WATERCRAFT COMPRISING A POSITIONING SYSTEM

Abstract

A watercraft includes a positioning system having a controller and at least two stationary mounted propulsion units that are stationary with respect to the watercraft for generating a forward and backward thrust with respect to the respective propulsion unit in a respectively fixed direction with respect to the watercraft. The controller is arranged for individually controlling the thrust generated by each of the two propulsion units for moving and steering the watercraft.

Claims

1. A watercraft comprising: a positioning system comprising a controller and at least two stationary mounted propulsion units that are stationary with respect to the watercraft for generating a forward and backward thrust with respect to the respective propulsion unit in a respectively fixed direction with respect to the watercraft; wherein the controller is arranged for individually controlling the thrust generated by each of the two propulsion units for moving and steering the watercraft, wherein the watercraft is arranged to be steered exclusively by the stationary mounted propulsion units, and wherein the watercraft does not comprise a rudder for steering.

2. The watercraft according to claim 1, wherein the watercraft is an autonomously operated vessel.

3. The watercraft according to claim 1, wherein at least one of the stationary mounted propulsion units is directed such that the respective forward and backward thrusts generate respective moments around the centre of gravity of the watercraft.

4. The watercraft according to claim 1, wherein the two stationary mounted propulsion units are mounted on opposite sides of the centre of gravity of the watercraft.

5. The watercraft according to claim 1, wherein the two stationary mounted propulsion units are arranged mirror symmetric with respect to a line of mirror symmetry of the watercraft.

6. The watercraft according to claim 1, wherein the two stationary mounted propulsion units are arranged at an angle with respect to each other.

7. The watercraft according to claim 1, wherein the respective fixed directions of the two stationary mounted propulsion units are such that the largest part of the respective generated thrusts is in a direction that is substantially parallel to a virtual centre line of the watercraft running from bow to stern.

8. The watercraft according to claim 1, wherein the positioning system comprises a third stationary mounted propulsion unit that is arranged for generating a forward and backward thrust with respect to said propulsion unit, and wherein the third stationary mounted propulsion unit is fixed at an angle with respect to a virtual centre line of the watercraft running from bow to stern, such that the largest part of the respective thrust is in in a direction that is substantially perpendicular to the virtual centre line.

9. The watercraft according to claim 8, wherein the forward direction and sideward direction span a two dimensional plane of movement of the watercraft and the controller is arranged for individually controlling the thrusts of the stationary mounted propulsion units, such that the positioning system is arranged to generate a resultant thrust in any direction of the two dimensional plane.

10. The watercraft according to claim 1, wherein at least one of the stationary mounted propulsion units is, as seen in the direction towards the centre of gravity, arranged at an outward angle towards the nearest of the starboard and port side of the watercraft.

11. The watercraft according to claim 1, wherein at least one stationary mounted propulsion unit is arranged between a central point, such as the centre of gravity, of the watercraft and the bow of the watercraft, and wherein at least one stationary mounted propulsion unit is arranged between central point of the watercraft and the stern of the watercraft.

12. The watercraft according to claim 4, wherein the two stationary mounted propulsion units are arranged on one side of the watercraft with respect to the central point, as seen in the surge direction, and wherein the third stationary mounted propulsion unit is mounted at the other side of the watercraft with respect to the central point, as seen in the surge direction.

13. The watercraft according to claim 1, comprising a position sensor system, wherein the position sensor system is arranged for determining a dynamic position of the watercraft and is connected to the controller that is arranged for controlling the stationary mounted propulsion units on the basis of the measured dynamic position.

14. The watercraft according to claim 0, comprising a position sensor system, wherein the position sensor system is arranged for determining a dynamic position of the watercraft and is connected to the controller that is arranged for controlling the stationary mounted propulsion units on the basis of the measured dynamic position; wherein the controller is arranged for maintaining a predetermined position of the watercraft by individually controlling the thrusts generated by the respective stationary mounted propulsion units.

15. The watercraft according to claim 130, wherein the position sensor system is arranged for determining an actual orientation and actual position of the watercraft and wherein said sensor system comprises at least one position sensor, such as a GPS, Galileo or similar sensor.

16. The watercraft according to claim 1, wherein a propulsion unit comprises a propeller and an electrical motor for driving the propeller.

17. The watercraft according to claim 16, wherein the propeller and the electrical motor of at least one propulsion unit are arranged in a propulsion unit housing having a connection section for fixedly connecting the propulsion unit housing to a hull of the watercraft.

