Maneuvering control device

Abstract

To provide a berthing technology suitable for ships with a rudder, a screw, and a bow thruster.SOLUTION: A maneuvering control device comprises: a trajectory planning part for generating a reference trajectory which guides a ship to a target position and a target azimuth and which is a time series signal of a reference position and a reference signal which is a time series signal of a reference azimuth; an error calculation part for calculating a yaw error which is an error around the yaw of the ship with respect to the reference azimuth and a sway error which is an error in a sway direction of the ship with respect to the reference position; and a feedback control part having a yaw control part for controlling a rudder angle so as to reduce the yaw error, a sway control part for controlling a bow thruster so as to reduce the sway error, and a surge control part for controlling a screw. The surge control part rotates the screw forward by the prescribed rotation amount when the ship does not reach a reverse position located at the prescribed reverse distance from the target position in the reference trajectory, and the surge control part rotates the screw in reverse by the prescribed rotation amount until the ship speed reaches zero when the ship exceeds the reverse position.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a technique for automatically steering a ship. [Background technology]

[0002] The unmanned ship project MEGURI2040 is known as an autonomous ship technology (see Non-Patent Document 1). Autonomous ship technology includes various technologies, among which the maneuvering technologies include berthing and unberthing, collision avoidance, and target tracking.

[0003] According to previous research on docking and undocking control, when the ship speed is extremely slow near the end of the route when docking and undocking, the rudder angle is turned to the maximum (see Non-Patent Document 2). This shows the difficulty of controlling a ship at an extremely slow speed when docking.

[0004] Also, a control method using a stern thruster proposed by the present inventor is known (see Non-Patent Document 3). However, ships equipped with stern thrusters are not widely used as coastal ships. [Prior art documents] [Patent documents]

[0005] [Non-Patent Document 1] Takeru SUZUKI. Challenge of technology development through meguri 2040.https: / / www.classnk.or.jp. [Non-Patent Document 2] Kazunari Hanyu, Shintaro Miyoshi, Development of an automatic berthing control system for unmanned ships - Automatic berthing control of one shaft, one rudder, and one bow thruster -, No.34, pp.21-24, May 2022. [Non-Patent Document 3] Fuyuki Hane, Cpp., Design of a Berthing and Unberthing System Using Positioning Control for Ships Equipped with Bow and Stern Thrusters, Proceedings of the Japan Society of Naval Architects and Ocean Engineers Conference, No. 36, pp. 1-9, June 2023. [Non-Patent Document 4] K. Oze, A. Yumuro, Y. Yoshimura, "Mathematical Modeling of Ship Maneuvering Motion", The Society of Naval Architects of Japan, 3rd Symposium on Maneuverability, 1981. Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a docking technique suitable for a ship equipped with a rudder, a screw and a bow thruster. [Means for solving the problem]

