JP5006228B2 - Linear structure position control system, linear structure position control method, and moving structure control system - Google Patents

Description

  The present invention is used in a moving structure including a moving body that floats on the water surface of a ship or the like, and an elastically deformable linear structure that is fixed to the moving body and extends in water, for example, a riser pipe. The present invention relates to a linear structure position control system and a position control method for controlling the position of the lower end of the robot so as to quickly reach a target position, and further to a moving structure control system.

In recent years, seabed excavation has been actively performed for resource development in the ocean. In the drilling ship, a drill pipe for drilling the seabed and a riser pipe for raising muddy water extend from the drilling ship to the seabed. The riser pipe is used to provide a drill pipe for excavation in the pipe and circulate high specific gravity mud required for excavation between the sea floor and the ship.
Undersea drilling work will be temporarily suspended depending on sea conditions. At this time, the riser pipe provided with the drill pipe in the pipe is separated from the BOP (Blow Out Preventer) which is a device provided in the drilling portion of the seabed, and the drilling ship is kept in a safe place. . On the other hand, when the excavation work is resumed, a reentry work for reconnecting the riser pipe extending from the excavation ship to the sea to the BOP is performed.

  Currently, the re-entry work of the riser pipe is performed manually by an operator over a long period of time. However, since the riser pipe is an extremely long pipe extending to the seabed, even if the work is performed over a long period of time, vibration due to elastic deformation is caused as the excavation ship moves. For this reason, the reentry work is repeated while moving and stopping the excavating ship while waiting for the vibration to settle so that the lower end of the riser pipe reaches the BOP position without the lower end of the riser pipe colliding with the BOP. Do. The excavation ship moves at this time when the operator designates a target position for the excavation ship movement.

  This reentry work is performed while waiting for the above-described riser pipe vibration to be attenuated, so even a specialized trained operator takes a long time, and the reentry work is extremely inefficient. ing. On the other hand, the following Non-Patent Document 1 proposes that only the angle of the upper end of the riser pipe and the lower end position of the riser pipe are observed, and the thrust force to be applied to the drilling ship is operated as a control target.

  However, since this thrust force operation is different from the designation of the moving position of the drilling ship performed by an actual operator, it is difficult to apply it in actual work. In addition, it is not possible to effectively use a DPS (Dynamic Positioning System) that is a position control device that generates a thrust force on the excavation ship based on the designation of the movement position mounted on the excavation ship.

"Demonstration experiment of DPS and reentry control considering riser pipe dynamics", Koderayama Wataru, Nakamura Masahiko, Sugawara Hiroyuki, Imogi Ryoyuki, Kamon Motoro, Igarashi Kazuyuki, Proc. Die No. 4, pp 297-300, 2007

  Therefore, in order to solve the above problems, the present invention utilizes a position control device provided in a moving body such as an excavation ship, so that the lower end position of a linear structure such as a riser pipe can be brought to the target position in a short time. It is an object of the present invention to provide a linear structure position control system, a linear structure position control method, and a moving structure control system that can be controlled so as to arrive.

  In order to achieve the above object, the present invention controls a position of the moving body using a command signal at a designated position so that the movable body floats on the water surface and the movable body is provided at the designated position so as to be movable to the designated position. A movable body position control device and a linear structure that is supported by the movable body and has an elastically deformable linear structure that extends underwater with a lower end supported as a free end. A linear structure position control system for controlling a position of a lower end to reach a set target position, an angle sensor for measuring an inclination angle of the upper end of the linear structure with respect to the moving body; A first position sensor for measuring a position of the lower end of the linear structure, a second position sensor for obtaining a current position of the movable body, and a position of the lower end of the linear structure is the target position. The angle sensor to reach Information on the obtained tilt angle, information on the position of the lower end obtained from the first position sensor, and information on the current position of the moving body obtained from the second position sensor, And a linear structure control device that generates a feedback control signal for the command signal at the designated position and supplies the feedback control signal to the movable body position control device. A body position control system is provided.

