Autopilot system for marine vessels

Abstract

An autopilot system for automatically steering a marine vessel is disclosed. The marine vessel comprises two electric motors connected to respective propulsors, two rudders, a rudder steering mechanism and a navigation system for determining the vessel position with respect to an intended course. The autopilot system can operate according to one or more autopilot modes comprising at least a motor steering autopilot mode wherein the autopilot system is configured to automatically control the rudder steering mechanism in order to lock the rudders at a fixed angle, and based on a feedback from the navigation system to independently and dynamically adjust power supply to each of the propulsors by independently and dynamically regulating electric power supply to the respective electric motors in order to maintain the vessel on course.

Claims

1. An autopilot system for automatically steering a marine vessel, the marine vessel comprising two electric motors respectively connected to a port side propulsor and to a starboard side propulsor, a port side rudder and a starboard side rudder and a rudder steering mechanism, a navigation system for determining the vessel position with respect to an intended course, wherein the autopilot system is configured to operate according to one or more autopilot modes, comprising at least a motor steering autopilot mode wherein the autopilot system automatically controls the rudder steering mechanism in order to lock the rudders at a fixed angle at which the rudders cause the least resistance, and based on a feedback from the navigation system to independently and dynamically adjust power supply to each of the port side propulsor and of the starboard side propulsor by independently and dynamically regulating electric power supply to the respective electric motors order to maintain the vessel on course, thereby reducing power consumption at a certain vessel velocity or increasing vessel velocity at a certain power consumption in the motor steering autopilot mode, while preserving the option to use the rudder steering mechanism for direction control at least in manual mode or other situations.

2. The autopilot system according to claim 1 wherein the autopilot system is configured to maintain a constant average vessel velocity and/or a constant average total electric power consumption.

3. The autopilot system according to claim 1 wherein the fixed angle is an angle at which the rudders parallel to a longitudinal axis of the vessel or bow heading or is an angle at which the rudders are parallel to the intended course.

4. The autopilot system according to claim 3 wherein the fixed angle is an angle at which the rudders are parallel to the longitudinal axis of the vessel or bow heading if the rudders are located aft with respect to the propulsors respectively and/or if the vessel comprises a port side keel and a starboard side keel aligned with the respective rudders and propulsors.

5. The autopilot system according to claim 3 wherein the fixed angle is an angle at which the rudders are parallel to the intended course if the rudders are located forward with respect to the propulsors respectively.

6. The autopilot system according to claim 1 wherein the fixed angle is an empirically determined angle at which effective average total electric power consumption is minimum at a certain vessel velocity for the intended course.

7. The autopilot system according to claim 1 wherein the autopilot system is responsive to a manual change of vessel velocity and/or manual change of course by re-adjusting the power supply to each of the port side propulsor and of the starboard side propulsor, while maintaining the rudders angle fixed.

8. The autopilot system according to claim 1 wherein the dynamic power adjustment is further based on any one or more actual data from any one or more additional sensors or data sources, the data including any one or more of wind direction, water current direction, wave direction, swell, depth, yaw, pitch, roll.

9. The autopilot system according to claim 1 wherein the autopilot system comprises an autopilot mode selection function and is further configured to operate according to one or more additional autopilot modes selected from a rudder steering autopilot mode and a hybrid steering autopilot mode.

10. The autopilot system according to claim 9 wherein according to the rudder steering autopilot mode the autopilot system is configured to maintain the electric power supply to each of the electric motors constant and to automatically and dynamically control the rudder steering mechanism in order to maintain the vessel course, and wherein according to the hybrid steering autopilot mode the autopilot system is configured to independently and dynamically regulate electric power supply to the respective electric motors and also to automatically and dynamically control the rudder steering mechanism in order to maintain the vessel on course.

11. The autopilot system according to claim 10 wherein the electric power supply to both electric motors is the same in the rudder steering autopilot mode.

12. The autopilot system according to claim 1 wherein manual control of the rudder steering mechanism is disabled when the autopilot system is activated and enabled as soon as the autopilot system is deactivated.

13. A marine vessel comprising two independently controllable electric motors respectively connected to a port side propulsor and to a starboard side propulsor, a port side rudder and a starboard side rudder and a rudder steering mechanism, a navigation system for determining the vessel position with respect to an intended course, and an autopilot system for automatically steering the marine vessel according to claim 1.

14. The marine vessel according to claim 13 further comprising a throttle mechanism comprising two independent handles for individual manual control of electric power supply to each electric motor respectively, wherein individual manual control of electric power supply to each electric motor is disabled when the autopilot system is activated.

