FLAPPING WING AERIAL VEHICLE

Abstract

A flapping wing aerial vehicle comprises at least a first and second wing, a support structure, to which the wings are connected, at least one flapping mechanism, comprising at least a first spar and a flapping actuator, the at least first spar being attached to the wing membrane of the first wing and/or the second wing, the flapping actuator being configured to pivot said at least one spar with respect to a flapping pivot axis substantially parallel to a Z-axis for inducing a flapping motion of said first wing and/or second wing; a first attitude control mechanism, configured to induce a pitch moment; a second attitude control mechanism, configured to induce a yaw moment; a third attitude control mechanism, configured to induce a roll moment; and an attitude controller, wherein the first attitude control mechanism, the second attitude control mechanism, and the third attitude control mechanism are separate mechanisms.

Claims

1.-12. (canceled)

13. A flapping wing aerial vehicle, for which an imaginary right-hand sided axis system comprising an X-axis, a Y-axis, and a Z-axis is defined, the flapping wing aerial vehicle comprising: at least a first wing and a second wing, the second wing being opposite to the first wing, each wing comprising a wing membrane, a root section, and a leading edge section; a support structure, to which the wings are directly or indirectly connected, the support structure extending substantially parallel to the Z-axis; at least one flapping mechanism, comprising at least a first spar and a flapping actuator, the at least a first spar being attached to the wing membrane of the first wing and/or the second wing, the flapping actuator being configured to pivot said at least one spar with respect to a flapping pivot axis substantially parallel to the Z-axis for inducing a flapping motion of said first wing and/or second wing; a first attitude control mechanism, configured to induce a pitch moment to the flapping wing aerial vehicle; and an attitude controller, configured to generate respectively a pitch control signal for controlling said first attitude control mechanism to induce a pitch moment; wherein the first wing comprises a first leading edge spar and the second wing comprises a second leading edge spar, said first and second leading edge spars being pivotable with respect to a first pivot axis substantially parallel to the Z-axis, allowing the dihedral angle of the corresponding wing to be changed, wherein the first attitude control mechanism comprises a first actuator, configured to pivot the first and second leading edge spars simultaneously in substantially the same direction with respect to a YZ-plane, for inducing a pitch moment to the flapping wing aerial vehicle, and wherein the first actuator is configured to pivot the first and second leading edge spars and the flapping actuator with respect to said first pivot axis.

14. The flapping wing aerial vehicle according to claim 13, wherein the first actuator comprises a servomotor with at least a first pivoting arm, coupled to the first and second leading edge spars, respectively, for controlling a pivotal movement of said first and second leading edge spars.

15. The flapping wing aerial vehicle according to claim 13, wherein the first wing and the second wing are spaced apart from each other and comprise a first root spar and a second root spar, respectively, attached to the root section of the respective wing membrane, and wherein the root spars are configured to pivot with respect to a second pivot axis that is substantially parallel to the Y-axis, allowing the inclination angle of the corresponding wing to be changed.

16. The flapping wing aerial vehicle according to claim 15, further comprising a second attitude control mechanism, configured to induce a yaw moment to the flapping wing aerial vehicle, wherein the first attitude control mechanism and the second attitude control mechanism are separate mechanisms, and wherein the second attitude control mechanism comprises a second actuator configured to pivot the first and second root spars with respect to said second pivot axis in substantially opposite directions for inducing a yaw moment to the flapping wing aerial vehicle.

17. The flapping wing aerial vehicle according to claim 16, wherein the second attitude control mechanism further comprises a control arm arranged between the first wing and the second wing, the first root spar being coupled to said control arm near one end thereof, and the second root spar being coupled to said control arm near another, opposing, end thereof, wherein said second actuator is configured to pivot the control arm with respect to a third pivot axis that is substantially parallel to the Z-axis, and wherein a pivoting movement of said control arm increases the inclination angle of one of the first and second wings, and decreases the inclination angle of the other one of the first and second wings.