Here, it is preferable that the linear structure control device changes a feedback gain used for generating the feedback control signal according to a moving speed of the moving body. At this time, the feedback gain is created using a mathematical model of the moving structure and information on response characteristics of the moving body position control device, and the control represents the observed variable in the mathematical model as a part of the state variable. The gain is set by applying optimal control that minimizes an evaluation function represented by a sum of squares of each component of the state variable of the control target model and the value of the designated position to the target model. preferable.
Further, the mathematical model of the moving structure is a model configured using the mathematical model of the moving body and the mathematical model of the linear structure, and the linear model is the mathematical model of the linear structure. It is preferable to use a model whose variable is a coefficient when the displacement of the elastic deformation in the space of the structure is mode-expanded by a predetermined function system.
Further, the linear structure control device corresponds to the degree of freedom of the mathematical model of the moving structure from the information of the inclination angle, the information of the position of the lower end, and the information of the current position of the moving body. It is preferable that an observation device for estimating information on the moving structure is provided, and the feedback control signal is generated using the information estimated by the observation device and the feedback gain.

  Furthermore, the present invention is used for a moving structure including a moving body that floats on a water surface, and an elastically deformable linear structure that is supported by the moving body and has an upper end supported at the lower end and extending into water. A moving structure control system for controlling the position of the lower end of the linear structure so as to reach a set target position, using a command signal at a designated position so as to be movable to a designated position. A moving body position control device that controls the position of the moving body, an angle sensor that measures an inclination angle of the linear structure with respect to the moving body, and a first position that measures the position of the lower end of the linear structure. The tilt angle obtained from the angle sensor so that the position sensor, the second position sensor for determining the current position of the moving body, and the position of the lower end of the linear structure reach the target position Information and the first position set. A feedback control signal for the command signal for the designated position is generated based on the information on the position of the lower end obtained from the second position sensor and the information on the current position of the moving body obtained from the second position sensor. And a linear structure control device that supplies the feedback control signal to the moving body position control device.

  At this time, when generating the feedback control signal, it is preferable that a feedback gain used for generating the feedback control signal is changed according to a moving speed of the moving body.

  Furthermore, the present invention provides a movable body that floats on the water surface, and a movable body position control device that is provided on the movable body and that controls the position of the movable body using a command signal for a designated position so that the movable body can move to a designated position. A position of the lower end of the linear structure is set with respect to the movable structure including an elastically deformable linear structure that is supported by the moving body and has an upper end supported in the lower end and a lower end as a free end. A method for controlling the position of a linear structure that is controlled so as to reach a set target position, wherein the current position of the moving body, an inclination angle of the linear structure with respect to the moving body, and the linear structure Based on the step of measuring the position of the lower end of the body, the information on the obtained tilt angle, the information on the position of the lower end, and the information on the current position of the moving body, the command signal for the designated position Generate a feedback control signal and The readback control signal to provide a position control method for one-dimensional structure characterized by having a step of supplying to the mobile position control device.

  At this time, when generating the feedback control signal, it is preferable that a feedback gain used for generating the feedback control signal is changed according to a moving speed of the moving body.

In the present invention, based on the information on the inclination angle of the upper end of the linear structure obtained from each sensor, the information on the position of the lower end of the linear structure, and the information on the current position of the moving body, the specified position A feedback control signal for the command signal is generated, and this feedback control signal is supplied to the position control device. For this reason, the position of the lower end of a linear structure can be reached to a target position in a short time using the moving body position control apparatus with which a moving body is provided conventionally.
In particular, according to the moving speed of the moving body, for example, by setting a value with the average value of the moving speed being non-zero, the feedback gain used for generating the feedback control signal is changed. The position of the lower end of the structure can be reached at the target position.
The feedback gain is obtained from a control target model created using a mathematical model of the moving structure and information on response characteristics of the moving body position control device. This control target model is a model that reproduces the behavior of an actual moving structure such as a drilling vessel equipped with a riser pipe, so it uses a feedback gain to adapt to the behavior of the actual moving structure in a short time. It can be controlled accurately.
Furthermore, since the observer can estimate the state variable of the entire moving structure corresponding to the variable of the mathematical model of the moving structure, accurate control can be performed based on the measured information.

