U.S. patent application number 14/198418 was filed with the patent office on 2018-03-22 for air vehicle flight mechanism and control method.
This patent application is currently assigned to AeroVironment, Inc.. The applicant listed for this patent is AeroVironment, Inc.. Invention is credited to Alexander Andryukov, Bart Dean Hibbs, Matthew Todd Keennon, Karl Robert Klingebiel, John Peter Zwaan.
Application Number | 20180079504 14/198418 |
Document ID | / |
Family ID | 43298202 |
Filed Date | 2018-03-22 |
United States Patent
Application |
20180079504 |
Kind Code |
A9 |
Keennon; Matthew Todd ; et
al. |
March 22, 2018 |
AIR VEHICLE FLIGHT MECHANISM AND CONTROL METHOD
Abstract
Heavier-than-air, aircraft having flapping wings, e.g.,
ornithopters, where angular orientation control is effected by
variable differential sweep angles of deflection of the flappable
wings in the course of sweep angles of travel and/or the control of
variable wing membrane tension.
Inventors: |
Keennon; Matthew Todd; (Simi
Valley, CA) ; Klingebiel; Karl Robert; (Simi Valley,
CA) ; Andryukov; Alexander; (Simi Valley, CA)
; Hibbs; Bart Dean; (Simi Valley, CA) ; Zwaan;
John Peter; (Simi Valley, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AeroVironment, Inc. |
Monrovia |
CA |
US |
|
|
Assignee: |
AeroVironment, Inc.
Monrovia
CA
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20150008279 A1 |
January 8, 2015 |
|
|
Family ID: |
43298202 |
Appl. No.: |
14/198418 |
Filed: |
March 5, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13532699 |
Jun 25, 2012 |
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14198418 |
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13023772 |
Feb 9, 2011 |
8210471 |
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13532699 |
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PCT/US10/37540 |
Jun 4, 2010 |
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13023772 |
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61184748 |
Jun 5, 2009 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B64C 2201/025 20130101;
B64C 33/025 20130101; B64C 2201/146 20130101; B64C 33/02 20130101;
B64C 19/00 20130101; B64C 2201/10 20130101 |
International
Class: |
B64C 33/02 20060101
B64C033/02; B64C 19/00 20060101 B64C019/00 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] This invention was made with Government support under
contract no. W31P4Q-06-C-0435 awarded by the US Army Aviation and
Missile Command. The US Government has certain rights in the
invention.
Claims
1. A method of air vehicle control, comprising: flapping first and
second control surfaces; and hovering the first and second control
surfaces in response to the flapping without the benefit of an
additional control surface.
2. An air vehicle apparatus, comprising: first and second flapping
control surfaces; wherein the first and second flapping control
surfaces are capable of providing hovering and control moments
without the benefit of additional control surfaces.
3. A method of air vehicle control, comprising: flapping first and
second wings horizontally about a fuselage, the first and second
wings having a first and second variable differential sweep angles
of deflection, respectively; and providing vertical and horizontal
vehicle orientation control in response to the horizontal
flapping.
4. The method of claim 3, further comprising: generating a roll
moment in response to the first sweep angle being larger than the
second sweep angle.
5. The method of claim 3, further comprising: inducing a left yaw
moment in the air vehicle in response to: deflecting the first wing
less than deflection of the second wing during a majority of a back
stroke of the flapping; and deflecting the second wing less than
deflection of the first wing during a majority of the forward
stroke of the flapping.
6. The method of claim 3, further comprising: inducing a right yaw
moment in the air vehicle in response to: deflecting the first wing
more than deflection of the second wing during a majority of a back
stroke of the flapping; and deflecting the second wing more than
deflection of the first wing during a majority of the forward
stroke of the flapping.
7. The method of claim 3, further comprising: inducing a forward
pitching moment in the air vehicle in response to: deflecting first
and second wings during a first portion of a forward stroke of the
flapping less than during a second portion of the forward stroke of
the flapping.
8. The method of claim 3, further comprising: inducing a forward
pitching moment in the air vehicle in response to: deflecting first
and second wings during a first portion of a backward stroke of the
flapping more than during a second portion of the backwards stroke
of the flapping.
9. The method of claim 3, further comprising: inducing a backward
pitching moment in the air vehicle in response to: deflecting first
and second wings during a first portion of a forward stroke of the
flapping more than during a second portion of the forward stroke of
the flapping.
10. The method of claim 3, further comprising: inducing a backward
pitching moment in the air vehicle in response to: deflecting first
and second wings during a first portion of a backward stroke of the
flapping less than during a second portion of the backwards stroke
of the flapping.
11. A method of air vehicle control, comprising: flapping first and
second airfoils about respective first and second adjacent pivot
points, the first and second airfoils configured to provide air
vehicle orientation control without the benefit of a third
airfoil.
12. The method of claim 11, wherein the flapping further comprises:
flapping the first airfoil in a first sweep angle about the first
pivot point; and flapping the second airfoil in a second sweep
angle about the second pivot point, the first and second sweep
angles being different to induce a roll moment in the air
vehicle.
