JPS5944664A - Tidal current direction and flow velocity estimating device - Google Patents

Abstract

PURPOSE:To estimate a tidal current direction and a flowvelocity without using a special tidal current meter, by estimating the tidal curent direction and the flow velocity by utilizing an automatic ship position holding device. CONSTITUTION:A processing device calculated a direction of a tidal current and a flow velocity from bow and stern direction force FX and ship's side direction force FY obtained from an automatic ship position holding device DSP, an output of a moment Mphi, and an output of a fluid force data storage device of a ship.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tidal current direction and/or speed estimating device installed on a ship. More specifically, the present invention relates to a device that can easily estimate the direction and speed of a tidal current using a conventional automatic ship positioning system (DPS).

DPS is used to hold the vessel in a fixed point. Normally, the DPS uses the ship's position data obtained from the positioning sensor and the azimuth sensor, and also compensates for the influence of the wind f' obtained from the wind direction and speed sensor. It calculates the applied bow-and-stern force, chordal force, and moment, and controls the propulsion device to apply these forces to the hull.

By the way, in consideration of energy conservation and hull response in the event of a failure, it is better to point the bow toward the tidal current as much as possible, but in order to do so, it is necessary to know the direction of the tidal current. 1. However, conventional DPSs are not equipped with a current meter because the anorker-type current meter is inconvenient to handle, and the ship-mounted current meter is expensive because it requires sophisticated statistical processing. Most of them are. Currently, the operator estimates the tidal current empirically from the load condition of the propulsion device (main propeller, Zydo thrust, etc.) and sets the heading, so the operator is required to have a perpendicular line, and accuracy is not expected. Therefore, the present invention can easily determine the direction of the tidal current without a special tidal current meter.
The object of the present invention is to provide a novel device capable of estimating flow velocity. , such purposes include a positioning sensor and a direction sensor for measuring the ship's position, a wind speed and direction sensor, and these d
[Based on data from the vessel Q] Automatic ship position maintenance that calculates the bow and stern direction force, lateral force, and moment to maintain the ship position against the tidal current, and issues an output control signal for the propeller in response to this. A central processing unit, a storage device for fluid force data regarding the vessel, and a processing device for calculating the direction and flow velocity of the tidal current from the fluid force data and the fore/aft direction force, lateral force, and moment. This is achieved by the tidal current direction/flow velocity estimating device of the present invention.

Hereinafter, the apparatus of the present invention will be explained in more detail with reference to the drawings and hardware.

FIG. 1 is a block diagram of the configuration of the apparatus of the present invention.

The device of the present invention utilizes the conventional 1) PS. As mentioned above, the DPS has a positioning sensor, direction sensor, and wind speed and direction sensor as measurement means, and the data obtained from these is processed by the PS central processing unit, and based on this, the propulsion device is activated to maintain the ship's position at a fixed point. Control. Here, since the wind force II compensation is performed using the data from the wind direction and wind speed R, the DPS central processing unit uses the three forces necessary to counter only the tidal current (i.e., the bow-and-stern direction force pl
x, lateral force FY and moment) Mψ) are obtained. D
There are several types of PS central processing unit systems.
If normal PID control is used, the above three forces can be obtained as one term, and if Kalman filter method is used, the above three forces can be obtained by reversing the sign of the steady force estimation. can get.

The device of the present invention accurately estimates the direction and velocity of the tidal current based on the numerical values of the above three forces obtained by DPS, and uses the fluid force data of the ship for this purpose.

The vJ2 diagram is a diagram showing the relationship between a ship and a tidal current, where β is the relative incidence angle of the tidal current and U is the ground velocity of the tidal current. Since the ground speed of the ship is small, if we ignore it, FX, FT, and Mψ will be as follows.

FX = -CX (A-U2/2,
,, ,・(1)Fy=: cY(β)・U2/
2 ・・・・・・(2) Mψ=-C70)
・U2/2 ・・・・・・(3) Here, C
X(1), CFI, 9) and Cψ(/9) are fluid force data specific to the ship, and can be determined by water tank tests, etc. Figures 3, 4 and 5 are CX (
A, CF(4) and CψQ). In the above equations (1) to (3), when the values of FX, FF and Mψ are given, the power flow can be estimated by finding β and U. Since there are two unknowns, (1)
It is sufficient to use two of the equations (3); in a normal ship shape, the absolute value of B'x- is small and the accuracy is poor, so β = 0°,
Equations (2) and (3) are used except for the vicinity of 180°.

