JP2022175993A - Automatic steering system for ship - Google Patents

Abstract

To provide a technology capable of automatically berthing and un-berthing a ship.SOLUTION: An automatic steering system for a ship comprises: a reference trajectory generating unit for generating a reference trajectory which includes a trajectory from a departure point to an arrival point, a reference distance that is a time function of a surge direction distance from the departure point to the arrival point, and a reference azimuth that is a time function of the azimuth based on a planned route; a movement control unit 121 for controlling the ship by a distance control that causes a position of the ship to follow the reference distance, and a route control that causes the position of the ship to follow the trajectory and the azimuth of the ship to follow the reference azimuth; a holding control unit 122 for controlling the ship to hold the position of the ship; and a switching unit 123 for switching from the control by the movement control unit to the control by the holding control unit when an intersection of a line extending from the position of the ship in a sway direction of the ship and the trajectory reaches the arrival point.SELECTED DRAWING: Figure 13

Description

The present invention relates to technology for automatically steering a ship.

In recent years, research and development on berthing and unberthing navigation has been vigorously promoted in the navigation technology of ships. To realize berthing and unberthing navigation, hull position control technology is required to move the hull position from the departure point, turn on the way, and stop at the destination point. A ship has a larger inertial force, a weaker braking force, and a weaker fluid resistance at low speeds than an automobile. Therefore, it is not easy to control the ship to stop.

Fuyuki Hane, “Design of berthing and unberthing control system including speed control using compass”, Proceedings of the Japan Society of Naval Architects and Ocean Engineers, 2019, 29: 497-503 Fuyuki Hane, “Design of ship position keeping device by decoupling and path order”, Proceedings of the Japan Society of Naval Architects and Ocean Engineers, May 2020, (30): 33-41 Fuyuki Hane, “Design by analytical method based on course keeping control for course keeping system”, Transactions of the Japan Society of Naval Architects and Ocean Engineers, January 2016, 23:33-44

A problem to be solved by the present invention is to provide a technique for automatically unberthing and unberthing a ship.

A marine autopilot system according to an embodiment includes a propulsion drive device capable of controlling the velocities in the surge direction and the sway direction and the angular velocity around the yaw, and a sensor for detecting the heading and the position of the hull. An automatic steering device, based on a planned route, a trajectory from a starting point to a destination point, a reference distance that is a time function of the surge direction distance from the starting point to the destination point, and a time function of the heading a reference trajectory generator for generating a reference trajectory including a reference bearing; distance control for causing the position of the ship to follow the reference distance; A movement control unit for controlling the ship, a holding control unit for controlling the ship to hold the position of the ship, and a sway direction of the ship from the position of the ship and a switching unit for switching from control by the movement control unit to control by the holding control unit when the intersection of the line and the trajectory reaches the arrival point.

According to the present invention, a ship can be automatically unberthed and unberthed.

1 is a block diagram showing the overall configuration of a system including a marine automatic steering device; FIG. It is a figure which shows the form of a planned route. 1 is a diagram showing a classification of control systems; FIG. FIG. 4 is a diagram showing reference angular velocities; FIG. 4 is a diagram showing a time series of reference orientations; FIG. 4 is a diagram showing reference speed; It is a figure which shows a planned course and a reference trajectory. 3 shows a controlled object including a hull model and a drive machine model; FIG. 4 is a diagram showing ship speed characteristics of a hull parameter _Tr ; FIG. 10 is a diagram showing errors in movement mode; FIG. 10 is a diagram showing errors in hold mode; It is a figure which shows the basic composition of a control system. It is a figure which shows the structure of a control part. It is a figure which shows the structure of the control system by a movement control part. It is a figure which shows the structure of the control system by a holding|maintenance control part. FIG. 4 is a diagram showing a planned route and a ship's position track when the tidal current is zero; FIG. 4 is a diagram showing a planned route and a ship's position track when there is a tidal current; FIG. 4 is a diagram showing the response of ship motion; FIG. 10 is a diagram showing the error response; FIG. 10 is a diagram showing a command response; FIG. 4 is a diagram showing the response of the driver output;

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(1 Configuration of marine automatic steering system)
First, a system including a marine autopilot according to this embodiment will be described. FIG. 1 is a block diagram of the overall configuration of a system including a marine autopilot.

