JP2009227035A - Method and system of relative position control for floating body and vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a system of relative position control for a floating body and a vessel capable of controlling a shuttle tanker to operate within a safety area according to the motion of a platform on the ocean. <P>SOLUTION: The system comprises various sensors 200 detecting an environmental situation around the shuttle tanker 1000, an external force database 10 stored by calculating in advance the relation between the environmental situation and an environmental external force affecting a hull depending on the environmental situation, an external force assessment means 20 evaluating the external force affecting the hull based on the result detected by the various sensors 200 and the data of the external database 10, a bow azimuth optimizing means 30 optimizing bow azimuth so that the external force becomes minimum, and a dynamic positioning control device 500 controlling the bow azimuth at least for a targeted floating body structure 2000 based on the output of the bow azimuth optimizing means 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a relative position control method and system, and more particularly to a relative position control method for a floating body and a ship for controlling the heading and position maintenance of a ship such as a shuttle tanker and a target offshore platform. Regarding the system.

  Offshore platforms are often used as floating bodies in systems that produce oil from the ocean floor. As this offshore platform, FPSO (Floating Production, Storage and Offloading) is generally used, but in recent years, MPSO (Monocolumn Full Floating) which has superior motion performance compared to FPSO. Concepts such as “Production Storage and Offloading” are proposed. Specifically, MPSO is a cylindrical or polygonal floating body in which oil produced is stored.

  When shipping oil from MPSO, it is necessary to hold the position of a ship (shuttle tanker) in a safe area even under various environments. However, although MPSO is held in position by mooring, it has become clear through experiments and the like that it has a long periodic motion due to environmental disturbance and a large periodic motion due to vortex-induced motion (VIM) due to flow. Therefore, it is necessary to control the shuttle tanker to perform relative movement according to the MPSO movement so that the shuttle tanker can be operated in the safe area according to the MPSO movement.

  In other words, in the case of MPSO, if a lateral movement occurs starting to exhibit a VIM phenomenon, the MPSO mooring line (or a complex mooring line consisting of a chain and a synthetic fiber cord) moves, so if the shuttle tanker is in this vicinity, If the hull does not move, the shuttle tanker will hit the mooring line. On the other hand, if the shuttle tanker goes too far or gets too close, there is a risk that the hose will cut and oil will leak, or the shuttle tanker will hit MPSO. Therefore, it is necessary to maintain a relative position while maintaining a proper heading and a certain distance.

  Such a situation is not limited to MPSO. In other words, the offshore platform needs to stay within a limited range without being damaged even if the largest typhoon arrives. In addition, not only the purpose of use (oil drilling / production, gas search / production, discovery of hydrothermal deposits, increased production of seafood, etc.), but the functions according to each purpose of use should continue to be demonstrated over a long period of time. Need to be guaranteed.

  However, until now, the necessity of the above-mentioned on the offshore platform has not been recognized, and there is no technology to deal with this. In addition, as a conventional position maintenance technology for shuttle tankers related to a general offshore platform, only absolute position maintenance technology has been attempted. That is, control using PID (Proportional Integral Derivative) control or other advanced optimal control theory so that the hull moves to the position (Xd, Yd) and direction (ψd) indicated by the operator. It was just something that did system design.

  For example, Patent Document 1 discloses a technical idea of controlling a thruster based on a deviation between a target relative angle and an actual relative angle between an offshore platform and a shuttle tanker, but the deviation occurs instead of feedforward. From the point that control is performed using fuzzy control from the above, and the control value based on the database reflecting the reality is not calculated, it has been difficult to provide a precise solution to the new problem described above.

  For example, Patent Document 2 discloses a technical idea of estimating and calculating actual ship parameters and performing feedforward control and feedback control based on the optimum reference course, but feedforward control is performed based on the deviation of the heading. There was a limit to errors and responsiveness due to the method of correcting the control parameters. Even if the error is only a little on a ship, it becomes a serious safety threat such as cutting a mooring line, so it is practically difficult as a precise solution to the new problem described above.

Further, Patent Document 3 discloses a technical idea of performing feedforward control based on the reference course based on the computation result of the trajectory computation unit and performing correction by feedback control. Since the reference course is obtained and the limit by the theoretical value is large, it is practically difficult as a precise solution to the new problem described above.
JP 2002-173091 A Japanese Patent Laid-Open No. 09-207889 Japanese Patent Laid-Open No. 08-207894

  Under such circumstances, the inventors of the present application have continued to examine whether the problem can be solved by applying and developing DPS (Dynamic Positioning System) control technology. It was created by conducting research while facing each other.

  Therefore, the present invention has been made to provide a solution that could not be achieved by the prior art to the new problem that has not been recognized by the above-described prior art. It is an object of the present invention to provide a relative position control method for a floating body and a ship that can be controlled so as to be able to operate in a safe area, and a system therefor.

  In order to achieve such an object, the relative position control method of a floating body and a ship according to the present invention is based on information from a sensor that detects an environmental condition around the hull and database information of an external force acting on the hull according to the environmental condition. It evaluates the external force acting on the hull, optimizes the heading so that the external force is minimized, and controls at least the heading with respect to the target floating body based on the optimized result.