18. The flapping wing aerial vehicle according to claim 17, wherein the control arm is arranged near a trailing edge of the first wing and the second wing, respectively.

19. The flapping wing aerial vehicle according to claim 16, wherein the second actuator comprises a servomotor with a pivoting arm, coupled to the first and second root spar, respectively, for controlling the movement of said first and second root spars.

20. The flapping wing aerial vehicle according to claim 13, further comprising a third attitude control mechanism, configured to induce a roll moment to the flapping wing aerial vehicle, wherein the first attitude control mechanism and the third attitude control mechanism are separate mechanisms, and wherein the third attitude control mechanism is configured to induce a roll moment to the flapping wing aerial vehicle by changing the flapping motion of the first and/or the second wing, for example by providing a flapping frequency and/or a flapping range for the first wing that is different from that for the second wing.

21. The flapping wing aerial vehicle according to claim 13, comprising two flapping mechanisms, each flapping mechanism comprising a spar that is attached to the wing membranes of the first wing, respectively, the second wing, and a flapping actuator, wherein the attitude controller is configured to control the flapping motion induced by each of the two flapping actuators separately.

22. The flapping wing aerial vehicle according to claim 20, wherein the third attitude control mechanism comprises two flapping mechanisms, and wherein the attitude controller is configured to send a first roll signal to the first flapping mechanism and a second roll control signal to the second flapping mechanism.

23. The flapping wing aerial vehicle according to claim 13, wherein the first attitude control mechanism is configured to induce only a pitch moment.

24. The flapping wing aerial vehicle according to claim 16, wherein the second attitude control mechanism is configured to induce only a yaw moment.

25. The flapping wing aerial vehicle according to claim 20, wherein the third attitude control mechanism is configured to induce only a roll moment.

26. The flapping wing aerial vehicle according to claim 13, wherein the first wing and the second wing each comprise a back wing portion and a front wing portion, adjoined at the root section of the wing, wherein the back wing portion and the front wing portion are configured to move away from and towards each other when a flapping motion of the wing is induced.

Description

[0062] These and other aspects of the invention as claimed will be more readily appreciated as the same becomes better understood by reference to the following detailed description and considered in connection with the accompanying drawings in which like reference symbols designate like parts.

[0063] FIG. 1 schematically shows an isometric view of a flapping wing aerial vehicle according to the invention;

[0064] FIG. 2A schematically shows an effect of operating an embodiment of a first attitude control mechanism of a flapping wing aerial vehicle according to the invention;

[0065] FIG. 2B schematically shows an effect of operating an embodiment of a second attitude control mechanism of a flapping wing aerial vehicle according to the invention;

[0066] FIG. 2C schematically shows an effect of operating an embodiment of a third attitude control mechanism of a flapping wing aerial vehicle according to the invention;

[0067] FIG. 3A schematically shows an embodiment of a first attitude control mechanism of a flapping wing aerial vehicle according to the invention;

[0068] FIG. 3B schematically shows an embodiment of a second attitude control mechanism of a flapping wing aerial vehicle according to the invention;

[0069] FIG. 3C schematically shows an embodiment of a flapping mechanism of a flapping wing aerial vehicle according to the invention; and

[0070] FIG. 4 schematically shows an isometric view of an embodiment of a first attitude control mechanism of a flapping wing aerial vehicle according to the invention.

[0071] Schematically shown in FIG. 1 is a flapping wing aerial vehicle, here a flapping wing micro aerial vehicle, FWMAV, for which an X-axis X, a Y-axis Y and a Z-axis Z is defined. In FIG. 1, the FWMAV is oriented substantially vertically, the positive X-axis X being directed substantially forwards. When hanging substantially still, this flight mode corresponds to a hovering position of the FWMAV. In this hovering position, the positive Y-axis Y points generally to the right, and the positive Z-axis Z generally points downwards.

