Wind propulsion system and marine vessel and method

Abstract

The disclosure concerns a wind propulsion system (4) for a marine vessel (2). The system (4) comprises a wingsail (6) having a leading edge (14) extending along a spanwise extension (S) of the wingsail (6), a base (8), an actuator arrangement (18), a detector arrangement (24), and a control arrangement (26). The actuator arrangement (18) is configured to move at least a portion of the wingsail (6) in relation to the base (8). The detector arrangement (24) is configured for determining at least a first wind direction at a first position (I) around or in front of the leading edge (14) and a second wind direction at a second position (II) around or in front of the leading edge (14). The control arrangement (26) is configured to control the actuator arrangement (18) based on at least the first and second wind directions.

Description

[0001] Wind Propulsion System and Marine Vessel and Method

[0002] TECHNICAL FIELD

[0003] The disclosure relates to a wind propulsion system for a marine vessel and to a marine vessel comprising a wind propulsion system. The disclosure further relates to a method for controlling a wind propulsion system for a marine vessel.

[0004] BACKGROUND

[0005] Sails have been known for a long time as means for propelling ships. Traditionally, flexible sails made from fabric have been mounted on masts to harness the power of wind and propel the ship.

[0006] Modern marine vessels commonly use fossil fuels and combustion engines to propel the vessel. Recently, wind propulsion systems for marine vessels have been recognised as a promising technology to reduce reliance on fossil fuels and mitigate the environmental impact of maritime transportation. Among these systems, those featuring wingsails have garnered attention due to their potential to provide efficient and sustainable propulsion.

[0007] To maximize the performance of a wingsail, or otherwise control its performance, it is essential to trim it according to the current wind inflow. A wingsail may be utilised in conjunction with an automated trimming algorithm. One widely used metric for achieving this alignment is the angle of attack, AoA, which represents the angle between a chordline of the wingsail and the incoming airflow. However, it is important to note that the AoA is not uniform along the span of the wingsail. Various factors can cause local variations in the AoA, making it necessary to consider these differences when designing an automated trimming algorithm.

[0008] US 11029323 discloses a sailing ship comprising an aerodynamic profile and a system for determining characteristics of an airflow incident on a leading edge of the aerodynamic profile. In order to be able to determine with precision the location of the stagnation-point at different zones along the leading edge of an aerodynamic profile, a system comprises rows of pressure sensors distributed on either side of the leading edge and forming, virtually, patterns that are spaced apart from one another in the form of simple polygonal lines, and a computer connected to the pressure sensors. The computer determines, along each of the patterns, a respective stagnation-point position that is defined by a curved abscissa for which a pressure interpolated on the basis of pressure measurements provided by the pressure sensors of the corresponding row is at a maximum, and by an altitude evaluated on the basis of respective altitude data from the pressure sensors of the corresponding row. SUMMARY

[0009] While the configurations of US11029323 have shown promise in measuring aerodynamic forces generated at the leading edge of an aerofoil shaped body, they also introduce potential drawbacks. Specifically, mounting onto, or integrating pressure sensors into an aerofoil-shaped body can affect its aerodynamic properties, potentially compromising overall performance of the aerofoil shaped body.

[0010] In light of these limitations, there remains a need for a wind propulsion system comprising a wingsail, which system can accurately sense the local angle of attack variations along a wingspan of the wingsail and provide conditions for wingsail trimming, accordingly. The present disclosure aims to address this challenge by providing a novel solution that overcomes the shortcomings of the and US 11029323 approaches while achieving improved performance and efficiency in marine vessels equipped with at least one wingsail.

[0011] To better address one or more of these concerns, one or more of a wind propulsion system, a marine vessel, and a method for controlling a wind propulsion system having the features defined in one or more of the independent claims is provided.

[0012] According to an aspect, there is provided a wind propulsion system for a marine vessel, the wind propulsion system comprising a wingsail having a leading edge extending along a spanwise extension of the wingsail, a base, an actuator arrangement, a detector arrangement, and a control arrangement. The wingsail is connected to the base. The actuator arrangement is configured to move at least a portion of the wingsail in relation to the base. The detector arrangement is configured for determining at least a first flow or wind direction at a first position in front of the leading edge and / or around the leading edge, and a second wind direction at a second position in front of the leading edge and / or around the leading edge, the first and second positions being arranged at a distance from each other along the spanwise extension. The control arrangement is configured to control the actuator arrangement based on at least the first and second wind directions.

[0013] Since the detector arrangement is configured for determining at least the first wind direction at the first position in front of the leading edge and the second wind direction at the second position in front of the leading edge and since the control arrangement is configured to control the actuator arrangement based on at least the first and second wind directions - the wind propulsion system is configured to accurately sense the wind direction at two or more positions spaced from each other spanwise. Alternatively, or additionally, the flow direction or wind direction may be determined around the leading edge of the wingsail. For example, flow sensors of the type flow sensing tabs may be used. The sensors can be arranged in a chordwise direction around the leading edge of the wingsail. Such flow sensing tabs allow for a determination of flow direction. By the flow sensing tabs, there is also a possibility to define flow rate (wind speed). Thus, local variations in the direction of the wind along the wingspan of the wingsail, and accordingly, the local angle of attack, AoA, and variations along the spanwise extension of the wingsail are considered by the control arrangement for accurately controlling the actuator arrangement to move at least a portion of the wingsail in relation to the base e.g., for trimming of the wingsail.

[0014] When the detector arrangement determines the first and second wind directions in front of the leading edge of the wingsail, such as by lidar, airflow chordwise along the wingsail remains undisturbed by the detector arrangement, which means that optimal operating conditions are provided for the wingsail.

[0015] According to a further aspect, there is provided a marine vessel comprising a wind propulsion system according to any one of aspect and / or examples discussed herein.

[0016] Accordingly, as mentioned above, local variations in the direction of the wind, and accordingly, the local AoA and variations thereof along the wingspan of the wingsail are considered by the control arrangement for controlling the actuator arrangement to move at least a portion of the wingsail and this so, without disturbing chordwise airflow over the wingsail.

[0017] According to a further aspect, there is provided a method for controlling a wind propulsion system for a marine vessel, the wind propulsion system comprising a wingsail having a leading edge extending along a spanwise extension of the wingsail. The method comprises steps of:

[0018] - detecting a first wind direction at a first position around or in front of the leading edge,

[0019] - detecting a second wind direction at a second position around or in front of the leading edge, the first and second positions being arranged at a distance from each other along the spanwise extension, and

[0020] - controlling an actuator arrangement of the wind propulsion system based on at least the first and second wind directions. Since the method comprises the steps of: detecting the first wind direction at the first position around or in front of the leading edge, detecting the second wind direction at the second position around or in front of the leading edge, and controlling the actuator arrangement of the wind propulsion system based on at least the first and second wind directions - the method allows an accurate control of the wind propulsion system based on the wind direction at two or more positions of the wingsail spaced from each other spanwise, without disturbing airflow chordwise along the wingsail.

[0021] The wind propulsion system is configured for at least contributing to the propulsion of a marine vessel, on which the wind propulsion system is mounted. The marine vessel may be a vessel used in seabound commercial transport of goods and / or passengers. However, the marine vessel may alternatively be a leisure yacht.

