A control surface control assembly for an aerial vehicle, an aerial vehicle, a method, a computer program and a computer-readable medium

Abstract

The disclosure relates to a control surface assembly (2) for an aerial vehicle (1), the control surface assembly (2) comprising: an actuator (20), a coupling element (22) arranged to connect the actuator (20) to the control surface (16), wherein the coupling element (22) comprises a first coupling piece (32), connected to the actuator (20) and a second coupling piece (34), wherein the second coupling piece (34) is in contact with a connection member (24) in a locked position, in which in the locked position the connection member (24) is arranged to limit the movement of the second coupling piece (34) and lock the control surface (16) in a fixed position and; the second coupling piece (34) is disconnected from the connection member (24) in an unlocked position, in which unlocked position the second coupling piece (34) is connected to the first coupling piece (32) and arranged to be pivoted by the first coupling piece (32), wherein the first coupling piece (32) is configured to be pivoted to a position in which the second coupling piece (34) connects to the first coupling piece (32).

Description

[0001] A control surface control assembly for an aerial vehicle, an aerial vehicle, a method, a computer program and a computer-readable medium

[0002] Technical field

[0003] The present disclosure relates to a control surface assembly for an aerial vehicle, an aerial vehicle, a method, a computer program and a computer-readable medium. More specifically, the disclosure relates to a control surface assembly for an aerial vehicle, an aerial vehicle, a method, a computer program and a computer-readable medium as defined in the introductory parts of the independent claims.

[0004] Background art

[0005] Aerial vehicles comprise control surfaces to control the flight direction. The control surfaces are attached to movable shafts, which extend from the body of the aerial vehicle. The control surfaces may consist of movable fins, and thus the fins constitute the control surfaces. Alternatively, a control surface may be hinged to a fixed fin of the aerial vehicle body. The control surfaces move in various directions in response to the movement of the movable shafts.

[0006] Control surface control assemblies for aerial vehicles comprise devices for locking the control surfaces in place prior to aerial vehicle launch. Such locking devices hold the control surfaces in rigid and stable positions to prevent wear and tear on the control assemblies responsible for operating the control surfaces. When an aerial vehicle is positioned on the exterior of an aircraft, the control surfaces of the aerial vehicle are subjected to high aerodynamic loading prior to launch and environmental issues such as ice buildup. The locking devices of the control surface control assembly prevent distortion and fatigue failures of the drive systems of the control surfaces, such as actuators and shafts.

[0007] The document EP3918267 Bl discloses a rudder control assembly, featuring a first actuator for steering the rudder, a coupling element for connecting the actuator to the rudder, and a second actuator for locking the rudder in a fixed position. The second actuator unlocks the rudder from the fixed position by retracting a locking element from the rudder. The rudder control assembly further comprises a method for testing the first actuator.Despite known solutions in the art, it is desired to achieve a control surface assembly for an aerial vehicle, which control surface assembly is functional and reliable.

[0008] Also, it is desired to achieve a control surface assembly for an aerial vehicle, which control surface assembly indicates that steering of a control surface does not work.

[0009] An object of the invention is therefore to achieve a control surface assembly for an aerial vehicle, which control surface assembly is functional and reliable.

[0010] A further object of the invention is to achieve a control surface assembly for an aerial vehicle, which control surface assembly indicates that steering of a control surface does not work.

[0011] It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above-mentioned problem.

[0012] According to a first aspect there is provided a control surface assembly for an aerial vehicle. The control surface assembly comprises an actuator connectable to a control surface, wherein the actuator is configured to steer the control surface. A coupling element is arranged to connect the actuator to the control surface, wherein the coupling element comprises a first coupling piece, which is pivotally arranged about a pivot axis, connected to the actuator and a second coupling piece connected to the control surface, wherein the second coupling piece is in contact with a connection member in a locked position, in which in the locked position the connection member is arranged to limit the movement of the second coupling piece and lock the control surface in a fixed position. The second coupling piece is disconnected from the connection member in an unlocked position, wherein in the unlocked position the second coupling piece is connected to the first coupling piece and arranged to be pivoted by the first coupling piece about the pivot axis. The first coupling piece is configured to be pivoted to a position in which the second coupling piece connects to the first coupling piece, so that the second coupling piece is fixed to the first coupling piece for steering the control surface. The control surface may be any type of surface that can control a traveling direction of the aerialvehicle, such as a rudder or fin. The control surface assembly may further comprise a sensor configured to measure the pivoting angle and / or the angle velocity.

