JP2915658B2 - Fuzzy control type fin stabilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fin stabilizer for a ship, and more particularly to a fuzzy control type fin stabilizer having a control system provided with a fuzzy inference section and having improved control characteristics.

[0002]

2. Description of the Related Art A conventional fin stabilizer comprises a fin mounted on a hull and a fin drive device capable of adjusting a fin angle of the fin, and furthermore, a sway angle detection capable of detecting a sway angle of the hull. And a control system for sending a control signal to the fin drive device based on a detection signal from these detectors.

FIG. 4 (control block diagram)
As shown in (1), an output signal (oscillation angle signal) φ from the oscillation angle detector and an output signal (oscillation angle signal) dφ / dt from the oscillation angular velocity detector are input. And
The oscillation angle signal φ is multiplied by an appropriate gain k ₁ by the amplifier 4 to become K ₁ φ, and the oscillation angular velocity signal dφ / dt.
Is branched into two signals, one of which is multiplied by an appropriate gain K ₂ by an amplifier 5 to be K ₂ dφ / dt, and the other signal is a swing angular acceleration signal d ² φ by a differentiator 3.
After the conversion to / dt ² , the amplifier 6 multiplies the gain K ₃ appropriately to obtain K ₃ d ² φ / dt ² .

Further, in the adder 12, output signals K ₁ φ, K ₂ dφ / dt, K ₃ from three amplifiers 4, 5, 6 are output.
Sum of the opposite sign of d ² φ / dt ² − (K ₁ φ + K ₂ dφ / dt +
K ₃ d ² φ / dt ² ) is calculated and sent to the fin drive as the fin angle operation amount α as the control signal.

[0005] Now, the fin stabilizer generates a rolling moment M _f 10 the water flow strikes the fin angle operation amount α to the fin 9 during advancement of the ship 8 as shown in FIG. 5, the rolling angle φ and a rolling angular velocity dφ / D
t, but according to the above control system, the fin angle operation amount α is determined by the output signals K ₁ φ, K ₂ dφ / dt, and K ₃ d ² from the three amplifiers. φ / dt ²
In the standing wave, as shown in FIG. 6, the signal can be represented by a vector α rotating by the angular frequency ω of the constant wave, and the vector α has a constant magnitude. , The locus of the vector α on the complex plane 15
Will draw a circle.

In FIG. 6, θ is a fluctuation angular velocity signal dφ.
/ Dt represents the delay angle of the fin angle operation amount vector α with respect to the signal vector K ₂ dφ / dt, and the delay angle θ is the signal vector K relating to the above-mentioned fluctuation angle signal.
₁ φ and the signal vector K ₃ d relating to the sway angular acceleration signal
OR K ₁ φ + K ₃ size of d ^{2 φ} / dt ² of ^{2 φ} / dt ² increases larger than the size of the vector K ₂ dφ / dt. The delay angle θ is constant in the standing wave, and K ₁
Since the vectors of φ + K ₃ d ² φ / dt ² , K ₂ dφ / dt and α rotate synchronously on the complex plane by the angular frequency ω of the standing wave, the vector of the real part of α and K ₁ φ + K ₃ d ² φ
The range of α when the vector of the real part of / dt ² is in the opposite direction gives the shaded area shown in FIG.

[0007]

By the way, in the conventional fin stabilizer as described above, when the fin angle operation amount vector α is in the shaded area shown in FIG. Vector K ₂ dφ
Since the direction of the vector of the real part of / dt is the same as the direction of the vector of the real part of α, there is a problem that the fin is operated in a direction to increase the oscillation angular velocity signal.

That is, when controlling the attitude of the hull using a normal fin stabilizer, it is necessary to set the gain K ₁ in the amplifier 4 high to increase K ₁ φ so that the oscillation angle φ is as small as possible. However, in this case, since the delay θ increases, the fluctuation angular velocity dφ / dt is increased, and as a result, the fluctuation angle φ increases.