15. The marine vessel according to claim 13 further comprising a rechargeable battery pack as electric power supply for the electric motors and at least one renewable energy source for recharging the battery pack.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 shows schematically a marine vessel comprising an autopilot system in a first autopilot mode.

[0042] FIG. 2 shows schematically the same marine vessel of [FIG. 1] with the autopilot system in a second autopilot mode.

[0043] FIG. 3 shows schematically the same marine vessel of [FIG. 1] and [FIG. 2] with the autopilot system in a third autopilot mode.

[0044] FIG. 4 shows schematically the same marine vessel of [FIG. 1] with the autopilot system in the first autopilot mode, but according to a different embodiment.

[0045] FIG. 5 shows schematically a variant of the marine vessel of [FIG. 1] with the autopilot system in the same first autopilot mode as in [FIG. 1], but configured in a different manner.

[0046] Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements whereas other elements may have been left out or represented in a reduced number in order to enhance clarity and improve understanding of the embodiments of the present disclosure.

DETAILED DESCRIPTION

[0047] FIG. 1 shows schematically a marine vessel 200 and in particular a catamaran with a port side hull 201 and a starboard side hull 202, comprising a port side electric motor 11 and a starboard side electric motor 12, respectively connected to a port side propeller 21 and to a starboard side propeller 22 via respective propeller shafts 23, 24, a rechargeable battery pack 210 as electric power supply for the electric motors 11, 12 and a photovoltaic system 220 as renewable energy source for recharging the battery pack 210. The marine vessel 200 may optionally comprise a port side keel 203 and a starboard side keel 204, e.g. in some cases when the marine vessel 200 is a sailing vessel. In particular, the marine vessel 200 comprises a vessel steering system 100 comprising a port side rudder 31 and a starboard side rudder 32 connected to each other, so that they can be deflected simultaneously with the same angle, and a rudder steering mechanism 30 comprising a steering wheel 33, a rudder control unit 34 connected to one or more rudder drive units 36 and at least one rudder angle feedback sensor 35. The vessel steering system 100 further comprises a navigation system 40 for determining the vessel position 41 with respect to an intended course 42. The vessel steering system 100 further comprises an autopilot system 50 for automatically steering the marine vessel 200 configured to operate according to one or more autopilot modes 51, 52, 53, eventually comprising an autopilot mode selection function to select between any of the autopilot modes 51, 52, 53. The autopilot system 50 comprises at least a motor steering autopilot mode 51 where the autopilot system 50 is configured to automatically control the rudder steering mechanism 30 in order to lock the rudders 31, 32 at a fixed angle, and based on a feedback from the navigation system 40 to independently and dynamically adjust power supply 15, 16 to each of the port side propeller 21 and of the starboard side propeller 22 respectively by independently and dynamically regulating electric power supply 15, 16 to the respective electric motors 11, 12 via respective motor control units 13, 14 in order to maintain the vessel 200 on course 42. In particular, the autopilot system 50 in the motor steering autopilot mode 51 is configured to dynamically correct the bow heading 43 in order to counteract the actual lateral forces 44 acting on the vessel 200 as the vessel position 41 advances and to maintain the vessel 200 on the intended course 42 by independently and dynamically adjusting the electric power supply 15, 16 to each of the port side motor 11 and starboard side motor 12, while maintaining the angle of the rudders 31, 32 fixed with respect to the bow heading 43. The port side rudder 31 and the starboard side rudder 32 are in this example located aft with respect to the port side propeller 21 and to the starboard side propeller 22 respectively. According to this embodiment, the fixed rudder angle is an angle at which the rudders 31, 32 are parallel to the longitudinal axis of the vessel 200 that is in line with the bow heading 43.

[0048] The autopilot system 50 may be configured to maintain a constant average vessel velocity or a constant average total electric power consumption 15, 16 or to provide an option to select between the two.

[0049] According to an embodiment, the dynamic electric power adjustment 15, 16 is further based on any one or more actual data from any one or more additional sensors 60 or data sources, the data including any one or more of wind direction, water current direction, wave direction, swell, depth, yaw, pitch, roll.

[0050] The autopilot system 50 in the motor steering autopilot mode 51 is responsive to a manual change of vessel velocity and/or manual change of course 42 by re-adjusting the electric power supply 15, 16 to each of the port side propeller 21 and of the starboard side propeller 22, while maintaining the rudders angle fixed. A manual change of course 42 may be enabled e.g. by digital control units 71, the pressing of which may result in a change of the bow heading 43 either towards left or towards right, e.g. stepwise in steps of 1 degree, 5 degrees, 10 degrees. Similarly, digital control units 72, the pressing of which may result in a manual change of vessel velocity, e.g. by a stepwise increase or decrease of vessel velocity, may be used.