  By providing such a configuration, an environmental condition around the hull is detected by a sensor, and the external force acting on the hull is estimated and evaluated based on this information and the database information of the external environmental force. Since this database is created based on detailed experiments and / or numerical calculations, such an evaluation is more accurate and realistic than that derived from theoretical formulas to reflect conditions closer to actual ships. It will be close to. By controlling the position and direction of the ship based on this more accurate information, the relative position holding control between the floating body and the ship can be performed accurately.

  The technical idea according to the present application is to develop the conventional DPS control technology of a ship into a relative position maintaining technology. This is to follow-up control while maintaining a relative positional relationship according to the movement of the target floating body in accordance with the development needs described above. To the dynamic positioning control device developed from the conventional hull position holding device, the heading is optimized and calculated based on the information from the sensor that detects the environmental situation around the hull and the external force database information that works on the hull according to the environmental situation, The azimuth that minimizes the external force is input to the dynamic positioning control device as a command value. The external force database means that the external forces acting on the ship are organized as a database based on numerical calculations and experimental results, and online estimation is realized. As input to the optimization calculation program, external force evaluation results obtained from environmental information such as wind, waves, and flow around the hull using sensors, etc., and targets that are trying to maintain relative positions (other ships and offshore platforms) Position information) is assumed.

  In this case, in addition to the feedback control for controlling the position and heading of the ship, it is possible to control the position and direction of the ship by performing feedforward control based on the result of external force evaluation.

  By configuring in this way, the instantaneous external force due to changes in environmental conditions is estimated, and based on this estimation, not only feedback but also feedforward control is performed, i.e., before the ship starts moving due to strong external force. Therefore, the control can be performed more reliably and efficiently.

  In other words, in accordance with the concept of estimating the external force and applying feedforward first, in principle, the external force is instantaneously estimated in advance, and an operation that minimizes this is returned to the actuator. It is possible to operate the ship in a safe area according to the movement of the ship. In this case, the present application builds a database based on experimental results and calculation results obtained by experiments at a large experimental facility, and against this, using this program to estimate the instantaneous external force, Precise evaluation is possible because calculations are performed. Therefore, based on the obtained accurate evaluation, for example, if an external force having a specific magnitude is applied in a specific direction, it can be evaluated using a database that the external force in the near future can be canceled.

  In the above case, the sensor can also be configured to detect wave, wind, and tidal current conditions as environmental conditions.

  By configuring in this way, information on wind (wind speed, direction, etc.), tidal current (tide speed, direction, etc.), and waves (cycle, height, direction, etc.) is acquired by a sensor as environmental information, and this is stored in a database. This makes it possible to accurately and accurately evaluate external forces. This concept can be applied even in the case of a floating body having a cylindrical shape or a polygonal column shape like MPSO, and the relative position can be appropriately maintained.

  That is, in the case of MPSO, the outer shape is just a cylinder or a polygonal column, and when there is a flow or the like, it starts to exhibit a phenomenon of VIM motion that sways sideways. Therefore, by acquiring the conditions of wind (wind speed, direction, etc.), tidal current (tide speed, direction, etc.), and waves (cycle, height, direction, etc.) as information by the sensor, this acquisition information and experiments and numerical values in advance By collating with the database obtained by calculation, higher external force can be evaluated.

  In the above case, the database information can be configured to be based on the numerical calculation result and / or experimental data of the hull external force according to the environmental conditions around the hull. By configuring in this way, it is possible to evaluate the external force more reflecting the reality. In other words, since the sea state is a phenomenon that is not practically complex enough to be explained by a hypothesis / theoretical equation using a single variable, at present, there is a large error in any theoretical equation. There is no formula to calculate numerically. Conversely, the error caused by any current theoretical formula is extremely large. On the other hand, marine accidents have a risk that the damage caused by this may sometimes be very serious. In other words, in view of the magnitude of the effects of accidents such as mooring line breakage and oil leakage caused by unexpected external force, there is a possibility that an error that cannot be practically tolerated by the theoretical formula may occur. large. Therefore, it can be said that the use of a database closer to the actual value is much more significant for maritime safety than the theoretical formula that generates an error that may cause marine accidents. It can be said that this application was made based on this concept.

  That is, a database about the relationship between tidal current, wind, and wave is created by experiment or / and numerical calculation. Based on this, actual values of tidal current, wind, and wave are sensed. Using the sensing data as a key (condition), the corresponding external force evaluation value is extracted from the database by the program, and the external force is evaluated. . If there is no corresponding value in this database, correction calculation is performed by a separate correction program. As a result of the external force evaluation, the direction in which the bow is turned to optimize the external force is minimized. In this way, using a database for external force evaluation and ensuring that this database reflects the results of numerical calculations supported by experiments and experiments, accurate external force evaluation and position and orientation correction based on this Etc. are possible.

  In addition, in the above case, the environment information around the floating body can be used for control in addition to or in place of the information related to the environment situation around the hull.

  By configuring in this way, in addition to or instead of the environmental conditions around the hull, the environmental conditions around the floating body are detected by a sensor, and the external force acting on the hull based on this information and the environmental external force database information It can also be used as an auxiliary or alternative to the external force evaluation based on the environmental conditions around the hull described above. In consideration of the environmental situation around the hull as well as the environmental situation around the hull, or by substituting the environmental situation around the hull in consideration of the environmental situation around the hull, the database comparison is performed. Depending on the relative relationship between the two, more accurate and faster external force evaluation becomes possible.

