JPH0425919B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ship body rocking reduction device, and more particularly to a ship body rocking reduction device for controlling rolling of a ship body.

[Conventional technology]

Hull rolling can cause seasickness, fatigue, and reduced work efficiency for passengers and crew members, and can also cause damage to cargo, equipment malfunction, and breakdowns, making it difficult to maneuver the ship, and reducing ship speed. It has the negative effect of causing

Conventionally, roll reduction fins are provided below the water surface on both sides of the hull, and the angle of attack of the fins is controlled in accordance with changes in the rolling angle of the hull, thereby controlling the rolling of the hull.

[Problem that the invention seeks to solve]

In such a ship body rocking reduction device, the rocking reduction effect can be enhanced by increasing the control gain of the fin angle of attack, but if the fin angle of attack is made too large, excessive force will act on the fin. Since there is a risk of damage, a limiter is used to restrict the angle of attack command value to a certain upper limit angle of attack (for example, about 24 degrees).

However, when rolling occurs due to bad weather or the like, the fin angle of attack often reaches the upper limit angle of attack, causing the limiter to operate, resulting in a sudden change in the sway reduction effect before and after the limiter operates. Such a sudden change in the sway reduction effect poses a problem in that it brings about adverse effects such as the aforementioned deterioration of riding comfort.

In order to solve this problem, for example, it is possible to reduce the control gain of the fin angle of attack to keep the angle of attack below the upper limit angle of attack even when a large rolling is expected. However, there is a problem in that the sway reduction effect during normal weather conditions is reduced.

An object of the present invention is to solve the above-mentioned problems of the conventional art. The goal is to provide equipment.

[Means for solving problems]

In order to achieve the above object, the present invention provides a hull sway reduction device that controls the angle of attack of sway reduction fins provided below the water surface on both sides of the hull in accordance with a detected change in the rolling angle of the hull. The present invention is characterized in that an angle-of-attack correction means is provided for correcting the control gain of the angle-of-attack control in inverse proportion to the average value of the angle-of-attack command values.

[Effect]

With the above configuration, when the average value of the angle of attack command values determined according to the degree of rolling of the hull increases, the control gain of the angle of attack is reduced, and conversely, when the average value decreases, Since the control gain will be increased, that is, the angle of attack control gain will be adjusted according to the degree of rolling, so if large rolling continues due to bad weather etc., the control gain will be automatically reduced. As a result, the frequency of operation of the limiter for preventing fin damage is significantly reduced, and since the control gain is automatically increased during normal rolling, the sway reduction effect is enhanced.

〔Example〕

FIG. 1 shows a block configuration diagram of an embodiment of the present invention, and FIG. 2 shows an overall configuration diagram obtained by applying the embodiment of FIG. 1. As shown in FIG. 2, rock reduction fins 2 are provided below the water surface on both sides of the hull 1, and the rock reduction fins 2 are operated by a fin actuator 3.
The angle of attack φ shown in FIG. 3 is made variable. When an external force such as a wave or wind shown by an arrow 4 is applied to the hull 1, the hull 1 is rolled in the direction shown by an arrow 5. The detected rolling angle θ is input to the control device 10. Also,
The hull 1 is provided with a ship speed meter 7, and the ship speed υ measured by the ship speed meter 7 is inputted to the control device 10. The control device 10 is configured as shown in FIG. The rolling angle θ detected by the rolling detector 6 is input to a noise filter 101, whereby noise is removed. Rolling angle θ output from noise filter 101
is input to the basic angle of attack command value calculation means 102, the horizontal holding control means 103, and the differentiation circuit 104. The output of the differentiating circuit 104 is multiplied by a gain _K4 in a gain setter 105, and the basic angle of attack command value calculation means 102 is used as a rolling angular velocity θ.
has been entered. Further, the output of the gain setter 105 is input to a differentiation circuit 107, and the rolling angular acceleration θ'' obtained by the differentiation process is input to the basic angle of attack command value calculation means 102.