  Hereinafter, the linear structure position control system, the linear structure position control method, and the moving structure control system of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

FIG. 1 is a diagram for explaining a reentry operation of a riser pipe in which the linear structure position control system, the linear structure position control method, and the moving structure control system of the present invention are preferably used.
The riser pipe (linear structure) 10 has an elastically deformable linear structure that is supported by an excavation ship 12 floating on the sea surface and extends toward the seabed. As will be described later, the excavation ship (moving body) 12 is equipped with a DPS (Dynamic Positioning System) which is a position control device that controls movement so as to be movable to a designated position. The upper end of the riser pipe 10 is supported by the excavation ship 12, and the lower end extends into the sea to form a free end. When the designated position is designated so that the drilling vessel 12 including the riser pipe 10 reaches the excavation point, the position of the lower end of the riser pipe 10 quickly reaches the position (target position) of the BOP 13 at the excavation point. Thus, a feedback control signal for the command signal at the designated position is given to the DPS. Thereby, the position of the excavation ship 12 is controlled.
Hereinafter, in the present embodiment, the position of the lower end of the riser pipe 10 promptly reaches the position (target position) of the BOP 13 at the excavation point with respect to the DPS that has received the command signal of the designated position for the excavation ship to move to the specified position. The riser pipe position control device that supplies a feedback control signal for the command signal at the designated position so as to reach the position will be mainly described.

FIG. 2 is a diagram showing a control system of the drilling ship 12 having the riser pipe 10. This control system corresponds to the moving structure control system in the present invention.
The excavation ship 12 includes a riser pipe 10, a plurality of thrusters 14 that generate thrust force (thrust) to move the excavation ship 12, and signals indicating the direction of the thruster 14 and the magnitude of the thrust force to each thruster 14. A DPS 16 to be provided, a hull position sensor 18 for acquiring the current positions x ₀ and y ₀ of the drilling ship 12, and a riser for measuring the inclination angles θ _x and θ _y of the upper end of the riser pipe 10 connected to the main body of the drilling ship 12. A tube angle sensor 20 and a ROV (Remotely Operated Vehicle) 22 that moves freely in the sea with respect to the main body of the excavation ship 12 and photographs the lower end of the riser pipe 10 and measures the positions x _le and y _le of the lower end. Based on the current position x ₀ , y _{0 of} the drilling vessel 12, the inclination angles θ _x , θ _y , and the position x _le , y _le at the lower end of the riser pipe 10, feedback on the signals at the designated positions x _c , y _c Generate control signal And, with this feedback control signal and the riser pipe controller 24 supplies the DPS16, to the main.
A system constituted by the hull position sensor 18, the riser pipe angle sensor 20, the ROV 22, and the riser pipe control device 24 corresponds to the linear structure position control system in the present invention.

  As the thruster 14, for example, an azimuth thruster or a side thruster is used. The thrusters 14 are provided at a total of three locations, for example, on the left and right ship bottoms behind the excavation ship 12 and on the ship bottom on the left and right center line in front of the excavation ship 12. The azimuth thruster is a thrust starting device in which the rotation shaft of a propeller that generates thrust rotates in a desired direction, and the side thruster is a thrust starting device that generates thrust only in the lateral direction (sway direction) of the hull.

The DPS 16 generates a signal representing the direction of the thrust force supplied to the thruster 14 and the magnitude of the thrust force for the designated positions x _c , y _c , and ψ _c input by the operator. At this time, the current position x ₀ , y ₀ , ψ ₀ output from the hull position sensor 18 is supplied, and the generated signal is controlled.

The hull position sensor 18 is a sensor that acquires a current position x ₀ , y ₀ , ψ ₀ of the excavation ship 12 using a GPS (Global Positioning System) and a direction measuring device.
The riser tube angle sensor 20 is a sensor that measures an inclination angle at the upper end of the elastically deformed riser tube 10, and an inclination angle meter is preferably used. Specifically, the inclination angle is an inclination angle θ _{x with} respect to the x axis of the xy orthogonal coordinate system set in advance on the hull, and an inclination angle θ _y with respect to the y axis.
The ROV 22 is a mobile body that is equipped with a television camera called a camera robot and can move in the sea. The ROV 22 obtains positions x _le and y _le at the lower end of the riser tube 10 from an image captured by the television camera by image processing.
Data obtained by the hull position sensor 18, the riser pipe angle sensor 20 and the ROV 22 are supplied to the riser pipe control device 24 as x ₀ , y ₀ , θ _x , θ _y , x _le and y _le .

