force of each attractive force attachment element in a manner wherein, when the attractive forces applied to the vessel surface by at least one of said mooring robot of each set reaches a first threshold, the controller operates in a manner to normalise the attractive force of each robot of each set. 
   
   
       18 . A vessel mooring system, suitable for mooring a vessel to a terminal, which may be a fixed or floating terminal (or a second vessel), said vessel mooring system comprising
 at least two mooring robots secured to a terminal, each mooring robot including   a base structure fixed relative to the terminal,   an attractive force attachment element engaged to the base structure, wherein said attractive force attachment element is releasably engageable with an adjacent vessel surface to secure the vessel to said terminal, said attractive force attachment element capable of exerting an attractive force generally normal to said vessel surface at where it is to be attached for counteracting external forces (“loading forces”) being exerted on the vessel; and   a variable actuator to establish the attractive force between said vessel and said attractive force attachment element   wherein for each robot, said system further includes   (a) a measuring device to measure the attractive force between the attractive force attachment element and the vessel to provide an “attractive force capacity reading” and   (b) a measuring device to measure the force between said attractive force attachment element and the base structure of said mooring robot at least in a direction generally parallel to the said normal to provide a “normal force reading”   (c) a sensor to monitor the relationship between said attractive force capacity reading and said normal force reading to provide a “mooring status reading”   (d) a controller to control the mooring robot responsive to said mooring status reading in a manner such that when the normal force reading in a direction tending to separate the attractive force attachment element from said vessel reaches an attractive force reading threshold, said controller initiates at least any one or both of selected from the following:
 i. inducing the variable actuator to establish said attractive force in a manner to vary said attractive force, and 
 ii. an alarm. 
   
   
   
       19 . The vessel mooring system of  claim 18 , wherein each mooring robot includes an actuator to actuate translational movement of the attractive force attachment element relative to the base structure in at least an athwartship direction, and wherein said actuator may in the event of the loading forces reaching a predetermined threshold, in addition initiate a displacement of attractive force attachment element of another robot of said system in the athwartship direction towards its said base structure, thereby causing the said other mooring robot to counteract an increased ratio of the loading forces exerted on the vessel. 
   
   
       20 . The vessel mooring system of  claim 18 , wherein said system further comprises
 a. a sensor to determine shear force holding capacity between said attractive force attachment element and said vessel resultant from said attractive force capacity reading, in a generally horizontal direction and perpendicular to said normal, to provide a “shear force holding capacity reading”   b. a sensor to measure the shear direction force, being a force generally parallel to said shear holding force, between said attractive force attachment element and said base structure of said mooring robot to provide a “shear force reading”   c. a sensor to monitor the relationship between said shear force capacity reading and said shear force reading to provide a “second mooring status reading”   
     wherein said controller for controlling the mooring robot is also responsive to said second mooring status reading in a manner such that when the shear force reading in a direction tending to allowing relative movement of said vessel and said attractive force attachment element, reaches a predetermined limit, said controller initiates at least one or more selected from the following:
 i. inducing the variable actuator to establish said attractive force in a manner to vary said attractive force, and 
 ii. an alarm. 
 
   
   
       21 . The vessel mooring system of  claim 19 , wherein said actuator to actuate translational movement of the attractive force attachment element comprises a linear actuator operable in at least the athwartship direction. 
   
   
       22 . The vessel mooring system of  claim 19 , wherein said actuator to actuate translational movement of the attractive force attachment element comprises a hydraulic linear actuator operable in at least the athwartship direction, said normal force measurement derived from a sensor to sense a hydraulic pressure of said hydraulic linear actuator. 
   