[0051] The vessel steering system 100 further comprises a throttle mechanism 80 comprising two independent handles 81, 82 for individual manual control of electric power supply 15, 16 to each electric motor 11, 12 respectively, where individual manual control of electric power supply 15, 16 to each electric motor 11, 12 is disabled when the autopilot system 50 is activated, at least in the motor steering autopilot mode 51. In particular, when the autopilot system 50 is activated, only manual control of vessel velocity either via digital control units 72 or by synchronous actuation of the throttle mechanism 80 is enabled. Also, manual control of the steering wheel 33 is disabled when the autopilot system 50 is activated. In general, manual control of the rudder steering mechanism 30 is disabled when the autopilot system 50 is activated, in any autopilot mode, and enabled as soon as the autopilot system 50 is deactivated.

[0052] [FIG. 2] shows schematically the same marine vessel 200 of [FIG. 1], where the autopilot system 50 comprises an autopilot mode selection function and is further configured to operate according to an additional rudder steering autopilot mode 52 and where this has been selected. According to the rudder steering autopilot mode 52 the autopilot system 50 is configured to maintain the electric power supply 15, 16 to each of the electric motors 11, 12 constant and to automatically and dynamically control the rudder steering mechanism 30, by dynamically adjusting the rudders angle ? with respect to the longitudinal axis of the vessel or bow heading 43, thus correcting the bow heading 43 in order to counteract the actual lateral forces 44 acting on the vessel 200 as the vessel position 41 advances and to maintain the vessel 200 on the intended course 42. In this example, the electric power supply 15, 16 to both electric motors 11, 12 is the same, but it may be respectively different, although constant, in other cases.

[0053] [FIG. 3] shows schematically the same marine vessel 200 of [FIG. 1] and [FIG. 2], where the autopilot system 50 comprises an autopilot mode selection function and is further configured to operate according to an additional hybrid steering autopilot mode 53 and where this has been selected. According to the hybrid steering autopilot mode 53 the autopilot system 50 is configured to independently and dynamically regulate power supply 15, 16 to each of the electric motors 11, 12 respectively, and also to automatically and dynamically control the rudder steering mechanism 30 by dynamically adjusting the rudders angle ? with respect to the longitudinal axis of the vessel or bow heading 43, thus correcting the bow heading 43, by the combined action of electric power control and rudder angle control, in order to counteract the actual lateral forces 44 acting on the vessel 200 as the vessel position 41 advances and to maintain the vessel 200 on the intended course 42.

[0054] [FIG. 4] shows the same vessel 200 of [FIG. 1] in the motor steering autopilot mode 51, where the rudder angle is fixed, with the difference that according to this embodiment, the fixed rudder angle is an empirically determined angle ? at which effective average total electric power consumption 15, 16 is minimum at a certain vessel velocity for the intended course 42. The angle ? remains fixed at least until a willful change of vessel velocity or change of intended course 42 occurs or if the total electric power consumption 15, 16 significantly changes along the course 42, in which case a new angle ? may be determined and fixed.

[0055] [FIG. 5] shows a marine vessel 200 that is a variant of the marine vessel 200 of [FIG. 1]-4, where the rudders 31, 32 are located forward with respect to the propulsors 21, 22 respectively. This configuration may be more typical in case of the electric motors 11, 12 being connected to the respective propulsors 21, 22 via e.g. a saildrive transmission system comprising a vertical intermediate shaft extending downward through the respective hulls 201, 202 that connects to propeller shafts 23, 24 respectively. The autopilot system 50 is in the motor steering autopilot mode 51. According to this embodiment, the fixed rudder angle is an angle ? at which the rudders 31, 32 are parallel to the intended course 42, the angle ? remaining fixed as long as the intended course 42 remains fixed. Of course, the autopilot system 50 may be configured to operate according to any of the other autopilot modes 52, 53 or according to different embodiments of the autopilot mode 51, as described above, also in connection to this variant of the marine vessel 200.

[0056] In the preceding specification, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one having ordinary skill in the art that the specific detail need not be employed to practice the present teaching. In other instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present disclosure.

[0057] Particularly, modifications and variations of the disclosed embodiments are certainly possible in light of the above description. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically devised in the above examples.

[0058] Reference throughout the preceding specification to one embodiment, an embodiment, one example or an example, means that a particular feature, structure or characteristic described in connection with the embodiment or example is included in at least one embodiment. Thus, appearances of the phrases in one embodiment, in an embodiment, one example or an example, in various places throughout this specification are not necessarily all referring to the same embodiment or example.

[0059] Furthermore, the particular features, structures, or characteristics may be combined in any suitable combinations and/or sub-combinations in one or more embodiments or examples.