13. The method of claim 11, wherein the flapping further comprises:
modulating a first and second boom stops of a first wing to limit a
sweep angle of deflection of the first wing between a forward
stroke boom position a backward stroke boom position.
14. The method of claim 13, wherein the first and second boom stops
are biased to provide a greater sweep angle of deflection in the
forward stroke than in the backward stroke to produce a net yawing
moment of the air vehicle.
15. The method of claim 13, wherein the first and second boom stops
define a neutral boom position to produce the same boom angle of
deflection of the first wing in the forward stroke as in the
backward stroke.
16. An air vehicle, comprising: a processor; at least one drive
motor in communication with the processor; a first flapping wing in
communication with one of the at least one drive motor; a second
flapping wing in communication with one of the at least one drive
motors; wherein the processor and the at least one drive motor are
configured to drive the first and second flapping wings to provide
lift and control moments without the benefit of either horizontal
or vertical stabilizers.
17. The air vehicle of claim 16, wherein the processor is
configured to provide commands resulting in first and second wing
movement selected from the group consisting of: variable
differential sweep angles of deflection of the first and second
flappable wings in the course of respective sweep angles of travel,
variable differential luffing of the respective first and second
flapping wings, and variable and differential angular velocity of
the respective first and second flapping wings.
18. The apparatus of claim 16, further comprising: means for
providing respective deflection angles for both a forward stroke
and a backward stroke of the first flapping wing.
19. The apparatus of claim 18, wherein the means for providing
respective deflection angles comprises a boom restraining yoke
slideably coupled to a first boom of the first flapping wing.
20. The apparatus of claim 16, wherein the means for providing
respective deflection angles comprises first and second boom stops
to engage the first flapping wing.
21. The apparatus of claim 16, further comprising: means for
providing luffing of the first flapping wing.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of International
Application No. PCT/US10/37540 filed Jun. 4, 2010 which claims the
benefit of U.S. Provisional Patent Application No. 61/184,748,
filed Jun. 5, 2009, and this application claims the benefit of U.S.
Provisional Patent Application No. 61/184,748 filed Jun. 5, 2009,
the disclosures of which are hereby incorporated herein by
reference in their entirety.
TECHNICAL FIELD OF ENDEAVOR
[0003] Heavier-than-air, aircraft having flapping wings where
angular orientation control is effected by variable differential
sweep angles of deflection of the flappable wings in the course of
sweep angles of travel and/or the control of variable wing membrane
tension.
BACKGROUND
[0004] Radio-controlled, heavier-than-air, aircraft having
sustainable beating wings, e.g., ornithopters.
SUMMARY
[0005] Exemplary embodiments of an air vehicle comprise a support
structure, e.g., a structural element of a fuselage, where the
support structure may further comprise a flapping drive element,
e.g., one or more motors configured to generate flapping angular
velocity, a first airfoil rotatably attached, e.g., via a joint, to
the support structure and a second airfoil rotatably attached,
e.g., via a joint, to the support structure. The first airfoil may
comprise a root-to-wingtip spar, or mast, a root spar, or boom, and
a scrim, or membrane, attached to, e.g., wrapped about or wrapped
about a tube that is disposed about, the first mast and the first
root spar. The first airfoil is configured to be driven to flap via
the flapping drive element, e.g., via gearing, pulleys, and/or
linkages. The second air foil comprises a second mast, second root
spar, and a second membrane attached to the second root spar and
the second mast. The second airfoil is also configured to be driven
to flap via the flapping drive element. Air vehicle control about
at least one axis of the vehicle, e.g., pitch, yaw, or roll, is
effected by at least one of: (a) variable membrane luffing, e.g.,
via increasing and decreasing the angle between the mast and the
root spar by the rotating the root spar relative to the mast
thereby loosening or making taut the surface of the membrane; (b)
variable root spar rotation travel limitation, e.g., via
repositionable boom tip travel stops, and (c) variable motor drive
speed, e.g., via a flapping drive element comprising two motors,
each driving one airfoil.
[0006] Exemplary embodiments include an air vehicle control device
comprising: a first flappable wing having a sweep angle of travel,
wherein the first flappable wing comprises a membrane attached to a
root spar and a mast, the membrane having surface tension
adjustable via rotation of the root spar relative to the mast; a
second flappable wing having a sweep angle of travel, wherein the
second flappable wing comprises a second membrane attached to a
second root spar and a second mast, the membrane having surface
tension adjustable via rotation of the second root spar relative to
the second mast; wherein the first flappable wing extends in a
radial direction from the air vehicle and the second flappable wing
extends in a radial direction from a side of the air vehicle
substantially opposite the first flappable wing; and thereby
configured to generate at least one of: a pitching torque, a
rolling torque and a yawing torque, by generating a difference
between luffing of the first flappable wing and luffing of the
second flappable wing. Other exemplary embodiments have the first
flappable wing further comprising a sweep angle of deflection
comprising a forward sweep angle of deflection and a backward sweep
angle of deflection; and a second flappable wing further comprising
a sweep angle of deflection comprising a forward sweep angle of
deflection and a backward sweep angle of deflection; where the
device is further configured to generate a yawing torque, by
generating at least one of: a difference between the forward sweep
angle of deflection of the first flappable wing and the forward
sweep angle of deflection of the second flappable wing, and a
difference between the backward sweep angle of deflection of the
first flappable wing and the backward sweep angle of deflection of
the second flappable wing.
