Active stabilizing device and method

Abstract

An active stabilizing device for a primary damping of rolling movements of a ship or other watercraft including a hull including at least one positioning device having a drive journal and a stabilizing fin with a stabilizing surface and a root, the drive journal being attached to the stabilizing fin at the root, the stabilizing surface having a leading edge and a trailing edge and being configured to be disposed underwater. The positioning device is configured to set an angle of attack of the stabilizing fin by rotating the drive journal about a first axis of rotation and to pivot the drive journal about a second axis of rotation to move the stabilizing fin between a forward position and a rearward position relative to a bow of the watercraft.

Claims

1. An active stabilizing device for a primary damping of rolling movements of a ship or other watercraft including a hull comprising: at least one positioning device including a drive journal and a stabilizing fin having a stabilizing surface and a root, the drive journal being attached to the stabilizing fin at the root, the stabilizing surface having a leading edge and a trailing edge and being configured to be disposed underwater, wherein the positioning device is configured to set an angle of attack of the stabilizing fin by rotating the drive journal about a first axis of rotation and to pivot the drive journal about a second axis of rotation to move the stabilizing fin between a forward position and a rearward position relative to a bow of the ship or other watercraft.

2. The active stabilizing device according to claim 1, wherein the positioning device is configured to rotate the drive journal through an angle of about 180 degrees.

3. The active stabilizing device according to claim 2, wherein a radius of curvature of the leading edge of the stabilizing fin is greater than a radius of curvature of the trailing edge of the stabilizing fin.

4. The active stabilizing device claim 2, wherein the drive journal extends through an inflow body that does not rotate together with the stabilizing fin.

5. The active stabilizing device according to claim 4, wherein the inflow body is fin-shaped and includes a leading edge facing in a direction of the bow.

6. The active stabilizing device according to claim 5, wherein a cross-sectional geometry of the inflow body is substantially the same as a cross-sectional geometry of the stabilizing fin adjacent to the inflow body.

7. The active stabilizing device according to claim 1, wherein the positioning device is configured to pivot the drive journal so that the leading edge of the stabilizing fin extends in a longitudinal direction of the ship or other watercraft.

8. The active stabilizing device according to claim 1, wherein the second axis of rotation is substantially vertical.

9. A method for damping rolling movements of a ship or other watercraft including a hull and having a bow and a stern comprising; providing at least one positioning device including a drive journal extending from the hull and a stabilizing fin having a stabilizing surface and a root, the drive journal being attached to the stabilizing fin at the root, the stabilizing surface having a leading edge and a trailing edge and being configured to be disposed underwater, periodically pivoting the drive journal about a pivot axis to move the stabilizing fin in a forward direction toward the bow and to move the stabilizing fin in a rearward direction toward the stern, and rotating the drive journal about a rotation axis so that the leading edge of the stabilizing fin faces in the forward direction when the stabilizing fin is moving in the forward direction and faces in the rearward direction when the stabilizing fin is moving in the rearward direction.

10. The method according to claim 9, wherein pivoting the drive journal comprises pivoting the drive journal through an angle of about 120 degrees.

11. The method according to claim 10, wherein rotating the drive journal comprises rotating the drive journal through an angle of about 180 degrees.

12. The method according to claim 11, including pivoting the drive journal to move the stabilizing fin to a rest position inside a receiving pocket in the hull of the ship or other watercraft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1-3 are perspective schematic views of a stabilizing surface of a stabilizing device in a first pivot direction in each of three different positions.

(2) FIGS. 4-6 are perspective schematic views of the stabilizing surface of the stabilizing device of FIG. 1 in a second pivot direction, oriented opposite the first pivot direction of FIGS. 1 to 3, in each of three different positions.

DETAILED DESCRIPTION

(3) FIGS. 1 to 3—which are referred to together in the further course of the description—are perspective schematic views of a stabilizing surface of a stabilizing device in a first pivot direction in each of three different positions.

(4) A watercraft or a ship 12 includes a conventional hull 14. For the predominant weakening of undesirable rolling movements an active stabilizing device 10 is integrated in the hull 14. Here the stabilizing device 10 includes, for example, a stabilizing surface 16 that is approximately rectangular and fin-like. If necessary the stabilizing surface 16 can also exhibit a peripheral contour of a polygon having more than four corners. The stabilizing surface 16 is pivotable about a pivot axis S and rotatable about an axis of rotation D using a suitable, preferably powerful, hydraulic positioning device 18 including a drive journal 20. In the region of its root 22 the stabilizing surface 16 is connected to the drive journal 20, preferably in a straight-line manner. An angled attaching of the stabilizing surface 16 to the drive journal 20 by, for example, 15° or more is also possible in individual cases.