[0007] One embodiment is a ship steering control device that controls a ship having a propulsion drive unit with a screw and a bow thruster, and sensors that detect the bow heading, hull position, and hull speed, and is equipped with a trajectory planning unit that generates a reference trajectory, which is a time series signal of a reference position, and a reference signal, which is a time series signal of a reference heading, that guide the ship to a target position and target heading, an error calculation unit that calculates a yaw error, which is the error around the yaw of the ship relative to the reference heading, and a sway error, which is the error in the sway direction of the ship relative to the reference position, a yaw control unit that controls the rudder angle to reduce the yaw error, a sway control unit that controls the bow thruster to reduce the sway error, and a feedback control unit that has a surge control unit that controls the screw, and the surge control unit is characterized in that when a reverse position that is a predetermined reverse distance from the target position on the reference trajectory has not been reached, the surge control unit rotates the screw forward by a predetermined rotation amount, and when the reverse position has been exceeded, the screw reverses by a predetermined rotation amount until the hull speed becomes zero. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an overall configuration of a control system including a ship steering control device. [Diagram 2] FIG. [Diagram 3]FIG. 13 is a diagram showing the time series response of ship speed u to modeled screw rotation. [Figure 4] FIG. 13 shows the time series response of inlet velocity uR to modeled screw rotation. [Diagram 5] FIG. 2 is a block diagram showing the configuration of a ship steering control device. [Figure 6] FIG. 2 is a diagram showing a trajectory plan for docking. [Figure 7] FIG. 13 is a diagram showing an error in docking control. [Figure 8] FIG. 2 is a block diagram showing a configuration of a feedback control unit. [Figure 9] FIG. 2 is a block diagram showing the configuration of a surge control unit. [Figure 10] FIG. 11 is a diagram showing an algorithm of a rotation control process. [Figure 11] FIG. 13 is a diagram illustrating an algorithm for a reverse rotation distance calculation process. [Figure 12] FIG. 11 is a diagram showing an algorithm for an on / off control process. [Figure 13] FIG. 1 is a diagram showing coupled motion control by a rudder and a bow thruster. [Figure 14] FIG. 13 is a diagram showing the result of a trajectory plan that satisfies the specifications. [Figure 15] FIG. 13 shows the results of turning the screw rotation from on to off. [Figure 16] FIG. 13 is a diagram showing the result of changing the screw rotation from on to reverse. [Figure 17] FIG. 13 is a diagram illustrating parameters of a surge model. [Figure 18] FIG. 13 is a diagram showing the model output obtained from the results of changing the screw rotation from on to off. [Figure 19] FIG. 13 is a diagram showing the output of the model obtained from the result of changing the screw rotation from on to reverse. [Figure 20] FIG. 13 is a diagram showing parameters of the yaw and sway models. [Figure 21] FIG. 4 is a diagram showing an algorithm for a steering angle calculation process. [Figure 22]FIG. 13 is a diagram showing the ship position and ship heading by a simulation in the absence of disturbance. [Diagram 23] FIG. 13 is a diagram showing simulated ship motion in the absence of disturbances. [Figure 24] FIG. 13 illustrates a simulated attitude error in the absence of disturbances. [Diagram 25] FIG. 13 is a diagram showing a control amount by a simulation in the absence of disturbance. [Figure 26] FIG. 11 is a diagram showing a hull position and a hull heading in a simulation in the presence of a first disturbance. [Figure 27] FIG. 11 is a diagram showing a ship motion according to a simulation in the presence of a first disturbance. [Figure 28] FIG. 13 is a diagram showing an attitude error by a simulation in the presence of a first disturbance. [Figure 29] FIG. 13 is a diagram showing a control amount by a simulation in the case where a first disturbance is present. [Diagram 30] FIG. 13 is a diagram showing a hull position and a hull heading in a simulation in the presence of a second disturbance. [Diagram 31] FIG. 11 is a diagram showing a ship motion according to a simulation in the presence of a second disturbance. [Diagram 32] FIG. 13 is a diagram showing an attitude error by a simulation in the presence of a second disturbance. [Diagram 33] FIG. 13 is a diagram showing a control amount by a simulation in the case where a second disturbance is present. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] (1 Control System) A control system including a ship maneuvering control device according to this embodiment will be described below. Fig. 1 is a block diagram showing the overall configuration of the control system including the ship maneuvering control device.

[0011] As shown in Fig. 1, the ship handling control device 1 in the present embodiment controls a ship having a hull 2 equipped with a propulsion drive device 3 and sensors 4.

[0012] The propulsion drive device 3 can control the surge speed u, the sway speed v, and the yaw angular velocity r, and is a drive device including a propulsion device and a steering device. The propulsion drive device 3 includes a screw as the propulsion device and a bow thruster, and includes a flap rudder as the steering device.

[0013] The sensors 4 include a gyrocompass that detects the bow azimuth of the hull 2, a speedometer that detects the speed of the hull 2 through water, a GNSS sensor that detects the hull position from a satellite positioning system (GNSS) such as GPS, and the like. The sensors 4 may include sensors capable of detecting the speed through water, the bow azimuth, and the hull position, respectively.

