JP2000225991A - Fin stabilizer controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove noise by a simple processing method by providing a filter processing a medium-level value among a specified number of sample values in a certain cycle as an average value in a certain cycle as for an input signal from a rolling sensor. SOLUTION: In a fin stabilizer controller controlling a stabilizer to be used for preventing rolling of a body of a vessel, a central value averaging filter 22 is provided to perform processing of a medium level value among at least three sample values in a certain cycle as an average value in a certain cycle as for an input signal from a rolling sensor 12 detecting rolling of the vessel body. The processing has a characteristic capable of ignoring pulse noise by the use of a relatively less sample valued. Accordingly, a large noise whose generation frequency is relatively less can be sufficiently removed by the filter 22 with a simple structure by the use of less sample value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fin stabilizer control device for processing noise contained in an input signal from a roll sensor in a fin stabilizer.

[0002]

2. Description of the Related Art A fin stabilizer is known as a device for preventing a ship from rolling in waves. This means that the movable fins that protrude outside the hull are tilted, and the lift obtained by creating the angle of attack of the fins with respect to the water flow flowing along the hull is opposed to the external force. It is to prevent.

FIG. 3 is a diagram showing a configuration of a conventional fin stabilizer. This fin stabilizer has a hull 10
Of the hull 10 from the roll sensor 12
Of the seawater, that is, the ship speed VH, is input to the anti-oscillation controller 11 from a ship speed sensor 13 such as a log for navigation. Then, the fin lift LD required for preventing the hull 10 from rolling is calculated by the anti-rolling controller 11 in accordance with the rolling angular velocity ωH of the hull 10.

[0004] Next, the anti-oscillation controller 11 calculates the required fin angle of attack αD from the required fin lift LD and the boat speed VH from the following equation (1) (derived in the form of αD =...). A command fin attack angle αD is output to the fin drive devices 3 and 3 via the limiter 14.

LD = (ρ / 2) VH ² CL (αD) A (1) CL (αD): lift coefficient, function of αD A: fin area ρ: seawater density The direction in which the chord of the fin 1 matches the direction of the water flow when navigating
As the neutral position of F (βF = 0), the fin tilt angle βF is detected by a tilt angle sensor (not shown), and the fin tilt angle is reduced so as to reduce the numerical deviation between the command fin attack angle αD and the fin tilt angle βF. The tilt angle βF is corrected, and the tilt of the fin 1 is controlled so that αD = βF.

As described above, by controlling the fin tilt angle βF so as to follow the command fin attack angle αD, an actual fin lift LF that follows the required fin lift LD is generated and incorporated into the vibration reduction controller 11. The intended reduction in roll of the calculated operation is almost achieved.

[0007] Further, from the roll sensor 12 to the anti-roll controller 1
For noise included in the input signal input to 1,
Normally, the above-described fin control calculation is performed after high-frequency components unnecessary for control are cut by an input filter (low-pass filter) (not shown) in the damping controller 11.

[0008]

However, in the prior art, if the input signal contains pulse-like noise generated when the motor or solenoid valve around the roll sensor 12 or the anti-roll controller 11 is started or stopped, The noise cannot be sufficiently cut by the input filter. In addition, when performing arithmetic averaging on the input signal, the influence of noise cannot be reduced unless the number of samples to be averaged is increased.

An object of the present invention is to provide a fin stabilizer control device capable of removing noise by simple processing.

[0010]

Means for Solving the Problems To solve the above problems and achieve the object, a fin stabilizer control device of the present invention is configured as follows.

[0011] The fin stabilizer control device of the present invention comprises:
In a fin stabilizer control device which controls a fin stabilizer used for roll prevention of a hull, an input signal from a roll sensor for detecting the roll of the hull is a middle one of at least three sample values in a fixed cycle. A filter for processing a value having a magnitude as an average value during the predetermined period;

[0012]

FIG. 1 is a diagram showing a configuration of a fin stabilizer control apparatus according to an embodiment of the present invention.
In FIG. 1, the same parts as those in FIG. 3 are denoted by the same reference numerals. The fin stabilizer control device A is applied instead of the anti-rolling controller 11 in FIG. Other configurations of the fin stabilizer are the same as those shown in FIG.
Description is omitted.

In FIG. 1, a roll sensor 12 and a boat speed sensor 13 are provided by an A / D in a fin stabilizer control device A.
It is connected to a converter 21. In the fin stabilizer control device A, an A / D converter 21 is connected to a D / A converter 24 via an input filter 22 and a fin control calculator 23. The D / A converter 24 is connected to the elevation angle limiter 14.

