EP2275342B1 - Method for reducing a vertical movement of a water vehicle - Google Patents

Description

The invention relates to a method for reducing a vertical movement of a watercraft.

For vessels, such as cargo ships, but also for submarines, it is necessary to ensure the ship's stability while driving. It is known that in certain sea conditions vibration movements of the vessel can be excited with a vertical component of motion, in particular rolling vibrations. Such vertical movements lead in the case of resonance to greatly increased deviations from the desired position of the vessel. For example, in the case of parameter-excited rolling vibrations, roll angles greater than 20 ° sometimes occur. In submarines in particular, strong parameter-excited rolling movements can occur due to the mass geometric properties of the hull. Thus, in submarines even roll angle of more than 40 ° have become known.

From the "Guidelines for monitoring ship stability" of the Federal Ministry of Transport, Building and Urban Development and the Maritime Trade Association of the Federal Republic of Germany of 31 March 2004, a method for reducing the risk of parametric roll resonance is known in which by prior estimation of the roll time of the ship and the knowledge of its Rolleigenperiode a resonance range for dangerous meeting periods with the incoming swell can be determined. Is located the vessel within the range of resonance, either the driving speed or the course can be adjusted as a countermeasure until the resonance area is left. The encounter period with the incoming sea state can be measured, for example, with the help of the pitching movements of the watercraft. It is disadvantageous that the determined resonance range is so great that partly unnecessary control and drive operations are performed.

It is therefore an object of the invention to provide a method by which the vertical movement of a watercraft can be reduced with few control and drive operations.

This object is achieved by a method having the features specified in claim 1. Advantageous embodiments are specified in the subclaims, the following description and the drawing.

The method according to the invention serves to reduce a vertical movement of a watercraft. For this purpose, a vertical motion resonance range for motion states of the watercraft is first determined. Then, during the drive, the state of motion of the watercraft is at least partially detected and determined whether this is in the vertical motion resonance range.

A determination of the vertical motion resonance range in the sense of this invention is to be understood as meaning, in particular repeated or continuous, determination of the vertical motion resonance range during travel. However, according to the invention, the vertical-motion resonance range can also be determined implicitly by determining whether the vertical movement unfolds, ie it is determined by observing the movement of the watercraft, whether the state of motion of the vessel coincides with a state of motion in the vertical motion resonance area.

According to the invention, the rolling motion of the watercraft forms the vertical movement and a rolling motion resonance area forms the vertical motion resonance area. In this way, straight rolling movements are reduced which endanger driving safety and ride comfort particularly frequently.

When it is determined that the traveling state of the vessel is in the vertical motion resonance area, according to the invention, the traveling speed and / or the heading of the vessel is changed until the vertical motion resonance area is exited. In this way, vertical movements can be reduced or their growth can be avoided. The reduced vertical movement increases driving safety enormously. Thus, capsizing of the vessel and possibly slipping or loss of cargo is safely avoided. In addition, increases the ride comfort for the crew with reduced vertical movement.

If the vertical motion resonance range is left, the originally intended course and the originally intended speed for the watercraft are preferably assumed again. In this way, it is only necessary to deviate from the planned course of the journey for a short time, so that when the method according to the invention is used, the envisaged total journey time also changes at best negligibly.

Under a vertical movement in the sense of this invention, each rotation or. To understand displacement movement about or along a main axis of inertia of the vessel, which is a vertical motion component having. For example, the lifting and pitching movements fall under the vertical movement.

In the method, the course and / or the travel speed of the watercraft are preferably changed or changed as a function of the previously determined propagation speed and / or the propagation direction of the water waves. In this way, for example, certain encounter frequencies of water waves can be avoided with the vessel, in which a large proportion of the kinetic energy of the sea state can couple into the vertical movement.

Preferably, in the method, at least by determining the frequency of encounter of the water waves with the vessel, it is determined whether the state of motion of the vessel is in the vertical motion resonance range. Thus, water waves can excite vertical movements in the vertical motion resonance range, in particular, when the frequency of encounter of the water waves with the watercraft is close to a resonance frequency of a vertical motion resonance. The frequency of encounter of the water waves with the vessel can be measured, for example, by detecting periodic movements of the vessel itself, such as by measuring the pitching motion of the vessel.