[0022] The wind propulsion system may herein alternatively be referred to as the propulsion system.

[0023] The wingsail of the wind propulsion system forms a rigid and controllable structure configured for engagement with wind in order to thus, propel the marine vessel.

[0024] At least a portion of the wingsail is moveable in relation to the base by the actuator arrangement. The base is configured for being arranged at a structure of the marine vessel. Accordingly, when installed in a marine vessel, at least a portion of the wingsail is moveable in relation to the marine vessel. For instance, a portion of the wingsail is moveable in relation to the marine vessel for trimming the wingsail to efficiently produce propulsive power.

[0025] For instance, the actuator arrangement may comprise one or more hydraulic and / or electric actuators for moving at least a portion of the wingsail.

[0026] The base being configured to be arranged at a deck structure of a marine vessel means that the base is configured for securing the wingsail directly to a deck of the marine vessel or indirectly to the deck, such as above or adjacent to the deck via e.g., a superstructure, a dedicated built-up structure, or similar structure of the marine vessel. The deck or the superstructure or the dedicated built-up structure may be reenforced specifically to withstand stress that the base and / or the wingsail may subject the deck and / or superstructure and / or dedicated built-up structure to during use of the wind propulsion system. Thus, propulsive power produced by the wingsail is transferred to the marine vessel via the base in order to at least contribute to the propulsion of the marine vessel. Accordingly, the wingsail being connected to the base means that the wingsail is connected, directly or indirectly, to a portion of the base, such as to an upper portion of the base. A lower portion of the base is connected to the deck of the marine vessel, either directly or indirectly as discussed above via a structure. For instance, such a structure may be configured to elevate the wingsail, i.e. the wind engagement unit, a distance above the deck of the marine vessel.

[0027] The at least one portion of the wingsail that is moveable in relation to the base by the actuator arrangement may be e.g., a movable portion of the wingsail configured for controlling a direction and / or a magnitude of a propulsive force produced by the wingsail and / or may be the wingsail as a whole, which may be pivotable in relation to the base.

[0028] The wingsail may comprise a main wingsail having an aerofoil shape and a flap having an aerofoil shape. An actuator of the actuator arrangement may control a position of the main wingsail in relation to the base and / or a position of the flap in relation to the main wingsail.

[0029] An actuator of the actuator arrangement may control one or more controllable aspects of the wingsail, such as an angular position of the wingsail in relation to the base thus, the direction at which wind meets a leading edge portion of the wingsail, i.e. the AoA of the wingsail and the stagnation-point of the airflow around the aerofoil of the wingsail may be controlled.

[0030] The terms span and spanwise relate to a lengthwise extension / direction of the wingsail i.e., including mainly a vertical component when the wingsail is installed on a marine vessel. The terms chord and chordwise relate to an extension / direction between the leading edge and a trailing edge of the wingsail i.e., in parallel with an airflow over the aerofoil of the wingsail, and including mainly a horizontal component when the wingsail is installed in a marine vessel. A chordline of the aerofoil of the wingsail is a straight line from the leading edge to the trailing edge of the wingsail. A camber of the aerofoil of the wingsail is a measure of the curvature of a mean line. The mean line, also called camberline, is the locus of points equidistant from the opposite surfaces of the aerofoil. The Angle of Attack, AoA, is an angle between the chordline and the wind direction blowing against the aerofoil. The stagnationpoint of the aerofoil is that point where the flow along the aerofoil is zero. When the aerofoil points with the leading edge straight against the wind, i.e. when the AoA = 0 degrees, the stagnation-point is at the tip of the leading edge. When the AoA 0 degrees, the stagnationpoint has moved away from the leading edge along the aerofoil of the wingsail towards the trailing edge. In case of the wingsail comprising a main wingsail and a flap, the aerofoil of the wingsail is formed collectively by the main wingsail and the flap. The detector arrangement may be any suitable detector arrangement for determining wind directions in front of the leading edge of the wingsail. The detector arrangement may determine wind direction by measuring the flow around the leading edge of the wingsail, suitably around the leading edge in chordwise direction.

[0031] The detector arrangement is configured for determining at least the first and second wind directions at spaced apart first and second positions. Namely, the wind direction and / or the wind speed may differ at different positions of the wingsail e.g., due to proximity of structures at the deck of the vessel, the distance from the deck of the vessel, the distance from the water level, etc.

[0032] The detector arrangement may be configured for determining more than two wind directions at spaced apart positions, such as at 3 - 20 different positions along the spanwise extension of the wingsail.

[0033] The detector arrangement may determine wind directions with respect to a frame of reference related to the wingsail, i.e. in a coordinate system related to the wingsail, such as a coordinate system including the chordline of the wingsail. Alternatively, or additionally, the detector arrangement may determine wind directions with respect to a frame of reference related to the marine vessel, i.e. in a coordinate system related to the marine vessel, such as a coordinate system including a bow - stern extension of the vessel and a port - starboard extension of the vessel. In the latter case, e.g., the control arrangement may be configured to recalculate the determined wind directions to a frame of reference related to the wingsail e.g. determining a local AoA at at least each of the first and second positions along the spanwise extension of the wingsail. The detector arrangement may according to a variant determine the flow and the direction of the flow (wind) and possibly the flow rate (wind speed).

[0034] The control arrangement is connected to the detector arrangement for receiving detector data therefrom. The detector data includes at least the first and second wind directions and may include further wind data such as wind speed. The control arrangement is connected to the actuator arrangement for controlling at least one actuator of the actuator arrangement. The control arrangement is configured to control the at least one actuator based on the detector data.

[0035] Since the control arrangement is configured to control the actuator arrangement based on at least the first and second wind directions, the control arrangement is configured to trim the wingsail based on at least the first and second wind directions. Thus, the control arrangement is able to contribute to efficient and safe propulsion of the marine vessel based on the first and second wind directions.

[0036] The control arrangement may be a dedicated control arrangement of the wind propulsion system and may be configured for communication with one or more control arrangements of the marine vessel. Alternatively, the control arrangement of the wind propulsion system may form part of a control arrangement of the marine vessel.

[0037] According to some examples, the detector arrangement may comprise at least a first anemometer arranged at the first position and a second anemometer arranged at the second position. Alternatively, or additionally, the detector arrangement may comprise a wind lidar configured to determine at least the first wind direction at the first position and the second wind direction at the second position. In this manner, the detector arrangement may be implemented in the propulsion system.

[0038] By incorporating at least the first and second anemometers at respective positions along the leading edge of the wingsail, the detector arrangement may provide precise measurements of wind direction and optionally other wind data such as e.g., wind speed. This enables the control arrangement to make informed decisions about wingsail trimming, resulting in improved overall performance and efficiency of the propulsion system. The first anemometer may be arranged on a first holding member extending from the wingsail to the first position in front of the leading edge, and wherein the second anemometer may be arranged on a second holding member extending from the wingsail to the second position in front of the leading edge.

[0039] The use of multiple anemometers allows for the detection of different wind directions along the leading edge of the wingsail, which may be taken into account by the control arrangement to control the actuator arrangement.

