KR0182082B1 - Vibration control method and equipment for a ship - Google Patents

Abstract

The present invention relates to a method and apparatus for removing vibration of a hull structure generated by a propulsion engine such as an engine and a propeller of a ship generated while operating a ship, and more particularly, to the contrary to the vibration generated in the hull It is a principle that attenuates and removes vibration of hull structure by generating phase vibration.It is based on vibration magnitude and phase change of hull structure according to control phase change of exciter using vibration generator (accelerator) and accelerometer. Vibration control method and apparatus for ships to determine the optimum control phase of the excitation for vibration cancellation, drive and maintain it to eliminate the hull type vibration.A signal amplifier that amplifies an electric signal and an analog / digital signal reading the signal. Digital input board which reads converter and digital signal, and recognizes input signal and calculates physical quantity It has a control unit consisting of a communication port that transmits control commands to the central processing unit and the excitation unit, and a digital / analog signal converter, and amplifies the vibration sensor of the structure under control, that is, the electrical signal of the accelerometer with a signal amplifier, The digital signal of the excitation force phase sensor of the exciter is input to the input board to control the control device to the central processing unit and the communication port.

Description

Marine vibration control method and device

1 is a conceptual diagram showing the overall configuration of the present invention.

2 is an explanatory diagram showing an optimal control phase determination method of the vibration control device according to the present invention.

3 is a flowchart showing a control algorithm of the vibration control device according to the present invention.

4 is a block diagram showing a configuration of the present invention.

5 is a superstructure vibration control test result table using the present invention.

* Explanation of symbols for main parts of the drawings

1: Exciter 2: Vibration Force Phase Sensor

3: ship propulsion engine phase sensor 4: accelerometer

5: control unit 6: signal amplifier

7: Analog / Digital Signal Converter 8: Input Board

9: central processing unit 10: communication port

11: Digital / Analog Signal Converter

The present invention relates to a method and apparatus for removing vibration of a hull structure generated by a propulsion engine such as an engine and a propeller of a ship generated while operating a ship, and more particularly, to the contrary to the vibration generated in the hull It is a principle that attenuates and eliminates vibration of hull structure by generating phase vibration.It is based on vibration size and phase change of hull structure according to control phase change of exciter by using vibration generator (accelerator) and accelerometer. It is a vibration control method and device for ship that removes the vibration of the hull structure by determining the optimum control phase of the exciter for vibration cancellation.

The present invention has been made on the premise of using an unexcited central exciter having a single frequency component, mainly a fixed eccentricity or a variable eccentricity.

Conventionally, the vibration control apparatus used in ships is to determine the vibration value of the structure to be controlled by manually changing the phase of the machine having the optimum phase øopt corresponding to point C in the optimum control phase determination method shown in FIG. After that, the exciter phase giving the smallest vibration value is determined as the optimum phase.

At this time, the actual vibration value is measured by using a separate vibration measurement and analysis device (eg accelerometer and frequency analyzer).

The above method only needs to be performed once when the dynamic characteristics of the structure to be controlled are constant. However, if the optimum control phase is changed due to a change in the dynamic characteristics of the structure to be controlled, the method has to be repeated and the driving phase of the vibration control device needs to be corrected.

In the case of ships, the dynamics vary depending on the load condition or the speed of operation.

Therefore, whenever the operating state changes, the control phase of the vibration control device should be corrected, but this is very difficult in reality, and the conventional ship vibration control device is installed to be permanently driven to the optimum phase determined in a specific operating state.

In this case, if the operating conditions are different, the control performance of the vibration control device is not only degraded, but the vibration control device increases the vibration of the ship when the dynamic characteristics of the structure to be controlled are severe.

The present invention is to solve the above-mentioned problems of the prior art by the applicant using a force-adjustable mechanical type excitation (Utility Model Registration Application No. 94-3105) two different from each other having a known phase difference by the control unit In order to control the phase of the sequential phase, the optimum phase of the vibration control device is determined by using the magnitude of the vibration of the structure to be controlled.

At this time, the vibration size is calculated by an algorithm in the control unit using the vibration signal measured by the accelerometer included in the vibration control device.

Hereinafter, the algorithm, structure, and effect of the present invention will be described in detail with reference to the accompanying drawings.

The hull vibration V (t) generated by the propulsion of a single frequency component by the propulsion engine (ship engine, propeller, etc.) and the vibration control device is generally expressed as:

Where A: vibration magnitude

w is the angular velocity of the vibration frequency (rad / sec)

θ: relative phase of vibration to vibration

Indicates. If you express these vibrations in complex quantities,

Same as

In Eq. (2), R and I are the real and imaginary parts of the vibration magnitude with respect to the reference phase wt of the vibration force, represented by one point (M in Fig. 2) on the complex plane, and vibrated through the integration process as in Eq. (3). Can be obtained directly from the signal.

When the vibration response due to the propulsion engine vibration force at a specific frequency w is V ₁ (t), and the vibration response due to the exciter generating vibration force at the same frequency is V ₂ (t), synthesis at frequency w is performed. Vibrations

It can be expressed as and can be represented by vector composition in complex plane as shown in Fig. 2.

The vibration synthesized by Eq. (4) draws the trajectory of the circle in the complex plane as shown in Figure 2 as the control phase of the exciter changes from 0 ° to 360 ° relative to the reference phase wt of the propulsion engine vibration force.