The present invention is intended to solve such a problem. By controlling the control system of the fin stabilizer by a fuzzy control system, the fins are operated in the direction in which the angular velocity of the hull increases. When the fin is controlled, the control amount of the fin (fin angle operation amount) is minimized,
It is an object of the present invention to provide a fuzzy control type fin stabilizer capable of further reducing the sway angle of a hull.

[0010]

In order to achieve the above object,
The fuzzy control type fin stabilizer of the present invention
Fins mounted on the ship's hull to reduce
A fin drive device that can adjust the fin angle of the fin
Fin stabilizer detects the sway angle of the hull.
Sway angle detector and motion that can detect the sway angle speed of the hull
Angular velocity detector and motion that can detect the oscillating angular acceleration of the hull
Angular acceleration detectors and detection signals from these detectors
A control system for sending a control signal to the fin drive device based on the
In addition, the control system detects the detection signal from the oscillation angle detector.
And the detection signal from the above-mentioned shaking angular acceleration detector
An addition circuit that performs addition on both signals, and
Convert these output signals to fuzzy intersection
The first rule antecedent and the detection from the oscillation angular velocity detector
A second conversion of the outgoing signal to a fuzzy intersection
Rule antecedent and the first and second rule antecedents above
Control signal to the fin drive based on the output signal from
To evaluate the fuzzy intersection for
The fuzzy inference unit and the output signal from the fuzzy inference unit are
A rule consequent part that fuzzifies and calculates the control signal
And the fuzzy inference unit is configured to calculate the sway angle of the hull.
When the above fin operation is performed in the direction of increasing degrees
In addition, a control characteristic that can minimize the control amount of the finPrepare
The inference table provided in the fuzzy inference section
Is composed of the 5 × 5 matrix shownSpecially
It is a sign. Where φ is the output signal of the oscillation angle detector (oscillation angle signal) K ₁ , K _Two , K _Three :gain

[0011]

In the fuzzy control type fin stabilizer of the present invention described above, the fin stabilizer control system is provided with a fuzzy operation section including a fuzzy inference section having a fuzzy inference table for realizing appropriate control characteristics. ,
When the fins are operated in the direction in which the hull's oscillating angular velocity increases, an operation of minimizing the control amount (fin angle operation amount) of the fins is performed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuzzy control type fin stabilizer as an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a control block diagram, and FIG. 2 is a characteristic diagram of a fin angle operation amount vector on a complex plane. FIG. 3 is a fuzzy inference table.

The fuzzy control type fin stabilizer of the present embodiment is provided with a fin on the hull so as to reduce the sway of the hull and a fin drive device (actuator, etc.) capable of adjusting the fin angle of the fin as in the prior art. ing. As shown in FIG. 1, the fin stabilizer of the present embodiment includes a sway angle detector 1 that can detect the sway angle of the hull, a sway angle detector 2 that can detect the sway angle of the hull, A differentiating circuit 3 capable of transmitting a signal of the swaying angular acceleration of the hull based on a detection signal from the detector 2, and the fin drive based on the detection signals from the detectors 1 and 2 and the output signal from the differentiating circuit 3; It has a control system that sends control signals to the device.

Although the oscillating angular acceleration detector in the present embodiment comprises the oscillating angular velocity detector 2 and the differentiating circuit 3, the oscillating angular acceleration detector may be constituted by a dedicated sensor. In addition, only a sway angular velocity detector is provided as a sensor, the sway angle is detected by integrating the sway angular velocity signal with an integrator, and the sway angular acceleration is differentiated by differentiating the sway angular velocity signal as described above. It can also be configured to detect, in which case the one including the integrator or differentiator constitutes the sway angle detector or the sway angular acceleration detector.