18. A method of controlling a watercraft according to claim 1, wherein the method comprises: determining planned movement of the watercraft; determining a required resultant thrust for achieving the planned movement; determining a required individual thrust of the respective stationary mounted propulsion units for obtaining the required resultant thrust; and driving the stationary mounted propulsion to deliver the required individual thrust of the respective stationary mounted propulsion units.

19. The method of controlling a watercraft according to claim 18, wherein the method further comprises: providing a target position of the watercraft; determining an actual position and/or rate of change of the actual position of the watercraft; and determining the planned movement of the watercraft on the basis of the target position of the watercraft and the actual position and/or rate of change of the actual position of the watercraft.

20. A positioning system for use in a watercraft according to claim 1.

Description

[0032] The present invention is further illustrated by the following figures, which show preferred embodiments of the watercraft, the method and the positioning system, and are not intended to limit the scope of the invention in any way, wherein:

[0033] FIG. 1 shows a 3D perspective of a first embodiment of the watercraft having three stationary mounted propulsion units.

[0034] FIG. 2 shows a schematic top-view of the first embodiment of the watercraft.

[0035] FIG. 3 shows a schematic bottom view of the first embodiment of the watercraft, wherein the arrangement of the stationary mounted propulsion units is of particular interest.

[0036] FIG. 4 shows a schematic side view of the first embodiment of the watercraft.

[0037] FIG. 5 shows a schematic bottom view of a second embodiment of the watercraft having an alternative arrangement of the stationary mounted propulsion units.

[0038] FIG. 6 shows a schematic bottom view of a third embodiment of the watercraft having yet another alternative arrangement of two stationary mounted propulsion units.

[0039] FIG. 7 shows a schematic bottom view of a fourth embodiment of the watercraft having a further alternative arrangement of two stationary mounted propulsion units.

[0040] FIG. 8 shows a schematic bottom view of a fifth embodiment of the watercraft having again a different arrangement of two stationary mounted propulsion units.

[0041] FIG. 1 shows a 3D perspective of a watercraft 1 having three stationary mounted propulsion units 4, 5, 6. The watercraft, also shown in FIGS. 2-4, is in the current embodiment a relatively small vessel 1 of approximately 2.5 m in length. The vessel 1 has a hull 2 that can be made from any suitable material, such as steel, aluminium, plastics and/or fibre-reinforced materials. A first hull mounted propulsion unit 5 is arranged for generating thrust in the forward and backward sailing directions I. A second hull mounted propulsion unit 6 (see FIGS. 3 and 4) is arranged on the other side of the vessel 1. The first and second hull mounted propulsion units 5, 6 are arranged near the stern 22 of the vessel 1. A third bow mounted propulsion unit 4 is arranged in a through hole 41 that is arranged through the hull 2 near the bow 21. The third bow mounted propulsion unit 4 is arranged to generate a thrust in the sideways directions II corresponding to the sway motion of the vessel 1, that is substantially perpendicular to the forward sailing direction I that is parallel to the surge motion of the vessel 1. The propulsion units 4, 5, 6 are thus stationary with respect to the watercraft for generating a forward and backward thrust with respect to the respective propulsion unit 4, 5, 6 in a respectively fixed direction with respect to the watercraft 1.

[0042] Also arranged near the stern 22 and the first and second hull mounted propulsion units 5, 6 are protective fins 23 that are also designed to be load bearing and to support the vessel 1 when placed on the ground, preventing damage to the first and second hull mounted propulsion units 5, 6.

[0043] The deck 3 of the vessel 1 comprises multiple bays 34 for batteries and the controller and/or additional payloads. These bays can be closed off using watertight hatches 35 for protecting the contents of the bays 34. Furthermore, a number of hoisting points 32 are provided on the deck 3 for hoisting the vessel 1 from, and into, the water. To allow for easily charging of the batteries, a charging socket 33 is provided on the deck 3.

[0044] An adjustable bridge 7 is provided wherein on the bridge sensor bracket 75 is provided for supporting a number of different sensors and/or sensor antenna's, such as GPS antenna's 71, a camera system 73 for remotely viewing the surroundings of the vessel 1. Furthermore, navigation lights 72 can be provided for low-visibility conditions. The bridge sensor bracket 75 is lockable at a number of different heights in order to obtain the best signal or view for the sensors, while allowing to pass underneath low structures, or for folding the bridge 7 to the deck 3 when transporting the vessel 1. The adjustment system of the adjustable bridge 7 comprises parallel arranged beams 74 that are mounted to the deck 3 and lockable in position by means of the bridge coupling members 76.