[0013] The invention provides a control surface assembly that secure the steering function of the control surface. The control surface pivots about a pivot axis when steering. When the control surface pivots in one direction about the pivot axis, the air stream that passes the control surface will exert a force on the control surface. The force acting on the control surface will steer the aerial vehicle on which the control surface is arranged. When the control surface pivots in the opposite direction about the pivot axis, the control surface will steer the aerial vehicle in another direction. Several control surfaces may be arranged on the aerial vehicle in order to increase the steering ability of the aerial vehicle. The control surface assembly, according to the invention, locks the control surface in a fixed position and thus prevents damage on the control surface assembly, and also enables testing of the steering function of the control surface.

[0014] By such a control surface assembly for an aerial vehicle, a control surface assembly which is functional and reliable is achieved. It is further advantageous to lock the control surface in a fixed position in order to prevent wear and tear on the control surface. It is further advantageous to set the control surface in an unlocked position in order to steer the aerial vehicle.

[0015] The second coupling piece is disconnected from the first coupling piece in the locked position, so that the first coupling piece is free to pivot about the pivot axis by the actuator.

[0016] By allowing the first coupling piece to freely pivot about the pivot axis allows for testing the functionality of the actuator without unlocking the control surface. Another advantage is that ice that may have been formed around the first coupling device can be removed by pivoting the first coupling device. Also, ice formed between the first and second coupling device can be removed by pivoting the first coupling device.

[0017] The second coupling piece comprises an axially movable shaft. The axially movable shaft comprises a first end part and a second end part. The first end part and the second endpart are located on opposite sides of the axially movable shaft. The second coupling piece is arranged on the control surface, so as to move them together about the pivot axis.

[0018] The axially movable shaft is movable in its axial or longitudinal direction. The axially movable shaft may be a rod or a stick, which has elongated extension. The axially movable shaft or a part of the axially movable shaft may have a shape that is complementary to the shape of the second coupling piece.

[0019] According to an example, the connection member comprises a groove, which is configured to accommodate the first end part of the axially movable shaft of the second coupling piece when the second coupling piece is locked in the locked position, and which the first end part is configured to exit the groove when the second coupling piece is situated in the unlocked position. In other words, the connection member comprises a groove, which is configured to accommodate the first end part of the axially movable shaft of the second coupling piece, wherein, in the locked position, the first end part of the axially movable shaft is positioned in the groove, and wherein the first end part is disconnected from the groove in the unlocked position.

[0020] According to an example, the first coupling piece comprises a bore, which is configured to receive the second end part of the axially movable shaft.

[0021] According to an example, a spring element, arranged to axially move the axially movable shaft towards the bore. In other words, the spring element may be arranged to displace the axially movable shaft towards the bore.

[0022] The spring element may be a coil spring, which pushes or pulls the axially movable shaft in an axial or longitudinal direction towards the first coupling piece. When the axially movable shaft is connected to the first coupling piece, the spring force from the spring element presses the axially movable shaft into the bore of the first coupling piece. The spring element thus ensures that the axially movable shaft is rigidly connected to the first coupling piece. Further, the spring element ensures that a rigid and accurate connection between the first and second coupling pieces is achieved, which enables an accurate transmission of the movements from the actuator to the control surface.The actuator is configured to control the first coupling piece to pivot in a way that aligns the bore with the axially movable shaft. Upon alignment, the axially movable shaft, which is subjected to the external force from the spring element, moves in the direction of the first coupling piece, and the second end part of the axially movable shaft enters the bore. The axially movable shaft is now fixed to the first coupling piece, and the control surface is unlocked and free to pivot about the pivot axis according to the movement from the actuator.

[0023] In the locked position, the first end part of the axially movable shaft is positioned in the groove of the connection member. The control surface, connected to the second coupling piece and the axially movable shaft, is therefore locked in a fixed position. When the second end part of the axially movable shaft moves in the direction of the first coupling piece and enters the bore, the first end part of the axially movable shaft exits the groove of the connection member. The second coupling piece, and therefore also the control surface, are disconnected from the connection member and are thereby in the unlocked position.