As shown in FIG. 1, a marine autopilot system 1 according to the present embodiment controls a marine vessel having a hull 2 provided with a propulsion drive device 3 and sensors 4 . In this embodiment, the propulsion drive device 3 is a drive device capable of controlling the velocities in the surge direction and the sway direction and the angular velocity around the yaw. Configured as a thruster.

The sensors 4 include a gyrocompass that detects the heading of the hull 2, a speedometer that detects the water speed of the hull 2, and a GNSS sensor that detects the hull position from a satellite positioning system (GNSS) such as GPS. It should be noted that the sensors 4 may include sensors capable of detecting the ship's heading and hull position.

The marine autopilot system 1 includes a reference trajectory generator 11 and a controller 12 . The reference trajectory generator 11 generates a reference trajectory based on the planned route output by the trajectory planer 5 . The control unit 12 outputs a command to the propulsion drive unit 3 based on the heading and hull position detected by the sensors 4 so that the hull 2 follows the reference trajectory generated by the reference trajectory generation unit 11. Controls hull speed and angular velocity.

(2.2 Berthing specifications)
(2.2.1 Planned route)
Explain the planned route. FIG. 2 is a diagram showing the form of the planned route.

The planned route, as shown in FIG. 2, includes a starting point, a destination point, ship speed and turning conditions, and is composed of a combination of straight lines and circular arcs. In FIG. 2, O-XY is the earth-fixed coordinate, ψ _plan is the planned direction, point A is the starting point, and point B is the reaching point. Points C, S, and F are the turning center point, starting point, and ending point, respectively, ρ is the turning radius, and ψ _set is the turning angle. Point D is the starting point of deceleration of the boat speed, and point E is the starting point of course change.

On the planned route, the ship is controlled so that its forward speed is accelerated from point A, passes through constant speed, is decelerated from point D, and reaches point B. Further, the ship starts to change course from point E, which is located closer to point S, in order to put the ship on the turning route.

(2.2.2 Overall operation)
The overall operation of the marine automatic steering system will be described schematically.

The marine automatic steering apparatus 1 first converges the azimuth ψ at the starting point A to the planned azimuth ψ _plan by turning control, then moves the hull position from the starting point A to the arrival point B and stops. Further, when the hull position after stopping has an error with respect to the arrival point B, the marine autopilot system 1 moves the hull position to the arrival point B by route sequence control and stops the hull.

The route sequence control is a control to cause the hull positions x, y and heading ψ in the surge direction and the sway direction to follow reference signals, which are time series signals of the reference position and reference heading in the surge direction and the sway direction. The signals are different in timing from each other and preferably generated so as not to overlap in time with other reference signals. Surge direction control, sway direction control, and azimuth control in route sequence control are state feedback controls based on the surge model, sway model, and yaw model of the hull model, respectively. Please refer to Non-Patent Document 2 for details of the route order control.

Among these operations, control for moving the hull position from the starting point A to the arrival point B will be described below as hull position control.

(2.3 Hull position control)
Hull position control will be described. FIG. 3 is a diagram showing the classification of control systems.

Hull position control includes a move mode and a hold mode. In the movement mode, the hull position is moved to the arrival point B following the reference trajectory. However, the hull position cannot necessarily match the arrival point B. The hold mode holds the hull position at the terminal point B', which is located in the vicinity of the arrival point B, i.e., is in error with respect to the arrival point B. When the hull position is held at the arrival point B, a transient phenomenon occurs due to the initial response (see Non-Patent Document 2). To reduce this transient, the hold mode holds the hull position at the endpoint B'.

(2.3.1 Reference Orbit)
A reference trajectory consists of positions and times that satisfy the trajectory plan and is used in locomotion mode. The control unit 12 determines the hull position along the reference trajectory using the point H, which is the intersection of the reference trajectory and the line pointing in the sway direction from the hull position, as the reference of the reference trajectory. For example, the control unit 12 starts changing course when the point H coincides with the point E.

(2.3.2 Outline of control system)
An outline of the control system will be explained. FIG. 3 is a diagram showing the classification of control systems.