(5) Merely by way of example the ship 12 moves here through the water 26 in a preferred direction of the arrow 24. The stabilizing device 10 is activated when a speed v of the ship 12 through the water 26 is practically zero, or relatively low in relation to normal travel or cruising speed of the ship 12, which is synonymous with a speed v of up to 4 knots. In accordance with the preferred direction of travel through the water 26, the hull 14 of the ship 12 includes a bow 28 and a stern 30 advantageously formed in terms of fluid flow.

(6) The hull 14 of the ship 12 is in general configured mirror-symmetric with respect to a hull longitudinal axis 32, that is, in addition to the stabilizing device 10 only schematically depicted here the hull 14 of the ship 12 preferably includes a further starboard-side stabilizing device formed mirror-symmetric with respect to the stabilizing device 10, but not depicted in drawing. Here the term “starboard side” means rightward in the direction of travel of the ship 12, while “port side” means leftward in the direction of travel of the ship 12. In the normal operating state of the ship 12 at least the stabilizing surface 16 of the stabilizing device 10 is always located completely under water 26.

(7) Here the pivot axis S coincides merely by way of example with a vertical axis H (so-called yaw axis) of an orthogonal coordinate system 32 of the hull 14, the vertical axis H being oriented essentially parallel to the force of gravity F.sub.G when the hull is not heeling, i.e., is lying level in the water 26. Varying from this the pivot axis S of the stabilizing surface 16 can optionally extend at an angle (not illustrated) inclined up to 45° with respect to the vertical axis H of the rectangular coordinate system 32. The pivot movements of the stabilizing surface 16 by the positioning device 18 occur about the pivot axis S by a pivot angle +μ, while if necessary rotational movements or changes of an angle of attack γ of the stabilizing surface 16 are also performed about the axis of rotation D.

(8) Here the axis of rotation D extends, for example, parallel with respect to a leading edge 40 and a trailing edge 42 of the stabilizing surface 16. Varying from this a non-parallel course of the axis of rotation D is possible in relation to the leading edge 40 and/or the trailing edge 42 of the stabilizing surface 16. To provide an inflow nose 44 having a suitable, fluidically optimal profiling a first radius of curvature R.sub.1 of the leading edge 40 is dimensioned significantly larger than a radius of curvature R.sub.2 of the trailing edge 42.

(9) A receiving pocket 50 in the hull 14 serves for preferably complete receiving of the stabilizing surface 16 when the stabilizing device 10 is inactive. In this case the stabilizing surface 16 is located in the so-called rest position wherein the axis of rotation D extends approximately parallel to the hull longitudinal axis 32.

(10) A flow-edge-side inflow body 60 or filling body not co-rotating with respect to the axis of rotation D is disposed in the region of the drive journal 20; the inflow body 60 or filling body is oriented essentially parallel to the hull longitudinal axis 32. A cross-sectional geometry of the inflow body 60, not shown for the sake of a better drawing overview, essentially corresponds in a connecting region 62, at least with an angle of attack γ of approximately 0°, to an also not-shown cross-sectional geometry of the stabilizing surface 16.

(11) A central plane 72 of the stabilizing surface 16 is defined by the leading edge 40 and the trailing edge 42. Here by way of example the angle of attack between the central plane 72 and the horizontal 70 is +γ.

(12) As shown in FIG. 1, the stabilizing surface 16 is located in a first position 80, that is, the stabilizing surface 16 here is pivoted back about the pivot axis S by way of example as far as possible toward the stern 30 of the hull 14. Starting from the first position 80 the stabilizing surface 16 is pivoted by the positioning device 18 in a first pivot direction 82, here facing the bow 28, until the stabilizing surface 16 has assumed a central position 84 according to FIG. 2 and projects from the hull 14 approximately at right angles. Here by way of example the angle of attack +γ of the stabilizing surface 16 remains unchanged, but if required can also be changed using the positioning device 18. Due to the positive angle of attack +γ a hydrodynamic lifting force F.sub.H1 acts on the pivoting stabilizing surface 16, which force F.sub.H1 is oriented opposite the force of gravity F.sub.G. Due to the hydrodynamic lifting force a (tilting) moment is caused about the hull longitudinal axis 32 of the ship 12, which (tilting) moment is used by the stabilizing device 10 for the greatest possible compensation of the rolling movements of the ship 12 occurring primarily about the hull longitudinal axis 32.