[0024] The second end part of the axially movable shaft and the bore have complementary shapes arranged to, upon engaging, connect the first coupling piece and the second coupling piece.

[0025] By having complementary shapes, the axially movable shaft and the first coupling piece are engaged, resulting in a play-free or low play connection between the axially movable shaft and the first coupling piece. Alternatively, or additionally, the complementary shapes result in an interference fit or a press-fit connection.

[0026] According to some examples, the complementary shapes of the second end part of the axially movable shaft and the bore are conically shaped.

[0027] The axially movable shaft or a part of the axially movable shaft may have a conical shape that is complementary to a conical shape of the bore. The bore or a part of the bore of the first coupling piece may have a complementary shape to the axially movable shaft. The bore, or a part of the bore may have a conical shape, which is complementary to a conical shape of the axially movable shaft or a part of the axially movable shaft, which has a conical shape.The complementary shapes thus ensure that the axially movable shaft is rigidly connected to the first coupling piece. Further, the complementary shapes ensure that a rigid and accurate connection between the first and second coupling pieces is achieved, which enables an accurate transmission of the movements from the actuator to the control surface. Furthermore, the complementary shapes ensure play-free connection or at least a low play connection between the first and second coupling pieces.

[0028] According to an example, the first coupling piece may be configured to, upon being rotated or pivoted by the actuator, move axially movable shaft away from the pivot axis. In an example, the actuator rotates the first coupling device which causes the axially movable shaft to move or be displaced in a direction away from the bore.

[0029] An advantage of move or displace the axially movable shaft is that ice that may have been formed around the axially movable shaft can be removed by pivoting the first coupling device which causes the axially movable shaft to be displaced.

[0030] According to an example, when the axially movable shaft is in a first position, the second coupling piece is locked in the locked position wherein the first end part of the axially movable shaft is in contact with the groove. When the axially movable shaft is in a second position, axially displaced in the opposite direction to the first position, the second coupling piece is in the unlocked position, wherein the first end part of the axially movable shaft has disengaged from the groove, and the second coupling piece is connected to the bore of the first coupling piece.

[0031] In the locked, first position, the axially movable shaft is disconnected from the first coupling piece. Thus, in the first position of the axially movable shaft, the actuator is disconnected from the control surface. In the unlocked, second position, the axially movable shaft is disconnected from the connection member and connected to the first coupling piece. Thus, in the second position of the axially movable shaft, the actuator is connected to the control surface. In other words, when the first coupling piece pivots about the pivot axis, the axially movable shaft and the bore align so that a part second end part enters the bore. At same time, the first end part of the axially movable shaft exits the groove of the connection member. An advantage of this design is that the control surface assembly can be used in small spaces. A further advantage is that the control surface assembly is robust and is resilient tosnow, ice, sand, dust and / or other dirt. A further advantage is that a safety test can be done before the actuator is connected to the control surface.

[0032] The control surface assembly is adapted to be arranged on an aerial vehicle. Such an aerial vehicle may be suspended under a wing of an aircraft. After launching the aerial vehicle, the control surface assembly is configured steer or maneuver the aerial vehicle. Several control surfaces may be arranged on the aerial vehicle in order to increase the steering ability of the aerial vehicle. In an example, the aerial vehicle may be attached to an aircraft, for example under a wing of an aircraft or under the fuselage of the aircraft.

[0033] According to a second aspect there is provided an aerial vehicle, comprising a control surface assembly. The aerial vehicle may be any type of aircraft, such as an airplane, a missile or a torpedo.

[0034] Before launch of the aerial vehicle and during flight of the aircraft the control surface is locked in a fixed position by the control surface assembly. Damages on control surface assembly due to aerodynamic effects are thus prevented. Before launch of the aerial vehicle and also during flight of the aircraft, the steering function of the control surface may be tested. Testing of the steering function of the control surface assembly before launch of the aerial vehicle increases the likelihood that the aerial vehicle function as intended. When the aerial vehicle is launched, the control surface is set in the unlocked position, allowing the actuator to control the control surface.

[0035] Since the control surface assembly is in the locked position before launch and during the flight of the aircraft, a safer aircraft is provided. Furthermore, keeping the control surface assembly locked before launch and during flight prevents the aerial vehicle from affecting the aircraft's manoeuvrability while flying.