[0040] The wind lidar may be arranged below the wingsail with a detection zone directed upwardly in front of the leading edge. The lidar may be arranged to rotate with the wingsail. In this way it can be ensured that it always detects the wind direction in front of the leading edge of the wing. The use of a wind lidar (Light Detection and Ranging sensor) as such or in combination with one or more anemometers provides precise measurements of wind direction and optionally other data such as e.g., wind speed. This enables the control arrangement to make more informed decisions about wingsail trimming, resulting in improved overall performance and efficiency.

[0041] According to an alternative, the first and second positions are on the leading edge and the detector arrangement may comprise flow sensing tabs configured to determine wind direction and / or flow rate, the sensing tabs being placed on each side of the leading edge. The tabs may thus be distributed chordwise around the leading edge of the wing, whereby it is possible to determine the stagnation point and therefore the local angle of attack. The flow sensors may be arranged in arrays at different spanwise positions to get information about the stagnation point over height. By using flow sensors, the stagnation point can be determined in a more straightforward way than when using previously known pressure sensors. The flow sensor tabs could either just give a flow direction output, i.e. 0 or 1. Alternatively they could give a linear value that contains information about both the direction and the flow rate, wherein the value is linear with the deflection of the tab. Pressure sensors require finding a good reference point to be able to determine over or under-pressure compared to the environment.

[0042] According to some examples, the detector arrangement may be further configured for determining at least a first wind speed at the first position and a second wind speed at the second position, and the control arrangement may be configured to control the actuator arrangement based on at least the first and second wind speeds. In this manner, further wind data may be provided for the control arrangement to perform precise control of the actuator arrangement.

[0043] By measuring both wind direction and speed at multiple points along the leading edge of the wingsail, the detector arrangement may provide a comprehensive understanding of current aerodynamic conditions of the wingsail. This information may enable the control arrangement to make informed decisions about wingsail trimming, taking into account not only the direction but also the intensity of the wind.

[0044] The ability to detect both wind speed and direction at multiple points along the leading edge may allow for precise optimisation of the wingsail's AoA. For instance, by considering both factors, the control arrangement may adjust the actuator arrangement in real-time to ensure that the wingsail is operating within its optimal performance range based on current wind data. This results in overall efficiency of the wind propulsion system and / or improved safety in use of the wind propulsion system under difficult ambient conditions such high wind speed, erratic wind conditions, high waves, etc. Also, the use of wind speed data may enable effective trimming strategies for varying wind conditions. For example, during gusty or turbulent winds, the control arrangement may adjust the wingsail's AoA to minimise drag and maintain stable operation of the wind propulsion system. In contrast, during steady-state wind conditions, the control arrangement may optimise the performance of the wind propulsion system by adjusting the wingsail's AoA to maximise propulsive power produced by the wingsail.

[0045] According to some examples, the wind lidar may be arranged below the wingsail with a detection zone directed upwardly in front of the leading edge. In this manner, the wind lidar may be arranged to provide relevant wind data from in front of the leading edge.

[0046] By placing the lidar below the wingsail and directing its detection zone upwardly in front of the leading edge, the system may detect changes in wind direction and optionally, wind speed before they reach the wingsail itself.

[0047] According to some examples, the first anemometer may be arranged on a first holding member extending from the wingsail to the first position in front of the leading edge, and the second anemometer may be arranged on a second holding member extending from the wingsail to the second position in front of the leading edge. In this manner, by placing the first and second anemometers on distinct holding members extending from the wingsail to their respective positions in front of the leading edge, anemometer placement may be optimised and interference with airflow along the aerofoil of the wingsail may be minimised.

[0048] This configuration may allow for precise measurement of wind conditions at specific points along the wingsail’s leading edge. The separate holding members may enable the anemometers to be positioned precisely where they are needed most, without being affected by obstructions that might distort their readings. This may result in accurate wind data collection and accordingly, reliable control arrangement and wind propulsive system performance.

[0049] The use of distinct holding members may also enable easy maintenance and replacement of individual anemometers, if necessary. By separating the anemometers from the wingsail itself by use of the holding member, the system may be designed with flexibility and reduced complexity, making it easy to service or upgrade specific components without affecting overall operation of wind propulsion system. According to some examples, the control arrangement may be configured to control the actuator arrangement based on a traveling parameter of the marine vessel and / or a weather condition parameter and / or a sea condition parameter. In this manner, the control arrangement may optimise wingsail trimming to ensure maximum efficiency and / or stability in a wide range of vessel operating scenarios.

[0050] For example, when navigating through rough seas and / or strong winds, the control arrangement may adjust the AoA of the wingsail to compensate for one or more of changing wind patterns, high stress on the wind propulsion system and in order to maintain stable vessel operation. By incorporating data on traveling speed, the system may also optimise performance during acceleration or deceleration phases, ensuring smooth transitions between different speeds.

[0051] The use of weather condition parameters allows the control arrangement to anticipate and adapt to changes in wind direction and intensity, enabling effective trimming strategies and trimming strategies geared towards vessel and / or propulsion system safety. Sea state conditions may also be taken into account, e.g. allowing the control arrangement to adjust the AoA of the wingsail to minimise drag and maintain stability in rough or choppy water conditions.

[0052] According to some examples, the wingsail may comprise a main wingsail having an aerofoil shape and a flap having an aerofoil shape. The actuator arrangement may be configured to move the main wingsail in relation to the base and / or to move the flap in relation to the main wingsail and / or the base. In this manner, the control arrangement may control the actuator arrangement to move the main wingsail and / or the flap of the wingsail based on at least the first and second wind directions.

[0053] The main wingsail and the flap, respectively, may be semi-rigid or rigid. The main wingsail and the flap may comprise one or more semi-rigid or rigid modules detachably connected to each other to form an integrated main wingsail or flap with the aerofoil shape. Thus, assembly of the wingsail close to or onboard a vessel is enabled. The main wingsail and the flap may be made of a rigid or semi-rigid material and have an aerofoil shape. Both the main wingsail and the flap have sidewalls, a leading edge and a trailing edge and a top end and a bottom end. By “rigid” material is meant a material, which may be a composition of several materials, that is not foldable and can support its own weight when rested upon parallel edges of such materials. “Semi-rigid” material is a material which is partly rigid and has some degree of flexibility but can still support its own weight when rested upon parallel edges of such material. Since the main wingsail and the flap are rigid / semi-rigid, it is possible to place the detector arrangement configured for determining at least a first flow or wind direction at a first position in front of the leading edge and / or around the leading edge, and a second wind direction at a second position in front of the leading edge and / or around the leading edge at any desired position along the height of the leading edge at a spanwise extension. Therefore, a flexible and accurate system can be provided.

[0054] Accordingly, a versatile propulsion system may be provided that e.g., may adapt propulsive power produced by the wingsail based on at least the first and second wind directions. This may be done by controlling the AoA of the wingsail by moving, such as rotating, the main wingsail in relation to the base. Additionally, the AoA of the wingsail may be controlled by moving the flap in relation to the main wingsail and / or in relation to the base.

[0055] Further, the camber of the wingsail may be controller by moving the flap in relation to the main wingsail.

[0056] According to some examples, the control arrangement may comprise a data table. The data table may comprise relationships between wind direction and stagnation-point position at least along a first aerofoil of the wingsail at a position along the spanwise extension corresponding to the first position and along a second aerofoil of the wingsail at a position along the spanwise extension corresponding to the second position. In this manner, by storing relationships between wind direction and stagnation-point position for specific points along the wingsail's spanwise extension in the data table, the wind propulsion system may optimise performance under various operating conditions based on at least the first and second wind directions as determined by the detector arrangement.