[0007] Exemplary embodiments include an assembly comprising: (a) a
first arm rotatably attached to a support structure and a second
arm rotatably attached to the support structure; (b) a first wing
comprising a membrane attached to a first mast and a first root
spar, the first wing mast rotationally attached to a first arm, and
the first root spar attached to a luffing control assembly; and (c)
a second wing comprising a membrane attached to a second mast and a
second root spar, the second wing mast rotationally attached to a
second arm, and the second root spar attached to the luffing
control assembly. The luffing control assembly may comprise a first
yang attached to the first root spar while allowing for some
rotational travel of the first root spar about the mast
longitudinal axis, a second yang attached to the second root spar
while allowing for some rotational travel of the second root spar
about the mast longitudinal axis, and a repositionable yang yoke
configured to receive the first yang and the second yang. Other
exemplary embodiments include the first arm further comprising a
first repositionable stop and a second repositionable stop together
defining a rotation angle of the first wing root spar about the
first wing mast; and the second arm further comprising a third
repositionable stop and a fourth repositionable stop together
defining a rotation angle of the second wing rootspar about the
second wing mast.
[0008] Embodiments also include a method of air vehicle control
comprising (in no particular order): (a) providing: (i) a first
flappable wing having a sweep angle of travel, and having a sweep
angle of deflection comprising a forward sweep angle of deflection
and a backward sweep angle of deflection; and (ii) a second
flappable wing having a sweep angle of travel, and having a sweep
angle of deflection comprising a forward sweep angle of deflection
and a backward sweep angle of deflection; wherein the first
flappable wing extends in a radial direction from the air vehicle
and the second flappable wing extends in a radial direction from a
side of the air vehicle substantially opposite the first flappable
wing; and (b) generating at least one of: a rolling torque and a
yawing torque, by generating at least one of: a difference between
the forward sweep angle of deflection of the first flappable wing
and the forward sweep angle of deflection of the second flappable
wing, and a difference between the backward sweep angle of
deflection of the first flappable wing and the backward sweep angle
of deflection of the second flappable wing. The method of air
vehicle control may further comprise generating a pitching torque
by changing the forward angle of deflection of the first flappable
wing based on its sweep angle and by changing the forward angle of
deflection of the second flappable wing based on its sweep angle.
Some embodiments of the invention may further comprise generating a
pitching torque by changing the backward angle of deflection of the
first flappable wing based on its sweep angle and by changing the
backward angle of deflection of the second flappable wing based on
its sweep angle.
[0009] Embodiments may also include a flapping device comprising:
(a) a rotating element having a center of rotation and a plane of
rotation; (b) a first capstan mounted about a shaft, the shaft
attached to the rotating element distal from the center of rotation
and substantially perpendicular to the plane of rotation; (c) a
first rocker member rotatably attached to a support structure; (d)
a first drive link rotatably attached to the first capstan and the
first rocker member; (e) a first arm rotatably attached to the
support structure and rotatably attached to the first rocker member
via a first rocker link; (f) a second capstan mounted about the
shaft; (g) a second rocker member rotatably attached to the support
structure; (h) a second drive link rotatably attached to the second
capstan and the second rocker member; and (i) a second arm
rotatably attached to the support structure and rotatably attached
to the second rocker member via a second rocker link. Some
embodiments of the mechanism embodiment have the rotating element
rotatably attached to the support structure.
[0010] Embodiments may also include an assembly comprising: (a) a
first arm rotatably attached to a support structure and a second
arm rotatably attached to the support structure; (b) a first wing
comprising a first mast and a first spar, the first wing mast
rotationally attached to a first arm, the first arm having a first
repositionable stop and a second repositionable stop together
defining a rotation angle of the first wing spar about the first
wing mast; and (c) a second wing comprising a second mast and a
second spar, the second wing mast rotationally attached to a second
arm, the second arm having a third repositionable stop and a fourth
repositionable stop together defining a rotation angle of the
second wing spar about the second wing mast. Some embodiments of
the assembly have the first stop disposed on a first pulley and the
second stop disposed on a second pulley, where the first pulley and
the second pulley are each rotatably repositionable via an actuated
linking member and where the third stop and fourth stop are each
rotatably repositionable via a second actuated linking member.