[0072] It is desired that the FWMAV can manoeuvre with respect to this hovering position. For example, it is desired when the FWMAV can perform a roll manoeuvre, wherein the FWMAV rotates around the X-axis X, a pitch manoeuvre, wherein the FWMAV rotates around the Y-axis Y, and a yaw manoeuvre, wherein the FWMAV rotates around the Z-axis Z.

[0073] As can be seen in FIG. 1, the FWMAV comprises a first wing 2 and a second wing 3, the second wing 3 being opposite to the first wing 2. In the specific embodiment, the first wing 2 and the second wing 3 are wing pairs, the first wing 2 comprising a back wing portion 2A and a front wing portion 2B, adjoined at a root section 22 of the wing 2 and the second wing 3 also comprising a back wing portion 3A and a front wing portion 3B, adjoined at a root section 32 of the wing 3. The wings 2, 3 comprising a back wing portion 2A, 3A and a front wing portion 2B, 3B is not strictly necessary.

[0074] Both wings 2, 3 comprise a wing membrane 21, 31, a root section 22, 32, and a leading edge section 23, 33.

[0075] Each wing portion 2A, 2B, 3A, 3B comprises a spar 51, 52, 53, 54, respectively, arranged near the leading edge section 23, 33 of the wing 2, 3 and attached to the wing membranes 21, 31, thereof.

[0076] The spars 51, 52, 53, 54 each form a part of a flapping mechanism 5A, 5B, said flapping mechanism further comprising a flapping actuator 55A, 55B. The flapping actuators 55A, 55B are each configured to pivot the at least one spar 51, 52, 53, 54 with respect to a flapping pivot axis F1, F2 that is substantially parallel to the Z-axis Z for inducing a flapping motion of said first wing 2 and said second wing 3, respectively.

[0077] This flapping motion is better shown with respect to FIG. 3C, wherein a flapping mechanism 5 is shown, comprising a flapping actuator 55, a first spar 51, 53 and a second spar 52, 54. The spars 51, 52, 53, 54 are movable towards and away from each other between an extended position (shown in solid lines, corresponding to spars 51, 52, 53, 54) and a collapsed position (shown in dashed lines, corresponding to spars 51, 52, 53, 54) by activating the flapping actuator 55, inducing a flapping motion M1 of the corresponding respective wings. Hence, the front wing portion and the back wing portion, that are attached to the spars 51, 52, 53, 54 are configured to move away from and towards each other when a flapping motion M1 of the wing is induced. By flapping the wings, a lift force is produced.

[0078] As visible in FIG. 1, the FWMAV shown comprises two flapping mechanisms 5A, 5B. In the embodiment shown, an attitude controller 9 is configured to control the flapping motion induced by each of the two flapping actuators 55A, 55B separately.

[0079] As such, an attitude control mechanism 8 is provided that comprises two flapping mechanisms 5A, 5B and wherein the attitude controller 9 is configured to send a first roll signal to the first flapping mechanism 5A, e.g. to the first flapping actuator 55A and a second roll control signal to the second flapping mechanism 5B, e.g. to the second flapping actuator 55B.

[0080] The effect of the attitude control mechanism is shown more clearly in FIG. 2C, wherein the flapping motion M1 of the wings 2, 3 with respect to a flapping pivot axis F1, F2 is indicated. In a normal condition, when there is no influence of wind, each of the wings 2, 3 may produce a lift force L, substantially equal for the first wing 2 and the second wing 3, such that the FWMAV can be stably controlled. The combined lift forces L may be substantially equal in magnitude to the mass of the FWMAV, such that the FWMAV is hanging still in the air, i.e. such that the FWMAV is hovering. The same lift force L, produced in a normal condition, is also shown in FIGS. 2A and 2B, as will be explained further below.

[0081] When the attitude control mechanism now changes the flapping motion M1 of the first wing 2 and/or the second wing 3, a roll moment R may be induced. Changing the flapping motion M1 can for example be achieved by providing a flapping range or by providing a flapping frequency for the first wing 2 that is different from that for the second wing 3, with the latter possibility, i.e. changing the flapping frequency, shown in FIG. 2C.