[0057] This approach may allow the control arrangement to make informed decisions about how to adjust the AoA of the wingsail based on real-time wind data provided by the detector arrangement and utilising the data from the data table. By considering both the stagnationpoint position and wind direction, the control arrangement e.g., may trim the wingsail to minimise drag and maximise propulsive power and / or trim the wingsail to minimise stress on the wind propulsion system, such as on the wingsail.

[0058] The data table may include angular directions of the wingsail, such as angular directions of the respective chordlines of the first and second aerofoils. The data table may comprise relationships between such angular directions and wind directions at the first and second aerofoils. Thus, current wind directions as provided by the detector arrangement may be correlated with current angular positions of the wingsail to determine stagnation-point position for the control arrangement to adjust the AoA of the wingsail.

[0059] According to some examples, the control arrangement may be configured to control the actuator arrangement to adapt at least one parameter related to the first and / or second aerofoil based on the stagnation-point positions respectively determined along each of the first and second aerofoils. In this manner, the control arrangement may adapt the performance of the propulsion system to various operating conditions, depending on wind directions and stagnation-point positions.

[0060] This adaptive approach may allow the control arrangement to make real-time adjustments to the wingsail's shape and orientation based on wind patterns. By adapting parameters such as AoA and / or camber of the aerofoil to conditions at specific points along the spanwise extension, the propulsion system may fine-tune its wingsail trimming e.g., in order to minimise drag and maximise propulsive power and / or prioritise low stress operation of the propulsion system under challenging ambient conditions.

[0061] According to some examples, the control arrangement may be configured to increase propulsive power generated by the wind propulsion system by controlling the actuator arrangement based at least on the first and second wind directions. In this manner, the control arrangement may increase propulsive power generated by the wind propulsion system based on wind directions at different positions along the spanwise extension of the wingsail.

[0062] This control may enable the propulsion system to adapt to changing wind patterns and / or vessel course changes in real-time. By considering at last two wind directions simultaneously, the control arrangement may make informed decisions about how to adjust the wingsail's shape and orientation to maximise propulsive power while minimising drag. This approach may allow the propulsion system to take advantage of even small changes in wind direction and / or speed at at least the first and second positions along the spanwise extension, enabling it to maintain optimal performance. This may result in improved vessel stability, reduced fuel consumption, and increased overall efficiency.

[0063] According to some examples, the control arrangement may be configured to reduce propulsive power generated by the wind propulsion system by controlling the actuator arrangement based at least on the first and second wind directions. In this manner, the control arrangement may reduce propulsive power generated by the wind propulsion system based on wind directions at least two different positions along the spanwise extension of the wingsail.

[0064] This control enables the propulsion system to adapt to changing wind patterns and / or a travel itinerary of the vessel in real-time. This approach of reducing propulsive power generated by the propulsion system may be utilised when ambient conditions of the vessel are challenging such as at high wind speeds, uneven wind conditions, or under high wave conditions to prioritise low stress operation of the propulsion system and / or vessel stability. An alternative situation may be when a traveling speed of the vessel is to be reduced e.g., due to speed restrictions and / or the vessel reaching a harbour or anchoring position.

[0065] By considering both wind directions simultaneously, the control arrangement may make informed decisions about how to adjust the wingsail's shape and orientation to reduce propulsive power. This may result in improved vessel stability and traveling reliability.

[0066] Further features and advantages will become apparent when studying the appended claims and the following detailed description.

[0067] BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Various aspects and / or examples, including particular features and advantages, will be readily understood from the examples discussed in the following detailed description and the accompanying drawings, in which:

[0069] Fig. 1 illustrates a marine vessel according to some examples,

[0070] Fig. 2 schematically illustrates stagnation point and AoA and flow sensing tabs on a wingsail to detect wind direction,

[0071] Fig. 3 schematically illustrates examples of a wind propulsion system for a marine vessel, Fig. 4a schematically illustrates a control arrangement,

[0072] Fig. 4b schematically illustrates a control arrangement in the context of a wind propulsion system,

[0073] Fig. 5 illustrates a method for controlling a wind propulsion system for a marine vessel, and Fig. 6 illustrates examples of a computer-readable storage medium.

[0074] DETAILED DESCRIPTION

[0075] Aspects and / or examples will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and / or clarity. Fig. 1 illustrates a marine vessel 2 according to some examples.

[0076] The marine vessel 2 comprises a wind propulsion system 4 according to any one of aspects and / or examples discussed herein, inter alia with reference to Figs. 2 - 5.

[0077] The vessel 2 may comprise more than one wind propulsion system. In the illustrated example, the vessel 2 comprises three wind propulsion systems 4, 4’, 4”. The wind propulsion systems 4, 4’, 4” may be of similar kinds or of different kinds.

[0078] The marine vessel 2 may comprise less than three, such as one or two wind propulsion systems 4 or more than three, such as within a range of 4 - 12, wind propulsion systems 4.

[0079] The wind propulsion system 4 comprises inter alia a wingsail 6 and a base 8.

[0080] The wingsail 6 comprises a main wingsail 10 having an aerofoil shape and a flap 12 having an aerofoil shape. The main wingsail and / or the flap may be rigid or semi-rigid.

[0081] Fig. 2 illustrates angle of attack (AoA), which represents the angle between a chord line (C) of the wing 6 and the incoming airflow (A). The wing 6 is in connection with a detector arrangement 24, which is described more in detail in Fig. 3. The detector arrangement 24 is configured for determining at least a first wind direction at a first position I around the leading edge 14 of the wingsail 6 and a second wind direction at a second position II around the leading edge 14. The first and second positions I, II are arranged at a distance from each other along the spanwise extension S. The detector arrangement 24 comprises an array of flow sensing tabs 56 (only one depicted with reference sign) arranged around the leading edge 14 and each side of the leading edge on the wing 6, i.e. in chordwise direction. The flow sensing tabs are configured to determine wind direction and optionally flow rate. The flow sensor tab 56 could either just give a flow direction output, i.e. 0 or 1 , or it could give a linear value that contains information about both the direction and the flow rate which value may be linear with the deflection of the tab. By mounting several tabs 56 distributed chordwise around the leading edge 14 of the wing 6 it is possible to determine the stagnation point and therefore the local angle of attack. It would be beneficial to mount several of those arrays at different spanwise positions as explained below in connection with Fig 3. In this way information about the stagnation point over height can be obtained. Fig. 3 schematically illustrates examples of a wind propulsion system 4 for a marine vessel. The marine vessel may be a marine vessel 2 as discussed herein e.g., with reference to Fig. 1. Accordingly, in the following with reference is also made to Fig. 1. Additionally, reference is made to Fig. 2 in which another embodiment of the detector arrangement was shown.

[0082] The wind propulsion system 4 comprises a wingsail 6. The wingsail 6 comprises a main wingsail 10 having an aerofoil shape and a flap 12 having an aerofoil shape. The wingsail 6 has a leading edge 14 and a trailing edge 16. Each of the leading and trailing edges 14, 16 extend along a spanwise extension S of the wingsail 6, at least in one out of three orthogonal dimensions.