[0011] Some embodiments of the assembly have the first stop
disposed on a first pulley and the second stop disposed on a second
pulley, where the first pulley and the second pulley are each
rotatably repositionable via an actuated linking member to increase
a first angle subtended by the first stop and the second stop, and
the third stop and fourth stop are each rotatably repositionable
via a second actuated linking member to increase a second angle
subtended by the third stop and the fourth stop.
[0012] Embodiments may also include a mechanism comprising: (a) a
rotating element having a center of rotation and a plane of
rotation; (b) a first capstan mounted about a shaft, the shaft
attached to the rotating element distal from the center of rotation
and substantially perpendicular to the plane of rotation; (c) a
second capstan mounted about the shaft; (d) a first arm mounted to
a third capstan, a first linking member connecting the third
capstan with the first capstan; (e) a second arm mounted to a
fourth capstan, a second linking member connecting the fourth
capstan with the second capstan; and (f) a third linking member
connecting the third capstan with the fourth capstan. In some
embodiments of the mechanism, the third capstan of the mechanism
may have a center of rotation, the fourth capstan may have a center
of rotation, and the center of rotation of the rotating element may
be substantially collinear with both the center of rotation of the
third capstan and the center of rotation of the fourth capstan. In
some embodiments of the mechanism, the first linking member may
comprise a cord, the second linking member may comprise a cord, and
the third linking member may comprise a cord.
[0013] Embodiments may also include a wing comprising: (a) a mast
engaging a fitment; (b) a spar engaging a fitment substantially
perpendicular to the mast; (c) a mast tube disposed about a portion
of the mast; (d) a spar tube disposed about a portion of the spar;
(e) a scrim attached to the spar tube and the mast tube; and (f) a
first batten disposed on the scrim and extending in a direction
radially from the intersection of the spar and the mast, the first
batten having a distal end proximate to an edge of the airfoil.
Some embodiments of the wing further comprise a strut disposed
proximate to the intersection of the mast and the spar, the strut
attached to the mast and the spar. Some embodiments of the wing
have the first batten further comprising a proximal end attached to
the strut. Some embodiments of the wing may further comprise a
second batten disposed on the scrim and extending in a direction
radially from the intersection of the spar and the mast, the second
batten having a distal end proximate to an edge of the airfoil.
Some embodiments of the wing have the second batten further
comprising a proximal end attached to the strut. Still other
embodiments of the wing further comprise a root socket configured
to fixedly receive the spar and configured to rotatably receive the
mast. In some embodiments, the planform of the wing is defined by
perimeter points comprising: the distal end of the first batten, a
distal end portion of the mast, a distal end portion of the spar, a
proximal end portion of the mast, and a proximal end portion of the
spar. In some embodiments, the planform of the wing is defined by
perimeter points comprising: the distal end of the first batten,
the distal end of the second batten, a distal end portion of the
mast, a distal end portion of the spar, a proximal end portion of
the mast, and a proximal end portion of the spar. Some embodiments
of the wing have a scrim comprising a polyvinyl fluoride film and
some other embodiments of the wing have a scrim comprising a
polyvinyl fluoride film further comprising a fiber mesh. For some
embodiments of the wing, the scrim comprises a fiber mesh
comprising intersecting lines of fiber mesh, the lines of fiber
mesh may be oriented at oblique angles relative to the spar tube
and relative to the mast tube. Some embodiments of the wing have
the mast comprising a carbon rod and the first batten may comprise
a carbon rod.
[0014] A flapping drive element may comprise two or more motors,
flap rate sensors, and circuitry to control and adjust the flap
rates of the two airfoils, each attached to an arm of the flapping
drive element. For example, a flapping drive element may comprise a
first motor driving a first rotating element, the first rotating
element having a center of rotation and a plane of rotation; a
first capstan mounted about a shaft, the shaft attached to the
rotating element distal from the center of rotation and
substantially perpendicular to the plane of rotation; a second
capstan mounted about the shaft; a first arm mounted to a third
capstan, a first linking member connecting the third capstan with
the first capstan; a second linking member connecting the fourth
capstan with the second capstan; and a third linking member
connecting the third capstan with the fourth capstan; a second
motor driving a second rotating element, the second rotating
element having a center of rotation and a plane of rotation; a
fifth capstan mounted about a second shaft, the second shaft
attached to the second rotating element distal from the center of
rotation and substantially perpendicular to the plane of rotation
of the second rotating element; a sixth capstan mounted about the