[0082] When the flapping frequency is changed for the first wing 2 with respect to the second wing 3, at least a roll moment R is induced. In FIG. 2C, it is shown that by decreasing the flapping frequency of the first wing 2 a lower lift force LR1 is produced and that by increasing the flapping frequency of the second wing 3 a higher lift force LR2 is produced.

[0083] Hence, the FWMAV produces a roll moment R that is positive with respect to the X-axis X, the FWMAV rolling to the right.

[0084] Hence, shown with respect to FIGS. 1, 2C, and 3C is an attitude control mechanism configured to induce a roll moment R to the FWMAV.

[0085] Referring again to FIG. 1, it is visible that the first wing 2 and the second wing 3 are spaced apart from each other and comprise a first root spar 24 and a second root spar 34, respectively. Each root spar 24, 34 is attached to the root section 22, 32 of the respective wing membrane 21, 31.

[0086] The root spars 24, 34 are configured to pivot with respect to a pivot axis PA2 that is substantially parallel to the Y-axis Y, as is better visible with reference to FIG. 2B. By pivoting the root spars 24, 34, the inclination angle of the wing 2, 3 is changed.

[0087] The root spars 24, 34 may further be pulled inwards, i.e. in the direction of the support structure 4, increasing the tension in the wing membranes 2. When the root spars 24, 34 can be pulled inwards, they may be relatively flexible to allow this movement. However, other components of the FWMAV may also have some play to allow this movement.

[0088] When the root spars 24, 34 are pulled inwards, the movement of the root spars 24, 34 is not a pure pivotal movement with respect to the pivot axis PA2, but a combination of a translational and a pivotal movement.

[0089] The FWMAV of the shown embodiment comprises an attitude control mechanism comprising a second actuator configured to pivot the first root spar 24 and the second root spar 34 with respect to said pivot axis PA2 in substantially opposite directions for inducing a yawing moment J to the flapping wing micro aerial vehicle.

[0090] The movement J1, J2 in opposite directions is more clearly shown in FIG. 2B. Shown in FIG. 2B is the lift vector L that is generated in a normal condition. When the root spars 24, 34 are now pivoted by the attitude control mechanism, as shown, the lift vector L is tilted. In the specific example of FIG. 2B, the lift vector LJ1 of the first wing 2 is tilted in a direction parallel to the negative X-axis X, i.e. backwards, and the lift vector LJ2 of the second wing 3 is tilted in a direction parallel to the positive X-axis X, i.e. forwards. This results in the generation of a yaw moment J, in this example a yaw moment J that is positive with respect to the Z-axis Z, the FWMAV yawing in a clockwise direction.

[0091] An schematic, exemplary embodiment of an attitude control mechanism 7 is shown in FIGS. 1 and 3B. The attitude control mechanism 7 shown in FIGS. 1 and 3B comprises a control arm 72 arranged between the first wing 2 and the second wing 3, the first root spar 24 being coupled to said control arm 72 near one end thereof, and the second root spar 34 being coupled to said control arm 72 near another, opposing, end thereof, wherein said second actuator 71 is configured to pivot the control arm 72 with respect to a third pivot axis PA3 that is substantially parallel to the Z-axis Z, and wherein a pivoting movement J1, J2 of said control arm 72 increases the inclination angle of one of the first 2 and second 3 wings, and decreases the inclination angle of the other one of the first 2 and second 3 wings.

[0092] As shown in FIG. 3B, the control arm 72 comprises two holes 73, 74, arranged at opposite ends of the control arm 72. The root spars 24, 34 extend through the holes in the control arm 72, such that a pivotal movement J1, J2 with respect to a third pivot axis PA3 that is arranged substantially parallel to the Z-axis of the control arm 72 by the actuator 71, shown in FIG. 3B, results in a pivotal movement of the root spars 24, 34 with respect to the second pivot axis PA 2 that is arranged substantially parallel to the Y-axis Y, shown in FIG. 2B.