[0015] The control system includes an amplifier 4 for multiplying the gain K ₁ to the detection signal φ from the upset angle detector 1, an amplifier 5 for multiplying the gain K ₂ to a detection signal d.phi / dt from upset angular velocity detector 2, the An amplifier 6 that multiplies the output signal d ² φ / dt ² from the differentiating circuit 3 by a gain K ₃ by time-differentiating the detection signal dφ / dt of the above into a fluctuation angular acceleration signal d ² φ / dt ^2.
And the output signal K ₁ φ from the amplifier 4
Output signal K ₂ dφ / dt from amplifier 5 and amplifier 6
And a fuzzy calculation unit 7 which receives the output signal K ₃ d ² φ / dt ² and calculates and outputs a fin angle operation amount α as a control signal of the fin drive device.

The fuzzy operation unit 7 includes an adder 7a for adding the output signal K ₁ φ from the amplifier 4 and the output signal K ₃ d ² φ / dt ² from the amplifier 6, and an output signal from the adder 7a. K ₁ φ + K ₃ d ² φ / dt ^{2 A} first rule antecedent part 7 b for converting to fuzzy intersection, and an output signal K ₂ from the amplifier 5
a second rule antecedent part 7c for converting dφ / dt into a fuzzy intersection, and a first rule antecedent part 7b
And a fuzzy inference unit 7d for evaluating and deriving a fuzzy product set of the fin angle operation amount α based on an output signal from the second rule antecedent unit 7c using an inference table (see FIG. 3), and a fuzzy inference unit 7d. A rule consequent part 7e for calculating the fin angle operation amount α by defuzzifying the output signal is provided.

Incidentally, the first rule antecedent part 7b
In the second rule antecedent part 7c, the elements of three or more stages (for example, large, medium large, medium, medium small, small, etc.) of large, medium, and small A score evaluation is performed. The fuzzy inference unit 7d performs an operation of assigning a partial evaluation point corresponding to an evaluation matrix (inference table) to the input from the rule antecedent units 7b and 7c. For example, the signal K ₁ φ + K from the first rule antecedent part 7b
₃ d ² φ / dt ² [-large] 40 points, [-medium] 10 points,
[0] 40 points, [medium] 10 points, [large] 0 points are output, and the second
From the rule antecedent 7c of the signal K ₂ dφ / dt [-
[Large] 0 points, [-Medium] 10 points, [0] 80 points, [Medium] 20 points, [Large]
Considering the point where the output is 0, the fuzzy inference unit 7d
Is given by the following equation as a 5 × 5 matrix [M].

(Equation 1) G: Gain, that is, generally the first and second rule antecedent parts 7b, 7c
Assuming that the calculation in F ₁ and F ₂ , the following equation can be used.

[M] = G [F ₂ (K ₂ dφ / dt)] [F ₁ (K ₁ φ + K ₂ d ² φ / dt ² )] Further, the rule consequent part 7 e outputs from the fuzzy inference part 7 d. The calculated matrix signal [M] is compared with an evaluation matrix (inference table), and the fin angle operation amount α is large, medium, 0,
The fin angle operation amount α is determined by adding and counting the scores of the medium and large points and calculating the center of gravity with respect to the portion having the large score. For example, if the result of the above addition
Large] 90 points, [-medium] 60 points, [0] 20 points, [medium] 5 points,
When the point becomes [large] 0, the following equation is calculated as the gain G '.

(Equation 3)

The inference table provided in the fuzzy inference unit 7d has characteristics such as the locus 11a for the fin angle operation amount vector α in FIG. 2, that is, the fluctuation angular velocity signal dφ.
When the fin is operated in a direction to increase / dt (FIG. 7)
In the present invention, the hatched area) has a characteristic that minimizes the fin angle operation amount as a control signal.
And a 5 × 5 matrix as shown in FIG.

