JP2003252292A - Ship attitude control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ship attitude control method guaranteeing stability, and capable of controlling only a necessary frequency band. <P>SOLUTION: This ship attitude control method uses a hull attitude controller having fin stabilizers provided on both side face parts of a hull, a sensor detecting a roll angular velocity or a roll angle of the hull, and a control calculation part outputting a proper operation amount to each the fin stabilizer based on a detection value of the sensor so that a proper roll angle is always maintained. Alternatively, the ship attitude control method uses a hull attitude controller having a trim tab provided in a rear end bottom part of the hull, sensors each detecting a pitch angular velocity/roll angular velocity or a pitch angle/roll angle of the hull, and a control calculation part outputting a proper operation amount to the trim tab based on detection values of the respective sensors so that a proper pitch angle/roll angle is always maintained. In the ship attitude control method, the output control to the fin stabilizer or the trip tab by the control calculation part is executed by an H infinity control method. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ship attitude control method.

[0002]

2. Description of the Related Art As a conventional attitude control method for a ship, for example, the method disclosed in Japanese Patent Laid-Open No. 3-114996 can be cited. In this example, the attitude of the ship is detected as a pitch angle and a roll angle, and a trim tab angle is controlled by performing a comparison calculation with a target pitch angle and a target roll angle that are separately provided. Further, in this example, the attitude of the ship can be automatically controlled regardless of the navigation conditions such as the speed of the ship.

[0003]

However, in the control operation method of this example, there arises a problem due to the use of the operation method based on proportional control, integral control, and derivative control. That is, pitch angle fluctuations and roll angle fluctuations, which are generally factors of ship attitude fluctuations, are a mixture of a large number of frequency components, among which frequency components that easily cause seasickness of passengers and It contains frequency components that tend to reduce the navigation capability. However, the conventional method described above has a problem in that the arithmetic unit cannot be configured to collectively and stably control a specific frequency band different from the above-mentioned undesirable frequency component. . Further, as another countermeasure, filtering the sensor output by a bandpass filter or the like is conceivable, but even this cannot guarantee the stable control system.

The present invention is intended to solve the above-mentioned problems, and provides a posture control method for a ship which guarantees stability and can control only a necessary frequency band. Has an aim.

[0005]

In order to achieve such an object, the present invention has the following constitution. (1) Fin stabilizers installed on both sides of the hull, a sensor for detecting the roll angle or roll angular velocity of the hull, and a proper operation for the fin stabilizer so as to always maintain an appropriate roll angle based on the detection value of the sensor. In a boat attitude control method using a hull attitude control device including a control calculation unit that outputs a quantity, output control to the fin stabilizer by the control calculation unit is performed by an H infinity control method. Attitude control method for ships. (2) A trim tab installed on the bottom of the rear end of the hull, and a sensor that detects the pitch angle or pitch angular velocity of the hull,
A sensor for detecting the roll angle or roll angular velocity of the hull, and a control operation unit for outputting an appropriate operation amount to the trim tab so as to always maintain an appropriate pitch angle or an appropriate roll angle based on the detection value of each sensor are provided. A ship attitude control method using a ship attitude control device, wherein output control to the trim tab by the control calculation unit is performed by an H infinity control method.

According to the present invention, in the attitude control method in the roll direction or the pitch direction, the H infinity control theory is applied to the control calculation unit, and only the specific frequency component is selectively controlled while the stability is guaranteed. As a result, it is possible to effectively use the control power and prevent the motion sickness of the passengers and the navigation performance of the ship from being deteriorated.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram showing an embodiment of a system according to the present invention. In FIG. 1, 1 is a roll angle detection sensor or roll angular velocity detection sensor, 2 is a roll angle control calculation device, 3 is a fin angle control device, 4 is a fin angle control mechanism, and 5 is a fin. Further, 6 is a pitch angle detection sensor or a pitch angular velocity detection sensor, 7 is a pitch angle control calculation device, 8 is a trim tab angle control device, 9 is a trim tab angle control mechanism, and 10 is a trim tab. 1
Reference numeral 1 indicates a hull. The roll angle control calculation device 2 and the pitch angle control calculation device 7 are configured by a computer that includes a storage device and a calculation device and is automatically processed by a program.