The control unit 12 has control systems for each of the movement mode and the hold mode. The control unit 12 causes the hull position to follow the position corresponding to the time set in the reference trajectory in the move mode, and holds the hull position at the terminal point B' near the arrival point B in the hold mode.

In FIG. 3, DC indicates distance control, TC indicates route control, and DP indicates route holding control. Further, the route keeping control includes the static stabilization control and the route sequence control described above. Static control is control for converging the hull position P to the terminal point B'.

In the movement mode, the control unit 12 obtains the error between the reference trajectory and the hull position from the point H, and corrects this error by distance control and route control. In the hold mode, the control unit 12 also corrects the error between the terminal point B' and the hull position by static control, and moves the hull position from the terminal point B' to the arrival point B by route sequence control. Note that the movement from the terminal point B' to the destination point B may be controlled by other control rules than the route order control.

(3 reference trajectory)
The reference trajectory will be explained. The reference trajectory is generated by the reference trajectory generator 11 and is configured based on the planned route. The control unit 12 causes the hull position to follow the reference trajectory. The reference trajectory has measures against the following factors in order to reduce control errors.

1. 2. Transient phenomena caused by changes in ship speed. 2. Transient phenomena caused by angular velocity during turning; Countermeasures against 1 and 2 above and route error caused by ship motion

These countermeasures are described below. For the sake of explanation, the above 2, the above 1, and the above 3 are described in this order.

(3.1 Reference direction)
The reference azimuth in the reference trajectory will be explained. FIG. 4 is a diagram showing reference angular velocities. FIG. 5 is a diagram showing a time series of reference orientations.

The trajectory plan for the reference bearing is set so as to satisfy the turning conditions of the planned route. The turning conditions are radius ρ, ship speed u _R , course change amount ψ _set , angular velocity r=u _R ÷ρ, acceleration time T _a , constant speed time T _v , and deceleration time T _d . Here, the subscript _R means reference signal. The sign of the amount of course change is set to ψ _set >0 to prevent complication of the formula. The reference azimuth is set so as to start changing course when point H passes point E, as shown in FIG.

As shown in FIG. 5, the time function of the reference azimuth ψ _R is given by the following equation.

ここで、添字_ａ，_ｖ，_ｄはそれぞれ加速モード、等速モード、減速モードを示し、添字_１，_２，_３はそれぞれ角加速度、角速度、角度を示す。また、μは軌道係数であり、加速時間は｛０≦ｔ＜Ｔ_ａ｝、等速時間は｛０≦ｔ＜Ｔ_ｄ｝、減速時間は｛０≦ｔ＜Ｔ_ｄ｝であり、Ｃは初期値である。変針量の符号が正ならば、μ_ａ＞０，μ_ｄ＞０になる。

Here, subscripts _a , _v , and _d denote acceleration mode, constant velocity mode, and deceleration mode, respectively, and subscripts ₁ , ₂ , and ₃ denote angular acceleration, angular velocity, and angle, respectively. μ is the orbit coefficient, the acceleration time is {0≦t<T _a }, the constant velocity time is {0≦t<T _d }, the deceleration time is {0≦t<T _d }, and C is Initial value. If the sign of the amount of course change is positive, μ _a >0 and μ _d >0.

The orbital coefficients and initial values in the above formula are as follows.

Since the amount of course change ψ _set is the sum of the amount of course change in each mode, the following equation is obtained.

Deriving the derivative of the reference direction at the start and end of each mode gives

になる。参照方位とその微分値は上式から各モードで滑らかに接続される。よって、制御システムは参照方位の微分値による過渡現象を生じ難くなる。

become. The reference orientation and its differential value are smoothly connected in each mode from the above equation. Therefore, the control system is less prone to transient phenomena due to differential values of the reference orientation.

(3.2 Reference distance)
The reference distance in the reference trajectory will be explained. FIG. 6 is a diagram showing reference speeds.