[0014] The ship handling control device 1 performs berthing control of the ship so that the azimuth and position of the hull coincide with the azimuth and position of the target value. The ship handling control device 1 calculates a control amount based on the setting information including a plurality of set values given in advance regarding the berthing control, the speed through water, the bow azimuth, and the hull position output from the sensors 4, and outputs the control amount to the propulsion drive device 3. Further, the ship handling control device 1 uses XY coordinates instead of latitude and longitude coordinates as the hull position.

[0015] (2 Control Target) (2.1 Hull Model) The hull model of the ship that is the control target of the ship handling control device will be described. Fig. 2 is a diagram showing the hull model.

[0016] In Fig. 2, O-XY is the earth-fixed coordinate, O B -X B Y B is the hull-fixed coordinate, O B is the center of gravity of the hull 2, and the sign is a right-handed system. Further, in the following equations, u represents the surge speed, v represents the sway speed, r represents the yaw angular velocity, ψ represents the bow azimuth, and δ represents the rudder angle. Also, λ represents the rotational speed of the screw that is on-off controlled, and the subscript b represents the bow thruster, λb indicates the propeller speed of the bow thruster.

[0017] (2.2 Surge motion model) This section explains the surge motion model. In this section, we model the ship speed and the inflow velocity to the rudder relative to the screw rotation. If we define the model as a first-order lag system, then

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[0020] (2.2.1 Modeling ship speed and inflow velocity into the rudder) The modeling of ship speed and inflow velocity to the rudder will be explained. Figure 3 shows the time series response of ship speed u to the modeled screw rotation. Figure 4 shows the time series response of inflow velocity uR to the modeled screw rotation.

[0021] As shown in Figures 3 and 4, the ship speed and inflow velocity are modeled from their time series responses to the screw rotation. 1 is the first line, the subscript 2 is the latter part, subscript H He stood up, L falls, LR is the falling edge during reversal.

[0022] In the case of ship speed u, the time constants for forward rotation ON, stop OFF and reverse rotation REV are set. Also, the inflow velocity u R In the case of , the flow velocity change caused by the screw rotation amount λ acts directly on the steering area, so u R It reacts quickly. It is modeled with two time constants at the rise or fall of λ. The time width and time constant are set in the first stage, and the time constant is set in the second stage.

[0023] (2.2.2 Effect on steering force) The effect on steering force will be explained.

[0024] u R is steering force F N Acting on the turning force gain K r and cross flow gain K v With reference to Non-Patent Document 4,

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[0027] Therefore, the turning force gain and the cross flow gain tend to be proportional to the square of the inflow velocity. If we assume that the rudder force is not fully developed when the inflow velocity is small, the turning force gain and the cross flow gain are

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[0029] (2.3 Ship motion model) The ship motion model will now be explained.

[0030] If the ship motion model is expressed in linear terms with three degrees of freedom, it becomes the following equation.

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[0033] Ω (bold) E B is a subscript B The subscript from the ship-fixed coordinate system represented by E is the matrix that converts the coordinates into Earth-fixed coordinates represented by the following formula:

[0034]

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[0035] (3) Control System (3.1 Ship steering control device) The configuration of the ship maneuvering control device will be described below with reference to Fig. 5, which is a block diagram showing the configuration of the ship maneuvering control device.

[0036] The ship steering control device 1 uses a trajectory tracking method to move the ship's attitude (heading, speed and position) from an initial value at the start of docking to a target value at the end, and then stops it. As shown in Fig. 5, the ship steering control device 1 includes a trajectory planning unit 11, an error calculation unit 12 and a feedback control unit 13. The trajectory planning unit 11 calculates a reference signal ψ which is a time-series signal for a reference heading and a reference position based on setting information indicating the docking conditions. R ,x R ,y R The error calculation unit 12 generates a trajectory plan based on the reference signal ψ R ,y R Based on the heading ψ and the ship position (x, y), the yaw error ψ e and sway error y e The feedback control unit 13 outputs a control amount that reduces the error calculated by the error calculation unit 12.