  Moreover, since this database is created based on detailed experiments and / or numerical calculations, this external force evaluation was derived by a theoretical formula in order to reflect a state closer to a real value than a simple theoretical value. More accurate and closer to reality than things.

  Furthermore, the relative position control system for a floating body and a ship according to the present application calculates and / or tests and stores in advance a sensor for detecting an environmental condition around the hull, and a relationship between the environmental condition and an external force acting on the hull according to the environmental condition. An external force evaluation means for evaluating the external force acting on the hull based on the detection result of the sensor and the data of the database, an optimization means for optimizing the heading so as to minimize the external force, and the optimization means And a dynamic positioning control device for controlling the heading with respect to the target floating body based on the output.

  At this time, the sensor has a function of sensing and acquiring information such as wind (wind speed, direction, etc.), tidal current (tide speed, direction, etc.), waves (cycle, height, direction, etc.) as environmental information. Refers to an instrument.

  The database has a function of converting environmental information and external force evaluation value information into data corresponding to each other.

  The external force evaluation means, for example, acquires the data in the database using the data acquired by the sensor as a search key, and estimates and calculates the external force (by performing an operation such as applying a certain coefficient in some cases). It is realized by an algorithm, a program having a function of performing the same evaluation, or a ROM (Read Only Memory), a chip or the like (hereinafter collectively referred to as “program etc.”) incorporating the same.

  The optimization means means having a function of optimizing the heading so that the external force is minimized. For example, this can be minimized with respect to the external force obtained (output) by the external force evaluation means. The function (algorithm) for calculating the azimuth is realized by a program that causes a computer to execute the function.

  In addition, the dynamic positioning control device compares the set values with the values such as the bow direction and position of the ship and controls the pod propellers and thrusters as actuators so as to eliminate deviations. A device having a function of taking a signal from the direction optimization means and controlling the heading with respect to a target floating body.

  By providing such a configuration, the environmental situation around the hull is detected by a sensor, the relation between the environmental situation and the external environmental force acting on the hull based on this environmental situation is calculated in advance, and the data detected by the sensor and the data in the database Based on the above, the external force evaluation means evaluates the external force acting on the hull. Since this database is created based on detailed experiments or numerical calculations supported by experiments, such an evaluation is derived by a theoretical formula to reflect a state closer to a real value than a simple theoretical value. It is more accurate and close to reality than the other. Next, the heading is optimized by the optimization means so that the external force is minimized. On this basis, the dynamic positioning control device controls the heading with respect to at least the target floating body based on the output of the optimization means. Since the control of the heading is based on the information with higher accuracy, the relative position holding control between the floating body and the ship can be performed.

  In the above case, the dynamic positioning control device has a feedback control unit that controls the position and the heading of the ship, and adds the output of the external force evaluation means as a feedforward control signal to the signal of the feedback control unit. It can also be configured to control.

  This feedback control unit is a unit that has a function of controlling the direction of reducing this deviation by comparing the current state variable amount with the target value and returning the deviation. A device having a function of calculating the deviation by comparing the position of the ship with respect to the target floating body, the heading and the current position, the direction based on the output of the converting means, and operating the actuator in a direction to correct the deviation, or A program or the like for realizing such a function by a computer.

  By configuring in this way, the output of the external force evaluation means is added as a feedforward control signal to the signal of the feedback control unit to control the position and heading of the ship, so that a strong external force is applied before the ship starts to move. This can be avoided at the stage.

  In this case, controlling the position of the ship and the heading direction, that is, changing the direction, means moving forward and backward, laterally, rotating and rotating. As described above, the feedback compares the current state quantity with the target value and returns the deviation. Although feedback control is generally applied to ordinary industrial equipment, the hull moves after external force is applied like a ship, and it takes time to correct the heading associated therewith, and the safety threat is a catastrophe. In applications that may lead to the problem, it is desirable to use the feedforward control together.

  In addition, according to the present application, it is only necessary to add an algorithm (program) to the conventional hull position holding device, that is, only to modify the software, so that it is not necessary to drastically change the current control system as a whole.

  Furthermore, according to the present application, since the hull direction is controlled so as to minimize the external force while maintaining the relative position, the actuator does not require a large thrust force and a small time constant actuator (pod, azimuth thruster, etc.). Does not require high-performance thrusters.

  According to the method of the present invention, the environmental condition around the hull is detected by a sensor, and the external force acting on the hull is evaluated based on this information and the environmental external force database information. Because it is created based on numerical calculations, such an evaluation is more accurate and closer to reality than that derived from a theoretical formula in order to reflect a state closer to the actual value than just a theoretical value. Become. By controlling the heading based on this more accurate information, the relative position holding control between the floating body and the ship can be performed. Therefore, it is possible to effectively and reliably avoid accidents such as cutting of mooring lines before reaching a dangerous area where an accident can occur.

  In addition, since the heading is controlled so that the external force is minimized, the actuator can be small and less energy is required to maintain the position. Therefore, it is possible to avoid a conservative design, and the effect is high in an economical sense.