The reference distance dR is determined by the distance from the starting point A to the reaching point _B in the surge direction. The trajectory plan of the reference distance is set so as to satisfy the ship speed condition of the planned route. Vessel speed conditions determine acceleration mode and deceleration mode. As shown in FIG. 6, the acceleration mode is set from the starting point A to the acceleration time ^Tau , and the deceleration mode is set from the point _D to the ^deceleration time _Tdu . The constant velocity mode is set between the acceleration mode and the deceleration mode, and is set to the time from the time when the acceleration time ^Tau has passed from the starting point _A until the point D is passed. Steering operation by reference heading is performed in constant velocity mode. Thus, trajectory plans for reference ranges can be constructed similarly to reference bearings. The control system is less prone to transients due to derivatives of reference distances as well as reference headings.

The reference distance d _R is, in formulas (1) to (3) described in (3.1 Reference orientation) above,

の置換をすれば良い。ここで、ｄ_Ｒは参照距離、ψ_Ｒは参照方位である。よって、参照距離は

should be replaced with where d _R is the reference distance and ψ _R is the reference orientation. So the reference distance is

になる。ここで、添字^ｕは参照距離に関し、Ｔ_Ｄは点Ｈが点Ｄを通過する時点を示す。

become. Here, the subscript ^u relates to the reference distance and TD indicates the point in time when point H passes point _D.

The distance dAD to point _D is given by the following equation.

ここで、

here,

である。

is.

(3.3 Reach correction)
Describe reach correction.

The reference trajectory is affected by the acceleration and deceleration times of the reference heading and the reference distance by taking measures against transient phenomena due to changes in ship speed and changes in angular velocity during turning.

The effect of reference orientation is shown. The course change time is from formula (9)

になる。ここで、Ｔ_ｒａｍｐはランプ入力を用いた時間で最短となる。等速時間は上式から、

become. Here, Tramp is the shortest time using the _ramp input. From the above equation, the constant velocity time is

になる。ここで、括弧の簡略化をする。よって、変針時間は

become. Here we simplify the parenthesis. Therefore, the course change time is

になり、Ｔ_ｒａｍｐよりＴ_ａだけ長くなる。そのため、参照方位による参照軌道はランプ入力のものに比べて遅れる。参照距離も同様に加速時間に伴う遅れを生じる。さらに、船体運動の時定数による応答遅れや横流れ速度による斜航角が加わる。そのため、参照軌道は数値計算によって求められる。

, which is _longer than T _ramp by Ta. Therefore, the reference trajectory due to the reference orientation lags that of the ramp input. The reference distance similarly suffers a lag with the acceleration time. In addition, a response delay due to the time constant of the hull motion and a skew angle due to the crossflow velocity are added. Therefore, the reference trajectory is obtained by numerical calculation.

Figure 7 shows the planned route and reference trajectory. In FIG. 7, the route after point F and point R is omitted, and the planned route turns right from the origin O to the north. For simplification of the calculation, the planned azimuth ψ _plan of the straight route is rotated northward as shown in FIG.

A reference trajectory is derived from a reference velocity and a reference bearing

になる。ここで、Ｒ_ｘ，Ｒ_ｙは点Ｒの位置、ｔ_Ｂは参照距離ｄ_Ｒが到達点Ｂに達するまでの時間、ｕ_Ｒｆ(ｔ)，θ_Ｒｆ（ｔ）はそれぞれ参照速度、参照角度で加速モード・等速モード・減速モードをもち、

become. Here, R _x and R _y are the positions of the point R, t _B is the time until the reference distance d _R reaches the arrival point B, u _Rf (t) and θ _Rf (t) are the reference velocity and the reference angle, respectively. It has acceleration mode, constant velocity mode, and deceleration mode,

である。ここで、ｓはラプラス演算子、θ_Ｒｆ（ｔ）の第２項は船体横流れ速度による斜航角成分であり、Ｔ_ｖ，Ｔ_ｒは、それぞれ、船体パラメータのｓｕｒｇｅ方向、ｙａｗ周りの時定数である。

is. Here, s is the Laplace operator, the second term of θ _Rf (t) is the oblique angle component due to the hull lateral flow velocity, and T _v and _Tr are the hull parameter surge direction and the time constant around yaw, respectively. is.

The route error d _r is obtained from the tangent line intercepts x _R and x _F at the turning end points R and F in FIG.