[0037] (3.2 Trajectory Planning Section) The operation of the trajectory planning unit will be described below. Fig. 6 is a diagram showing a trajectory plan relating to berthing.

[0038] As shown in Fig. 6, the trajectory planning unit 11 generates a reference trajectory, which is a time-series signal of a position, and a reference signal, which is a time-series signal of a reference orientation, that satisfy the specifications for berthing, by a first generation process and a second generation process. 1 indicates the first generation process, and the subscript 2 indicates that it is related to the second generation process. R indicates a reference value, and bold indicates a time series signal.

[0039] The first generation process maintains the ship speed and ψ set andy set Reference orientation ψ (bold) that satisfies andR and reference sway position y (bold) R The second generation process reduces the ship speed and calculates u set and x set and satisfy the reference surge position x (bold) R Calculate x (bold) R is a reference value and is not actually used.

[0040] (3.3 Berthing Error) The error calculated by the error calculation unit will now be described. Fig. 7 is a diagram showing errors in docking control.

[0041] In Figure 7, point R is the reference position, point P is the ship's position, point H is the intersection point between the reference trajectory and the perpendicular line that passes through point P and is perpendicular to the reference trajectory, and (ψ) is the ship's heading at point P. The berthing error becomes zero when the three points P, R, and H are coincident.

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[0044] (3.4 Feedback control section) The configuration and operation of the feedback control unit will be described with reference to Fig. 8, which is a block diagram showing the configuration of the feedback control unit.

[0045] The feedback control unit 13 advances the ship's position by controlling the screw rotation on and off between DEs on the reference trajectory (see FIG. 6 ), and adjusts the course error y e and the heading error ψ eand are converged to zero by bow thruster rotation control and rudder angle control.

[0046] Furthermore, the feedback control unit 13 reverses the screw rotation until the surge speed becomes zero during the EG interval (see FIG. 6) on the reference trajectory, and stops the screw rotation when the surge speed becomes zero. In other words, the target position is a position based on the reverse rotation start position, which is the position at which the reverse rotation of the screw starts, and the amount of movement of the hull position due to the reverse rotation time, which is the time for which the screw rotation is reversed. The reverse rotation start position is calculated by the feedback control unit 13 during control.

[0047] As shown in Fig. 8, the feedback control unit 13 includes a surge control unit 131, a sway control unit 132, and a yaw control unit 133. The sway control unit 132 and the yaw control unit 133 have the same structure. The sway control unit 132 e The bow thruster propeller rotation amount λ is adjusted so that b and the yaw control unit 133 outputs ψ e The command rudder angle δ is set so that c The surge control unit 131 controls the rotation of the screw on and off or reverses the screw based on the input setting value and forward position x. The amount of screw rotation λ output by the surge control unit 131 is a constant value that is preset based on the characteristics of the ship to be controlled.

[0048] (3.4.1 Surge control section) The configuration and operation of the surge control unit will be described below with reference to Fig. 9, which is a block diagram showing the configuration of the surge control unit.

[0049] 9, the surge control unit 131 includes a rotation control unit 131A and an ON / OFF control unit 131B, and does not use a regulator system like the sway control unit 132 and the yaw control unit 133. The surge control unit 131 outputs a screw rotation amount λ and a stop flag flgStop. The stop flag flgStop is output to the sway control unit 132 and the yaw control unit 133, and the bow thruster rotation amount λ b and command rudder angle δ c This is a flag that instructs the sway control unit 132 and the yaw control unit 133 to stop outputting.

[0050] (3.4.1.1 Rotation control process) The rotation control process performed by the rotation control unit will now be described with reference to Fig. 10, which is a diagram showing an algorithm for the rotation control process.