[0093] The second actuator 71 shown in FIG. 3B comprises a servomotor with a pivoting arm 75, coupled to the first 24 and second 34 root spar via the control arm 72, respectively, for controlling the movement of said first 24 and second 34 root spars.

[0094] As further visible in FIG. 1, the control arm 72 is arranged near a trailing edge of the first wing 2 and the second wing 3, respectively.

[0095] Hence, shown with respect to FIGS. 1, 2B, and 3B is an attitude control mechanism, configured to induce a yaw moment J to the FWMAV.

[0096] Referring again to FIG. 1, further shown are a support structure 4, to which the wings 2, 3, are indirectly connected, the support structure 4 extending substantially parallel to the Z-axis Z, an embodiment of an attitude control mechanism 6, configured to induce a pitch moment P to the FWMAV, and a battery 10. Said attitude control mechanism is explained in more detail with reference to FIGS. 2A, 3A, and 4.

[0097] Shown in FIG. 2A are a first wing 2 and a second wing 3, the first wing comprising first leading edge spars 51, 52 attached to the wing membrane 21 of the first wing 2 near the leading edge section thereof, and the second wing 3 comprising second leading edge spars 53, 54 attached to the wing membrane 31 of the second wing 3 near the leading edge section thereof. The first 51, 52 and second 53, 54 leading edge spars are pivotable with respect to a first pivot axis PA1 substantially parallel to the Z-axis Z, such that a pivotal movement P1, P2 of the leading edge spars 51, 52, 53, 54 can be induced.

[0098] When such a pivotal movement P1, P2 is induced, the dihedral angle of the wings 2, 3 is changed, and the lift vector LP1, LP2 is moved along a line that is substantially parallel to the X-axis X, as shown. As the movement P1, P2 of the wings 2, 3 is a pivotal movement, the lift vector LP1, LP2 will however generally not purely be moved along a line that is substantially parallel to the X-axis X, but also move inwards somewhat, i.e. along a line parallel to the Y-axis Y. This latter effect is relatively minor.

[0099] With the lift vectors LP1, LP2 being moved towards a location in front of the centre of gravity CG, in the specific example of FIG. 2A, a pitching moment M is generated that is negative with respect to the Y-axis Y.

[0100] In the specific embodiment of FIG. 3A, the first attitude control mechanism 6 comprises a first actuator 61, configured to pivot the first 51, 52 and second 53, 54 leading edge spars simultaneously in substantially the same direction with respect to a YZ-plane, for inducing a pitching moment to the flapping wing micro aerial vehicle. The pivotal movement P1, P2 of the first 51, 52 and second 53, 54 leading edge spars is indicated.

[0101] Visible in FIG. 3A is that the first actuator 61 is configured to not only pivot the first 51, 52 and second 53, 54 leading edge spars, but also the flapping actuators 55A, 55B with respect to said first pivot axis PA1.

[0102] In the specific embodiment of FIG. 3A, the first actuator 61 comprises a servomotor with at least a first 62 pivoting arm, coupled to the first 51, 52 and second 53, 54 leading edge spars via connection arms 63, 64, respectively, for controlling said pivotal movement P1, P2 of said first 51, 52 and second 53, 54 leading edge spars.

[0103] These connection arms 63, 64 are more clearly shown in FIG. 4, which shows a mutual connection between connection arms 63, 64 by means of a gear wheel. One of the connection arms 64 is connected to the pivoting arm 62 of the actuator 61, said connection arm 64 being directly controlled by the actuator 61. Due to the mutual connection of the connection arms 63, 64, when the second connection arm 64 is pivoted in a particular direction, the first connection arm 63 is similarly pivoted in the same direction with respect to the YZ-plane. Alternatively, it can be recognized that the first connection arm 63 and the second connection arm 64 are rotated in opposite directions.