The riser pipe control device 24 detects x ₀ , y ₀ , θ _x , θ _y , x _le , y _le observed by each sensor.
As observation data to an observer (observer) 26, which will be described later, and the estimated state variable x ^* including at least the estimated position of the drilling vessel 12 calculated from the observer 26 and the current value of the lower end of the riser pipe 10 U = −F · x ^* −F _I · x _I is obtained using a value x _{I obtained} by integrating the error between the position and the target position from the control start time and a predetermined feedback coefficient matrix F and F _I. In this signal, the position component of the excavation ship 12 is extracted and supplied to the DPS 16 as a feedback control signal. That is, the feedback signal u for the command signals at the designated positions x _c and y _c is generated, and the position component of this signal is supplied to the DPS 16. The feedback coefficient matrices F and F _I are called from storage means (not shown) and changed according to the average value of the moving speed of the excavating ship 12 moving in the reentry work.

X _0, y ₀ is the observation _{data, θ x, θ y, x} le, the observer for calculating from y _le estimated state variable x ^*, the estimated state variables using the observer x ^*, and feedback gain matrix F, F _I, the elastic deformation of the riser tube 10, movement of the drilling vessel 12, and is obtained from the controlled object model expressed using a mathematical model including the response characteristics of the DPS16. This point will be described later.

In the reentry operation of the riser pipe 10, first, the riser pipe is assembled on the excavation ship 12 that has arrived near the excavation point. Thereafter, signals of designated positions x _c , y _c , ψ _c (yaw angle of the hull) are supplied to the DPS 16 in response to an instruction input from the operator. In the DPS 16, based on the supplied signal, a signal indicating the size and direction of the thruster is supplied to each thruster 14 to operate the thruster 14. Further, a target position that is the position of the BOP 13 is set.
Drillship 12 is designated position x _c, designated position x _c by specified y _c, but starts to move closer to y _c, riser pipe 10 which is supported by the drillship 12, by this movement, or by tidal current, etc. The lower end of the riser pipe 10 does not necessarily reach the position (target position) of the BOP 13 due to elastic deformation.
In the control method of the present invention, the riser angle sensor 20 measures the inclination angles θ _x and θ _{y at the} upper end and the lower end positions x _le and y _{le of the} riser tube 10 by the ROV 22. Further, the current position x ₀ , y _{0 of the} excavation ship 12 is measured by the hull position sensor 18. These measured data of θ _x , θ _y , x _le , y _le , x ₀ , y ₀ are supplied to the riser pipe control device 24.
In the riser pipe control device 24, based on the supplied data of x ₀ , y ₀ , θ _x , θ _y , x _le , y _le , feedback control signals for designated designated positions x _c , y _c , that is, A signal having a position component of the control signal u = −F · x ^* −F _I · x _I is generated, and this feedback control signal is supplied to the DPS 16.
Thereby, the DPS 16 is adjusted with respect to the command signal so that the lower end position of the riser pipe 10 reaches the position (target position) of the BOP 13.

Next, the configuration of the riser pipe control device 24 and a model used for realizing the configuration will be described.
The controlled object model used in the present invention is combined into one model using a mathematical model that reproduces the elastic deformation of the riser pipe 10, an equation of motion model of the drilling ship 12, and a characteristic model that represents the dynamic characteristics of the DPS 16. Is.
Feedback gain matrices F and F _I are calculated by applying LQI (Linear Quadratic Optimum Control With Integral Action) control to a control target model created using these models.
On the other hand, the riser pipe control device 24 generates observation signals x ₀ and y in order to generate a control signal u = −F · x ^* −F _I · x _I including a feedback control signal for the target position command signal. An observer (also referred to as an observer) that calculates an estimated state variable x ^* from ₀ , θ _x , θ _y , x _le , and y _le is provided. This observer is constructed using the above control target model. is there.