[0051] The rotation control unit 131A controls the screw rotation and executes a rotation control process for guiding the forward direction position of the hull 2 ​​to a target value at predetermined intervals according to an algorithm shown in FIG.

[0052] In Figure 10, xx (x) is the ground distance in the forward direction, xRev is the distance over which the thrust is reversed, and uu is the ground speed in the forward direction. sigProp is a thrust signal that determines whether or not to move forward, with 0 indicating off and 1 indicating on. flgStop is a stop flag, with 0 indicating not stopped and 1 indicating stopped. flgRot is a rotation on / off flag, with 0 indicating rotation off and 1 indicating rotation on. flgLamda is a rotation status flag, with 0 indicating rotation stopped, 1 indicating forward rotation, and -1 indicating reverse rotation. Here, forward rotation is the rotation direction of the screw that moves the hull 2 ​​forward, and reverse rotation is the rotation direction of the screw that moves the hull 2 ​​backward.

[0053] The signals flgRot and sigProp are output to the ON / OFF control unit 131B and are used in the ON / OFF control process described later. The value of xRev is calculated by the reverse rotation distance calculation process described later.

[0054] According to this rotation control process, when xx is less than xRev, the rotation control unit 131A rotates the screw forward. At this time, 1 is substituted for sigProp, and the value of flgRot is substituted for flgLamda.

[0055] Also, if xx is greater than or equal to xRev, the screw is rotated in reverse so that the ship speed decreases to zero. At this time, 0 is assigned to sigProp, -1 is assigned to flgLamda, and 0 is assigned to flgRot.

[0056] In addition, when the ship speed reaches zero, the rotation control unit 131A stops the rotation of the screw, stops the control by the sway control unit 132 and the yaw control unit 133, and adjusts the bow thruster rotation amount λ b and command rudder angle δ c is set to zero. At this time, 0 is assigned to flgLamda and 1 is assigned to flgStop.

[0057] (3.4.1.2 Reverse Distance Calculation Process) The reverse rotation distance calculation process performed by the rotation control unit will now be described with reference to Fig. 11, which is a diagram showing an algorithm for the reverse rotation distance calculation process.

[0058] The reverse distance xRev is calculated based on the surge motion state of the target ship. The time response of the ship speed u when the thrust is reversed is

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[0063] Prior to the reversal distance calculation process, flgDec, xSet, xRev, uRev(u rev ) are set to initial values. In this embodiment, the initial values ​​are set to flgDec=0, xSet=400, xRev=xSet, and uRev=-5.3*0.514. Here, flgDec is a deceleration flag, with 0 indicating no deceleration and 1 indicating deceleration.

[0064] The rotation control unit 131A controls the docking control loop by G (xGhat in FIG. 11) is obtained from equation (22), and the reverse distance calculation process is executed at predetermined intervals. When flgDec is 0 and xGhat is equal to or greater than xSet, rotation control unit 131A assigns 1 to flgDec and xx to xRev. In other words, rotation control unit 131A calculates the forward ground distance at the time when it is determined that the preset xSet is equal to or less than xGhat as the reverse distance.

[0065] (3.4.1.3 ON / OFF control processing) The ON / OFF control process by the ON / OFF control section will now be described with reference to Fig. 12, which shows an algorithm for the ON / OFF control process.

[0066] The ON / OFF control unit 131B controls the screw rotation amount by alternately executing the ON / OFF control process shown in Fig. 12 and the rotation control process at each duty ratio period. The duty ratio is determined by the duration of ON and OFF. The ON / OFF control unit 131B also outputs flgRot to the rotation control unit 131A every time the ON / OFF control process is executed.

[0067] 12, jcount is an integer value indicating the on-time of the pulse signal of the duty ratio, and jcount2 is an integer value indicating the off-time of the pulse signal of the duty ratio, both of which are set in advance. j is a counter value indicating the number of times the ON / OFF control process is executed, jon is a counter value that counts the times when the pulse is on, and joff is a counter value that counts the times when the pulse is off, and these are given initial values ​​before the ON / OFF control process is started. The difference between j and joff is substituted for jonx, and the difference between j and jon is substituted for joffx.