  Further, according to the method of the present invention, instantaneous external force is estimated, and not only feedback but also feedforward control is performed based on this estimation, that is, it is avoided at a stage before the ship starts moving due to strong external force. Since the correction is made in the direction that can be performed, the ship can be operated in the safe area according to the movement of the floating body more reliably and efficiently. That is, it is possible to achieve relative position holding control and safe mooring in at least an external sense.

  Furthermore, according to the method according to the present invention, information on wind (wind speed, direction, etc.), tidal current (tide speed, direction, etc.), and waves (cycle, height, direction, etc.) are acquired by a sensor as environmental information. By comparing this with the database, it is possible to accurately and precisely evaluate the external force acting on the hull, and to determine the optimum direction that minimizes the force. For this reason, it is possible to cover the external force elements acting on the ship as sea conditions, and it is possible to correctly estimate the external force.

  This concept can be used to appropriately perform the relative position holding control even in the case of a floating body having a columnar shape or a polygonal column shape such as MPSO other than a ship.

  In addition, wind, tidal current, and wave data can be used as so-called sea state data not only for ships and floating bodies but also for general maritime activities.

  Furthermore, according to the method of the present invention, in addition to or instead of the environmental situation around the hull, the environmental situation around the floating body is detected by a sensor, and the hull is based on this information and database information of environmental external forces. Since the external force acting on the body is evaluated, the environmental condition around the floating body can be used as an auxiliary or an alternative to the external force evaluation based on the environmental condition around the hull. Further, depending on the relative relationship between the floating body and the ship, more accurate or faster external force evaluation is possible. In other words, when the floating body is located in front of the wave and upstream of the wind and tidal current from the ship, it is possible to quickly detect changes in the environmental conditions detected by the ship, and to enable faster external force evaluation and control. Further, in the case of a floating body that has been operating for many years, it is possible to link to more precise relative position control from the accumulated results of these sea state data over a long period of time.

  Furthermore, according to the relative position control system of the floating body and the ship according to the present invention, the environmental situation around the hull is detected by the sensor, and the relationship between the environmental situation and the environmental external force acting on the hull is calculated and stored in advance. The external force evaluation means evaluates the external force acting on the hull based on the data in the database and the information detected by the sensor. Since this database is created based on detailed experiments and calculation results supported by the experiments, such an evaluation is derived by a theoretical formula to reflect a state closer to a real value than a simple theoretical value. It is more accurate and close to reality than the other. Next, the heading is optimized by the optimization means so that the external force is minimized. On this basis, the dynamic positioning control device controls the heading with respect to at least the target floating body based on the output of the optimization means. Since the control of the heading is based on the above-described information with higher accuracy, the relative position holding control between the floating body and the ship can be performed accurately and can be kept within a predetermined range. Therefore, it is possible to effectively and reliably avoid accidents such as cutting of mooring lines before reaching a dangerous area where an accident can occur.

  Since the dynamic positioning control device only needs to add an algorithm (program) to the conventional hull position holding device, that is, only to modify the software, it is not necessary to make a major change to the current control device. New control technology can be provided at a low price including application to

  Further, according to the relative position control system of the floating body and the ship according to the present invention, the heading is controlled by adding the output of the external force evaluation means as the feedforward control signal to the signal of the feedback control unit. It is possible to prevent danger. That is, the output of the external force evaluation means is also adopted as a feedforward control signal, and the heading is controlled together with the signal of the feedback control unit. In other words, instantaneous external force is estimated, and not only feedback but also feedforward control is performed based on this estimation, that is, correction is made in a direction in which it can be avoided before a strong external force is applied. Efficiently, the ship can be operated in a safe area according to the movement of the floating body. That is, relative position holding control, safe mooring, and smooth shipment of oil or the like from the floating body can be achieved.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In the following, the scope necessary for explanation for achieving the object of the present invention will be schematically shown, and the scope necessary for explanation of the relevant part of the present invention will be mainly explained, and the explanation will be omitted. Are according to known techniques.

  FIG. 1 is a diagram schematically showing a positional relationship between a floating structure and a ship according to an embodiment of the present invention. As shown in the figure, the environment of the system according to the present application is configured such that a shuttle tanker 1000 as a ship and a floating structure 2000 as a floating body are linked by a hose 3000 to pump out oil.

  2 is a more detailed view of FIG. 1, (a) is an elevation view of the shuttle tanker 1000, (b) is a plan view of the shuttle tanker 1000, and (c) is a plan view of the floating structure 2000. Each figure is represented. As shown in FIG. 4B, the shuttle tanker 1000 has a tidal current sensor 210 (A: port, B: starboard), a wind sensor, for example, on its deck, for sensing the environmental conditions around the shuttle tanker 1000. 220, wave sensor 230 (A: port, B: starboard). Further, the shuttle tanker 1000 includes a GPS (Global Positioning System) 240, a gyro 250, and a pod / thruster 300 (A: port, B: starboard). Since the tidal current sensor 210 (A, B) and the wave sensor 230 (A, B) are provided on the left and right sides, respectively, the influence of the shuttle tanker 1000 itself due to the tidal current and the direction of the wave can be compensated.