In the method, the vertical motion resonance range is preferably determined by determining at least one resonance frequency of the vertical movement. In particular, the vertical motion resonance range represents a frequency interval including the resonance frequency. Alternatively or additionally, the vertical motion resonance range can be determined by an integer fraction, for example half, or by an integer multiple of the resonance frequency of the vertical movement. Further, the vertical motion resonance area formed in preferred embodiments of the method by one or more frequencies, which are in a rational relationship with at least one resonance frequency of the vertical movement.

In a preferred embodiment of the method according to the invention, if appropriate, the phase of the water waves impinging on the vessel is changed relative to the vibration-like vertical movements of the vessel by course or travel speed changes of the vessel. For example, vibration-like vertical movements of the vessel can be damped at a suitable phase by the sea.

According to the invention, in the method, the state of motion of the vessel is at least partially detected, by determining at least one component of the location and / or orientation of the watercraft and / or their - in particular first - time derivation. In preferred developments of the invention, alternatively or additionally, at least one further, in particular the second, time derivative of the component is determined. In accordance with the invention, the determination of the aforementioned variables may be understood, on the one hand, as a computational determination, for example in such a way that a time derivation of the variables to be determined is integrated over time. An alternative mathematical determination can be made such that the variable to be determined itself represents a time derivative of a detected variable and is calculated from the time course of this detected variable. On the other hand, determination can also be understood to mean a measurement, for example by means of sensors such as acceleration sensors or roll rate meters. Particularly preferably, the state of motion of the watercraft is detected by relating at least two of the above-mentioned components to one another. Ideally, the course of the roll angle and the vertical position of the vessel are linked to each other.

Preferably, for the at least partial detection of the state of motion of the watercraft and / or the propagation direction and / or speed of the water waves, data of a satellite-supported navigation system is used. Thus, the acquired data on the state of motion of the vessel or the movement of the water waves can be transformed, for example, into the earth-fixed coordinate system. In this way, the influence of course and / or speed ratings of the vessel from the data on the state of motion of the vessel or the movement of the water waves can be deducted. For example, this data can then be filtered with a high-pass filter whose time constant is not limited by time scales on which rate changes occur. For example, a filtering be appropriate on long time scales to achieve the most accurate determination of the propagation direction of the water waves.

In the method, the change of course and / or travel speed of the watercraft by means of at least one machine and / or at least one actuator of the watercraft is expediently carried out automatically. For example, these actuators are the rudder (s), especially in cruise ships and yachts, for laterally mounted fins for roll stabilization, as well as submarines additionally or alternatively to the or the rudder. Preferably, all available actuators and / or the machine of the watercraft are used for this purpose.

In an advantageous development, the method, the vertical motion damping is increased, provided that the state of motion of the vessel is located within the vertical motion resonance range. For example, the vertical motion damping is increased via a subordinate control method, which counteracts the vertical movement.

Expediently, the vertical motion damping is increased by means of at least one or more devices from the group of machines, side fins, rudders, ailerons, for example divided, oppositely-moving ailerons and / or optionally further actuators. In the method according to the invention, these actuators need not be available solely for damping the vertical movement, but at the same time they can also be used to change the course and / or travel speed of the watercraft as described above. For this purpose, if necessary, the controls of the machine or the actuators - for example, for adjusting rudder / fin angles, engine power, etc. - for the purpose of changing course or speed of the vessel and for the purpose of vertical motion damping suitable superimposed. For example, the damping can be taken into account by the machine or by the actuators in control circuits, which are designed to change the course or speed of the watercraft. Conversely, the controls for changing course or speed can also be done in subordinate control loops for damping the vertical movement by means of the machine or the actuators. For example, the respective drives can be added in a corresponding control.

Advantageously, in the method, the strength of the excitation of the vertical movement in a state of motion of the vessel within the vertical motion resonance range is reduced by the change of the pitch amplitude of the vessel, preferably by a subordinate control method, which counteracts the pitching movement. This is particularly relevant in the case where the vertical motion resonance region is formed by a rolling motion resonance region. Just pitching movement and rolling motion often couple strongly with each other, so that pitching movements at a corresponding frequency can drive roll motions resonantly. Further preferably, in a state of motion of the vessel within the vertical motion resonance area, the intensity of the excitation of the vertical motion is reduced by the change of the yaw angle of the vessel, preferably by a subordinate control.

Conveniently, the ramming amplitude is influenced by means of at least one depth rudder of the watercraft.

Suitably, in the method according to the invention, the state of motion of the vessel is determined via an inertial platform.