[0036] According to a third aspect there is provided a method, performed by a control device, for testing an actuator of a control surface assembly according to the first aspect, comprising: activating the actuator for pivoting the first coupling piece when the control surface is locked in locked position, and determining if the first coupling piece pivots when activating the actuator.By such a method, an actuator of a control surface assembly for an aerial vehicle may be tested in order to achieve a control surface assembly which is functional and reliable, and which indicates if steering of the control surface works before launching the aerial vehicle. The testing method further secures the steering function of the control surface. The method according to the invention further enables testing of the steering function of the control surface even though the control surface is locked and is not able to pivot about its pivot axis. For example, the method activates the actuator to pivot 2-5 degrees, so that the second coupling piece is still in the locked position. The sensor determines if the first coupling piece pivots and sends a signal to the control device to stop the test.

[0037] According to a fourth aspect, there is provided a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to the third aspect.

[0038] According to a fifth aspect, there is provided a data processing unit comprising a computer program product for testing an actuator of a control surface assembly. The data processing unit comprising a computer program product comprising a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium having thereon a computer program comprising program instructions. The computer program is loadable into a data processing unit and is configured to cause a processor to carry out the method for testing an actuator of a control surface assembly.

[0039] Effects and features of the second through fifth aspects are, to a large extent, analogous to those described above in connection with the first aspect. Embodiments mentioned in relation to the first aspect are largely compatible with the second through fifth aspects.

[0040] The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure.Brief of the

[0041]

[0042] The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings.

[0043] Figure 1 schematically shows a perspective view of the control surface assembly according to an example of the present disclosure.

[0044] Figure 2a and 2b schematically shows a cross-sectional view of the control surface assembly in a locked position.

[0045] Figure 3a and 3b schematically shows a cross-sectional view of the control surface assembly in an unlocked position.

[0046] Figure 4 schematically shows a perspective view of the control surface assembly according to an example of the present disclosure.

[0047] Figure 5 shows a flowchart of a method according to an example.

[0048] Figure 6 schematically illustrates a control device according to an example.

[0049] Figure 7 schematically illustrates an aerial vehicle according to an example.

[0050] Detailed

[0051] The present disclosure will now be described with reference to the accompanying drawings, in which preferred example embodiments of the disclosure are shown. The disclosure may, however, be embodied in other forms and should not be construed as limited to the herein disclosed embodiments. The disclosed embodiments are provided to fully convey the scope of the disclosure to the skilled person. The present disclosure is related to a control surface assembly. The control surface assembly can also be named rudder control assembly. The control surface can also be named rudder.

[0052] Figure 1 schematically shows a perspective view of the control surface assembly 2 according to an example of the present disclosure. The control surface assembly 2 comprisesan actuator 20 connectable to a control surface 16 via an axially movable shaft 36 and second coupling piece 34. The second coupling piece 34 is in contact with a connection member 24. The control surface 16 is pivotally arranged about a pivot axis 28, at a fixed fin 4. However, the fin 4 and control surface 16 may be an integrated part, so that the fin 4 is pilotable. The actuator 20 is configured to steer the control surface 16, when connected to the control surface 16. A coupling element 22 is provided for connecting the actuator 20 to the control surface 16. The coupling element 22 comprises a first coupling piece 32. The control surface 16 is pivotally arranged about a pivot axis 28 when steering. A control device 100 is connected to the actuator 20 for controlling the actuator 20. The control surface assembly 2 further comprises a sensor 21 configured to measure the pivoting angle and / or the angle velocity.

[0053] Figure 1 further shows that the control surface assembly 2 is connected to an aerial vehicle 1.

[0054] Figure 2a and 2b schematically shows a cross-sectional view of the control surface assembly 2 in a locked position. The control surface assembly 2 comprises an actuator 20 connectable to a control surface (not shown), wherein the actuator 20, in an unlocked position, is configured to steer the control surface. The control surface assembly 2 further comprises a coupling element 22 arranged to connect the actuator 20 to the control surface, wherein the coupling element 22 comprises a first coupling piece 32, which is pivotally arranged about a pivot axis 28, connected to the actuator 20. The control surface assembly further comprises a second coupling piece 34 connected to the control surface.