  Further, as shown in FIG. 6C, the floating structure 2000 has a tidal current sensor 2210 (A) for sensing the environmental condition around the floating structure 2000, for example on the floating structure 2000. C), wind sensor 2220, wave sensor 2230 (A to C), GPS 2240, and gyro 2250 are arranged. Since three tidal current sensors 2210 (A to C) and three wave sensors 2230 (A to C) are provided at about 120 ° each, the effect of the floating structure 2000 itself due to the tidal current and the direction of the waves should be compensated. Can do.

  The tidal current sensors 210 and 2210 are devices and instruments having a function of sensing and acquiring information relating to tidal currents (tidal speed, direction, etc.) as environmental information.

  The wind sensors 220 and 2220 are devices and instruments having a function of sensing and acquiring information relating to wind (wind speed, direction, etc.) as environmental information.

  The wave sensors 230 and 2230 are devices / instruments having a function of sensing and acquiring information related to waves (period, height, direction, etc.) as environmental information.

  The pod propeller / thruster 300 is a function of a part of the propulsion device (actuator) of the ship. For example, the pod propeller / thruster 300 is realized by a pod propeller in which the propeller rotates about 360 degrees in the horizontal direction or a side thruster that moves the ship in the lateral direction.

  FIG. 3 conceptually shows an outline and overall concept of a block configuration when the technical idea according to the present invention is viewed as a system for realizing a relative position control method of a floating body and a ship according to an embodiment of the present invention. FIG.

  As shown in the figure, the system according to the present invention mainly includes an external force database 10, an external force evaluation unit 20, a heading optimization unit 30, a tidal current sensor 210, a wind sensor 220, a wave sensor 230, a pod / thruster 300, A DP (Dynamic Positioning) controller 400, a shuttle tanker 1000 on which these are mounted, and a floating structure 2000 linked with the shuttle tanker are configured. As shown in the figure, the external force database 10, the external force evaluation unit 20, and the heading optimization unit 30 are arranged in the evaluation estimation unit 100. May be present / arranged. Further, the tidal current sensor 210, the wind sensor 220, and the wave sensor 230 are collectively arranged in the sensor unit 200.

  The external force database 10 includes environmental information such as wind (wind speed, direction, etc.), tidal current (tide speed, direction, etc.), waves (cycle, height, direction, etc.), and values evaluated as external forces at this time. It means that the experiment is conducted in the experiment facility many times and is formed in the form of an experiment database, or / and the calculation result by numerical calculation is made into a database.

  The external force evaluation unit 20 has a function of estimating the instantaneous external force from the external force database 10 using a program described later. It is realized by an algorithm, a program programmed so as to realize such a function, or a ROM (Read Only Memory), a chip and the like (hereinafter, collectively referred to as “program etc.”) incorporating the same. Moreover, it is not limited to simple estimation. For example, if there is such an external force, or if it is directed in such a direction, the external force should be reduced, the function to be obtained by calculation using the database 10 is provided. You can also.

  The heading optimization unit 30 has a function of optimizing the heading so that the external force is minimized, and is programmed to calculate the external force estimated by the external force evaluation unit 20 in a direction in which the external force is minimized. Etc.

  Since the tidal current sensor 210, the wind sensor 220, the wave sensor 230, and the pod / thruster 300 have been described above, the description thereof is omitted here.

  The DP controller 400 is a device having a function of controlling at least the heading with respect to the target floating body based on the output of the heading optimization unit 30. This may be a device that realizes a function of driving the pod propeller / thruster 300 to control the movement of the ship to a desired position, or may be realized as a concept including the pod / thruster 300 driven in this way. Good.

  The shuttle tanker 1000 is a ship that can be used when oil is shipped from the floating structure 2000, and includes the various sensors (210 to 230), the GPS 240, and the gyro 250 as described above.

  The floating structure 2000 is an FPSO or MPSO as an offshore platform, but its use is not limited. For example, oil drilling / production, gas search / production, discovery of hydrothermal deposits, increased production of seafood, etc. You may have it. In addition, each sensor arranged for sensing environmental conditions around the floating structure 2000 may be operated in combination with each sensor related to the shuttle tanker 1000, or may be operated independently. It is possible to obtain a certain effect also by making it.

  Next, the floating body and ship relative position control method according to an embodiment of the present application mainly configured as described above and the operation of the system will be described.

  As shown in FIG. 3, first, each sensor senses and acquires environmental information around the shuttle tanker 1000 using the situation in the external environment as information. Specifically, the tidal current sensor 210 (A: port, B: starboard) indicates the tidal current information (tidal speed, direction, etc. relating to the tidal current) among the environmental conditions around the shuttle tanker 1000, and the wind information (velocity, direction relating to the wind). Etc.) and the wave sensor 230 (A: port side, B: starboard side) respectively acquire wave information (period, height, direction, etc. relating to the wave). For a plurality of sensors, a process for obtaining a correct value is performed.

  The external environment information acquired in this way is passed to the evaluation estimation unit 100. In the evaluation estimation unit 100, the external force evaluation unit 20 searches the external force database 10 for external force information corresponding to the passed information, get. Information obtained in this way, or information obtained by performing an operation such as a constant coefficient multiplication (not shown) on this information as the case may be, is an external force evaluation (estimation) value. If the corresponding data does not exist at the time of this database search, it may be derived by a separate (not shown) complementing process.