(A) Mathematical model that reproduces elastic deformation of the riser tube 10 The riser tube 10 is represented by a beam model whose upper end is fixed at a position of (x ₀ , y ₀ , z ₀ ), as shown in FIG. This beam model is expressed by four degrees of freedom of displacement (w _x , w _y , w _z ) and twist ψ around the rotation axis. In consideration of the fact that the riser tube is in the sea, the beam model includes a force of an additional mass effect proportional to the acceleration and a fluid drag force proportional to the square of the relative velocity with the fluid as the fluid force. The upper end of the beam model includes an external force that reproduces the force acting from the excavation ship 12 and a moment around the axis.
Since the displacement of such a beam model is determined by time and position, as shown in the following formula (2), time and position are separated, and in order to express displacement by position, this displacement is expressed as a function system. This is shown in the mode expansion used. Specifically, mode expansion is performed using a first type 0th-order Bessel function. In the present invention, the mode expansion is not limited to the first kind 0th-order Bessel function. Various function systems including orthogonal function systems can be used.
The following equation (1) is an equation representing the deformation behavior of the beam model in which η is expressed as a degree of freedom.
The following equation (2) is a mode expansion equation based on the first type 0th-order Bessel function.

In addition to the above x ₀ , y ₀ , z ₀ , and ψ, η in the above equation (1) is free to use the coefficients q _x , q _y , and q _z when mode expansion is performed with the first kind 0th-order Bessel function. Included as a degree (variable).

Here, since the beam model represents the behavior of vibration, the distribution of the displacement (w _x , w _y , w _z ) of the beam model changes with time. Therefore, as shown in the above formula (2), the distribution of displacement is separated into a function that depends on time and a function that depends on space, and at this time, the function (displacement) that depends on space is classified into the first kind 0th order Bessel. Mode expansion is performed using the function J ₀ . Therefore, the coefficients q _x , q _y , and q _z are the coefficients when the mode expansion is performed using the first type 0th-order Bessel function J ₀ . These coefficients are time dependent functions. That is, the distribution of displacement in space is represented by a first kind zero-order Bessel function J _0, the function coefficients according to one zero-order Bessel function J ₀ when the mode expansion varies with time. The coefficients at this time are represented by q _xi , q _yi , and q _zi (i = 1 to N: N is the order of mode expansion). The coefficients q _x , q _y , and q _z are vectors whose components are q _xi , q _yi , and q _zi . The q _xi , q _yi , and q _zi are used in the above equation (1). FIGS. 4A to 4D show first-order to fourth-order displacements a _i (z) of the first kind zero-order Bessel function. 4A to 4D, the horizontal axis is normalized by the length l of the riser pipe 10. In the present invention, the order of mode expansion is preferably about N = 8. This is because when N is less than 8, high-order mode vibration is not reproduced, and when N is greater than 8, the calculation processing time becomes long.
The mathematical model that reproduces the elastic deformation of the riser tube 10 has been described above.

(B) motion equation of the motion equation model drillship 12 drillship 12, as shown in FIG. 5 orthogonal, in the orthogonal coordinate system xi-yi, a bow direction of the velocity component u _s drilling vessel 12 and the direction This is expressed as shown in the following formula (3) using the velocity component v _s in the direction of rotation and the rotational angular velocity r _s around the center of gravity. F _x , F _y , and N _z are external forces and moments received from the riser tube 10, and have a relationship of action and reaction with the vector f including the external forces F _x , F _y , and N _z in the above equation (1). .

The mathematical model that reproduces the elastic deformation of the riser pipe 10 thus created and the equation of motion model of the drilling vessel 12 are obtained by eliminating F _x , F _y , and N _z as shown in the following formula (4): A mathematical model of the drilling vessel 10 with the riser pipe 10 is obtained. At this time, the component z ₀ of η in the expression (1) of the riser pipe 10 is ignored and omitted. Further, the following equation (4) is a nonlinear equation linearized with respect to the moving speed V so that analysis is possible. In the equation (4), the average value of the moving speed when the moving speed V fluctuates by the control is used as a substitute for the moving speed V. Therefore, when this average value changes, equation (4) also changes, so that the mathematical model itself of the drilling vessel 10 provided with the riser pipe 10 is changed. As a result, feedback gain matrices F and F _I described later also change. When the moving speed is 0, the position of the lower end of the riser pipe 10 and the position of the upper end cause substantially in-phase vibrations. For this reason, a phase shift does not occur, and the actual behavior of the riser pipe 10 does not match. For this reason, the average value used as the moving speed is preferably set to non-zero.