Next, an embodiment of a ship attitude control method according to the present invention will be described.

A model expressing the attitude of the hull is described by the following equations (1) to (5).

[0011]

[Equation 1]

[0012]

[Equation 2]

[0013]

[Equation 3]

[0014]

[Equation 4]

[0015]

[Equation 5]

Where Δφ _fin : fin setting angle (rad) Δθ: hull roll angle (rad) x: state quantity y: observed quantity u: manipulated variables a, b, c, d: model coefficient (1) above The formula and the formula (2) represent the attitude model of the hull. The input of this model is the fin setting angle u, and the output is the hull roll angle Δθ. Therefore, it is a mathematical model with one input and one output. The H-infinity control theory is applied when configuring the attitude control device for the obtained 1-input 1-output attitude model. According to this H-infinity control theory, as will be described later, a posture including an original controlled object and various weighting functions given at the time of designing is called a generalized plant, and an attitude that exhibits a control effect according to various weights. A control system can be configured, and as described above, the attitude control operation can be limited to a certain frequency band. As a result, the drive power input to the fin stabilizer or trim tab is
It can be used efficiently in the frequency band where fluctuations are desired to be suppressed.

FIG. 2 shows a control target (generalized plant) when designing the attitude control controller according to the present invention. 12 is a ship attitude model, 13 is an H infinity controller, 14 is a disturbance input w, 15 is a control input (operation amount) u,
16 is a weighting function W _T , 17 is a control amount z ₁ , 18 is a weighting function W _S , 19 is a control amount z ₂ , and 20 is an observation output y.

There are various model errors that should be taken into consideration at the time of design. Here, as typical ones,
Let us consider the dead time element that is the sum of the detection delay of the roll angle sensor and the reaction delay of the fin stabilizer.

FIG. 3 shows the gain of the transfer function and weight function W _T of a general dead time. The 16 weighting functions W _T are set to cover this general dead time transfer function.

As a dead time range, for example, T = T
Considering _delay (sec), as W _T ,

[0021]

[Equation 6]

It is known that this is all right. Here, S is a scalar constant.

The eighteen weight functions W _S are, for example,

[0024]

[Equation 7]

Set as follows. Here, G _WS and T _WS are scalar constants.

This weighting function W _S is for making the transfer function from the disturbance input w to the observation output y small. The larger the gain of the weighting function W _S , the more influence the disturbance input w has on the observation output y. Becomes smaller.

FIG. 4 shows the gain of the weighting function W _S. As shown in FIG. 4, if the weighting function W _S is set as in equation (7), the effect of suppressing the roll angle variation in the low frequency band is enhanced, and a posture control system in which a steady error does not occur can be obtained. The bandwidth can be arbitrarily set by T _WS .
At the time of actual design, it may be set so as to include, for example, the primary resonance frequency and the secondary resonance frequency of the roll angle vibration mode.

In the H infinity design method, the transfer function from the disturbance input w and the control input u ₁ to the evaluation quantities z ₁ and z ₂ and the observation output y is the transfer function of the original controlled object, G _P , and the scalar constant. Is I,

[0029]

[Equation 8]

When expressed as, it is possible to derive a compensator C (s) that makes the H infinity norm of the transfer function from the disturbance input w to the evaluation quantities z ₁ and z ₂ smaller than a given γ. it can. The method of obtaining a compensator based on the H-infinity theory is described in, for example, "The 41st System Control Information Workshop" Basics of H-Infinity Control "Text: System Control Information Society of Japan." A program for calculating the compensator C (s) using is equipped in a commercial control system design CAD and can be easily used today. This is a theory that transcends optimal control theory in the sense that the closed-loop characteristics of the control system can be specified by giving weights, where the weighting function W _T is determined so as to cover the model error to be considered at the time of design, for the weighting function W _S, it can be relatively freely set within a range in which the controller can be solved. in the example shown, by setting the weight function W _S as its gain in the low frequency region is increased In the low frequency region becomes higher effect occupying become large effect of suppressing the roll angle variation.