[0055] Figure 2a and 2b further shows that the second coupling piece 34, arranged on the control surface 16, comprises an axially movable shaft 36. The axially movable shaft 36 is arranged to travel along a shaft axis 30. The axially movable shaft 36 comprises a first end part 50 and a second end part 52. The first coupling piece 32 comprises a bore 38, which when rotated to face the second end part 52 is configured to receive the axially movable shaft 36. The bore 38 may be conically shaped. The axially movable shaft 36 may be conically shaped. More specifically, the second end part 52, of the axially movable shaft 36 is conically shaped. The control surface assembly 2 may further comprise a spring element 40, arranged to axially move the axially movable shaft 36 towards the bore 38. When the second coupling piece 34 is in a locked position, the second coupling piece 34 is in contact with a connection member 24,via the axially movable shaft 36, wherein the connection member 24 is arranged to limit the movement of the second coupling piece 34, thus lock the control surface 16 in a fixed position.

[0056] The connection member 24 comprises a groove 46, which is configured to receive the first end part 50 of the axially movable shaft 36 when the axially movable shaft 36 is positioned in the locked position. The first end part 50 is configured to exit the groove 46 when the axially movable shaft 36 is moved to the unlocked position, thus releasing the second coupling piece 34 from the connection member 24 and connecting the second coupling piece to the first coupling piece 32. The axially movable shaft 36 is thus connected to the bore 38.

[0057] Figure 3a and 3b schematically shows a cross-sectional view of the control surface assembly 2 in an unlocked position. When in the unlocked position, the second coupling piece 34 is disconnected from the connection member 24, caused by pivoting the first coupling piece 32 about the pivot axis 28, and connected to the first coupling piece 32, resulting in a connected position, released from the connection member 24.

[0058] In an example, the actuator 20 pivots the first coupling piece 32 to a position where the bore 38 and the axially movable shaft 36 align. The second end part 52 then enters the bore 38. The axially movable shaft 36 is moved towards the bore 38 with help of the spring element 40 so a press-fit connection between the first coupling piece 32 and the control surface 16 is achieved. At the same time as the second end part 52 enters the bore 38, the first end part 50 exits the groove 46, thereby unlocking the control surface assembly 2 from the connection member 24. In the unlocked position, the actuator 20 controls the angle of the control surface 16 via the coupling element 22.

[0059] Figure 4 schematically shows a perspective view of the control surface assembly 2 according to an example of the present disclosure.

[0060] Figure 5 shows a flowchart of a method according to an example. The method relates to the control surface assembly 2 disclosed in figure 2a, 2b, 3a and 3b. The method is performed by a control device 100 for testing an actuator 20 of a control surface assembly 2. The method comprises the steps of: activating slOl the actuator 20 to pivoting the first coupling piece 32 when the control surface 16 is locked in locked position, and determiningslO2, by the sensor 21, if the first coupling piece 32 pivots when activating slOl the actuator 20.

[0061] Figure 6 depicts schematically a data processing unit comprising a computer program product (P) for testing an actuator 20 of a control surface assembly 2. Figure 6 depicts a data processing unit 410 comprising a computer program product comprising a non-transitory computer-readable storage medium 412. The non-transitory computer-readable storage medium 412 having thereon a computer program comprising program instructions. The computer program is loadable into a data processing unit 410 and is configured to cause a processor 411 to carry out the method for testing an actuator 20 of a control surface assembly 2.

[0062] Figure 7 schematically illustrates a side view of an aerial vehicle 1, provided with a control surface assembly 2 according to an example. The aerial vehicle 1 comprises an elongated body 40, with a front part 60 and a rear part 80. The rear part 80 comprises an opening 100 for an engine 120, such as a jet engine or a rocket engine. The aerial vehicle 1 comprises fins 4 and control surfaces 16. At the rear part 80 of the aerial vehicle 1, fins 4 are arranged, which are provided with steerable control surfaces 16. Several fins 4 and control surfaces 16 may be arranged on the aerial vehicle 1 in order to increase the steering ability of the aerial vehicle 1. Each control surface 16 is provided with a control surface assembly 2 according to the present disclosure. The control surface assembly 2 comprises components, that are arranged at the control surface 16 and within the body 40 of the aerial vehicle 1.

[0063] The person skilled in the art realizes that the present disclosure is not limited to the preferred embodiments described above. The person skilled in the art further realizes that modifications and variations are possible within the scope of the appended claims.

[0064] Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims.