Characteristic model DPS16 representing the response characteristic of (c) DPS16 the current position from the hull position sensor 18 x _0, y ₀ as shown in FIG. 2, with [psi _0, designated position x _c, y _c, performing feedback control with respect to a command signal [psi _c, but there is a need to identify the response characteristics of the feedback control at this time. Specifically, gains K _P , K _I and K _D in the PID control shown in the following formula (5) are obtained. The response of the position of the lower end of the riser pipe 10 measured at that time coincides with the calculation result by moving the hull of the excavation ship 10 equipped with the actual DPS 16 in plain water by giving a sine wave command signal in the front-rear direction. Thus, the gains K _P , K _I , and K _D are calculated. Further, the following equation (6) is introduced in consideration of a delay from when the thrust force and the thrust direction command are given to the thruster 14 until the command is realized. The time constant T _T in equation (6) is identified by actual measurement.
Thus, the mathematical model of the drilling vessel 10 into which the response characteristic of the DPS 16 is introduced is represented as a controlled object model in which x is a state variable and y is an observation output, as shown in the following equation (7). The state variable x is a variable including at least the state variable η of the mathematical model of the drilling ship 10 including the riser pipe 10. Here, the yaw angle ψ is not controlled because it is sufficiently controlled. The state variable η of the mathematical model of the excavation ship 10 includes observation variables corresponding to observation data x ₀ , y ₀ , θ _x , θ _y , x _le , and y _le described later.

Thus the obtained controlled object model, by applying the LQI (Linear Quadratic Optimum Control With Integral Action) control, the feedback gain matrix F, F _I is calculated. Since the feedback gain matrices F and F _I are calculated using a mathematical model that changes according to the moving speed V as described above, the feedback gain matrices F and F _I correspond to the moving speed V as described above. Change.
Specifically, the LQI control is designed as follows.
As shown in the following equation (8), a cumulative integrated value x _I is determined from the control start time of the error between the current position of the lower end of the riser pipe 10 and the set target position η _d of the lower end of the riser pipe 10. Then, an expanded system model is created by adding this cumulative integral value x _I to the state variable of the controlled object model as shown in the following equation (9).

In the expanded system model represented by the above formula (9), a system that defines a control signal u including a feedback control signal represented by the following formula (11) in order to minimize the evaluation function J represented by the following formula (10) Feedback gain matrices F and F _I are calculated. The feedback gain matrices F and F _I are calculated by setting eigenvalues that stabilize the system. Here, the evaluation function J uses the sum of squares of the components of the state variable x of the expanded system model and the values of the designated positions x _c and y _{c in} the above formula (9), more specifically, the weighted sum of squares. The evaluation function expressed. In the following equation (10), x ₁ , x ₂ ,..., X _nx are each component of the state variable x in equation (9), and nx represents the number of state variables x. In the present invention, the evaluation function is not particularly limited as long as it is a quadratic evaluation function used in the control system.

The feedback gain matrices F and F _I calculated in this way are calculated in advance according to the above-mentioned average value that is used as a substitute for the moving speed V, and the average value is stored in the storage means (not shown) of the riser pipe control device 24. It is good to associate and memorize. In the present embodiment, LQI control is used. However, the present invention is not limited to this. The feedback gain matrix is applied by applying an optimum regulator that obtains a state feedback control signal that minimizes a quadratic evaluation function. Can also be requested.
During reentry operations, feedback gain matrix F that is set according to the average value, call the F _I, the control signal u which includes a feedback control signal is generated as follows.

Here, as the control signal u, the state variable x is used as shown in the above equation (11). However, not all components of the state variable x can be measured by the actual excavation ship 10 and the riser pipe 12. For this reason, an observer as shown below is constructed using the observation data that can be measured, that is, the y components x ₀ , y ₀ , θ _x , θ _y , x _le , and y _le in Equation (7). It calculates the estimated state quantities x ^*, using the estimated state quantity calculated in place of the state variable x x ^*. That is, the riser pipe control device 24 includes an observer 26 shown below.