  Next, the evaluation (estimated) value of the external force thus obtained is passed to the heading optimization unit 30. The heading optimization unit 30 determines the result of the external force evaluation, the direction and position of the floating structure 2000, and the like. Based on this, the direction of the bow should be optimized. For example, this is realized by a program or the like so that an algorithm for performing a certain calculation process, that is, an external force obtained (output) by the external force evaluation unit 20 is calculated in a direction in which the external force is minimized.

  Next, a command for correcting the heading / position and the like of the bow using the optimum value obtained in this way is issued, and so-called feedback control is performed so as to minimize the external force. Specifically, the heading optimization unit 30 generates optimization information based on the external force obtained by the external force evaluation unit 20, and determines the heading of the bow to minimize the external force based on this information. The command information is sent to the output side of the feedback signal of the DP controller 400 to perform a correction operation. Such feedback control can operate so as to be fed back and appropriately corrected even when an external action that disturbs the control system, such as a sudden wave, wind, or power flow, occurs. By frequently performing such feedback control, robust relative position holding control can be performed. In this case, the frequency of control is most preferably about 1/10 second interval, but may be performed at intervals of several seconds to several tens of microseconds.

  In parallel with such feedback control, the heading optimization unit 30 generates optimization information from the external force obtained by the external force evaluation unit 20, and based on this information, the evaluation estimation unit 100 sends the information to the pod propeller / thruster 300. On the other hand, feed forward control is applied. This means that various external factors that suddenly disturb control occur, and feedback control that cannot be corrected unless the influence of external factors appears in principle cannot be dealt with and threatens safety. Even if a possible situation is expected, even if external factors that disturb control, such as sudden waves, winds, or tidal currents, occur before the impacts appear as external forces, The necessary corrective action is performed so as to eliminate the influence as much as possible.

  In this case, controlling the heading, that is, changing the direction means rotating or rotating. In addition to the azimuth control, the position control is achieved by driving the pod / thrusters 300A and 300B in the front-rear direction and further using the pod / thruster 300C in the lateral direction. As described above, the operation feedback is to compare the current state quantity with the target value and return the deviation. Although feedback control is generally applied to ordinary industrial equipment, the hull moves after external force is applied like a ship, and it takes time to correct the heading associated therewith, and the safety threat is a catastrophe. In applications that may lead to the problem, it is desirable to use feedforward control together. Therefore, the output of the external force evaluation unit 20 is also adopted as a feedforward control signal and is controlled together with the signal of the feedback control unit. That is, an operation signal corresponding to the output of the external force evaluation unit 20 is sent to the pod / thruster 300 in addition to the input side of the DP controller 400 so that the heading and position are controlled in advance.

  In addition, regarding the maintenance of the relative position of the floating structure 2000 and the shuttle tanker 1000, that is, the relative distance, the feedforward control is performed in addition to the feedback when the environmental situation changes so that the set relative distance can be maintained. Made.

  In other words, instantaneous external force is estimated, and not only feedback but also feedforward control is performed based on this estimation, that is, correction is made in a direction in which it can be avoided before a strong external force is applied. Efficiently, the shuttle tanker 1000 can be operated in the safety area in accordance with the movement of the floating structure 2000. That is, relative position holding control, safe mooring, and smooth shipment of oil or the like from the floating body can be achieved.

  In this embodiment, the dynamic positioning device 500 includes the DP controller 400, a feedback signal unit such as the heading / position, a signal node of the external force evaluation unit 20, and a signal node of the heading optimization.

  In addition, although the idea which uses feedback control and feedforward control together was demonstrated above, the idea which concerns on this application is not necessarily limited to this, You may perform only feedback control. Even in such a case, since the estimation / evaluation based on the empirical database by numerical calculation is performed, the relative position holding and the correction operation can be appropriately performed with respect to the external force.

  In the above description, it has been described that each sensor acquires environment information around the shuttle tanker 1000, and the acquired external environment information is passed to the evaluation estimation unit 100. In addition to this information or in addition to this information, Instead, it is also possible to obtain the environment information around the floating structure 2000 by sensors mounted on the floating structure 2000 and design the acquired external environment information to be passed to the evaluation estimation unit 100. . The position of the floating body may be controlled by collating such data with the data of the database related to the floating body (not shown) and determining the external force.

  By doing in this way, the external environment information of the floating structure 2000 can be used as an aid for the external force evaluation of the shuttle tanker 1000. Furthermore, depending on the relative relationship between the floating structure 2000 and the shuttle tanker 1000, more accurate or faster external force evaluation can be performed. That is, when the floating structure 2000 is in front of the wave and upstream of the wind and tide compared to the shuttle tanker 1000, a change in the environmental condition detected by the shuttle tanker 1000 can be detected quickly, and faster external force evaluation and control can be performed. Is possible. Further, in the floating structure 2000 that has been operating for many years, these long-term external environment information can be accumulated as sea state data, and can be linked to precise relative position control based on them.

  FIG. 4 shows a state in which the shuttle tanker 1000 is held and moored in a safety area for operation with respect to the target floating structure 2000 or held in a relative position as a result of performing the control as described above. It is the conceptual diagram which represented the objective state made like that notionally.