になる。ここで、αは点Ｒの傾き、Δは微小な変化量、ψ_ｓｅｔは変針量である。

become. Here, α is the slope of the point R, Δ is the amount of minute change, and ψ _set is the amount of course change.

Therefore, a policy for correcting the course error _dr is to move the course change starting point to a point E that is ahead of the starting point S of the trajectory plan by _dr . Point E is the WOP (Wheel Over Point), and moving to point E is called reach correction.

(4. Hull control)
A control system that makes the hull follow the reference trajectory and the hull position initial value will be explained.

(4.1 Control object)
A controlled object will be explained. FIG. 8 shows a controlled object including a hull model and a drive machine model. FIG. 9 is a diagram showing ship speed characteristics of the hull parameter _Tr .

The controlled object consists of a hull model and a driving machine model, as shown in FIG.

(4.1.1 Hull model)
The hull model is represented by the subscript _u for the surge direction, the subscript _v for the sway direction, and the subscript _r for around the yaw.

とする。ここで、ｓはラプラス演算子、Ｐ（ｓ）は伝達関数、Ｕ（ｓ）はｓｕｒｇｅ速度、Ｖ（ｓ）はｓｗａｙ速度、Ｒ（ｓ）はｙａｗ角速度である。また、Λｕ（ｓ），Θｖ（ｓ），Θｒ（ｓ）は制御入力（指令量）であり、それぞれプロペラ回転数、２つの角度である。船体モデルの伝達関数は

and where s is the Laplace operator, P(s) is the transfer function, U(s) is the surge velocity, V(s) is the sway velocity, and R(s) is the yaw angular velocity. Λu(s), Θv(s), and Θr(s) are control inputs (instruction amounts), which are the propeller rotation speed and two angles, respectively. The transfer function of the hull model is

である。ここで、Ｔ，Ｋはいずれも船体パラメータで、それぞれ時定数とゲインである。

is. Here, both T and K are hull parameters, a time constant and a gain, respectively.

FIG. 9 shows ship speed (water speed) characteristics of the hull parameters. In FIG. 9, only _Tr is shown among the hull parameters, but other variables { _Kr , Ku, _Tu , _Kv , _{Tv }} are also related to ship speed. The low-speed characteristics in _Tr are assumed to be the inertia term, ignoring propulsion resistance. From FIG. 9, the hull parameters have the following ship speed characteristics.

1. The holding mode region is |u|≦2kn and is constant.
2. The movement mode range is u>2kn and is proportional to ship speed.

(4.1.2 Drive machine model)
The drive machine model will be explained.

The azimuth thruster model of the driver (hereafter ATM) controls the thrust vector by its propeller speed (not reversed) and its direction. The directional angle (opening) and number of rotations are limited. In FIG. 8, the rotational speed λ and thrust F of the two ATMs are

になる。ここで、添字_ｆ，_ａは船首（ｆｏｒｅ）、船尾（ａｆｔ）を示し、λ_ｆ，λ_ａはそれぞれプロペラ回転数、λ_０は一定回転数、Ｆは対水推力、Ｘ_ｕは推力係数である。その方向は

become. Here, subscripts _f and _a indicate the fore and aft, λ _f and λ _a are the propeller rotation speed, λ ₀ is the constant rotation speed, F is the thrust against water, and X _u is the thrust coefficient. be. the direction is

になる。ここで、θは船の基線からの推力方向の角度である。よって、発生する力とモーメントγは、

become. where θ is the angle of the thrust direction from the ship's baseline. Therefore, the generated force and moment γ are

になる。ここで、ｌはミッドシップから駆動機までのレバー長でｌ_ｆ＝ｌ_ａ＝ｌである。

become. Here, l is the lever length from the midship to the driving machine, and l _f =l _a =l.

On the other hand, if the ATM output γ is replaced by the command amount,

の関係をもつ。

have a relationship of

(4.2 Definition of error)
(4.2.1 Movement Mode)
An error in the movement mode will be explained. FIG. 10 is a diagram showing errors in the movement mode.

As shown in FIG. 10, the error in the movement mode is set for each of the straight route and the arc route.