FIG. 6 is expressed by Expression (9) using observation data x ₀ , y ₀ , θ _x , θ _y , x _le , and y _le measured by the hull position sensor 18, the riser tube angle sensor 20, and the ROV 22. It is a figure which shows the structure of the apparatus which estimates the state variable x.
Here, the matrices A, B, and C _M are matrices of the controlled object model expressed by the above equation (7). That is, the matrices A, B, and C _M are matrices defined by the mathematical model represented by Expression (8). The matrix H is an observer gain, and when (C _M , A) is observable, it can be obtained by setting an eigenvalue in the observer 26.
The observer 26 is represented by the following formula (12).

In this way, the estimated state quantity x ^* is calculated using the observer 26 configured using the matrices A, B, C _M , and H, and is calculated using the estimated state quantity x ^* and Expression (8). by using the x _I, according to the following equation (13), generates a control signal u. A signal component for the command signal at the designated position in the control signal u is output from the riser pipe control device 24 as a feedback control signal and supplied to the DPS 16.

Using such a riser pipe control device 24, the effectiveness of the control method of the present invention was confirmed.
First, the drilling vessel and the riser pipe were assumed to be 1/55 models, and a numerical experiment was performed to reproduce the reentry work using the above-described control target model that reproduced this model.

The control method used for the numerical experiment of the reentry work is control 1 to control 3. The control 1 is feedback control of the deviation between the lower end position of the riser pipe and the target position of the BOP. This is equivalent to the operation of adjusting the position by an annual operation while the operator is viewing an image transmitted from the ROV 22. To do.
Control 2 is a control method when the average value representing the moving speed of the drilling ship is set to zero. Control 3 is a control method when the average value is non-zero. Controls 2 and 3 correspond to the control method of the present invention.

  FIGS. 7 (a) and 7 (b) are the results of reproducing the hull moving forward in plain water so that the position of the lower end of the riser pipe reaches the target position. In the figure, control 1 is indicated by reference numeral 1, control 2 is indicated by reference numeral 2, and control 3 is indicated by reference numeral 3. The control 1 shows that the position of the hull and the position of the lower end of the riser pipe vibrate greatly and this vibration does not converge. On the other hand, it can be seen that the control 2 and the control 3 quickly reach the target position without vibration.

FIGS. 8A and 8B show the results under conditions where a tidal current acts on the upper half of the riser pipe. Under this condition, we reproduced that the hull moves forward so that the position of the lower end of the riser pipe reaches the target position. Similar to FIGS. 7A and 7B, it can be seen that in the controls 2 and 3, the position of the lower end of the riser pipe quickly reaches the target position. 9 (a) and 9 (b) are enlarged views of FIGS. 8 (a) and 8 (b) and the difference is easily shown. As can be seen from FIGS. 9A and 9B, it can be seen that the control 3 reaches the target position quickly without overshooting as compared with the control 2.
From the above, it can be seen that the control methods 2 and 3 which are control methods of the present invention are more effective than conventional control methods. In particular, it has been found that the position of the lower end of the riser pipe 10 can reach the target position of the BOP 13 in a short time by setting the average value representing the moving speed as non-zero as in Control 3.

  As described above, the linear structure position control system, the linear structure position control method, and the moving structure control system of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiment, and the gist of the present invention is described. Of course, various improvements and modifications may be made without departing from the scope.

It is a figure explaining the reentry work of the riser pipe where the linear structure position control system of the present invention, the position control method of a linear structure, and the moving structure control system are used suitably It is a figure explaining the control system of a riser pipe which is an example of the linear structure position control system of the present invention. It is a figure explaining the mathematical model of the riser pipe | tube used in the system shown in FIG. (A)-(d) is a figure explaining the deformation | transformation mode of a riser pipe | tube used in the mathematical model demonstrated in FIG. It is a figure explaining the equation of motion of the excavation ship used in the system shown in FIG. It is a figure explaining the observer used in the system shown in FIG. (A), (b) is a figure which compares and shows an example of the control result of the control system using the method of this invention, and the control system using the conventional method. (A), (b) is a figure which compares and shows the other example of the control result of the control system using the method of this invention, and the control system using the conventional method. It is the figure which expanded and showed the control result shown to Fig.8 (a), (b).