[0068] The ON / OFF control unit 131B turns off the pulse signal for jcount2 when flgRot is 0. At this time, when joffx is equal to or greater than jcount2 and sigProp is 1, the ON / OFF control unit 131B assigns 1 to flgRot and assigns j to jon.

[0069] Furthermore, the ON / OFF control unit 131B turns on the pulse signal for jcount when flgRot is 1. At this time, when jonx is equal to or greater than jcount1, the ON / OFF control unit 131B assigns 0 to flgRot and assigns j to joff.

[0070] (3.4.2 Yaw control section and sway control section) The yaw control section and the sway control section will now be described. Fig. 13 is a diagram showing the coupled motion control by the rudder and the bow thruster.

[0071] The yaw control by the yaw control unit 133 and the sway control by the sway control unit 132 are performed by coupled motion control. As shown in Fig. 13, the coupled motion control corrects the heading error by the rudder force and the course error by the bow thruster thrust. It is assumed that the closed loop system by the coupled motion control is stable.

[0072] The coupled motion control must operate simultaneously. When the rudder is turned, it generates an angular velocity and a lateral drift velocity in the hull 2. The angular velocity (heading error) is handled by the yaw control system, but the lateral drift velocity (route error) cannot be handled. At this time, the route error is corrected by the sway control system using the bow thruster thrust, but at the same time, a moment is generated around the yaw. In this way, the correction of the heading error and route error has the characteristic that it is prone to vibration phenomena due to interference between the yaw motion and the sway motion. For details on yaw control and sway control, please refer to non-patent document 3.

[0073] (3.4.2.1 Feedback Control) The correction formula for feedback control by the yaw control section and the sway control section (subscript ~ )teeth,

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[0076] (3.4.3 Effects of disturbances) The effect of disturbance will now be described.

[0077] The disturbance components in this embodiment are assumed to be the hull characteristics, tides, and wind forces. When the screw rotation is stationary (near the target value), surge and sway velocity biases and yaw angular velocity biases occur. At this time, only the bow thruster thrust (see FIG. 13) can be used.

[0078] The condition for the yaw and sway closed loop to be stable is

[0079]

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[0080] However, ψ c , ψ set ,r bias Since it is impossible to control, the bow thruster operation is stopped. Naturally, all control variables become zero near the target value, so the vessel attitude (heading, speed and position) will drift if there is a disturbance component.

[0081] (4 Verification) The ship maneuvering control device according to this embodiment is verified by simulation to confirm its effectiveness.

[0082] (4.1 Specifications) The specifications for the simulation will be explained.

[0083] The specifications in the simulation are to move the ship's position from point D to point G as shown in Fig. 6. In this specification, the docking direction is starboard, the time is within 30 minutes, and the initial value (subscript 0 ) is ψ 0 =45deg,u 0 = 2kn = 1.03m / s, and the achieved value (subscript set ) is ψ set =0deg,u set =0kn,x set =400m,yset =50m.

[0084] (4.2 Trajectory Planning) The trajectory planning in the simulation will now be described. Fig. 14 is a diagram showing the results of a trajectory planning that satisfies the specifications.

[0085] The result of the trajectory planning that satisfies the specifications shown in Fig. 14 is c 1 = 0.95, τ u =204.5s,x 1 =210.4m,y 1 =50×c 1 =47.5m,ψ 1 =2.2deg,at t 1 = 193.8s, where the subscript 1 represents matters related to the reference trajectory and reference signal generated by the first generation process.

[0086] (4.3 Hull parameters) (4.3.1 Surge model parameters) The parameters of the surge model in the simulation will be described. Fig. 15 is a diagram showing the result of changing the screw rotation from on to off. Fig. 16 is a diagram showing the result of changing the screw rotation from on to reverse. Fig. 17 is a diagram showing the parameters of the surge model. Fig. 18 is a diagram showing the output of the model obtained from the result of changing the screw rotation from on to off. Fig. 19 is a diagram showing the output of the model obtained from the result of changing the screw rotation from on to reverse.