The orientation error ψ _e is

になる。ここで、ψは船首方位、ψ_Ｒは参照方位である。

become. where φ is the heading and φ _R is the reference bearing.

The course error y _e is the distance between the hull position P and the point H.

になる。ここで、Ｌ(ｘ，ｙ)は直線の式で計画航路から定まり、

become. Here, L(x, y) is determined from the planned route by a linear equation,

である。ここで、ａ，ｂ，ｃは直線の係数である。ｙ_ｅは点Ｐを与えると求まる。

is. where a, b, and c are linear coefficients. Given the point P, y _e can be obtained.

The distance error d _e depends on the distance to the position on the trajectory plan.

に定められる。ここで、ｄ_ｅは距離誤差、ｄ_Ｒは参照位置Ｒまでの距離、ｄ_Ｈは点Ｈまでの距離

defined in where d _e is the distance error, d _R is the distance to the reference position R, d _H is the distance to the point H

である。ここで、添字^Ｌ，^Ｃはそれぞれ直線軌道、円弧軌道を示し、（０）は初期値であり、

is. Here, the suffixes ^L and ^C indicate a straight trajectory and an arc trajectory, respectively, (0) is the initial value,

である。ここで、ψ_Ｈは円弧上の点Ｈの方位である。

is. where ψ _H is the orientation of point H on the arc.

(4.2.2 Hold mode)
The error in hold mode will be explained. FIG. 11 is a diagram showing errors in hold mode. Note that FIG. 11 shows a state in which the moving mode is switched to the holding mode.

Switching from the moving mode to the holding mode shown in FIG. 11 is performed when the point H based on the hull position P reaches the arrival point B. As shown in FIG. At this time, the reaching point of the hold mode is changed from B to the terminal point B'. Therefore, the terminal point B' is the terminal position of the hull position P in the movement mode. This replacement from the reaching point B to the terminal point B' prevents the transient phenomenon due to the initial value of the hold mode (see Non-Patent Document 2).

When switching from the move mode to the hold mode, the position and heading of the hull position P are replaced with the terminal point B'. That is, the following formula is obtained.

The orientation error ψ _e is

になる。ここで、ψは船首方位、ψ_Ｂ’は移動モードの最終方位である。

become. where ψ is the heading and ψ _B ′ is the final heading of the travel mode.

The position errors x _e and y _e are represented by the hull coordinates and are given by the following equations.

ここで、Ω_Ｂ ^Ｅ（ψ）は地球座標（添字^Ｅ）から船体座標（添字_Ｂ）に変換する行列であり、

where Ω _B ^E (ψ) is a matrix that transforms from earth coordinates (subscript ^E ) to hull coordinates (subscript _B ),

である。

is.

(4.3 Control system)
The control system will be explained. FIG. 12 is a diagram showing the basic configuration of the control system. FIG. 13 is a diagram showing the configuration of a control unit. 14 and 15 are diagrams showing configurations of control systems by the movement control section and the holding control section, respectively.

As described above, the control system consists of distance control (DC), course control (TC), and course keeping control (DP) (see FIG. 3). The basic configuration of the control system, as shown in FIG. 12, is to input an error, output a command, and update the control gain using the hull parameter corresponding to the water speed.

As shown in FIG. 13 , the control unit 12 includes a movement control unit 121 that performs control in the movement mode, a holding control unit 122 that performs control in the holding mode, and a switching unit 123 . The switching unit 123 detects equation (48) from the hull position and switches the control subject to the movement control unit 121 or the holding control unit 122, thereby switching the control system from the movement mode to the holding mode.

14 and 15, C(s) indicates a controller. In FIG. 14, the subscript _d indicates distance control, the subscript _t indicates course error control, and the subscript _h indicates heading control. In FIG. 15, subscripts _x 1 , _y 2 , and _ψ indicate hull position holding control, and correspond to surge, sway, and yaw, respectively. As shown in FIG. 14, the movement control unit 121 has a distance controller, a route controller, and a direction controller. Further, as shown in FIG. 15, the hold control unit 122 has hull position hold controllers corresponding to surge, sway, and yaw, respectively. Since the controllers other than the route controller have the same configuration, the hull parameters and design parameters corresponding to these controllers are given to function as a distance controller, heading controller, and hull position holding controller.