second shaft; a fourth linking member connecting the seventh
capstan with the fifth capstan; a second arm mounted to a eighth
capstan, a fifth linking member connecting the eighth capstan with
the sixth capstan; and a sixth linking member connecting the
seventh capstan with the eighth capstan; and circuitry controlling
a flapping rate of the first motor and the second motor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Embodiments of the invention are illustrated by way of
example and not limitation in the figures of the accompanying
drawings, and in which:
[0016] FIG. 1 depicts an aircraft having two flapping airfoils;
[0017] FIG. 2A depicts an exemplary airfoil;
[0018] FIG. 2B depicts the flexibility and luffing of the exemplary
airfoil of FIG. 2A;
[0019] FIG. 2C depicts the flexibility and luffing of the exemplary
airfoil of FIG. 2A;
[0020] FIG. 3A depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil deflected
less than its right airfoil in a forward stroke of the wings;
[0021] FIG. 3B depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil deflected
less than its right airfoil in a backward stroke of the wings;
[0022] FIG. 3C depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil deflected
more than its right airfoil in a forward stroke of the wings;
[0023] FIG. 3D depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil deflected
less than its right airfoil in a backward stroke of the wings;
[0024] FIG. 4A depicts instantaneous thrust vectors and cumulative
thrust vectors for the left and right sides of a vehicle such as in
FIGS. 3A and 3B;
[0025] FIG. 4B depicts instantaneous thrust vectors and cumulative
thrust vectors for the left and right sides of a vehicle such as in
FIGS. 3A and 3B;
[0026] FIG. 4C depicts instantaneous thrust vectors and cumulative
thrust vectors for the left and right sides of a vehicle such as in
FIGS. 3C and 3D;
[0027] FIG. 4D depicts instantaneous thrust vectors and cumulative
thrust vectors for the left and right sides of a vehicle such as in
FIGS. 3C and 3D;
[0028] FIG. 5A depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil deflected
less than its right airfoil in a backward stroke of the wings;
[0029] FIG. 5B depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil deflected
more than its right airfoil in a forward stroke of the wings;
[0030] FIG. 5C depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil deflected
more than its right airfoil in a backward stroke of the wings;
[0031] FIG. 5D depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil deflected
less than its right airfoil in a forward stroke of the wings;
[0032] FIG. 6A depicts instantaneous thrust vectors and cumulative
thrust vectors for the left and right sides of a vehicle such as in
FIGS. 5A and 5B;
[0033] FIG. 6B depicts instantaneous thrust vectors and cumulative
thrust vectors for the left and right sides of a vehicle such as in
FIGS. 5C and 5D;
[0034] FIG. 7A depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil and its
right airfoil both deflected less in the beginning of a forward
stroke (fore stroke) of the wings than the deflection at the end of
the forward stroke which is depicted as larger in deflected
angle;
[0035] FIG. 7B depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil and its
right airfoil both deflected more in the beginning of a backward
stroke (backstroke) of the wings than the deflection at the end of
the backward stroke which is depicted as smaller in deflected
angle;
[0036] FIG. 7C depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil and its
right airfoil both deflected more in the beginning of a forward
stroke (fore stroke) of the wings than the deflection at the end of
the forward stroke which is depicted as smaller in deflected
angle;
[0037] FIG. 7D depicts in a top view an aircraft having a nose tip
oriented in the forward direction with its left airfoil and its
right airfoil both deflected less in the beginning of a backward
stroke (backstroke) of the wings than the deflection at the end of
the backward stroke which is depicted as larger in deflected
angle;
[0038] FIG. 8A depicts instantaneous thrust vectors and cumulative
thrust vectors for the left and right sides of a vehicle such as in
FIGS. 7A and 7B;
[0039] FIG. 8B depicts instantaneous thrust vectors and cumulative
thrust vectors for the left and right sides of a vehicle such as in
FIGS. 7A and 7B;
[0040] FIG. 8C depicts instantaneous thrust vectors and cumulative
thrust vectors for the left and right sides of a vehicle such as in
FIGS. 7C and 7D;
[0041] FIG. 8D depicts instantaneous thrust vectors and cumulative
thrust vectors for the left and right sides of a vehicle such as in
FIGS. 7C and 7D;
[0042] FIG. 9 depicts an exemplary flapping drive assembly
including a motor, a gearing assembly, a left arm and a right arm
rotatably attached at a pin of a drive gear, where the pin is
offset from the center of rotation of the drive gear;
[0043] FIG. 10A depicts a portion of the drive assembly of FIG.
10B;
[0044] FIG. 10B depicts an exemplary flapping drive assembly and
mechanism;
[0045] FIG. 11A depicts in exploded view an exemplary wing;
[0046] FIG. 11B depicts an assembled exemplary wing;
[0047] FIG. 12 depicts an exemplary flapping drive assembly and
mechanism, similar to combining a pair of the embodiments of FIG.