[0087] The parameters of the surge model are set from the results of a simulation using the MMG model (details omitted). In this simulation, the main specifications of the ship to be controlled were assumed to be: ship type: container ship (204 TEU), ship length: perpendicular length 83 m, ship width: width 13.5 m, gross tonnage: 749 tons.

[0088] In the input of the screw rotation amount λ, the application time is 200 s, and in FIG. 15, On=100 rpm, Off=0 rpm, and in FIG. 16, On=100 rpm, Rev.Off=-100 rpm. R The steady-state values ​​of u and u are the same, 7.2kn at On=100rpm and -5.3kn at Rev.Off=-100rpm. The steady-state value during normal rotation is larger in absolute value than during reverse rotation. This is because the fluid resistance in the forward direction is smaller than that in the reverse direction. Also, of the two graphs shown in Figure 16, the steady-state value of u in the lower graph is R does not take into account values ​​below zero because the MMG model is not supported.

[0089] The parameters of the surge model (see Fig. 3 and Fig. 4) are shown in Fig. 17, which are obtained from Fig. 15 and Fig. 16. The output using these values ​​is shown in Fig. 18 and Fig. 19. In this way, we were able to match equations (1) and (2) to the characteristics of the target ship in the simulation.

[0090] (4.3.2 Yaw-sway model parameters) The parameters of the yaw model and the sway model in the simulation will be described below. Fig. 20 is a diagram showing the parameters of the yaw and sway models.

[0091] The parameters of the target ship and control system in the simulation are set from the parameters of the yaw and sway models shown in Figure 20.

[0092] (4.4 Calculation conditions) The calculation conditions in the simulation will be described below. Fig. 21 is a diagram showing an algorithm for the steering angle calculation process.

[0093] The calculation conditions in the simulation are as follows. The step time is st=0.1sm and the calculation time is 10 minutes. The reference signal is the one shown in Figure 14. However, the surge reference signal x R is not used. The surge parameters of the target ship are set based on Figure 17, and the yaw and sway models are set based on Figure 20. Regarding the disturbance component, the current component is U c =1kn,ψ c =45deg, yaw bias component is r bias = ±1 deg s -1 Let us assume that. The main control parameters are proportional gain K p = 1, and the damping coefficient is ζ = 0.7071. The correction coefficient is ρ = √2. For the ρ correction, equation (23) is implemented. In the simulation, the commanded steering angle δ c The relationship between the rudder angle δ is based on the algorithm of the rudder angle calculation process shown in Fig. 21. In Fig. 21, actDelta is a control signal for steering operation determined based on the inflow speed.

[0094] (4.5 Simulation Results) (4.5.1 When there are no disturbance components) The simulation results when there is no disturbance component will be described. Fig. 22 to Fig. 25 are diagrams showing the ship position and ship direction, ship motion, attitude error, and control amount, respectively, in a simulation when there is no disturbance. In this simulation, the distance for reversing the propulsive force is x rev =285.1m.

[0095] The simulation results when there is no disturbance component are as follows. As shown in Figure 22, R and y, ψ R The relationship between x, y, and ψ is shifted due to the difference in coordinate positions. x, y, and ψ reach the target values. As shown in Figure 23, when the screw rotation is turned on, u R The rudder force (u R >2m / s) acts. Meanwhile, u gradually increases, and x rev After that, it slows down and becomes zero. v,r are oscillatory, but converge to zero. As shown in Figure 24, ψ e causes an error in the + direction, and ye is ψ e The error is smaller. · As shown in Figure 25, λ turns the screw rotation on and off, and x rev Since then, the situation has been reversed. b Yes e This reflects δ c are continuous, but u R Due to the effect of δ, δ is operating when λ is on.