(4.3.1 Route control)
Next, route control will be explained.

Course control converges the course error y _e to zero, and consists of heading control and course error correction. See Non-Patent Document 3 for details of the route control. Azimuth control also corrects for steering angle offset. The course error control corrects the course error due to the tidal current component by adding an integral action.

Azimuth control is an estimator plus a state feedback gain, and is given by the following equation.

ここで、ψ_ｅは方位誤差でありψ_ｅ＝ψ_Ｒ－ψ、θ_ｒは航路制御の指令であり、ｘ_ｈ＾＝［ｘ_ｒ＾ ｘ_ｗ＾ θ_ｒｏ＾］^Ｔ，ｘ_ｒ＾＝［ψ_ｅ＾ ｒ_ｘ＾］^Ｔ，ｘ_ｗ＾＝［ξ＾ ψ_ｗ＾］^Ｔである。添字＾は推定値、添字^Ｔは転置行列を示し、ξは変数である。また、Ｋ_ｈは推定ゲイン、Ｆ_ｈはフィードバックゲインであり、

Here, ψ _e is a heading error, ψ _e =ψ _R −ψ, θ _r is a command for route control, and x _h ^=[x _r ^ x _w ^ θ _ro ^] ^T ,x _r ^=[ ψ _e ̂ r _x ̂] ^T , x _w ̂=[ξ̂ ψ _w ̂ ] ^T . The subscript ^ indicates an estimated value, the subscript ^T indicates a transposed matrix, and ξ is a variable. Also, K _h is the estimated gain, F _h is the feedback gain,

である。ここで、ｆ，ｋはゲインの要素、Ｏ_ｉ×ｊはｉ行ｊ列のゼロ行列である。Ｋ_ｒ，Ｔ_ｒ，Ｔ_ｒ３＝０は船体パラメータでそれぞれ旋回力ゲインと２つの時定数である。ζ_ｗ，ω_ｗはいずれも波浪パラメータであり、それぞれ減衰係数、固有周波数である。

is. Here, f and k are gain elements, and O _i×j is a zero matrix of i rows and j columns. K _r , T _r , T _r3 =0 are the hull parameters, the turning force gain and the two time constants, respectively. Both ζ _w and ω _w are wave parameters, a damping coefficient and a natural frequency, respectively.

The route error control is the filtered route error multiplied by the route gain, which is given by the following equation.

ここで、Ｔ_ｙはフィルタ時定数、ｆ_ｙは航路ゲイン、ｆ_ｉは積分ゲイン、Ｋ_ｖは船体パラメータで横流れゲイン、θ_ｒｏ＾は推定舵角オフセットである。

Here, T _y is the filter time constant, f _y is the route gain, f _i is the integral gain, K _v is the hull parameter and the crossflow gain, and θ _ro ^ is the estimated rudder angle offset.

The command by route control is expressed by the following formula.

(4.3.2 Distance control and hull position holding control)
Distance control and hull position retention control will be described.

Both the distance control and the hull position holding control are configured in the same manner as the azimuth control. By giving hull parameters and design parameters for distance control and hull position maintenance control to equation (52), a control system for distance control and hull position maintenance control is obtained.

(5 Verification)
The effectiveness of the marine automatic steering system according to this embodiment is verified by simulation.

(5.1 Simulation conditions)
Simulation conditions will be explained.

In the simulation, it is assumed that the computation time is 25 minutes, the first half of which is controlled by the movement mode, the latter half of which is controlled by the hold mode, and the increment time is 0.1 s. The disturbance is assumed to be a tidal current component of 1.0 kn, facing north. Also, the hull parameters are constant values, not corresponding to speed. The set values for the planned route are shown below.

As for the driving machine, the constant rotation speed is λ ₀ =110 rpm, and the angle limit is 45 degrees.

The hull parameters and major design parameters are shown below.

ここで、Ｋ_ｐは比例ゲイン、ζは減衰係数であり、ｍは移動モード、ｈは保持モードを示す。なお、比例ゲイン、減衰係数の詳細については非特許文献３を参照されたい。

where _Kp is a proportional gain, ζ is a damping coefficient, m is a moving mode, and h is a holding mode. For details of the proportional gain and damping coefficient, refer to Non-Patent Document 3.