10, where each has four capstans;
[0048] FIG. 13 depicts an exemplary assembly for limiting root
spar, or boom, travel;
[0049] FIGS. 14A-14C depict in a side view the exemplary assembly
of FIG. 13;
[0050] FIG. 15A depicts the motion of a string to rotate the
position of a first boom stop by rotating a first pulley element
about a pivot point on a support structure;
[0051] FIG. 15B depicts in a bottom up view the boom stops extended
of a relatively high deflecting angle of the boom for a first wing
position of a stroke;
[0052] FIG. 15C depicts in a bottom up view the boom stops extended
of a relatively high deflecting angle of the boom for a second wing
position of a stroke;
[0053] FIG. 16 depicts a wing assembly and the pair of pulley
elements for the boom stops;
[0054] FIG. 17A depicts an example where each boom stop is
positioned to allow for a relatively large deflection angle,
compared to 17B, for both the forward stroke and the backward
stroke;
[0055] FIG. 17B depicts an example where each boom stop is
positioned to allow for a relatively small deflection angle,
compared to 17A, for both the forward stroke and the backward
stroke;
[0056] FIG. 18A depicts stops in a neutral position as to the yaw
channel;
[0057] FIG. 18B depicts stops biased to the right where the
flapping of the wing and movement of the boom between the two
stops--to one stop during the forward stroke and to the other stop
during the rearward stroke--would generate a thrust vector having a
right-oriented component;
[0058] FIG. 18C depicts stops biased to the left where the flapping
of the wing and movement of the boom between the two stops--to one
stop during the forward stroke and to the other stop during the
rearward stroke--would generate a thrust vector having a
left-oriented component;
[0059] FIG. 19 depicts an alternate means of boom travel control
where a cord or string is controlled by a servo and fed, via
eyelets, to the boom and fixed at a distal portion of the boom;
[0060] FIG. 20A depicts control of the orientation of the boom
during flapping may be effected by rotating the cord or string to
position the boom for a backward stoke;
[0061] FIG. 20B depicts control of the orientation of the boom
during flapping may be effected by rotating the cord or string to
position the boom for a backward stoke;
[0062] FIG. 21A depicts a three-axis servo boom yang assembly;
[0063] FIG. 21B depicts an exemplary aircraft having a flapping
mechanism;
[0064] FIG. 22 depicts a portion of an exemplary aircraft having a
flapping mechanism;
[0065] FIG. 23 depicts a portion of an exemplary aircraft having a
flapping mechanism;
[0066] FIG. 24A depicts the gimbaled yoke tilted toward the left
airfoil and away from the right airfoil;
[0067] FIG. 24B depicts the gimbaled yoke tilted toward the right
airfoil and away from the right airfoil;
[0068] FIG. 25A depicts a boom yang system where separate boom yang
engages the yoke and provides structural support for a variable
boom stop lever;
[0069] FIG. 25B-25D depict actuation of the boom stop lever for yaw
control;
[0070] FIG. 26 is an exemplary top level block diagram of the
control and propulsion system of an aircraft embodiment;
[0071] FIG. 27 is a top level functional block diagram of a
flapping frequency controller;
[0072] FIG. 28 is an exemplary top level block diagram of a servo
controller;
[0073] FIG. 29 is an exemplary top level block diagram of an
angular rate controller;
[0074] FIG. 30 is an exemplary top level block diagram of an
angular rate controller;
[0075] FIG. 31 depicts an exemplary wing;
[0076] FIG. 32 depicts in cross sectional view the wing of FIG.
31;
[0077] FIG. 33 depicts in a an edge on view of FIG. 31 to
rotatability of the membrane about the mast;
[0078] FIG. 34 depicts in a cross section view of wing FIG. 31 the
membrane wrapped around a tube within which is disposed the mast,
or root-to-wingtip spar;
[0079] FIG. 35 depicts another means of attachment where a separate
piece of material is used to attach the tube to the membrane;
[0080] FIG. 36 depicts another means of attachment where the
membrane edge has a t-shape portion when viewed edge on, and the
t-shaped portion, or orthogonal edge surface, is inserted within
the mast tube, and may be held in place by the mast element;
[0081] FIG. 37 depicts an exemplary airfoil having two battens and
membrane fold-over portions;
[0082] FIG. 38 depicts an exemplary airfoil having two battens,
membrane fold-over portions, and where the battens have membrane
overlays;
[0083] FIG. 39 depicts the airfoil of FIG. 37 where the membrane
material is a foam membrane;
[0084] FIG. 40 depicts an airfoil without battens and no membrane
fold-overs;
[0085] FIG. 41 depicts an airfoil having two battens, membrane
fold-overs and an arcuate cutout region between the mast sleeve and
the root spar sleeve;
[0086] FIG. 42 depicts an angular airfoil of relatively reduced
surface area;
[0087] FIG. 43 depicts an airfoil made of a foam membrane having
two curving battens, and membrane fold-overs;
[0088] FIG. 44 depicts a fixture for making an airfoil;
[0089] FIG. 45 depicts a membrane blank having a filament grid
fixed to a working surface;
[0090] FIG. 46 depicts the fixture of FIG. 44 positioned over the
membrane blank;
[0091] FIG. 47 depicts a cut and fold-over step along the mast and
root spar;
[0092] FIG. 48 depicts the battens applied to the surface of the
membrane and a cut step for the remainder of the planform; and
[0093] FIG. 49 depicts a removal of an exemplary airfoil from the
blank.