(13) For this purpose the stabilizing device 10 includes a complex sensor system for detecting rolling-, pitching- and yawing-movement as well as the speed and further ship-relevant parameters in the water 26 in real time, on the basis of which a not-depicted efficient digital control- and/or regulating-device of the stabilizing device 10 controls the positioning device 16 such that in particular the undesirable rolling movements of the ship about the hull longitudinal axis 32 can be reduced as effectively as possible. Here a height of the hydrodynamic lifting force F.sub.H1 varies with the pivot speed of the stabilizing surface 16 or the relative speed between the stabilizing surface 16 and the water 26, and the angle of attack γ.

(14) FIG. 3 shows the stabilizing surface 16 in a second position 86 that is reached after a further pivoting of the stabilizing surface 16 by the pivoting device 18 about the pivot axis S by the angle +β toward the bow 28 or the first pivot direction 82.

(15) According to the disclosure the leading edge 40 of the stabilizing surface 16 is always oriented independently of the respective current pivot and incidence angle β, preferably always essentially toward the inflowing water 26, whereby the positioning device 10 is particularly energy efficient. Starting from the second position according to FIG. 3, by moving further in the first pivot direction 82 the stabilizing surface 16 reaches the rest position of the stabilizing surface 16, wherein in the ideal case the stabilizing surface 16 is received completely in the receiving space and such that it is terminally flush with the hull 14. In the rest position there is thus no significant change of the hydrodynamic properties of the hull 14 and in particular no relevant increase of the flow resistance.

(16) When the second position 86 is reached, using a positioning device 18 a reversal of the first pivot direction 82 is effected in a second pivot direction 90 that is oriented opposite to the first pivot direction 82, wherein the stabilizing surface 16 is preferably simultaneously rotated by approximately half a rotation or by an angle of rotation α of 180° about the axis of rotation D such that the stabilizing surface 16 assumes the further positions according to FIGS. 4 to 6. Varying from this, larger or smaller angles of rotation α of the stabilizing surface 16 about the axis of rotation D are also possible.

(17) Here a free end surface 96 of the stabilizing surface 16 is provided by way of example with a rib structure oriented parallel to the center plane 72 and not shown for the sake of drawing clarity; the rib structure includes a plurality of parallel ribs for minimizing, in particular for reducing, turbulences and eddies.

(18) FIGS. 4 to 6—which are referred to together in the further course of the description—illustrate a perspective view of the stabilizing surface of the stabilizing device in a second pivot direction, oriented opposite the first pivot direction according to FIGS. 1 to 3, in each of three different positions.

(19) The hull 14 of the ship 12 is in turn moved through the water again in the direction of the white arrow 24. In FIG. 4 the stabilizing surface 16 of the stabilizing device 10 is still located in the second position 86. However, in contrast to the position of FIG. 3, the stabilizing surface 16 is rotated about its axis of rotation D by approximately half a rotation or 180°, such that during subsequent further pivoting of the stabilizing surface 16 the leading edge 40 is optimally flowed-against by the surrounding water 26. This makes possible a considerable reduction of the energy demand of the stabilizing device 10.

(20) In addition, in contrast to FIGS. 1 to 3 there is, merely by way of example, an approximately constant angle of attack −γ here between the horizontal 70 and the central plane 72 of the stabilizing surface, whereby a hydrodynamic downthrust force F.sub.H2 oriented in the direction of the force of gravity F.sub.G is generated by the stabilizing surface 16 and serves for damping rolling movements of the hull 14 of the ship 12 about the hull longitudinal axis 32. The level of the hydrodynamic downthrust force F.sub.H2 is in turn dependent on the pivot speed of the stabilizing surface 16 or a relative speed resulting therefrom between the stabilizing surface and the water 26. Furthermore a speed v of the hull 14 of the ship 12 different from zero influences the downthrust force FH2 under certain circumstances. In the reversal points of the pivot movement of the stabilizing surface 16, that is, in the first and second position of the stabilizing surface 16, wherein preferably the rotation is also provided by the angle of rotation α of 180° or half the rotation about the axis of rotation D, the downthrust force F.sub.H2 can consequently become small.