The fuzzy control fins stabilizer of the present embodiment, which is configured as described above, set high and the gain K ₁ for the purpose of reducing the sway angle when performing attitude control of the hull for the perturbation angle signal φ Even if the oscillation angular velocity signal d
When the fin is operated in the direction of increasing φ / dt, the operation amount α of the fin is extremely small, so that there is no problem such as reversely oscillating which has conventionally been a problem in the above case. In addition, the posture control performance can be improved.
Further, in this embodiment, since the fuzzy control is combined with the conventional control, a stable fin angle operation amount α can be obtained even in irregular waves, and the fin angle operation amount vector α as shown in FIG. There is an advantage that an unstable phenomenon such as hunting does not occur even though the trajectory 11 has a non-linear curved portion 11a.

[0020]

As described above in detail, according to the fuzzy control type fin stabilizer of the present invention, when the fin is operated in the direction in which the oscillating angular velocity of the hull increases,
Since the control system has a control characteristic that minimizes the control amount of the fin, the fin angle operation amount as the fin control amount during the return of the hull from the tilted state to near neutral while the hull is oscillating is provided. Is minimized, and the problem that the conventional fin is operated in the direction of increasing the swing angular velocity, and the fin is greatly swung to the opposite side by the momentum, is solved, and the hull attitude control can be reliably performed. In addition, since the fuzzy control generally has a feature of being strong against disturbance and having high stability, it is generated due to an unstable phenomenon caused by a non-linear portion in a trajectory of a fin angle operation amount vector and irregularities. An advantage is obtained in that the instability of the calculation of the fin angle operation amount can be prevented.

[Brief description of the drawings]

FIG. 1 is a control block diagram of a fuzzy control type fin stabilizer as one embodiment of the present invention.

FIG. 2 is a characteristic diagram of a fin angle operation amount vector in the fuzzy control type fin stabilizer of FIG. 1;

FIG. 3 is a fuzzy inference table relating to the fuzzy control type fin stabilizer of FIG. 1;

FIG. 4 is a control block diagram of a conventional fin stabilizer.

5A is a front view of a hull having a fin stabilizer, and FIG. 5B is a side view thereof.

FIG. 6 is a characteristic diagram of a fin angle operation amount vector of the conventional fin stabilizer.

FIG. 7 is a characteristic diagram in which main parts in FIG. 6 are indicated by oblique lines.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Jaw angle detector 2 Jaw angular velocity detector 3 Differentiator 4, 5, 6 Amplifier 7 Fuzzy operation part 7a Addition circuit 7b First rule antecedent part 7c Second rule antecedent part 7d Fuzzy inference part 7e Rule consequent Part 11a locus φ swing angle signal dφ / dt swing angular velocity signal d ² φ / dt ² swing angular acceleration signal α fin angle manipulated variable

Claims (1)

(57) [Claims] 1. A fin stabilizer comprising a fin mounted on a hull for reducing the sway of the hull and a fin drive device capable of adjusting the fin angle of the fin, wherein the sway angle of the hull can be detected. A detector, a rocking angular velocity detector that can detect the rocking angular velocity of the hull, a rocking angular acceleration detector that can detect the rocking angular acceleration of the hull, and controlling the fin drive device based on a detection signal from these detectors A control system for sending a signal, the control system comprising: an addition circuit that performs addition on both signals based on a detection signal from the sway angle detector and a detection signal from the sway angle acceleration detector; and A first rule antecedent part for converting the output signal of the above into a fuzzy intersection, and a second rule for converting the detection signal from the above-mentioned fluctuation angular velocity detector into a fuzzy intersection. A fuzzy inference unit that evaluates a fuzzy intersection for a control signal to the fin drive device based on an output signal from the first and second rule antecedents with an inference table, A rule consequent section for defuzzifying the output signal from the fuzzy inference section to calculate the control signal, wherein the fuzzy inference section performs the operation of the fin in a direction in which the oscillating angular velocity of the hull increases. Is provided in the fuzzy inference unit to provide control characteristics that can minimize the control amount of the fin.
The inference table is composed of the following 5 × 5 matrix.
A fuzzy control type fin stabilizer characterized in that: Where φ: output signal of the oscillation angle detector (oscillation angle signal) K ₁ , K ₂ , K ₃ : gain