[0045] FIG. 3 clearly shows the mirror symmetric setup of the positioning system with respect to the mirror symmetry line III. As described above, the third, bow mounted propulsion unit 4 is arranged to generate a thrust in the sideways directions II, as is indicated by the large arrows, whereas the first and second hull mounted propulsion units 5, 6 are arranged for generating thrust in the sailing direction I, as is indicated by the large arrows. The thrust generated by the respective propulsion units 4, 5, 6 all have a respective moment arm a4, a5, a6 with respect to the centre of gravity CG of the vessel 1, such that a stand-still or close to stand-still, the vessel 1 can move independently in any direction (i.e. sway, surge and yaw) by individually controlling the thrust generated by the different propulsion units 4, 5, 6. Thereby, rudders or rotatable mounted propulsion units that can rotate the thrust in the plane defined by sway and surge are not required for maintaining the position of the vessel 1. In addition, when at speed, whereby the rotational point of the vessel 1 will typically move from the centre of gravity over the mirror symmetry line III, the vessel 1 can be regulated in speed and steered to port or starboard sides by individually controlling the thrust of the respective stationary mounted propulsion units 4, 5, 6, or even by only using and regulating the thrust of the first and second hull mounted propulsion units 5, 6. Hence, a highly manoeuvrable vessel 1 obtained that has a minimum of movable parts.

[0046] The bridge sensor 75 bracket on the bridge 7 for above water measurements and the moonpool bracket 8 for underwater measurements the system is sensor agnostic and can be equipped with different (user specific) sensors/equipment. This increases the adaptability and thereby deployability of the vessel 1 for different applications and environments.

[0047] FIG. 5 shows a schematic bottom view of a second embodiment of the watercraft 101 having an alternative arrangement of the stationary mounted propulsion units 104, 105, 106. The third forward mounted propulsion unit 104, for instance being the third bow mounted propulsion unit 4 according to the first embodiment. The first and second stationary mounted propulsion units 105, 106 are still arranged mirror symmetric with regards to the mirror symmetry line III, but are (as seen with respect to the mirror symmetry line) arranged at an outward angle α, such that the respective arms a105, a106 are increased with respect to the arrangement of the first embodiment. Hereby, the same amount of thrust leads to a larger moment around the centre of gravity CG, whereby this leads to an increase steering manoeuvrability of the vessel 1, i.e. increased response in the yaw direction ψ, at the cost of a slightly decreased energy efficiency when going straight in the surge direction I. This embodiment can move independently in any direction (i.e. surge I, sway II and yaw ψ) by individually controlling the thrust generated by the different propulsion units 104, 105, 106. Hereby, the required change of position can be effected.

[0048] FIG. 6 shows a schematic bottom view of a third embodiment of the watercraft 201 having yet another alternative arrangement of two stationary mounted propulsion units 205, 206. The third embodiment is equal to the second embodiment, with the difference that no third forward mounted propulsion unit 104 is provided. Hereby, the vessel 201 loses the ability to have a pure sideways (i.e. sway) displacement. Nonetheless, the vessel 201 is still able, by the use of only the two stationary mounted propulsion units 205, 206 to have pure rotations around the centre of gravity CG (i.e. pure yaw ψ), and a pure forward/backward movement (i.e. pure surge I). Hence, a vessel not requiring the stay on exactly the same position can be mounted with such a propulsion system.

[0049] FIG. 7 shows a schematic bottom view of a fourth embodiment of the watercraft having a further alternative arrangement of two stationary mounted propulsion units 305, 305. The difference with the third embodiment being the location of the two stationary mounted propulsion units 305, 306, and the effect of the generated thrusts on the steering properties of the vessel 1. By placing the two stationary mounted propulsion units 305, 306 symmetrically with respect to the mirror symmetry line III on a perpendicular line IV that is perpendicular to the mirror symmetry line III and that runs through the centre of gravity (and/or the rotation point) CG, sideways and sway movement can be achieved in addition to surge and sway movements.

[0050] FIG. 8 shows a schematic bottom view of a fifth embodiment of the watercraft 401 having again a different arrangement of two stationary mounted propulsion units 404, 405. Hereby, the first stationary mounted propulsion unit 405, that is mounted near the stern 422 of vessel 401 is arranged in the mirror symmetry line, i.e. central line III, such that the thrust is generated through the centre of gravity CG of the vessel 401 and thus no steering moment is generated for turning the vessel in the yaw direction ψ. The second stationary propulsion unit 404 that is mounted near the bow 421 is arranged for generating thrust in the sway direction II, thereby also (due to moment arm a404) generating a moment in the yaw direction ψ, and thus allow for steering the vessel 401.

[0051] The embodiment shown thus all do not require a rudder for manoeuvring the vessel in the water. It is noted that the present invention is not limited to the embodiment shown, but extends also to other embodiments falling within the scope of the appended claims.