[0083] The wind propulsion system 4 further comprises a base 8. The wingsail 6 is connected to the base 8 and is moveable in relation to the base 8.

[0084] The base 8 is configured to be arranged at a deck or a deck structure of the marine vessel 2. The base 8 may be connected directly to the deck of the vessel 2. Alternatively, the base 8 may be connected to a superstructure or a dedicated built-up structure for at least part of the wind propulsion system 4 of the vessel 2, such as dedicated for the wingsail 6.

[0085] The wind propulsion system 4 further comprises an actuator arrangement 18. The actuator arrangement 18 is configured to move at least a portion of the wingsail 6 in relation to the base 8.

[0086] In Fig. 3, the actuator arrangement 18 is schematically shown. According to some examples such as in the example of Fig. 3, the actuator arrangement 18 may form part of a hydraulic system. The actuator arrangement 18 may comprise a hydraulic rotary actuator 20 for pivoting the wingsail 6 in relation to the base 8 and a hydraulic cylinder 22 for moving, such as pivoting, the flap 12 in relation to the main wingsail 10. The hydraulic system is not shown in detail in Fig. 3. The skilled person is aware of various designs of hydraulic systems, including at least one hydraulic pump and controllable valves and being suitable for powering the hydraulic rotary actuator 20 and the hydraulic cylinder 22.

[0087] Alternatively, the actuator arrangement 18 may comprise one or more electric actuators for moving at least a portion of the wingsail 6. Thus, in the example of Fig. 3, the actuator arrangement 18 is configured to move the wingsail 6 in relation to the base 8 and the flap 12 in relation to the main wingsail 10, which means that the flap 12 is also moveable in relation to the base 8.

[0088] When the flap 12 is moved in relation to the main wingsail 10, a camber of the wingsail 6 is altered.

[0089] The wind propulsion system 4 further comprises a detector arrangement 24. The detector arrangement 24 is configured for determining at least a first wind direction at a first position I in front of the leading edge 14 of the wingsail 6 and a second wind direction at a second position II in front of the leading edge 14, as also described in connection with Fig. 2. The first and second positions I, II are arranged at a distance from each other along the spanwise extension S.

[0090] The wind propulsion system 4 further comprises a control arrangement 26. The control arrangement 26 is configured to control the actuator arrangement 18 based on at least the first and second wind directions as determined by the detector arrangement 24.

[0091] For instance, the actuator arrangement 18 is configured to position the main wingsail 10 in relation to the base 8 and / or to position the flap 12 in relation to the main wingsail 10. Thus, the AoA of the wingsail 6 can be adjusted by the actuator arrangement 18 under the control of the control arrangement 26. Optionally, a camber of the wingsail 6 may be adjusted by the actuator arrangement 18 under the control of the control arrangement 26.

[0092] Accordingly, the control arrangement 26 is configured to control the actuator arrangement 18 to adjust a direction and / or a magnitude of a propulsive force produced by the wind propulsion system 4 based on at least the first and second wind directions.

[0093] Examples of the control arrangement 26 are further discussed below with reference to Figs. 4a and 4b.

[0094] Fig. 4a schematically illustrates a control arrangement 26 to be utilised in connection with different aspects and / or examples of the wind propulsion system 4 for a marine vessel 2 discussed herein. Fig. 3b schematically illustrates the control arrangement 26 in the context of the wind propulsion system 4. In the following, reference is also made to the discussions of Figs. 1, 2, 3 and 5. The control arrangement 26 is also shown in Fig. 3.

[0095] The control arrangement 26 is configured to control an actuator arrangement 18 of the wind propulsion system 4 based on at least first and second wind directions as determined by the detector arrangement 24 of the wind propulsion system 4.

[0096] The control arrangement 26 comprises at least one calculation unit 30, which may take the form of substantially any suitable type of processor circuit or microcomputer, e.g. a circuit for digital signal processing (digital signal processor, DSP), a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The herein utilised expression “calculation unit” may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above.

[0097] The control arrangement 26 comprises a memory unit 32. The calculation unit 30 is connected to the memory unit 32, which provides the calculation unit 30 with, e.g. stored programme code, data tables, and / or other stored data which the calculation unit 30 needs to enable it to do calculations and to control the actuator arrangement 18 and the wind propulsion system 4. The calculation unit 30 is also adapted to store partial or final results of calculations in the memory unit 32. The memory unit 32 may comprise a physical device utilised to store data or programs, i.e. sequences of instructions on a temporary or permanent basis. According to some examples, the memory unit 32 may comprise integrated circuits comprising silicon-based transistors. The memory unit 32 may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or nonvolatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different examples.

[0098] In a known manner, the control arrangement 26 is provided with respective devices (not shown) for receiving and / or sending input and output signals. These input and output signals may comprise waveforms, pulses or other attributes, which can be detect as information by signal receiving devices, and which can be converted to signals processable by the calculation unit 30. Input signals are supplied to the calculation unit 30 from such input receiving devices. Output signal sending devices are arranged to convert calculation results from the calculation unit 30 to output signals for conveying to signal receiving devices of other parts of the control arrangement 26 and / or of the wind propulsion system 4.

[0099] Each of the connections to the respective devices for receiving and sending input and output signals may take the form of one or more from among a cable, a data bus, e.g. a CAN (controller area network) bus, a MOST (media orientated systems transport) bus or some other bus configuration, or a wireless connection. In the example depicted, only one calculation unit 30 and memory unit 32 are shown, but the control arrangement 26 may alternatively comprise more than one calculation unit and / or memory.

[0100] Mentioned as examples, the output signal sending devices may send control signals to the actuator arrangement 18. The input signal receiving devices may receive signals from the detector arrangement 24 and position sensors 34 indicating wingsail position in relation to the base 8 and / or flap 12 position in relation to the main wingsail 10.

[0101] A data table of the control arrangement 26 may comprise relationships between wind direction and stagnation-point position at least along a first aerofoil of the wingsail 6 at a position along the spanwise extension S corresponding to the first position I and along a second aerofoil of the wingsail 6 at a position along the spanwise extension S corresponding to the second position II. The data table may include angular directions of the wingsail 6, such as angular directions at the respective chordlines of the first and second aerofoils. The data table may comprise relationships between such angular directions and wind directions at the first and second aerofoils.

[0102] Further examples of a data tables may be e.g.; a table containing relationships between wind directions and stagnation-point positions i.e. chordwise positions of stagnation-point, a table containing relationships between wind directions and AoA of the wingsail 6, a table containing relationships between a coordinate system related to the wingsail 6 and a coordinate system related to the marine vessel 2.

[0103] Examples of data may be determined, measured, monitored, and / or calculated data. The control arrangement 26 is connected to various sensors and actuators in order to receive input and provide output for performing the various aspects and examples of the method discussed herein. Some of the sensors 34, i.e. the position sensors, are exemplified above. An example of actuators may be the actuators 20, 22 of the actuator arrangement 18 for moving wingsail 6, such as the main wingsail 10 in relation to the base 8 and / or a position of the flap 12 in relation to the main wingsail 10.

[0104] The control arrangement 26 is configured to perform a method 100 according to any one of aspects and / or examples discussed herein, see e.g. below with reference to Fig. 5.