[0104] In the embodiment shown, the connection arms 63, 64 are each connected to a frame 56A, 56B of the flapping actuator 55A, 55B, respectively, and can influence the position of this frame 56A, 56B. As both the leading edge spars 51, 52, 53, 54 as well as the movement of the root spar 24, 34 will effect a movement of the leading edge spar 51, 52, 53, 54, as these are mutually connected via flapping actuators 55A and 55B respectively.

[0105] Referring again to FIG. 1, the FWMAV further comprises an attitude controller 9, configured to generate respectively a pitch control signal for controlling said first attitude control mechanism 6 to induce a pitch moment P, a yaw control signal for controlling said second attitude control mechanism 7 to induce a yaw moment J, and two roll control signals for controlling said third attitude control mechanism 8 to induce a roll moment R.

[0106] Further with reference to FIG. 1, a FWMAV is shown comprising a first attitude control mechanism 6, the second attitude control mechanism 7, and the third attitude control mechanism 8, which are embodied as separate mechanisms.

[0107] More specifically, the first attitude control mechanism 6 is advantageously configured to induce only a pitch moment P, the second attitude control mechanism 7 is configured to induce only a yaw moment J, and the third attitude control mechanism 8 is configured to induce only a roll moment R.

[0108] As explained in detail above, a flapping wing aerial vehicle 1, for which an imaginary right-hand sided axis system comprising an X-axis X, a Y-axis Y, and a Z-axis Z is defined, comprises: [0109] at least a first wing 2 and a second wing 3, the second wing 3 being opposite to the first wing 2, each wing 2, 3 comprising a wing membrane 21, 31, a root section 22, 32, and a leading edge section 23, 33; [0110] a support structure 4, to which the wings 2, 3 are directly or indirectly connected, the support structure 4 extending substantially parallel to the Z-axis Z; [0111] at least one flapping mechanism 5, 5A, 5B, comprising at least a first spar 51, 52, 53, 54 and a flapping actuator 55, 55A, 55B, the at least a first spar 51, 52, 53, 54 being attached to the wing membrane 21, 31 of the first wing 2 and/or the second wing 3, the flapping actuator 55, 55A, 55B being configured to pivot said at least one spar 51, 52, 53, 54 with respect to a flapping pivot axis F1, F2 substantially parallel to the Z-axis Z for inducing a flapping motion M1 of said first wing 2 and/or second wing 3; [0112] a first attitude control mechanism 6, configured to induce a pitch moment P to the flapping wing aerial vehicle; [0113] a second attitude control mechanism 7, configured to induce a yaw moment J to the flapping wing aerial vehicle; [0114] a third attitude control mechanism 8, configured to induce a roll moment R to the flapping wing aerial vehicle; [0115] an attitude controller 9, configured to generate respectively a pitch control signal for controlling said first attitude control mechanism 6 to induce a pitch moment P, a yaw control signal for controlling said second attitude control mechanism 7 to induce a yaw moment J, and roll control signal for controlling said third attitude control mechanism 8 to induce a roll moment R;
wherein the first attitude control mechanism 6, the second attitude control mechanism 7, and the third attitude control mechanism 8 are separate mechanisms. The first and second wings 2, 3 respectively comprise first 51, 52 and second 53, 54 leading edge spars being pivotable with respect to a first pivot axis PA1 substantially parallel to the Z-axis. The first attitude control mechanism 6 comprises a first actuator 61, configured to pivot the first 51, 52 and second 53, 54 leading edge spars simultaneously in substantially the same direction with respect to a YZ-plane. The first actuator 61 is configured to pivot the first 51, 52 and second 53, 54 leading edge spars and the flapping actuator 55, 55A, 55B with respect to said first pivot axis PA1.

[0116] As required, detailed embodiments of the present invention are disclosed herein. However, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the invention.

[0117] The terms a/an, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language, not excluding other elements or steps). Any reference signs in the claims should not be construed as limiting the scope of the claims or the invention.

[0118] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0119] The term coupled, as used herein, is defined as connected, although not necessarily directly.