DETAILED DESCRIPTION
[0094] Embodiments of the present invention include
radio-controlled, heavier-than-air, aircraft having flapping wings,
e.g., ornithopters, where the vehicle orientation control is
effected by variable differential sweep angles of deflection of the
flappable wings in the course of sweep angles of travel, variable
differential luffing of the wings, and/or variable and differential
angular velocity of wing flapping. Embodiments of the air vehicle
comprise two wings, or airfoils, having the principal functions of
providing lift and generating control moments or torques about the
air vehicle. Either of two such airfoils may be disposed on each
side of the fuselage, or structural body, of the air vehicle. Each
wing comprises a root-to-wingtip spar, or mast, having a proximal
end proximate to the wing root, and a distal end proximate to the
wingtip. Each wing comprises a root spar, or boom, proximate to the
proximal end of the mast, and the boom may be oriented, fixedly
rotationally, but otherwise substantially orthogonal to the mast. A
lifting surface membrane element for each wing is attached to the
respective mast and the boom, and the membrane and boom may rotate
or pivot about the longitudinal axis of the mast. The wings may be
driven by an onboard flapping drive element, e.g., at least one
motor and mechanical movement so as to be flapped and their
wingtips circumscribe arcs about the longitudinal axis of the air
vehicle. If the boom is free to travel some angular amount about
the mast, then the distal end of the boom and the trailing edge of
the lifting surface tend to trail the motion of the mast and
leading portion of the lifting surface during flapping strokes. The
distal end of the boom may be variably restrained relative to the
mast, thereby variably limiting the angular travel of the boom
about the mast and/or varying the wing membrane slack, or luffing
of the membrane. A thrust force may be generated via the airfoils,
each airfoil's thrust having an instantaneous magnitude depending
on the direction of mast flapping, i.e., a forward stroke or an
backward stroke, the angle of each boom relative to its respective
mast and/or the amount of luffing in the wing membrane and/or the
angular velocity of the wing during the stroke.
[0095] FIG. 1 depicts an aircraft 100 having two airfoils 101, 102
a left (port) airfoil 101 and a right (starboard) airfoil 102, each
attached to the aircraft structure 103, such as the fuselage, and
where the flapping in the forward direction of the aircraft, where
the wingtips of the airfoils generally circumscribe arcs 104, 105
in the horizontal plane about the aircraft 100 and, their
respective extents of travel each define a sweep angle of
travel.
[0096] FIG. 2A depicts an exemplary airfoil 200 having a leading
portion 201 comprising a sleeve 202 for receiving a mast tube
element and a sleeve 203 for receiving a boom tube element. The
airfoil as depicted includes two stiffening elements, i.e., battens
204, 205, disposed on a surface membrane of the airfoil 200. FIG.
2B depicts the flexibility of the exemplary airfoil of FIG. 2A
where the leading portion swings about a pivot point 210, and in a
plane orthogonal to the root spar sleeve 203, to circumscribe a
flapping angle 211. FIG. 2C depicts the flexibility of the
exemplary airfoil of FIG. 2B where the leading portion 201 is
further swung about a pivot point and the distal end of the boom
establishes a sweep angle of deflection 220. The trailing edge 230
and distal portion of the root spar, or boom, tends to trail the
leading portion 201, and if boom travel is permitted but limited,
the distal end of the boom and the boom sleeve 203 will trail by a
sweep angle of deflection 231. Generally, the larger the sweep
angle of deflection, the lower the thrust generated by the airfoil.
If the boom is permitted to decrease its angle relative to the mast
232, then the airfoil membrane will experience increased luffing.
Generally, the greater the luffing, the lower the thrust generated
by the airfoil.
[0097] FIG. 3A depicts in a top view an aircraft 310 having a nose
tip 311 oriented in the forward direction with its left airfoil 312
deflected, e.g., 20 degrees, an angle less than its right airfoil
313, e.g., 40 degrees, in a forward stroke 314, 315 of each of the
wings 312, 313. Accordingly, the left wing generates more thrust
upward than the right wing. FIG. 3B depicts in a top view the
aircraft 310 having a nose tip oriented in the forward direction
with its left airfoil 312 deflected, e.g., 20 degrees, an angle
less than its right airfoil 313, e.g., 40 degrees in a backward
stroke 324, 325 of the wings 312, 313. Accordingly, this generates
a roll moment about (over the top of) the vehicle 310. FIG. 3C
depicts in a top view of the aircraft 310 having a nose tip
oriented in the forward direction with its left airfoil 312
deflected, e.g., 40 degrees, and angle more than its right airfoil
313, e.g., 20 degrees in a forward stroke 314, 315 of the wings
312, 313. Accordingly, the right wing 313 generates more thrust
upward than the left wing 312. FIG. 3D depicts in a top view the
aircraft 310 having a nose tip oriented in the forward direction
with its left airfoil 312 deflected, e.g., 40 degrees, an angle
more than its right airfoil 313, e.g., 20 degrees in a backward
stroke 324, 325 of the wings 312, 313. Accordingly, this generates
a roll moment about the vehicle 310 in the angular direction
opposite that of FIG. 3B.