[0105] As discussed above, the wind propulsion system 4 comprises the actuator arrangement 18 configured to move at least a portion of the wingsail 6 in relation to the base 8, the detector arrangement 24 configured for determining at least a first wind direction at the first position I in front of the leading edge 14 of the wingsail 6 and a second wind direction at the second position II in front of the leading edge 14, and the control arrangement 26 configured to control the actuator arrangement 18 based on at least the first and second wind directions as determined by the detector arrangement 24.

[0106] The first and second positions I, II are arranged at a distance from each other along the spanwise extension S of the wingsail 6.

[0107] Since the detector arrangement 24 determines the first and second wind directions on or in front of the leading edge 14 of the wingsail 6, the chordwise airflow along the wingsail 6 is not disturbed by the detector arrangement 24.

[0108] Since the control arrangement 26 is configured to control the actuator arrangement 18 based on at least the first and second wind directions at the first and second positions I, II, respectively, the control arrangement 26 is able take local variations in the direction of the wind along the spanwise extensions S of the wingsail 6 into account.

[0109] For instance, a mean value of the first and second wind directions, a weighted mean value where one of the first and second wind directions is given more weight, etc. may be utilised in the control of the actuator arrangement 18.

[0110] For instance, depending on ambient conditions, local variations in the direction of the wind along the spanwise extensions S of the wingsail 6 may be utilised in different manners. When trimming the wingsail 6 for maximum propulsive power, the different wind directions at the first and second positions I, II may be considered in a certain manner. When trimming the wingsail 6 under challenging weather and / or sea conditions, the different wind directions at the first and second positions I, II may be considered in a different manner. In Fig. 4a, again, the actuator arrangement 18 is exemplified with a hydraulic rotary actuator 20 for moving, such as pivoting the wingsail 6 in relation to the base 8 and a hydraulic cylinder 22 for moving, such as pivoting, the flap 12 in relation to the main wingsail 10.

[0111] In the illustrated example and as shown in Fig. 4b, the detector arrangement 24 comprises a first anemometer 36 arranged at the first position I and a second anemometer 38 arranged at the second position II. The detector arrangement 24 may comprises further anemometers arranged at a distance from the leading edge 14 at further positions along the spanwise extension S of the wingsail 6. As explained above in connection with Fig. 2, the detector arrangement 24 may additionally or alternatively comprise flow sensor tabs 56.

[0112] Additionally, or alternatively, the detector arrangement 24 comprises a wind lidar 40 configured to determine at least the first wind direction at the first position I and the second wind direction at the second position II. The wind lidar 40 may be configured to determine further wind directions at further positions along the spanwise extension S of the wingsail 6.

[0113] Since, in a known manner, the wind lidar 40 may be configured to base its determination of wind directions on reflections off e.g. suspended aerosols in the air / wind, the first and second positions I and II may differ between two different determinations of the wind directions.

[0114] Since the wind lidar 40 also is able to determine at what distance from the wind lidar 40 reflections take place the location of these variable first and second positions I, II are known and the control arrangement 26 can include the distance data in its calculations and control of the wingsail 6.

[0115] In the illustrated example, the detector arrangement 24 is further configured for determining at least a first wind speed at the first position I and a second wind speed at the second position II. Such determining of the first and second wind speeds may be done by the first and second anemometers 36, 38 and / or the wind lidar 40.

[0116] The control arrangement 26 is further configured to control the actuator arrangement 18 based on at least the first and second wind speeds.

[0117] In this manner, current aerodynamic conditions of the wingsail 6 are determined in a precise manner. In addition to the determined first and second wind directions, the determined first and second wind speeds enable the control arrangement 26 to control the actuator arrangement 18 more precisely to achieve a desired effect under current wind conditions, as thus determined. For instance, wingsail 6 trimming, for maximum propulsive power and / or for prioritised safe propulsion of the vessel 2 may be achieved.

[0118] In the illustrated example, the wind lidar 40 is arranged below the wingsail 6 with a detection zone 41 directed upwardly in front of the leading edge 14 to provide relevant wind data in front of the leading edge 14 of the wingsail 6. The wind lidar 40 can be connected to a rotating axis 9 of the wingsail. In this way the wind lidar is arranged to rotate with the wingsail. Therefore, it can determine the wind direction if front of the leading edge of the wingsail. The wind lidar 40 may be fixed in relation to the base 8. In such case, the wind data determined by the wind lidar 40 is provided in a coordinate system related to the base 8 and accordingly, to the vessel 2. The wind lidar 40 may be fixed to the wingsail 6. In such case, the wind data determined by the wind lidar 40 is provided in a coordinate system related to the wingsail 6 and accordingly, is provided relative to the wingsail 6.

[0119] The control arrangement 26 may be configured to convert wind data in the coordinate system related to the wingsail 6 to the coordinate system related to the vessel 2 and / or vice versa.

[0120] In the illustrated example, the first anemometer 36 is arranged on a first holding member 42 extending from the wingsail 6 to the first position I in front of the leading edge 14. The second anemometer 38 is arranged on a second holding member 44 extending from the wingsail 6 to the second position II in front of the leading edge 14.

[0121] The use of the holding members 42, 44 enables precise positioning of the first and second anemometers 36, 38 at the first and second positions I, II. The use of the holding members 42, 44 may also enable easy maintenance and replacement of individual anemometers.

[0122] Since the first and second anemometers 36, 38 extend from the wingsail 6, the wind data determined by the first and second anemometers 36, 38 is provided in a coordinate system related to the wingsail 6 and accordingly, is provided relative to the wingsail 6.

[0123] In the illustrated example, the control arrangement 26 is configured to control the actuator arrangement 18 based on a traveling parameter of the marine vessel 2 and / or a weather condition parameter and / or a sea condition parameter. Thus, in addition to wind direction and optionally wind speed, the control arrangement 26 may consider further vessel 2 influencing factors when controlling the actuator arrangement 18 and the wind propulsion system 4. Accordingly, the control arrangement 26 may comprise, or may be connected to a, herein, generally termed input device 46.

[0124] The input device 46 may provide a traveling parameter collecting function. Such travelling parameters may include one or more of: vessel speed, travel itinerary, movements of the vessel 2 as established e.g. by pitching and rolling sensors aboard the vessel 2, etc.

[0125] The input device 46 may receive weather condition parameters from a weather report service or from weather sensors aboard the vessel 2.

[0126] The input device 46 may receive sea condition parameters from a weather report service and / or movement sensors e.g. pitching and rolling sensors aboard the vessel 2.

[0127] Thus, the control arrangement 26 is able to optimise wingsail 6 trimming to ensure maximum efficiency, such as maximum propulsive power under current operating conditions of the vessel 2. Alternatively, or additionally, the control arrangement 26 is able to optimise wingsail 6 trimming to ensure maximum vessel 2 stability under current operating conditions. Alternatively, or additionally, the control arrangement 26 is able to optimise wingsail 6 trimming to balance propulsive power and vessel 2 stability to fulfil certain criteria under current operating conditions. Alternatively, or additionally, the control arrangement 26 is able to optimise wingsail 6 trimming to ensure certain safety aspects under current operating conditions.

[0128] As discussed above, the wingsail 6 comprises a main wingsail 10 having an aerofoil shape and a flap 12 having an aerofoil shape. The actuator arrangement 18 is configured to move the main wingsail 10 in relation to the base 8 and / or to move the flap 12 in relation to the main wingsail 10 and / or the base 8.