Explanation of symbols

10 Riser tube 12 Drilling vessel 14 Thruster 15 BOP
16 DPS
18 Hull Position Sensor 20 Riser Tube Angle Sensor 22 ROV
24 Riser pipe control device 26 Observer

Claims (9)

A movable body that floats on the water surface, a movable body position control device that is provided on the movable body and that controls the position of the movable body using a command signal of a designated position so that the movable body can move to a designated position; And a linear structure that is elastically deformable and has a lower end that extends into water with the lower end being a free end, and the position of the lower end of the linear structure reaches a set target position. A linear structure position control system for controlling
An angle sensor that measures an inclination angle of the upper end of the linear structure with respect to the moving body;
A first position sensor for measuring the position of the lower end of the linear structure;
A second position sensor for determining a current position of the moving body;
Information on the tilt angle obtained from the angle sensor and information on the position of the lower end obtained from the first position sensor so that the position of the lower end of the linear structure reaches the target position. And a current position information of the moving body obtained from the second position sensor, a feedback control signal for the command signal of the designated position is generated, and the feedback control signal is A linear structure position control system, comprising: a linear structure control apparatus that supplies the position control apparatus.   The linear structure position control system according to claim 1, wherein the linear structure control device changes a feedback gain used for generating the feedback control signal according to a moving speed of the moving object.   The feedback gain is created using a mathematical model of the moving structure and information on response characteristics of the moving body position control device, and is a control target model that represents an observed variable in the mathematical model as a part of a state variable. The gain set by applying optimal control that minimizes an evaluation function represented by a sum of squares of each component of the state variable of the controlled object model and the value of the designated position. Linear structure position control system. The mathematical model of the moving structure is a model configured using the mathematical model of the moving body and the mathematical model of the linear structure,
The linear model according to claim 3, wherein a model having a coefficient as a variable when the displacement of elastic deformation in the space of the linear structure is mode-expanded in a predetermined function system is used as a mathematical model of the linear structure. Structure position control system.   The linear structure control device corresponds to the degree of freedom of the mathematical model of the moving structure from the information on the tilt angle, the information on the position of the lower end, and the information on the current position of the moving body. The observation apparatus which estimates the information of a moving structure is provided, The said feedback control signal is produced | generated using the information estimated with this observer, and the said feedback gain. Linear structure position control system. A movable body that floats on a water surface, and an elastically deformable linear structure that has an upper end supported by the movable body and has a lower end that is a free end and extends into water. A moving structure control system that controls a position of a lower end to reach a set target position,
A moving body position control device for controlling the position of the moving body using a command signal of a designated position so as to be movable to a designated position,
An angle sensor for measuring an inclination angle of the linear structure with respect to the moving body;
A first position sensor for measuring the position of the lower end of the linear structure;
A second position sensor for determining a current position of the moving body;
Information on the tilt angle obtained from the angle sensor and information on the position of the lower end obtained from the first position sensor so that the position of the lower end of the linear structure reaches the target position. And a current position information of the moving body obtained from the second position sensor, a feedback control signal for the command signal of the designated position is generated, and the feedback control signal is used as the moving body position control. A moving structure control system comprising: a linear structure control device supplied to the apparatus.   The moving structure control system according to claim 6, wherein when generating the feedback control signal, a feedback gain used for generating the feedback control signal is changed according to a moving speed of the moving body. A movable body that floats on the water surface, a movable body position control device that is provided on the movable body and that controls the position of the movable body using a command signal of a designated position so that the movable body can move to a designated position; The lower end of the linear structure reaches a set target position with respect to the movable structure including the elastically deformable linear structure extending in water with the lower end supported as a free end. A linear structure position control method for controlling
Measuring a current position of the moving body, an inclination angle of the linear structure with respect to the moving body, and a position of a lower end of the linear structure;
Based on the obtained information on the tilt angle, the information on the position of the lower end, and the information on the current position of the moving body, a feedback control signal for the command signal of the designated position is generated, and this feedback control signal Supplying to the movable body position control apparatus. A method for controlling the position of a linear structure, comprising: 9. The position control method for a linear structure according to claim 8, wherein when generating the feedback control signal, a feedback gain used for generating the feedback control signal is changed according to a moving speed of the moving body.

Images