Preferably, the inventive method for reducing the vertical movement of a submarine is performed. Particularly in the case of submarines, particularly parameter-excited rolling vibrations can occur in an intensified form during navigation, since their hull is not regularly optimized to avoid rolling movements. Rather, submarines for roll behavior on unfavorable mass geometric conditions. These unfavorable circumstances are suitably compensated by the method according to the invention.

Fig. 1

schematisch ein Signalschaltbild einer Regelung zur Ausführung eines eine Grundlage für die Erfindung bildenden Verfahrens und

Fig. 2

schematisch ein Signalschaltbild einer alternativen Regelung.

The invention is explained in more detail with reference to embodiments shown in the drawing. Show it:

Fig. 1

schematically a signal diagram of a control for carrying out a basis for the invention forming method and

Fig. 2

schematically a signal diagram of an alternative control.

The illustrated in the signal diagrams, the basis for the invention forming method reduces the rolling motion of a ship. For example, it is a cruise ship, a cargo ship or a submarine. Furthermore, can the method described can be used in a corresponding manner to reduce the pitching movement.

In the method, the state of motion of the ship is first detected. For this purpose, sensors are provided which measure the state of motion of the ship in terms of its six degrees of freedom, d. H. the position of the ship in the three spatial directions as well as the orientation of the ship are determined by means of the sensors. In addition, the time derivatives of the aforementioned sizes are determined, d. H. The speed of the ship along the three spatial directions and the angular velocities of the ship's rotational movements around its main axes of inertia are determined. The determination of these time derivations is done either by a direct measurement via specially provided for this purpose sensors or mathematically from each time sequentially measured values of position and / or orientation of the ship. For example, the input data for the position or orientation of the ship can also be obtained from the temporal integration of the time derivatives of position and orientation of the ship. Via acceleration sensors, the second time derivatives of the position and the orientation of the ship are also measured, so that the acceleration of the ship along the three spatial directions and the angular acceleration about the main axes of inertia of the ship are part of the input data.

The aforementioned set of input data forms a state vector x which describes the state of motion of the ship. In addition, the method determines position data from the data of a satellite-based navigation system, such as the Global Positioning System (GPS). This position data forms another set of input data, which is summarized in a vector GPS . The two aforementioned sets of input data x and GPS are fed to a filter device 1. In the filter device 1, the data sets x and GPS are appropriately filtered and thus freed from interference. Furthermore, redundant data for the input data x and GPS are available to the filter device 1 via further sensors, with which the filter device 1 carries out averaging of the input data. The input data thus cleaned by filtering or averaging are available as data sets x and G p s for further processing.

In a similar manner, predetermined set values for actuators of the ship are adjusted in a second filter device 2 by further subordinate control devices. These target variables include, inter alia, the setpoint speed of a machine n , the desired angle of a rudder surface δ ₁ , in the case of a submarine the desired angle of the depth rudder δ ₂ and target values of other actuators. The filter device 2 provides the adjusted nominal values ñ , δ ₁ and δ ₂ for further processing.

In the evaluation device 3, the proximity of the adjusted movement state x to the state of a parameter-excited rolling oscillation is determined on the basis of one or more defined criteria. The proximity of the state of motion to the roll resonance state is characterized by a data set called resonant level RL .

In a second evaluation device 4, the propagation direction of the water waves relative to the ship, the wave propagation speed and other characteristic magnitudes of the wave excitation are determined from the adjusted movement state x . These parameters are summarized in a dataset, here referred to as wave excitation q _w . Furthermore, the evaluation device 4 is provided with the adjusted GPS data GPS , on the basis of which the wave excitation q _{w is transformed} into an earth-fixed coordinate system, so that the influence of course and speed of the ship is calculated out. In this earth-fixed coordinate system, the wave excitation q _{w is} filtered. In particular, this filtering allows increased accuracy in determining the propagation direction of the water waves.

The resonant level RL, the cleared state of motion of the vessel x and the wave excitation q _w are passed to a controller 6 which checks the resonant level RL to see if the state of motion of the vessel x is critically close to parameter-excited roll vibration, ie if the state of motion is within a roll resonance range is. If the state of motion of the watercraft is in the roll resonance range, the speed and the yaw angle of the ship are changed by means of a control law such that the distance of the movement state x to the state of the parameter-excited rolling vibration increases. A suitable specification for changing the yaw angle depends essentially on the wave excitation q _w , in particular on the propagation direction of the water waves. In the control law thus represents the state of motion x the control variable. The manipulated variables for speed and yaw angle change are formed by nominal variables O1 for the machine and nominal variables O2 for a rudder, which the existing on board, subordinate Aktorreglern 7 and 8 for the operation of these actuators be supplied. Also, the other actuators 6 setpoints O5 are specified by the control device.