   
       23 . A vessel mooring system for controlling the mooring of a vessel with a wharf facility, said system comprising:
 at least one mooring robot for releasably fastening to said vessel, said mooring robot including
 i. a fixed structure fastened to said wharf facility, 
 ii. an attractive force attachment element for releasable engagement with a planar vertical surface of vessel, said attractive force attachment element moveably disposed from said fixed structure to allow its movement relative to said facility in 3 generally orthogonal directions, these being a generally vertical direction, a first horizontal direction generally normal to the vertical surface and a second horizontal direction generally parallel to the planar vertical surface, said attractive force attachment element capable of exerting an attractive force normal to said vessel surface at where it is to be attached for counteracting external forces (“loading forces”) being exerted on the vessel 
 iii. an actuator to actuate movement of the attractive force attachment element in at least said first and second horizontal direction; 
   a sensor to generate a force signal representative of a force between the fixed structure and said attractive force attachment element in a direction generally parallel to said first horizontal direction;   a sensor to generate a force signal representative of a force between the fixed structure and said attractive force attachment element in a direction generally parallel to said second horizontal direction;   a sensor to determine a force signal representative of the attractive force between said attractive force attachment element and said vessel in said first horizontal direction (the “tensile holding force”);
 a sensor to generate a force signal representative of the force between said attractive force attachment element and said vessel in said second horizontal direction (the “shear holding force”); and 
 an actuator responsive to said first and second and third mentioned sensors which, when one or more conditions are true, 
   which conditions are selected from:   (a) the force measured by said first mentioned sensor to determine a force signal reaches a predefined value which is approaching the tensile holding force, and   (b) the force measured by said second mentioned sensor to generate a force signal reaches a predefined value approaching the shear holding force,   actuates any one or more selected from the following;   (a) an alarm and   (b) a variation in the attractive force of said attractive force attachment element with said vessel and   (c) inducing the actuator to change the disposition of said attractive force attachment element relative to said wharf facility in a direction to reduce one or both of the tensile holding force and the shear holding force to below said predefined values.   
   
   
       24 . A mooring system for releasably affixing a vessel floating at the surface of a body of water to a terminal which is secured to the bottom of said body of water wherein said vessel is subjected to loading forces resultant from any one or more of wind, tides, water currents, waves, vessel loading levels, and movement actuated by said system, said system comprising
 at least one mooring robot which includes   a) a base structure affixed to one of said terminal or said vessel,   b) an attractive force attachment element engaged to said base structure, said attractive force attachment element adapted to become affixed to and establish an attachment with a surface of the other of said one of said terminal or vessel, said attachment being of an attractive kind establishing an attractive holding force generally normal to the surface at which it is to attach;   a sensor to determine the attractive holding force of said attractive force attachment element when said attractive force attachment element is in an attached relationship with said surface;   a sensor to determine a component of the attractive holding force in the shear direction when said attractive force attachment element is in an attached relationship with said surface, said shear direction holding force (herein after “horizontal shear direction holding force”) being in a direction which is generally horizontal and perpendicular to the normal direction to the surface;   a sensor for determining at least one or more selected from a group comprising of   a. the force (herein after “tensile force”) applied by said surface to said attractive force attachment element in a direction generally parallel to said normal, and   b. the force (herein after “horizontal shear force”) applied by said surface to said attractive force attachment element in a generally horizontal direction and perpendicular to said normal, and   a comparator for allowing comparison between
 i) said the attractive holding force and said tensile force and 
 ii) said the horizontal shear direction holding force and said horizontal shear force. 
   
   
   
       25 . The mooring system of  claim 24  wherein said comparator will actuate, when one or both of the following conditions occur
 i. said tensile force reaches a predetermined limit being a limit below the attractive holding force but approaching said attractive holding force in a direction to tend towards the release of said attractive force attachment element with said surface, and   ii. said horizontal shear force reaches a predetermined limit being a limit below the horizontal shear direction holding force but approaching said horizontal shear direction holding force in a direction to tend towards a relative movement in a horizontal direction between said surface and said attractive force attachment element,   one or more selected from   i. an actuator to establish and vary said attractive force, in a manner to vary said attractive holding force, and   ii. an alarm.   
   
   
       26 . The mooring system of  claim 24 , wherein said sensor to determine the attractive holding force of said attractive force attachment element when said attractive force attachment element is in an attached relationship with said surface includes
 a sensor suitable for determining the force between said attractive force attachment element and said surface in a direction generally normal to said surface, and   a sensor responsive to the signal from said sensor to determine the effective attractive holding force.   
   
   
       27 . The mooring system of  claim 24 , wherein said attractive force attachment element is movably engaged to said base structure by a linkage mechanism, and there is provided an actuator to actively actuate the movement of said attractive force attachment element relative to said base structure in a direction parallel to said horizontal shear force direction, and in a direction generally parallel to said tensile force direction. 
   