(21) FIG. 5 illustrates the central position 84 of the stabilizing surface 16, wherein it is in turn oriented essentially at right angles to the hull 14 of the ship 12. Due to the further pivoting by the positioning device 18 of the stabilizing surface 16 toward the second pivot direction 90, the stabilizing surface 16 of the stabilizing device 10 ultimately reaches the first position 80 again according to FIG. 6.

(22) In the further course of the description the inventive method shall be briefly explained, again with reference to FIGS. 1 to 6.

(23) In a first method step a) with no heeling of the hull 14, the periodic pivoting of the at least one stabilizing surface 16, set at an angle of attack specified by a positioning device 18, is effected about the pivot axis S, essentially parallel to the force of gravity F.sub.G or the in the direction of the force of gravity, by the pivot angle of ±β up to reaching the first or the second position 80, 86. Here the central position 84 is cyclically traversed. With respect to the central position 84 of the stabilizing surface 16, the pivot angle β can be up to ±60°. A positive pivot angle +β defines a pivot movement about the pivot axis S in the clockwise direction, and a negative pivot angle −β a pivot movement about the pivot axis S in the counterclockwise direction, each as seen in plan view.

(24) According to the method a change of the angle of attack γ of the stabilizing surface 16 can be effected in a range of up to ±60° with respect to the horizontal 70 in the course of the oscillating pivot movements about the pivot axis S in the two pivot directions 82, 90.

(25) In a second method step b) during changing from the first to the second pivot direction 82, 90 and vice versa, i.e., in the respective reversal points of the pivot movement or when reaching one of the two positions 80, 86 of the stabilizing surface 16, a rotation of the stabilizing surface 16 is effected by the positioning device 18 by at least approximately half a rotation or by the angle of rotation α of 180° about the axis of rotation D of the stabilizing surface 16.

(26) Consequently the inflow nose 44 of the leading edge 40 is always acted upon by the surrounding water 26, whereby the energetic efficiency of the stabilizing device 10 is significantly increased in active roll-damping operation.

(27) According to FIGS. 1 to 6, according to the method, in active roll-damping operation the free end side 96 of the stabilizing surface 16, which free end side 96 is directed away from the drive journal 20 of the positioning device 18, follows a trajectory that approximately corresponds to a rectangle, or FIG. 8 on its side, or an infinity sign.

(28) Representative, non-limiting examples of the present invention were described above in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Furthermore, each of the additional features and teachings disclosed above may be utilized separately or in conjunction with other features and teachings to provide improved active stabilizing devices and methods.

(29) Moreover, combinations of features and steps disclosed in the above detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Furthermore, various features of the above-described representative examples, as well as the various independent and dependent claims below, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

(30) All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.

REFERENCE NUMBER LIST

(31) 10 Stabilizing device

(32) 12 Ship

(33) 14 Hull

(34) 16 Stabilizing surface

(35) 18 Positioning device

(36) 20 Drive journal

(37) 22 Root (stabilizing surface)

(38) 24 White arrow

(39) 26 Water

(40) 28 Bow

(41) 30 Stern

(42) 32 Hull longitudinal axis

(43) 40 Inflow edge

(44) 42 Outflow edge

(45) 44 Inflow nose

(46) 50 Receiving pocket

(47) 60 Inflow body

(48) 62 Connecting region

(49) 70 Horizontal

(50) 72 Central plane (stabilizing surface)

(51) 80 First position (stabilizing surface)

(52) 82 First pivot direction

(53) 84 Central position (stabilizing surface)

(54) 86 Second position (stabilizing surface)

(55) 90 Second pivot direction

(56) 96 Free end side (stabilizing surface)

(57) FH1 Hydrodynamic lifting force

(58) FH2 Hydrodynamic downthrust force

(59) FG Gravitational force

(60) H Vertical axis

(61) D Axis of rotation

(62) S Pivot axis

(63) α Angle of rotation (stabilizing surface)

(64) β Pivot angle (stabilizing surface)

(65) γ Angle of attack (stabilizing surface)

(66) R1 First radius of curvature

(67) R2 Second radius of curvature

(68) v Speed (watercraft, ship)