Resonance level RL and adjusted movement state x are also transmitted to another control device 5. The control device 5 first determines on the basis of the resonance level RL whether the movement state of the ship x is so close to a state of a parameter-excited rolling vibration that the ship's movement must be damped. If this is the case, set values for actuators of the ship are based on the movement state x according to a control law calculated, which are used for damping. In the embodiment shown, these are z. B. Nominal O3 for the side fins. In addition, the controller determines 5 setpoints O4 for more directly acting on the roll and ramming behavior of the ship actuators, for example, the submarines in the case of submarines.

The previously described Aktorsoll sizes ñ , δ ₁ , δ ₂ are in the in Fig. 1 Embodiment considered internally in the controllers 5 and 6. Alternatively ( Fig. 2 ), the setpoint variables O1 , O2 , ..., O5 for the actuators in the subordinate Aktorregiern 7, 8 and 9 are added, the filtering of the Aktorsoll variables ñ, δ ₁ , δ ₂ can be done completely separately via the filter device 2 ,

LIST OF REFERENCE NUMBERS

x

- measured state of movement of the ship

x

- Adjusted state of motion of the vessel

GPS

- GPS data

GPS

- adjusted GPS data

RL

- Resonance level

q _w

- Wave excitation

n

- Target speed machine

δ ₁

- desired angle rudder

δ ₂

- Sollwinkel depth rudder

ñ

- adjusted setpoint speed machine

δ ₁

- adjusted target angle rudder

δ ₂

- adjusted target angle rudder

O1

- nominal machine sizes

O2

- Nominal rudder

O3

- Nominal sizes of side fins

O4

- Nominal depth rudder

O5

- nominal values

1

- Filter device

2

- Filter device

3

- Evaluation device

4

- Evaluation device

5

- Control device

6

- Control device

7

- Subordinate actuator controller

8th

- Subordinate actuator controller

9

- Subordinate actuator controller

Claims (11)

1. A method for reducing a vertical movement of a vessel, with which firstly a vertical movement resonance region for movement conditions (x) of the vessel is determined afresh during the travel of the vessel, with which the movement condition (x) of the vessel is then at least partly detected during the travel by way of at least one component of the location and/or of orientation of the vessel, and/or its temporal derivative being determined, and determining whether this movement condition (x) lies in the vertical movement resonance region, whereupon if one ascertains that this movement condition (x) lies in the vertical movement resonance region, the travel speed of the vessel and/or the course is changed until the vertical movement resonance region has been left, wherein a roll movement forms the vertical movement, and the vertical movement resonance region is formed by the roll movement resonance region.
2. A method according to claim 1, with which the vertical movement resonance region is determined by way of evaluating at least one resonance frequency of the vertical movement.
3. A method according to one of the preceding claims, with which the first temporal derivative of a component of the location and/or of the orientation of the vessel is determined for the at least partial detection of the movement condition (x) of the vessel.
4. A method according to one of the preceding claims, with which data (GPS) of a satellite-supported navigation system is used for the at least partial detection of the movement condition (x) of the vessel.
5. A method according to one of the preceding claims, with which the change of the course and/or of the travel speed of the vessel is effected automatically by way of at least one engine and/or at least one actuator of the vessel.
6. A method according to one of the preceding claims, with which, with a movement condition (x) of the vessel within the vertical movement resonance region, the vertical movement damping is increased, preferably via a secondary closed-loop control method, which counteracts the vertical movement.
7. A method according to claim 6, with which the vertical movement damping is increased by way of at least one or more of the following devices: engine, side fins, side rudder, depth rudder and/or further actuators of the vessel.
8. A method according to claim 5 and 7, with which, with a movement condition (x) of the vessel within the vertical movement resonance region, one or more actuators and/or one or more engines of the vessel together are applied for changing the course and/or travel speed of the vessel as well as for increasing the vertical movement damping.
9. A method according to one of the preceding claims, with which, with a movement condition (x) of the vessel within the vertical movement resonance region, the strength of the excitation of the vertical movement is reduced by way of changing the pitch amplitude of the vessel, preferably by way of a secondary closed-loop control method, which counteracts the pitch movement.
10. A method according to claim 9, with which the pitch amplitude is influenced by way of at least one depth rudder of the vessel.
11. A method according to one of the preceding claims, with which the movement condition (x) of the vessel is determined by way of an inertia platform.

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