  As described above in detail, according to the method of one embodiment of the present invention, the environmental conditions around the shuttle tanker 1000 are detected by the tidal current sensor 210, the wind sensor 220, and the wave sensor 230, and the information and external force are detected. When the external force evaluation unit 20 evaluates the external force acting on the shuttle tanker 1000 based on the information in the database 10, the external force database 10 is created based on detailed experiments and / or numerical calculations. Therefore, in order to reflect a state closer to the actual value than the mere theoretical value, the evaluation becomes more accurate and closer to reality than that derived from the theoretical formula. By controlling the heading and position based on this more accurate information, the relative position control between the floating structure 2000 and the shuttle tanker 1000 can be performed accurately, and the relative position can be maintained. Therefore, it is possible to effectively and surely avoid the accident of cutting the mooring line before reaching the danger area where the accident can occur, or to the oil spill due to cutting of the hose 3000 due to excessive force applied to the hose 3000. Accidents can be prevented.

  Further, since the heading is controlled so that the external force is minimized, the pod propeller / thruster 300 as the actuator can be small, and the energy required for maintaining the relative position can be reduced.

  Further, according to the method according to an embodiment of the present invention, an instantaneous external force is estimated, and based on this estimation, not only feedback but also feedforward control is performed, that is, a strong external force is applied and the shuttle tanker 1000 body starts to move. Since the correction is performed in such a direction as to avoid this at the previous stage, the shuttle tanker 1000 can be operated in the safety area in accordance with the movement of the floating structure 2000 more reliably and efficiently. That is, retention within a limited range and safe mooring by this can be achieved.

  Furthermore, according to the method of the embodiment of the present invention, information on wind (wind speed, direction, etc.), tidal current (tide speed, direction, etc.), and waves (cycle, height, direction, etc.) as environmental information is used. 210, the wind sensor 220, and the wave sensor 230, and by collating this with the external force database 10, the external force acting on the shuttle tanker 1000 body can be evaluated accurately and precisely, and the external force can be estimated to be minimized. Become. Further, by providing a plurality of tidal current sensors 210 and wave sensors 230 in relation to the shuttle tanker 1000 and the floating structure 2000, the influence of the floating structure 2000 itself due to the tidal current and the direction of the waves can be compensated. Wind, tidal current, and wave information can also be stored and used as comprehensive oceanographic data near the shuttle tanker.

  In addition, according to the method according to the embodiment of the present invention, the external force database 10 regarding the relationship among tidal currents, winds, and waves is created by experiment or / and numerical calculation. The actual values of tidal current, wind, and wave are sensed on this, and the sensing data is used as a key (condition), and the corresponding external force evaluation value is pulled out from the database on the program side. At 20, the external force is evaluated. If there is no corresponding value in the external force database 10, correction calculation is performed by a separate correction program. As a result of the external force evaluation, the direction in which the bow is turned to optimize the external force is minimized. As described above, the external force database 10 is used for the external force estimation, and the external force database 10 is secured so that the experimental value and the calculated value supported by the experiment are reflected. The direction can be corrected.

  Furthermore, according to the method according to an embodiment of the present invention, in addition to or instead of the environmental situation around the shuttle tanker 1000, the environmental situation around the floating structure 2000 is detected by a sensor and used. And controlled by the DP controller 400. Alternatively, the external force acting on the shuttle tanker 1000 can be evaluated based on this information and the environmental external force database information, and can be used as an auxiliary for the external force evaluation based on the environmental conditions around the shuttle tanker 1000 described above. The database is checked after taking into consideration the environmental conditions around the floating body as well as the environmental conditions around the shuttle tanker 1000, or by taking into consideration the environmental conditions around the floating body by substituting the environmental conditions around the shuttle tanker 1000. Therefore, depending on the relative relationship between the floating structure 2000 and the shuttle tanker 1000, more accurate or faster external force evaluation is possible. In addition, information such as wind, tidal current, and waves detected by environmental sensors around the floating body can be stored and used as comprehensive sea state data near the floating body.

  Further, according to the relative position control system of the floating body and the ship according to the embodiment of the present invention, the environmental situation around the shuttle tanker 1000 is detected by the sensor, and the relationship between the environmental situation and the environmental external force acting on the hull according to the environmental situation is detected. The external force evaluation unit 20 evaluates / estimates the external force acting on the shuttle tanker 1000 based on the data of the external force database 10 calculated and stored in advance through experiments and information detected by the sensor. Since this external force database 10 is created based on detailed experiments and numerical calculations supported by the experiments, this evaluation is performed in order to reflect a state closer to a real value than a simple theoretical value. It is more accurate and realistic than what is derived by the formula. Next, the heading is optimized by the optimization means so that the external force is minimized. On this basis, the dynamic positioning control device 500 controls at least the heading with respect to the target floating body based on the output of the optimization means. Since the control of the heading is based on the above-described information with higher accuracy, the relative position control between the offshore platform and the shuttle tanker can be performed accurately, and the relative position can be maintained. Therefore, it is possible to effectively and reliably avoid accidents such as cutting of mooring lines before reaching a dangerous area where accidents are possible.