The point C on the locus line of the synthesized vibration response of FIG. 2 is where vibration by the propulsion engine and vibration by the exciter are opposite phases, so that the synthesized vibration is the smallest. Is the optimal phase of.

If the vibration response due to the propulsion force of the propulsion engine is driven at the same frequency V ₁ and the same frequency, and the vibration of the deception when the control phase is 0, V ₂ , the synthesized vibration is the point A of FIG. 2. Can be represented. Similarly, if the vibration of the deception in the case of the control phase of ø _add is V ₃ , the synthesized vibration can be represented by the point B in FIG. 2.

At this time, the magnitude of the excitation force is the same, so the absolute magnitude of V ₂ and V ₃ is the same.

Therefore, if the vibration response at points A and B of FIG. 2 is V _A and V _B , the following relation is established between V _A , V _B , V ₁ , V ₂ , and V ₃ .

From the relational expression of equation (5), the vibration response V ₂ of the structure to be controlled by the deception in case the control phase is 0 can be seen as follows.

Where A ₂ and θ ₂ are the magnitude and relative phase of the vibration response due to the excitation, respectively.

The vibration response V ₁ due to the propulsion engine can be known as follows using the known V ₂ and equation (5).

A ₁ and θ ₁ are the magnitude and relative phase of vibration response by propulsion engine alone, respectively.

In Figure 2, the relative phase of the vibration response

The optimum control phase of the exciter is

Is determined.

Power control is exerted in the excitation force is required in order to fully offset the vibration caused by the driving engine when the groups with group size with F _opt is

Is given by

In the present invention, when the optimum point moves due to the change of the operating state of the ship after the steady state driving at the optimum point is started, the present invention minimizes the vibration of the structure to be controlled by using the numerical derivative of the vibration response to the change of the phase and vibration force. Determine the optimum phase and magnitude of the excitation force of the exciter.

Where ø ₁ and F _m are the magnitude and phase of the vibrator, respectively, and A ₁ or A _m is the magnitude of the hull vibration represented by the propulsion of the propulsion engine and the vibrator.

1 and m are control sequences in the abnormal control, and β _ø and β _F are weights of appropriate amounts in consideration of control stability.

The control by equations (11) and (12) may be selectively applied only if the operational state of the ship is constantly changing.

1 is a conceptual diagram showing the overall configuration of the present invention and Figure 4 is a block diagram showing the configuration of the present invention.

The controller 5 sends the signal to the signal amplifier 6 which amplifies the vibration sensor of the vessel structure to be controlled, that is, the electric signal (vibration magnitude) of the accelerometer 4, and reads the signal from the analog / digital signal converter 7 to perform a central operation. The digital signal of the phase sensor 2 of the ship propulsion engine (ship engine, propeller) and the phase sensor 2 which sensed the vibration force phase signal of the exciter 1; The physical quantity required for controlling the exciter 1 in the central processing unit 9 by recognizing the signal after being inputted to the readout device and the digital / analog signal converter 11 again. ) Is a control structure that gives a control command.

3 shows the execution procedure of the control unit, and FIG. 5 shows the result of performing the superstructure horizontal vibration control test applied to a 300,000-ton crude oil carrier using the vibration control device of the present invention.

Thus, the present invention basically requires a vibration phase signal of the excitation machine, a vibration phase signal of the propulsion engine, and a vibration signal of the vessel structure to be controlled in addition to the excitation machine. The control unit will perform.

The determination of the optimum control phase is based on the oscillation (point A) and the arbitrary control phase ø _add at the control phase 0 of the exciter when the magnitude and the relative phase of the vibration are shown in the complex plane as shown in FIG. The vibrations (point B) are measured, respectively, and the vibrations caused only by the excitation (expression (6)) and the vibrations caused only by the propulsion engine (expression (7)) are obtained.

From this, the control phase φ _opt to minimize vibration is determined by equation (9) and driven to the control phase of the exciter.

The vibration at this time is represented by the second C point, and in order to completely cancel the vibration, the vibration force of the exciter is adjusted as in Equation (10).

When the optimum point changes due to a change in external conditions after reaching a steady state, the optimum point can be continuously followed by equations (11) and (12).

Therefore, the control phase and the magnitude of the vibration force of the exciter for the optimum vibration control every time the device of the present invention is determined, there is an effect that can always perform the optimum vibration control even if the dynamic characteristics and operating conditions of the vessel changes The vibration signal is directly used in the vibration control device.

Claims (2)

Vibration magnitude of the control target structure according to the phase change of the excitation force of the exciter by using the vibration force generated in the ship structure with the vibration generator of the single frequency component (accelerator), the accelerometer for measuring the vibration of the structure And analyzing the phase change and determining and driving the optimum control phase and vibration force of the exciter for vibration cancellation to remove the vibration of the ship structure. A signal amplifier 6 for amplifying an electric signal, an analog / digital signal converter 7 for reading the signal, a digital input board 8 for reading the digital signal, and a physical quantity necessary for controlling the exciter 1 by recognizing the input signal. A control target sensor, i.e., an accelerometer, having a control unit (5) consisting of a communication device (10) for transmitting a control command to the exciter (1) and a central processing unit (9) for calculating a function, and a digital / analog signal converter (11). Amplify the electrical signal of (4) with the signal amplifier (6) and input the digital signal of the phase sensor (3) of the ship propulsion engine and the vibration force phase sensor (2) of the exciter (1) to the input board (8). Vibration control device for ships, characterized in that to give a control command to the excitation (1) to the central processing unit (9) and the communication port (10).