Since the course error control does not include an integral action, the course error due to the tidal current component occurs. The scale conversion is _γr ′= _0.2γr , and the coefficient for angular conversion of the sway direction command speed is 45deg/10kn. The reach amount is reach=76.0 m under the above conditions.

(5.2 Simulation results)
Simulation results will be explained. 16 to 21 all show simulation results. FIG. 16 and FIG. 17 are diagrams showing the planned route and the ship's position track when there is no tidal current and when there is tidal current, respectively. FIG. 18 is a diagram showing the response of ship motion. FIG. 19 shows the error response. FIG. 20 is a diagram showing a command response. FIG. 21 is a diagram showing the response of the driver output.

As shown in FIG. 16, the reach amount seems to be large during turning, but the course error converges to zero after turning. Of FIGS. 16 to 21, only FIG. 16 shows the simulation results when there is no power flow.

As shown in FIG. 17, the route error is caused by the tidal current, but converges to a constant value. The error between the terminal point B' and the reaching point B is 25.5 m.

As shown in FIG. 18, the surge speed u cannot converge to the ground speed before the turn in the first half due to insufficient time or distance. The sway velocity v produces an interference error with the yaw motion during turning in the first half, but is stable. There is no problem with the yaw angular velocity r.

As shown in FIG. 19, the convergence of x _e is worse than that of y _e and ψ _e . y _e and ψ _e are

になる（非特許文献３参照）。ここで、ｆ_１は方位制御の比例ゲイン、ｆ_ｙは航路ゲイン、ｖ_ｃＲは参照方位の法線方向潮流成分、ｕ_Ｒは船速である。未収束状態を考慮すれば、上式と図１９に示される結果は妥当である。後半の初期応答ではｘ_ｅの過渡誤差は２０ｍ強を生じる。

becomes (see Non-Patent Document 3). where f1 is the proportional gain of heading control, _fy is the course gain, _vcR is the normal current component of the reference _heading , and _uR is the ship speed. Considering the unconverged state, the above equation and the results shown in FIG. 19 are reasonable. In the latter half of the initial response, the transient error of _xe is a little over 20 m.

As shown in FIG. 20, in the latter half of the hold mode, the command is biased to hold the hull position at the terminal point B'.

As shown in FIG. 21, there is no saturation limitation in the driver output response.

Therefore, it was confirmed that the control by the marine autopilot system 1 according to the present embodiment was properly operated.

Embodiments of the invention are provided by way of example and are not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and its equivalents.

1 marine automatic steering device 2 hull 3 propulsion drive device 4 sensor 11 reference trajectory generation unit 12 control unit 121 movement control unit 122 holding control unit 123 switching unit

Claims (3)

An autopilot for a marine vessel that controls a marine vessel comprising a propulsion drive device capable of controlling the velocities in the surge and sway directions and the angular velocity around the yaw;
Based on the planned route, a reference trajectory including a trajectory from a starting point to a destination point, a reference distance that is a time function of the surge direction distance from the starting point to the destination point, and a reference bearing that is a time function of the bearing a reference trajectory generator that generates
A movement control unit that controls the vessel by distance control that causes the position of the vessel to follow the reference distance, and route control that causes the position of the vessel to follow the trajectory and the azimuth of the vessel to follow the reference azimuth. When,
a holding control unit that controls the ship to hold the position of the ship;
A line extending from the position of the ship in the sway direction of the ship, and a switching unit that switches from control by the movement control unit to control by the holding control unit when the intersection with the trajectory reaches the arrival point. Automatic steering system for ships. The holding control unit controls the ship so as to reduce an error between the position of the ship and the arrival point when the holding position of the ship is not the arrival point. marine automatic steering system. each of the movement control unit and the holding control unit updates a control gain based on a hull parameter corresponding to the water speed of the ship;
The hull parameter is proportional to the water speed at a water speed greater than a predetermined water speed threshold in the control by the movement control unit, and is equal to or less than the water speed threshold in the control by the holding control unit. 3. The automatic marine steering system according to claim 1 or 2, wherein the constant at .

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