  In addition, according to the relative position control system for a floating body and a ship according to an embodiment of the present invention, the output of the external force evaluation unit 20 is added as a feedforward control signal to the feedback control unit signal to control the heading. Therefore, it becomes possible to immediately prevent danger. That is, the output of the external force evaluation unit 20 is also adopted as a feedforward control signal, and the heading and position are controlled together with the signal of the feedback control unit. In other words, instantaneous external force is estimated, and not only feedback but also feedforward control is performed based on this estimation, that is, correction is made in a direction in which it can be avoided before a strong external force is applied. Efficiently, the shuttle tanker 1000 can be operated in the safety area in accordance with the movement of the floating structure 2000. That is, relative position maintenance, safe mooring by this, and smooth shipment of oil etc. from the floating body can be achieved.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, the case where information on wind (wind speed, direction, etc.), tidal current (tide speed, direction, etc.), and wave (cycle, height, direction, etc.) is mainly exemplified and described above as environmental information. The technical idea of the invention is not limited to these, and can be applied even when other information is added.

  In the above description, the MPSO is mainly exemplified as the floating structure 2000, and one embodiment for carrying out the technical idea according to the present invention has been described. However, the present application is not limited to this, and various floating bodies are used. However, it is possible to apply the present invention not only to oil drilling / production but also to various other purposes.

  By the way, the control coefficient of the control controller such as PID control is not considered to be applicable to the conventional decision method based on experience for the purpose of this application which controls the ship according to the movement of the floating body. It seems necessary to propose and establish a new method (optimum design method) that takes into account.

  Moreover, when the movement of the target has regularity, it may be developed to learning control. Regarding these points, the methodology can be established by obtaining various findings from experiments and numerical simulations through ongoing research.

  Further, the above is merely an example of an embodiment for realizing the technical idea according to the present invention, and the technical idea according to the present invention can be applied to other embodiments. is there.

  Furthermore, even if the apparatus, method, and system produced using the present invention are listed and commercialized as a secondary product, the value of the present invention is not reduced at all.

  The present invention clearly responds to the needs of offshore oil production systems in the deep and deep water areas that are expected to appear on the market in the future, and is sufficient not only in the field of offshore oil production but also in various marine engineering fields. It is thought that it will be used for. Therefore, it brings great benefits to society in general and various industries in general.

It is the figure which showed schematically the positional relationship of the floating body and ship which concern on one Embodiment of this invention. FIG. 2 is a more detailed view of FIG. 1, in which (a) is an elevation view of the shuttle tanker 1000, (b) is a plan view of the shuttle tanker 1000, and (c) is a plan view of the floating structure 2000. FIG. 1 is a block diagram schematically showing the outline and overall concept of a block configuration when a technical idea according to the present invention is viewed as a system for realizing a relative position control method of a floating body and a ship according to an embodiment of the present invention. It is a configuration block diagram. As a result of the control as described above, the state in which the shuttle tanker 1000 is held and moored in the safety zone for operation or held in the relative position with respect to the target platform, or the target state to do so. It is a conceptual diagram represented notionally.

Explanation of symbols

10 external force database, 20 external force evaluation unit, 30 bow direction optimization unit, 100 evaluation estimation unit, 200 sensor unit, 210 tidal current sensor, 220 wind sensor, 230 wave sensor, 300 pod / thruster, 400 DP controller, 500 dynamic positioning control Equipment 1000 Shuttle tanker, 2000 Floating structure

Claims (7)

  The external force acting on the hull is evaluated based on the information from the sensor that detects the environmental situation around the hull and the database information of the environmental external force acting on the hull according to the environmental situation, and the heading is optimized so that the external force is minimized. A method for controlling a relative position between a floating body and a ship, wherein at least a heading with respect to a target floating body is controlled based on an optimized result.   2. The floating body and ship according to claim 1, wherein, in addition to feedback control for controlling the position and heading of the ship, feedforward control is performed based on the result of the external force evaluation to control the position and direction of the ship. Relative position control method.   3. The relative position control method for a floating body and a ship according to claim 1, wherein the sensor detects a state of a wave, a wind, and a tidal current as the environmental state.   3. The relative position control method for a floating body and a ship according to claim 1, wherein the database information is based on a numerical calculation result and / or experimental data of a hull external force according to an environmental condition around the hull. .   The relative position between the floating body and the ship according to claim 1 or 2, wherein the environmental information around the floating body is used for control in addition to or in place of the information related to the environmental condition around the ship body. Control method.   A sensor for detecting an environmental condition around the hull, a database in which the relationship between the environmental condition and an external force acting on the hull according to the environmental condition is stored in advance by numerical calculation and / or experiment, a detection result of the sensor, and data in the database External force evaluation means for evaluating the external force acting on the hull based on the above, optimization means for optimizing the heading so as to minimize the external force, and at least the heading with respect to the target floating body based on the output of the optimization means A relative positioning control system for a floating body and a ship, characterized by comprising a dynamic positioning control device for controlling the vehicle.   The dynamic positioning control device has a feedback control unit that controls the position and heading of the ship, and adds the output of the external force evaluation means as a feedforward control signal to the signal of the feedback control unit, so that the position and direction of the ship 7. The relative position control system for a floating body and a ship according to claim 6, wherein:

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