Specifically, Cψ/CY in Figures 4 and 5 to 6
Create a graph of 1~, and write the graph corresponding to Figures 3, 4, and 6.
- storing the pull in the data storage of the inventive device; D
Since FX, FY, and Mψ are calculated in the PS central processing unit, the processing unit of the present invention calculates Cψ/cY using equations (2) and (3), and stores the corresponding size table in Fig. 6 in the storage device. Find the corresponding β from Next, after finding CYCA from the table corresponding to Fig. 4 of the storage device, (2
) Find U using the formula. , However, when Mψ and FY are small values, there is no current or the current is near β-〇°, 180°, so in the processing device of the present invention, the third
Corresponding to the figure - Cx(A'f: is determined from the cheagle, and then U is determined using equation (1).

As described above, the device of the present invention estimates the direction β and flow velocity U of the tidal current, but the estimated tidal current may differ somewhat from the actual tidal current due to the following reasons. a) Obtained by water tank tests, etc./hiCX(β
LCr(1) and Cψ(A may not completely match those of the actual ship.

(b) ,,I: CX(1), Cy(A and Cψ(A) do not take into account the effect of changes in water flow around the ship due to the propulsion device.

(c) The values of Fx, Fy, and Mψ are determined based on the output of the propulsion device of the ship, but the power used by the propulsion device is not necessarily known accurately.

Therefore, in order to improve the accuracy of tidal current estimation, the device of the present invention can be provided with means for modifying the tables in the storage device corresponding to Figures 3, 4 and 6 in accordance with the actual ship at sea. . For this purpose, an apparent tidal current setting device and an apparent tidal current generating device are attached.

The apparent tidal current setting device is for setting the appropriate apparent tidal current speed U* and apparent tidal current direction β*, and based on this, the apparent tidal current generator uses the ship position data relative to the ground from the positioning sensor. X and Y, respectively, are
β*)t is added to obtain X*&Y* (here, t is time), and this is manually input to the DPS central processing unit as positioning data. As a result, the DPS is calculated as if the ground current velocity U*El and direction β* (however, this β*
is the angle measured clockwise from the positioning sensor's Hanging is the force necessary to resist currents, including currents. Therefore, in sea areas and points in time where the actual currents can be ignored (such conditions are relatively easy to obtain),
Appropriate appearance estimates β and U in the processing device by generating a current, checks the difference between this and the set values β* and U*, and changes the data in the storage device from the data change terminal so that this difference disappears. Correct the data.

As a result, the accuracy of estimating the direction and velocity of the tidal current by the device of the present invention is extremely accurate regardless of the accuracy of the fluid force data and other conditions.

Incidentally, once the tidal current has been estimated by the device of the present invention, the position can be maintained with less energy consumption by automatically controlling the bow of the ship to face in the direction of the estimated tidal current. It goes without saying that the apparatus of the present invention is preferably provided with a control means for this purpose. Furthermore, the estimated tidal current speed can be used in the following way when changing the heading of the ship. That is,
F l x , F / y and M for each Δβ by the formula %
By determining ′ψ, it is possible to obtain in advance the tidal current counterforce required to hold the hull at a fixed point at each turning angle when turning the ship's heading in the direction of the tidal current. By using it for control, it becomes easy to change the heading while keeping the hull at a fixed point.

As described above, according to the device of the present invention, tidal current information can be obtained at low cost and with high accuracy without the need for special tide 151f, and based on this, it is possible to maintain the position of the ship with low energy consumption.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the configuration of the apparatus of the present invention, FIG. 2 is a diagram showing the relationship between a ship and tidal current, and FIGS. 3 to 6 are graphs of fluid force data of the ship. Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (3)

[Claims] (1) Vessel (In the installed tidal current direction/current speed estimation device, a positioning sensor and azimuth sensor for measuring the ship's position, a wind direction and speed meter, and to maintain the ship's position against the tidal current based on data from these instruments) an automatic ship position maintenance central processing unit that calculates the bow-and-stern direction force, chord direction force, and moment tra of the vessel and issues output control signals for the propulsion device based on these; a storage device for fluid force data regarding the vessel; and a storage device for fluid force data regarding the vessel; A device for estimating the direction and velocity of a tidal current, the IFI feature being a processing device for calculating the direction and velocity of a tidal current from data and -F ship heading force, chordal force and moment. (2) Based on the data from the positioning sensor, the apparent value is set by the tidal current setting device, and the tidal current is added to this data, which is manually input to the automatic ship positioning central processing unit. The device of item 1, which is provided with a generator and a terminal for changing data in the storage device. (3) A first control means for controlling the ship's position so that the bow faces the tidal current based on the estimated tidal current direction and current speed obtained by the processing device for calculating the tidal current direction and current speed. Section equipment.