The roll sensor 12 outputs an analog signal indicating the roll angular velocity ωH of the hull 10 to the A / D converter 21. The A / D converter 21 converts the input analog signal into a digital signal and outputs the digital signal to the input filter 22. The input filter 22 performs processing described later on the input digital signal to cut noise, and outputs the digital signal to the fin control calculation unit 23. The fin control calculation unit 23 performs the above-described fin control calculation based on the input digital signal and the like, and outputs a digital signal related to the fin control to the D / A converter 24. The D / A converter 24 is
The input digital signal is converted into an analog signal and output to the elevation angle limiter 14.

FIGS. 2A to 2C are diagrams showing a process of signal processing in the fin stabilizer control device configured as described above. FIG. 2A shows an analog signal (roll signal) input from the roll sensor 12 to the A / D converter 21, and pulse-like noise occurs in average random noise. . The frequency of this pulse noise is relatively low (about two or three times a minute) and its magnitude is large.

FIG. 2B shows a digital signal received by the input filter 22 after A / D conversion in the A / D converter 21. The sampling period (for example, 0.1 second) shown in FIG. Each sample value is shown. As shown in the figure, due to the influence of the pulse-like noise, the digital signal fluctuates greatly at the location where the noise occurs.

FIG. 2C shows an example in which the digital signal shown in FIG. 2B is averaged, and the average is obtained at every averaging period (for example, 0.3 seconds) shown in FIG. Indicates the value. In the figure, the squares indicate the result of the arithmetic averaging process performed conventionally, and indicate the arithmetic average of three sample values during the previous averaging cycle.

The circles indicate the result of the median value averaging process according to the present invention, and among the three values in the previous averaging cycle, the second largest value is adopted and used as the average value. That is, the median value is the average value except for the maximum value and the minimum value among the three values. In the median value averaging process described above, when an average value is obtained from four or more sample values in the averaging cycle, a sample value having a medium size among the four or more values (the number of sample values is In the case of an even number, the arithmetic mean of the two values of medium size) is taken as the average value. In the median value averaging process, the accuracy of the average value is improved by increasing the number of sample values used for this, but there is a feature that pulse-like noise can be ignored with a relatively small number of sample values.

As shown by the squares in FIG. 2C, in the conventional arithmetic averaging processing, the average value increases sharply at the point where the noise is generated due to the influence of pulse noise. However, as shown by the circles, the average value is affected by the pulse-like noise by using a simple calculation that sets the median value of the three sample values in the averaging period to the average value in the averaging period. And the occurrence of pulse noise can be ignored. In order to reduce the influence of pulse noise in the arithmetic averaging process, it is necessary to increase the number of sample values in the averaging cycle by several times.

Since the averaging period is desirably set to about 1/100 of the period of tilting the fin for control, an increase in the number of samples to be averaged is not preferable because the averaging period becomes longer.

The input filter 22 performs a low-pass filter process such as a first-order lag on the digital signal on which the above-described median operation has been performed, if necessary.
Output to 3.

It should be noted that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention, for example, by applying to an input signal from a boat speed sensor.

(Summary of Embodiment) The configuration, operation and effect shown in the embodiment are summarized as follows.

The fin stabilizer control apparatus shown in the embodiment is a fin stabilizer control apparatus for controlling a fin stabilizer used for preventing the hull from rolling. The fin stabilizer control apparatus receives an input from a roll sensor 12 for detecting the hull of the hull. A filter 22 is provided for processing a signal having a medium magnitude among at least three sample values in a certain period as an average value in the certain period.

As described above, according to the fin stabilizer control apparatus, noise having a relatively small frequency and a large magnitude can be sufficiently removed with a simple, inexpensive and compact filter 22 using a small number of samples.
The control of the fin stabilizer ignoring this noise can be performed.

[0026]

According to the fin stabilizer control apparatus of the present invention, noise having a relatively small frequency and a large magnitude can be sufficiently removed by using a simple, inexpensive and compact filter using a small number of samples. The control of the fin stabilizer ignoring this noise can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a fin stabilizer control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a process of signal processing in the fin stabilizer control device according to the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a fin stabilizer according to an embodiment of the present invention and a conventional example.

[Explanation of symbols]

 A: Fin stabilizer controller 1 ... Fin 2 ... Fin shaft 3 ... Fin drive device 10 ... Hull (outer plate) 11 ... Decline controller 12 ... Roll sensor 13 ... Ship speed sensor 14 ... Angle of attack limiter 21 ... A / D converter 22 ... Input filter 23 ... Fin control operation unit 24 ... D / A converter

Claims (1)

[Claims] 1. A fin stabilizer control device for controlling a fin stabilizer used for roll prevention of a hull, wherein at least three sampled values in a fixed period of an input signal from a roll sensor for detecting the roll of the hull are provided. A filter for processing a value having a medium magnitude as an average value during the predetermined period.