[0129] According to some examples, the control arrangement 26 is configured to control the actuator arrangement 18 to adapt at least one parameter related to the first and / or second aerofoil based on the stagnation-point positions respectively determined along each of the first and second aerofoils. As discussed above, the first aerofoil of the wingsail 6 is at a position along the spanwise extension S corresponding to the first position I and the second aerofoil of the wingsail 6 is at a position along the spanwise extension S corresponding to the second position II. Positions of the first and second aerofoils are indicated with respective dash-dotted lines i, ii in Fig. 4b. Thus, for instance, parameters such as AoA and / or camber of the aerofoil may be adapted to conditions at specific points along the spanwise extension S. The AoA may be adjusted by the hydraulic rotary actuator 20 of the actuator arrangement186 under the control of the control arrangement 26 and the camber of the aerofoil may be adjusted by the hydraulic cylinder 22 of the actuator arrangement 18 under the control of the control arrangement 26.

[0130] According to some examples, the control arrangement 26 is configured to increase propulsive power generated by the wind propulsion system 4 by controlling the actuator arrangement 18 based at least on the first and second wind directions.

[0131] Thus, the wingsail 6 may be trimmed for increased propulsive power e.g., when wind conditions change and / or when the vessel 2 changes course. This may be the case when ambient conditions of the vessel 2 are good and when vessel speed is prioritised.

[0132] According to some examples, the control arrangement 26 is configured to reduce propulsive power generated by the wind propulsion system 4 by controlling the actuator arrangement 18 based at least on the first and second wind directions.

[0133] Thus, the wingsail 6 may be trimmed for reduced propulsive power e.g., when wind conditions change and / or when the vessel 2 changes course and / or when vessel speed is to be reduced. This may be the case when ambient conditions of the vessel 2 are challenging and / or when the vessel 2 is traveling in an area with speed restrictions.

[0134] Fig. 5 illustrates a method 100 for controlling a wind propulsion system for a marine vessel.

[0135] The marine vessel may be a marine vessel 2 as discussed herein e.g., with reference to Fig. 1. The wind propulsion system may be a wind propulsion system 4 as discussed herein e.g., with reference to Figs. 1 - 4b. Accordingly, in the following reference is also made to Figs. 1 - 4b.

[0136] The wind propulsion system 4 comprises a wingsail 6 having a leading edge 14 extending along a spanwise extension S of the wingsail 6.

[0137] The method 100 comprises steps of:

[0138] - Detecting 102 a first wind direction at a first position I in front of the leading edge 14, - Detecting 104 a second wind direction at a second position II in front of the leading edge 14, the first and second positions I, II being arranged at a distance from each other along the spanwise extension S, and

[0139] - Controlling 106 an actuator arrangement 18 of the wind propulsion system 4 based on at least the first and second wind directions.

[0140] The steps of detecting 102, 104 the first and second wind directions may be performed by a detector arrangement 24. as discussed above. The step of controlling 106 the actuator arrangement may be performed by a computer or control arrangement 26 as discussed above. The actuator arrangement 18 may be an actuator arrangement 18 configured for moving at least a portion of the wingsail 6 in relation to a base 8 of the wind propulsion system 4, as discussed above.

[0141] According to some examples, the method 100 may comprise steps of:

[0142] - determining 108 at least a first wind speed at the first position I,

[0143] - determining 110 a second wind speed at the second position II, and

[0144] - controlling 112 the actuator arrangement 18 based on at least the first and second wind speeds. In this manner, the actuator arrangement 18 may be controlled based not only on wind direction data but may include more information about current wind conditions at the first and second positions I, II. Thus, the moving of at least a portion of the wingsail 6 may be precisely performed.

[0145] According to some examples, the method 100 may comprise a step of:

[0146] - controlling 114 the actuator arrangement 18 based on a traveling parameter of the marine vessel 2 and / or a weather condition parameter and / or a sea condition parameter. In this manner, as discussed above, in addition to being based on wind data, wingsail 6 trimming may be optimised to ensure maximum efficiency and / or stability in a wide range of operating scenarios of the marine vessel 2. The operating scenarios are characterised by different traveling parameters of the marine vessel 2, and / or different weather condition parameters and / or different sea condition parameters.

[0147] According to some examples, the method 100 may comprise steps of:

[0148] - determining 116 a first stagnation-point position of a first aerofoil of the wingsail 6 at a position along the spanwise extension S corresponding to the first position I, based on the first wind direction, - determining 118 a second stagnation-point position of a second aerofoil of the wingsail 6 at a position along the spanwise extension S corresponding to the second position II, based on the second wind direction, and

[0149] - controlling 120 the actuator arrangement 18 to adapt at least one parameter of the first and / or second aerofoil based on the stagnation-point positions respectively determined along each of the first and second aerofoils. In this manner, the performance of the wind propulsion system 4 may be adapted to various operating conditions, depending on wind directions and stagnation-point positions. For instance, parameters such as AoA and / or camber of the aerofoil of the wingsail 6 may be adapted to conditions at specific points along the spanwise extension S.

[0150] According to some examples, the method 100 may comprise a step of:

[0151] - increasing 122 propulsive power generated by the wind propulsion system 4 by controlling the actuator arrangement 18 based on at least the first and second wind directions. In this manner, the wingsail 6 may be trimmed for increase propulsive power e.g., when wind conditions change and / or when the vessel 2 changes course. This may be the case when ambient conditions of the vessel 2 are good and when vessel speed is prioritised.

[0152] According to some examples, the method 100 may comprise a step of:

[0153] - reducing 124 propulsive power generated by the wind propulsion system 4 by controlling the actuator arrangement 18 based on at least the first and second wind directions. In this manner, the wingsail 6 may be trimmed for reduced propulsive power e.g., when wind conditions change and / or when the vessel 2 changes course and / or when vessel speed is to be reduced. This may be the case when ambient conditions of the vessel 2 are challenging and / or when vessel speed is to be reduced.

[0154] According to a further aspect, there is provided a computer program comprising instructions which, when the program is executed by a computer, causes the computer to carry out a method 100 according to any one of aspects and / or examples discussed herein.

[0155] One skilled in the art will appreciate that the method 100 for controlling a wind propulsion system for a marine vessel may be implemented by programmed instructions. These programmed instructions are typically constituted by a computer program, which, when it is executed in a computer or calculation unit 30, ensures that the computer or calculation unit 30 carries out the desired control, such as the method steps 102 - 124 discussed herein. The computer program is usually part of a computer-readable storage medium which comprises a suitable digital storage medium on which the computer program is stored. Fig. 6 illustrates examples of a computer-readable storage medium 99 comprising instructions which, when executed by a computer or calculation unit 30, cause the computer or calculation unit 30 to carry out the steps of the method 100 according to any one of aspects and / or examples discussed herein.