The basic angle of attack command value calculation means 102 calculates the basic angle of attack command value φ ₁ shown in the following equation (1) based on the input rolling angle θ, rolling angular velocity θ′, and rolling angular acceleration θ″. It is configured.

φ ₁ =−K ₁ (θ−θ ₀ )−K ₂ θ′−K ₃ θ″ (1) In other words, the rolling angle θ is
The signal is input to an adder 112 via a gain setter 111. Further, the rolling angle θ is input to the rolling center angle calculation means 113.
This rolling center angle calculating means 113 is designed to obtain the center angle θ ₀ of the entire rolling width, that is, the natural inclination of the hull 1 due to one load, etc., and the calculated rolling center angle θ ₀ is calculated by the switch SW ₃
The rolling angle θ is input to the adder 110 via the adder 110, thereby making it possible to correct the rolling angle θ to the value from the natural tilt position. The rolling angular velocity θ' is inputted to the adder 112 via a gain setter 114, and the rolling angular acceleration θ'' is inputted to the adder 112 via a gain setter 115.
12 is input. The basic angle-of-attack command value θ ₁ obtained in this way is the angle-of-attack correction means 11
6 is input.

On the other hand, the horizontal holding control means 103
It consists of SW ₄ , an integration circuit 117, and a gain setter 118, and when switch SW ₄ is closed, it integrates the rolling angle θ and obtains a rolling angle integral value θint, which is obtained by multiplying the rolling angle θ by a constant gain _K5 . It is output to the angle correction means 116 and the adder 119. In addition,
SW ₃ and SW ₄ are interlocked so that either one is closed. Further, the ship speed υ measured by the ship speed meter 7 is input to the ship speed correction means 120. The ship speed correction means 120 adjusts the speed according to the ship speed υ because if the angle of attack φ of the rock reduction fin 2 is too large when the ship speed is high, an excessive force may be applied to the rock reduction fin 2 and damage it. Angle of attack φ
A ship speed correction value φ(υ) determined in advance according to the ship speed υ is output to the angle of attack correction means 116. Note that the ship speed correction means 120 is formed with a limiter, and a correction function having hysteresis characteristics is set in order to prevent inching.

The angle of attack correction means 116 includes an angle of attack average value calculation means 123 for calculating the average value (RMS value) φave of the basic angle of attack command value φ', a comparator 124, and a gain adjuster 125.
It is formed from. Angle of attack average value calculation means 12
3, as shown in FIG. 4, calculates the average angle of attack value φave for the immediately preceding fixed period T and outputs it to the comparator 124. The comparator 124 calculates a gain correction coefficient α shown in the following equation (2) based on the input rolling angle integral value θint, average angle of attack value φave, and ship speed correction value φ(υ). It is designed to be calculated and input to the gain adjuster 125.

α=φ(υ)−θint/φave×β……(2) In addition, β in equation (2) is a constant value (for example, 1 %)
This is a coefficient set to be as follows.

The gain adjuster 125 adjusts the basic angle of attack command value φ ₁ output from the basic angle of attack command value calculating means 102 to
It is multiplied by a gain coefficient K ₆ corresponding to the gain correction coefficient α outputted from the comparator 124 and outputted to the adder 119 as a corrected basic angle of attack command value φ ₂ . The adder 119 adds the corrected attack angle command value φ ₂ and the rolling angle integral value θint, and inputs the sum to the limiter 130 via the operation switch SW ₇ which is closed when the control device 10 is operated. has been done. The limiter 130 has an upper limit angle of attack value (for example,
24°).