Claims

CLAIMS1. A control surface assembly (2) for an aerial vehicle (1), the control surface assembly (2) comprising:- an actuator (20) connectable to a control surface (16), wherein the actuator (20) is configured to steer the control surface (16);- a coupling element (22) arranged to connect the actuator (20) to the control surface (16), wherein the coupling element (22) comprises a first coupling piece (32) and a second coupling piece (34), wherein the first coupling piece (32) is pivotally arranged about a pivot axis (28) and connected to the actuator (20), the second coupling piece (34) is connected to the control surface (16), wherein the second coupling piece (34) is in contact with a connection member (24) in a locked position, wherein in the locked position the connection member (24) is arranged to limit the movement of the second coupling piece (34) and lock the control surface (16) in a fixed position and;wherein the second coupling piece (34) is disconnected from the connection member (24) in an unlocked position, wherein in the unlocked position the second coupling piece (34) is connected to the first coupling piece (32) and arranged to be pivoted by rotating the first coupling piece (32) about the pivot axis (28), characterized in that the first coupling piece (32) is configured to be pivoted to a position in which the second coupling piece (34) connects to the first coupling piece (32), so that the second coupling piece (34) is fixed to the first coupling piece (32) for steering the control surface (16).

2. The control surface assembly (2) according to claim 1, wherein the second coupling piece (34) is disconnected from the first coupling piece (32) in the locked position, so that the first coupling piece (32) is free to pivot about the pivot axis (28) by the actuator (20).

3. The control surface assembly (2) according to any of claims 1-2, wherein the second coupling piece (34) comprises an axially movable shaft (36), which axially movable shaft (36) comprises a first end part (50) and a second end part (52).

4. The control surface assembly (2) according to claim 3, wherein the connection member (24) comprises a groove (46), which is configured to receive the first end part (50) of the axially movable shaft (36) of the second coupling piece (34), wherein, in the locked position, the first end part (50) of the axially movable shaft (36) is positioned in the groove (46), and wherein the first end part (50) is disconnected from the groove (46) in the unlocked position.

5. The control surface assembly (2) according to any of claims 3 or 4, wherein the first coupling piece (32) comprises a bore (38), which is configured to receive the second end part (52) of the axially movable shaft (36).

6. The control surface assembly (2) according to any of claims 3-5, wherein a spring element (40) is arranged to axially move and / or displace the axially movable shaft (36) towards first coupling piece (32).

7. The control surface assembly (2) according to any one of claims 5-6, wherein the second end part (52) of the axially movable shaft (36) and the bore (38) have complementary shapes arranged to, upon engaging, connect the first coupling piece (32) and the second coupling piece (34).

8. The control surface assembly (2) according to claim 7, wherein the complementary shapes of the second end part (52) of the axially movable shaft (36) and the bore (38) are conically shaped.

9. The control surface assembly (2) according to claim 7 or 8, wherein first coupling piece (32) is configured to, upon being rotated by the actuator (20), move the axially movable shaft (36) away from the pivot axis (28).

10. The control surface assembly (2) according to any one of claims 5-9, wherein when the axially movable shaft (36) is in a first position, the second coupling piece (34) is locked in the locked position wherein the first end part (50) of the axially movable shaft (36) is in contact with the groove (46) and when the axially movable shaft (36) is in a secondposition, axially displaced in the opposite direction to the first position, the second coupling piece (34) is in the unlocked position, wherein the first end part (50) of the axially movable shaft (36) has disengaged from the groove (46) and the axially movable shaft (36) is connected to the bore (38).

11. An aerial vehicle (1), comprising a control surface assembly (2) according to any of the preceding claims and a control surface (16), where in control surface assembly (2) is arranged to unlock and pivot the control surface (16).

12. A method, performed by a control device (100), for testing an actuator (20) of a control surface assembly (2) according to claim 1, comprising:- activating (slOl) the actuator (20) for pivoting the first coupling piece (32) when the control surface (16) is locked in locked position, and- determining (sl02), by a sensor (21), if the first coupling piece (32) pivots when activating (slOl) the actuator (20).

13. A computer program (P) comprising instructions which, when the program (P) is executed by a data processing unit (410) cause the data processing unit (410) to carry out the method according to claim 12.

14. A computer-readable medium (412) comprising instructions, which when executed by a data processing unit (410), cause the data processing unit (410) to carry out the method according to claim 12.

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