[0156] The computer-readable storage medium 99 may be provided for instance in the form of a data carrier carrying computer program code for performing at least some of the steps 102 - 124 according to some examples when being loaded into the one or more calculation units 30. The data carrier may be, e.g. a ROM (read-only memory), a PROM (programable readonly memory), an EPROM (erasable PROM), a flash memory, an EEPROM (electrically erasable PROM), a hard disc, a CD ROM disc, a memory stick, an optical storage device, a magnetic storage device or any other appropriate medium such as a disk or tape that may hold machine readable data in a non-transitory manner. The computer-readable storage medium may furthermore be provided as computer program code on a server and may be downloaded to the calculation unit 30 remotely, e.g., over an Internet or an intranet connection, or via other wired or wireless communication systems.

[0157] The computer-readable storage medium 99 shown in Fig. 6 is a nonlimiting example in the form of a USB memory stick.

[0158] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0159] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0160] It is to be understood that the foregoing is illustrative of various examples and that the invention is defined only by the appended claims. A person skilled in the art will realize that the examples may be modified, and that different features of the examples may be combined to create examples other than those described herein, without departing from the scope of the invention, as defined by the appended claims.

Claims

CLAIMS1. A wind propulsion system (4) for a marine vessel (2), the wind propulsion system (4) comprising a wingsail (6) having a leading edge (14) extending along a spanwise extension (S) of the wingsail (6), a base (8), an actuator arrangement (18), a detector arrangement (24), and a control arrangement (26), wherein the wingsail (6) is connected to the base (8), wherein the actuator arrangement (18) is configured to move at least a portion of the wingsail (6) in relation to the base (8), wherein the detector arrangement (24) is configured for determining at least a first wind direction at a first position (I) in front of the leading edge (14) and / or around the leading edge (14) and a second wind direction at a second position (II) in front of the leading edge (14) and / or around the leading edge (14), the first and second positions (I, II) being arranged at a distance from each other along the spanwise extension (S), and wherein the control arrangement (26) is configured to control the actuator arrangement (18) based on at least the first and second wind directions.

2. The wind propulsion system (4) according to claim 1, wherein the first and second positions are in front of the leading edge (14) and the detector arrangement (24) comprises at least a first anemometer (36) arranged at the first position (I) and a second anemometer (38) arranged at the second position (II).

3. The wind propulsion system (4) according to claim 2, wherein the first anemometer (36) is arranged on a first holding member (42) extending from the wingsail (6) to the first position (I) in front of the leading edge (14), and wherein the second anemometer (38) is arranged on a second holding member (44) extending from the wingsail (6) to the second position (II) in front of the leading edge (14).

4. The wind propulsion system (4) according to claim any one of claims 1 to 3, wherein the first and second positions are in front of the leading edge (14) and the detector arrangement (24) comprises a wind lidar (40) configured to determine at least the first wind direction at the first position (I) and the second wind direction at the second position (II), wherein the wind lidar (40) is arranged below the wingsail (6) with a detection zone (41) directed upwardly in front of the leading edge (14) and wherein the lidar is arranged to rotate with the wingsail.

5. The wind propulsion system according to any one of claims 1-4, wherein the first and second positions are comprised around the leading edge (14) in chordwise direction and thedetector arrangement (24) comprises flow sensing tabs (56) configured to determine wind direction and / or flow rate.

6. The wind propulsion system (4) according to any of claims 1 to 5, wherein the detector arrangement (24) is further configured for determining at least a first wind speed at the first position (I) and a second wind speed at the second position (II), and wherein the control arrangement (26) is configured to control the actuator arrangement (18) based on at least the first and second wind speeds.

7. The wind propulsion system (4) according to any one of the preceding claims, wherein the control arrangement (26) is configured to control the actuator arrangement (18) based on a traveling parameter of the marine vessel (2) and / or a weather condition parameter and / or a sea condition parameter.

8. The wind propulsion system (4) according to any one of the preceding claims, wherein the wingsail (6) comprises a main wingsail (10) having an aerofoil shape and a flap (12) having an aerofoil shape, and wherein the actuator arrangement (18) is configured to move the main wingsail (10) in relation to the base (8) and / or to move the flap (12) in relation to the main wingsail (10) and / or the base (8).

9. The wind propulsion system (4) according to any one of the preceding claims, wherein the wingsail (6) is rigid or semi-rigid.

10. The wind propulsion system (4) according to any one of the preceding claims, wherein the control arrangement (26) comprises a data table, the data table comprising relationships between wind direction and stagnation-point position at least along a first aerofoil (i) of the wingsail (6) at a position along the spanwise extension (S) corresponding to the first position (I) and along a second aerofoil (ii) of the wingsail (6) at a position along the spanwise extension (S) corresponding to the second position (II).

11. The wind propulsion system (4) according to claim 10, wherein the control arrangement (26) is configured to control the actuator arrangement (18) to adapt at least one parameter related to the first and / or second aerofoil (i, ii) based on the stagnation-point positions respectively determined along each of the first and second aerofoils (i, ii).

12. The wind propulsion system (4) according to any one of the preceding claims, wherein the control arrangement (26) is configured to increase propulsive power generated by thewind propulsion system (4) by controlling the actuator arrangement (18) based at least on the first and second wind directions.

13. The wind propulsion system (4) according to any one of the preceding claims, wherein the control arrangement (26) is configured to reduce propulsive power generated by the wind propulsion system (4) by controlling the actuator arrangement (18) based at least on the first and second wind directions.

14. A marine vessel (2) comprising a wind propulsion system (4) according to any one of the preceding claims.

15. A method (100) for controlling a wind propulsion system (4) for a marine vessel (2), the wind propulsion system (4) comprising a wingsail (6) having a leading edge (14) extending along a spanwise extension (S) of the wingsail (6), wherein the method (100) comprises steps of:- detecting (102) a first wind direction at a first position (I) around or in front of the leading edge (14),- detecting (104) a second wind direction at a second position (II) around or in front of the leading edge (14), the first and second positions (I, II) being arranged at a distance from each other along the spanwise extension (S), and- controlling (106) an actuator arrangement (18) of the wind propulsion system (4) based on at least the first and second wind directions.

16. The method (100) according to claim 15, comprising steps of:- determining (108) least a first wind speed at the first position (I),- determining (110) a second wind speed at the second position (II), and- controlling (112) the actuator arrangement (18) based on at least the first and second wind speeds.

17. The method (100) according to claim 15 or 16, comprising a step of:- controlling (114) the actuator arrangement (18) based on a traveling parameter of the marine vessel (2) and / or a weather condition parameter and / or a sea condition parameter.

18. The method (100) according to any one of claims 15 - 17, comprising steps of:- determining (116) a first stagnation-point position of a first aerofoil (i) of the wingsail (6) at a position along the spanwise extension (S) corresponding to the first position (I) based on the first wind direction,- determining (118) a second stagnation-point position of a second aerofoil (ii) of the wingsail (6) at a position along the spanwise extension (S) corresponding to the second position (II) based on the second wind direction, and- controlling (120) the actuator arrangement (18) to adapt at least one parameter of the first and / or second aerofoil (i, ii) based on the stagnation-point positions respectively determined along each of the first and second aerofoils (i, ii).

19. The method (100) according to any one of claims 15 - 18, comprising a step of:- increasing (122) propulsive power generated by the wind propulsion system (4) by controlling the actuator arrangement (18) based on at least the first and second wind directions.

20. The method (100) according to any one of claims 15 - 18, comprising a step of:- reducing (124) propulsive power generated by the wind propulsion system (4) by controlling the actuator arrangement (18) based on at least the first and second wind directions.

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