Regarding the operation of the embodiment configured in this way,
This will be explained next. First, close the changeover switch SW ₃ ,
The operation will be described when the changeover switch SW ₄ is opened, that is, in the natural tilt mode with the horizontal holding control means 103 removed, and when the function of the rolling center angle calculation means 113 is utilized. Based on the rolling angle θ detected by the rolling detector 6, the rolling angular velocity θ′ and the rolling angular acceleration θ″ are determined by the differentiating circuit 104 and the differentiating circuit 107, respectively, and are input to the basic angle of attack command value calculation means 102. Then, the basic angle of attack command value φ ₁ is determined by the above equation ( ₁ ).
It is multiplied by a control gain K ₆ corresponding to the gain correction coefficient α output from the comparator 124 and output to the adder 119 as a corrected angle of attack command value φ ₂ .

This angle of attack command value φ ₂ is output to the fin actuator 3 via the limiter 130 when the operation switch SW ₇ is closed. As a result, a vibration reduction operation is performed to suppress the rolling that occurs around the natural inclination angle θ ₀ .

Here, FIG. 5 shows the sway reduction effect of this embodiment in comparison with the conventional example. When a large rolling occurs, according to the conventional example, the angle of attack command value φc exceeds the upper limit angle of attack value, as shown by the curve A indicated by the dashed line in FIG. As a result, the anti-sway effect corresponding to the shaded area is reduced, and the rolling angle θ of the hull 1 is accompanied by rapid fluctuations, as shown by curve A' in FIG.

On the other hand, according to this embodiment, the angle of attack command value is adjusted to within the upper limit angle of attack value as shown by the curve B in FIG. It will change smoothly like B′. This prevents deterioration in riding comfort and the like.

According to this embodiment, even when there is a small rolling, the angle of attack command value φc is the same as the curve B in Fig. 5a, so that the sway reduction effect is improved, and the angle of attack command value φc is the same as that shown in Fig. 5b. It is easy to understand that the curve B' is smaller than the curve B'.

According to the present embodiment described above, the control gain K ₆ is adjusted according to the average value φave of the basic angle of attack command value φ ₁ during the immediately preceding fixed period T, and the angle of attack command value φ ₂ corrected thereby is adjusted. Since the anti-swing fin is controlled using the angle of attack command value φc, in other words, the control gain _K6 is controlled in inverse proportion to the magnitude of rolling, so it automatically responds to fluctuations in rolling. This has the effect of maintaining a high vibration reduction effect and preventing cavitation.

Also, close changeover switch SW ₄ and open SW ₃ ,
When the horizontal holding control means 103 is activated, the integral value θint corresponding to the constant deviation of the rolling angle θ from the vertical axis is output to the adder 119, where the angle of attack command value φ ₂ is corrected and the horizontal state is maintained. controlled to do so.

〔Effect of the invention〕

As explained above, according to the present invention, since the angle of attack control gain is corrected in inverse proportion to the average value of the angle of attack command values in the immediately preceding fixed period, it is possible to automatically respond to rolling fluctuations. Correspondingly, it is possible to maintain a high vibration reduction effect and also to prevent damage to the fins.

[Brief explanation of drawings]

FIG. 1 is a detailed block configuration diagram of an embodiment of the present invention, FIG. 2 is an overall configuration diagram of a vibration reduction device to which the embodiment shown in FIG. 1 is applied, and FIG. 3 is a sectional view of a vibration reduction fin. Figure 4 is a diagram for explaining the average value of the angle of attack.
FIG. 5 is a diagram for explaining the operation of the present invention. DESCRIPTION OF SYMBOLS 1... Hull, 2... Swing reduction fin, 3... Fin actuator, 6... Rolling detector, 7... Ship speed meter,
DESCRIPTION OF SYMBOLS 10... Control device, 102... Basic attack angle command value calculation means, 116... Attack angle correction means, 123... Attack angle average value calculation means, 124... Comparator, 125... Gain adjuster, 130... Limiter.

Claims (1)

[Claims] 1. In a hull reduction device that suppresses hull rolling by controlling the angle of attack of roll reduction fins installed below the water surface on both sides of the hull in accordance with detected changes in the rolling angle of the hull, A ship body sway reduction device comprising an angle of attack correction means for correcting a control gain of angle of attack control in inverse proportion to an average value of angle of attack command values.