[0096] (4.5.2 When the first disturbance component is present) The simulation results when the first disturbance component is present will now be described. Fig. 26 to Fig. 29 are diagrams showing the hull position and hull heading, hull motion, attitude error, and control amount obtained by the simulation when the first disturbance component is present, respectively.

[0097] In the simulation with the first disturbance component, the reversal distance is x rev =299.0m. As shown in Figures 26 to 29, a drift error due to the disturbance occurs from around 4 minutes. r bias =+1deg·s -1 Therefore, it corresponds to the + type of equation (25), and is a condition that can drive a bow thruster.

[0098] (4.5.3 When there is a second disturbance component) The simulation results when the second disturbance component is present will now be described. Fig. 30 to Fig. 33 are diagrams showing the hull position and hull heading, hull motion, attitude error, and control amount obtained by the simulation when the second disturbance component is present, respectively.

[0099] In the simulation when there is a second disturbance component, x rev =292.0m, r bias =-1deg s -1 As shown in Figs. 30 to 33, when equation (25) is not satisfied, the closed loop system diverges when the bow thruster is driven. As shown in Fig. 32, ψ e The sign of ψ is shown in FIG. e The opposite is true.

[0100] (5 conclusions) The above-mentioned ship steering control device can be summarized as follows.

[0101] When designing the ship steering control device 1, the ship speed and the inflow speed to the rudder were modeled. The modeling is based on a first-order lag system and is approximated by a time constant and a time width. The ship steering control device 1 comprises a trajectory planning unit 11, an error calculation unit 12 and a feedback control unit 13. The surge control unit 131 controls the screw rotation on and off, and decelerates the boat 2 from the reverse rotation start position. The sway control unit 132 and the yaw control unit 133 use a regulator method (estimator and state feedback). In a simulation, the ship maneuvering control device 1 was evaluated both with and without disturbances, and it was confirmed that the ship maneuvering control device 1 was effective.

[0102] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0103] 1. Ship steering control device 2. Hull 3 Propulsion Drive 4 Sensors 11 Orbit Planning Division 12 Error calculation section 13 Feedback control section 131 surge control unit 132 sway control section 133 yaw control section

Claims

1. A ship steering control device for controlling a ship having a propulsion drive device having a screw and a bow thruster, and sensors for detecting a bow direction, a hull position, and a hull speed, comprising: a trajectory planning unit that generates a reference trajectory, which is a time series signal of a reference position, and a reference signal, which is a time series signal of a reference orientation, for guiding the ship to a target position and a target orientation; an error calculation unit that calculates a yaw error, which is an error around a yaw of the ship relative to the reference orientation, and a sway error, which is an error in a sway direction of the ship relative to the reference position; A feedback control unit including a yaw control unit that controls a rudder angle so as to reduce the yaw error, a sway control unit that controls the bow thruster so as to reduce the sway error, and a surge control unit that controls the screw, The surge control unit rotates the screw forward by a predetermined rotation amount when a reverse position that is a predetermined reverse distance from the target position on the reference trajectory has not been reached, and rotates the screw reversely by a predetermined rotation amount until the hull speed becomes zero when the reverse position has been exceeded.

2. 2. The ship maneuvering control device according to claim 1, wherein the surge control unit causes the yaw control unit to set the rudder angle to zero and the sway control unit to set a control amount of the bow thruster to zero when the hull speed becomes zero.

3. The surge control unit is configured to estimate a target value x^ Ｇ is equal to or greater than a preset threshold value, the distance to the target position is calculated as the reverse rotation distance; t is the time from the start of reverse rotation, u ０ is the initial ship speed, u ｒｅｖ < 0 is the steady ship speed when reversing, T ｕ ＬＲ is the time constant during reverse rotation, and the time Δt until the vessel speed becomes zero is [0010] The moving force Δx when the screw rotates in the reverse direction is [0025] Then, the estimated target value x^ Ｇ teeth [0030] 3. The ship maneuvering control device according to claim 1, wherein:

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