FIG. 5 shows the above H infinity controller
An example applied to the roll angle control computing device in the present invention is shown. Reference numeral 21 is a roll angle set value, 22 is an H infinity controller, 23 is attitude dynamics, and 24 is a roll angle control calculation device.

FIG. 6 shows an example in which the method according to the present invention and the conventional method are compared in response to the initial roll angle deviation. In the conventional method, since the control target is up to the higher-order modes, it takes time for the control energy to be dispersed in each mode, and as a result, the roll angle deviation becomes zero.
On the other hand, in the control system designed by the method according to the present invention, in contrast to the conventional method, since the control operation is limited to the low frequency band, the attitude control effect in the low frequency band becomes large, The convergence is improved.

In the above-described embodiment, the fin stabilizers installed on both side surfaces of the hull are properly adjusted so that the proper roll angle is always maintained based on the detection value of the sensor for detecting the roll angle or the roll angular velocity of the hull. Although the attitude control method of the ship in which the H infinity control method is applied to the control calculation unit that outputs the operation amount has been described, the sensor that detects the pitch angle or the pitch angular velocity of the hull and the roll angle or the roll angular velocity of the hull are described. Based on the detection value of the sensor that detects the H value, the control calculation unit that outputs the appropriate operation amount to the trim tab installed on the bottom of the rear end of the hull is always set to H The same applies to a ship attitude control method to which the large control method is applied.

[0034]

According to the present invention described above, the H infinity control theory is applied to the construction of the attitude control system of a ship,
By weighting on the frequency axis, it is possible to limit the frequency band of operation of the attitude control system, and prevent the dispersion of control energy, which was a problem in the conventional method, thus improving the efficiency of the attitude control system. Can be improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a system showing an embodiment of the present invention.

FIG. 2 is a control target diagram of the attitude control controller according to the present invention.

FIG. 3 is a frequency characteristic diagram of gain of the weighting function W _T.

FIG. 4 is a frequency characteristic diagram of gain of the weighting function W _S.

FIG. 5 is a conceptual diagram of a roll angle control computing device according to the present invention.

FIG. 6 is a comparison diagram of the method according to the present invention and a conventional method.

[Explanation of symbols]

1 Roll Angle Detection Sensor or Roll Angular Velocity Detection Sensor 2 Roll Angle Control Calculation Device 3 Fin Angle Control Device 4 Fin Angle Control Mechanism 5 Fin 6 Pitch Angle Detection Sensor or Pitch Angular Velocity Detection Sensor 7 Pitch Angle Control Calculation Device 8 Trim Tab Angle Control Device 9 Trim tab angle control mechanism 10 Trim tab 11 Hull 12 Ship attitude model 13 H infinity controller 14 Disturbance 15 Control input (manipulation amount) 16 Weight function W _T 17 Control amount z ₁ 18 Weight function W _S 19 Control amount z ₂ 20 Observation output y 21 Roll Angle Setting Value 22 H Infinity Controller 23 Posture Dynamics 24 Roll Angle Control Computing Device

Claims (2)

[Claims] 1. A fin stabilizer installed on both side surfaces of a hull, a sensor for detecting a roll angle or a roll angular velocity of the hull, and a fin stabilizer for always maintaining an appropriate roll angle based on a detection value of the sensor. In a ship attitude control method using a ship attitude control device including a control operation unit that outputs an appropriate operation amount, output control to the fin stabilizer by the control operation unit is performed by an H infinity control method. Attitude control method for ships. 2. A trim tab installed on the bottom of the rear end of the hull, a sensor for detecting the pitch angle or pitch angular velocity of the hull, a sensor for detecting the roll angle or roll angular velocity of the hull, and the detection values of the respective sensors. On the basis of a ship attitude control method using a ship attitude control device including a control operation unit that outputs an appropriate operation amount to the trim tab so as to always maintain an appropriate pitch angle or an appropriate roll angle, based on the control operation unit, A ship attitude control method, wherein output control to a trim tab is performed by an H infinity control method.