   
       28 . The mooring system of  claim 24 , wherein said attractive force attachment element is movably engaged to said base structure by a linkage mechanism, and wherein there is provided an actuator to actively actuate the movement of said attractive force attachment element relative to said base structure parallel to said horizontal shear force direction, and comprising an actuator to actively actuate the movement generally parallel to said tensile force direction wherein said comparator for allowing comparison further initiates, when one or both of the following conditions are met;
 i. said tensile force reaches a predetermined limit being a limit below the attractive holding force but approaching said attractive holding force in a direction to tend towards the release of said attractive force attachment element with said surface, and   ii. said horizontal shear force reaches a predetermined limit being a limit below the horizontal shear direction holding force but approaching said horizontal shear direction holding force in a direction to tend towards a relative movement in a horizontal direction between said surface and said attractive force attachment element;   a change in velocity (acceleration or deceleration) of said attractive force attachment element by one or both of said actuator to actively actuate movement in order for said tensile force and/or horizontal shear force to remain below their respective limits.   
   
   
       29 . The mooring system of  claim 24 , wherein said attractive force attachment element comprises a variable attractive force attachment element wherein its attractive force may be varied by a controller to control the attractive force. 
   
   
       30 . The mooring system of  claim 29 , wherein said attractive force attachment element comprises a vacuum cup defining a pressure controllable cavity when engaged with said surface and wherein said controller to control the attractive force comprises a vacuum pump which is in fluid communication with said cavity to control the pressure in said cavity. 
   
   
       31 . The mooring system of  claim 24 , wherein said sensor to determine the shear direction holding force of said attractive force attachment element with said surface when said attractive force attachment element is in an attached relationship with said surface also determines the shear direction holding force (herein after “vertical shear-direction holding force”) in a generally vertical direction and perpendicular to said normal and wherein a sensor to measure the force (herein after “vertical shear force”) applied by said surface to said attractive force attachment element in the generally vertical direction and perpendicular to said normal is provided, to compare said vertical shear direction holding force with said vertical shear force. 
   
   
       32 . The mooring system of  claim 31 , wherein said sensor for allowing comparison will also initiate, when said vertical shear force reaches a predetermined limit being a limit below the vertical shear direction holding force but approaching said vertical shear direction holding force in a direction to tend towards a relative movement in a vertical direction between said surface and said attractive force attachment element,
 one or more selected from
 i. establishing and varying said attractive force, in a manner to vary said attractive holding force, and 
 ii. an alarm. 
   
   
   
       33 . The mooring system of  claim 24 , wherein said sensor to determine the horizontal shear force and/or tensile force includes
 a sensor to measure responsive to such force(s) and which is capable of generating a signal indicative of such force(s), and   a sensor to read which is capable of reading the generated signal, and wherein the said sensor to measure said sensor to read provides a signal useable by said comparator allowing comparison.   
   
   
       34 . The mooring system of  claim 24 , wherein
 said sensor to determine the attractive holding force includes   a sensor to measure responsive to such force and which is capable of generating a signal indicative of such force, and   a sensor to read which is capable of reading the generated signal, and   wherein said sensor to measure and said sensor to read provide a signal useable by said comparator allowing comparison.   
   
   
       35 . The mooring system of  claim 34 , wherein said attractive force attachment element comprises a vacuum cup defining a pressure controllable cavity when engaged with said surface and wherein said controller to control the attractive force comprises a vacuum pump which is in fluid communication with said cavity to control the pressure in said cavity, said sensor responsive to said attractive force comprising a pressure transducer engaged with said mooring robot in manner to measure the pressure differential between the cavity of said vacuum cup and ambient atmospheric pressure. 
   
   
       36 . The mooring system of  claim 24 , wherein said sensor to measure the said horizontal shear direction holding force uses a calculator to calculate such horizontal shear direction holding force from said measured attractive holding force. 
   
   
       37 . The mooring system of  claim 36 , wherein the calculator to calculate utilizes a table of empirically collected attractive holding force varying and dependent horizontal shear direction holding force data reliant on which said horizontal shear direction holding force can be determined. 
   
   
       38 . The mooring system of  claim 29 , wherein said actuator to actively actuate comprises at least one hydraulic ram. 
   
   
       39 . The mooring system of  claim 29 , comprising a sensor to measure the displacement of said attractive force attachment element relative to said base structure. 
   
   
       40 . The mooring system of  claim 29 , wherein an alarm is sounded when one of more of the limit of movement of said attractive force attachment element relative to said base structure is reached. 
   
   
       41 . The mooring system of  claim 29 , wherein the displacement of said attractive force attachment element relative to said base structure is visually represented. 
   
   
       42 . The mooring system of  claim 24 , wherein said attractive forces is able to be controlled by human input. 
   
   
       43 . The mooring system of  claim 29 , wherein said displacement is able to be controlled by human input.