[0098] FIGS. 4A and 4B depict idealized instantaneous thrust
vectors 410-413 and idealized average cumulative thrust vectors
420-423 for the left and right sides of a vehicle, such as in FIGS.
3A and 3B. Exemplary wing deflections are depicted for each wing at
three positions in a stroke. Accordingly, the vehicle generates
roll moment to effect a right roll, according to the right hand
rule. FIGS. 4C and 4D depict idealized instantaneous thrust vectors
430-433 and idealized average cumulative thrust vectors 440-443 for
the left and right sides of a vehicle such as in FIGS. 3C and 3D.
Again, exemplary wing deflections are depicted for each wing at
three positions in a stroke. Accordingly, the vehicle generates
roll moment to effect a left roll, according to the right hand
rule.
[0099] FIG. 5A depicts in a top view an aircraft 310 having a nose
tip oriented in the forward direction with its left airfoil 312
deflected, e.g., 20 degrees, an angle less than its right airfoil
313, e.g., 40 degrees in a backward stroke 324, 325 of the wings
312, 313. Accordingly, the left wing 312 generates more thrust
upward than the right wing 313. FIG. 5B depicts in a top view the
aircraft 310 having a nose tip oriented in the forward direction
with its left airfoil 312 deflected, e.g., 40 degrees, an angle
more than its right airfoil 313, e.g., 20 degrees in a forward
stroke 314, 315 of the wings 312, 313. Accordingly, this
arrangement generates a yaw moment counterclockwise about the
vehicle 310, i.e., a left yawing motion. FIG. 5C depicts in a top
view the aircraft 310 having a nose tip oriented in the forward
direction with its left airfoil 312 deflected, e.g., 40 degrees, an
angle more than its right airfoil 313, e.g., 20 degrees in a
backward stroke 324, 325 of the wings 312, 313. Accordingly, the
right wing 313 generates more thrust upward than the left wing 312.
FIG. 5D depicts in a top view the aircraft having a nose tip
oriented in the forward direction with its left airfoil 312
deflected, e.g., 20 degrees, an angle less than its right airfoil
313, e.g., 40 degrees in a forward stroke 314, 315 of the wings
312, 313. Accordingly, this generates a yaw moment about the
vehicle 310 in the angular direction opposite that of FIG. 5B,
i.e., a right yawing moment.
[0100] FIG. 6A depicts idealized average cumulative thrust vectors
610-611 for the left and right sides of a vehicle, such as in FIGS.
5A and 5B, where the left wing fore stroke has the left wing in a
high angle of deflection, the left wing back stroke has the left
wing in a low angle of deflection, while the right wing fore stroke
has the right wing in a low angle of deflection and the right wing
backstroke has the right wing in a high angle of deflection.
Exemplary wing deflections are depicted for each wing at two
positions in a stroke. Accordingly, in the plane of yaw rotation
640, the horizontal components of the thrust vectors are
projected--indicating the vehicle generates yaw moment to effect a
counterclockwise or left yaw maneuver. FIG. 6B depicts idealized
average cumulative thrust vectors 650-651 for the left and right
sides of a vehicle, such as in FIGS. 5C and 5D, where the left wing
fore stroke has the left wing in a low angle of deflection, the
left wing back stroke has the left wing in a high angle of
deflection, while the right wing fore stroke has the right wing in
a high angle of deflection and the right wing backstroke has the
right wing in a low angle of deflection. Exemplary wing deflections
are depicted for each wing at two positions in a stroke.
Accordingly, in the plane of yaw rotation 640, the horizontal
components of the thrust vectors are projected--indicating the
vehicle generates yaw moment to effect a clockwise or right yaw
maneuver.
[0101] Pitching moment can be generated by changing the mass
balance of the vehicle, differential throttling of the flapping
motor or flapping motors, and/or cyclically changing the angles of
deflections of the airfoils, i.e., cyclic pitch control. FIG. 7A
depicts in a top view an aircraft 310 having a nose tip oriented in
the forward direction with its left airfoil 312 and its right
airfoil 313 both deflected less in the beginning of a forward
stroke (fore stroke) of the wings than the deflection at the end of
the forward stroke which is depicted as larger in deflected angle,
i.e., a larger sweep angle of deflection. The deflection grows
larger as the wing sweeps forward. Accordingly, the wings each
generate more thrust upward during the beginning of the forward
stroke than at the end of the forward stroke. FIG. 7B depicts in a
top view an aircraft 310 having a nose tip oriented in the forward
direction with its left airfoil 312 and its right airfoil 313 both
deflected more in the beginning of a backward stroke (backstroke)
of the wings than the deflection at the end of the backward stroke
which is depicted as smaller in deflected angle, i.e., a smaller
sweep angle of deflection. The deflection grows smaller as the wing
sweeps backward. Accordingly, the wings each generate more thrust
upward during the beginning of the backward stroke than at the end
of the backward stroke. Accordingly, this cyclic pitch control
generates a forward pitching moment, i.e., a pitching control
authority about the vehicle in an angular direction that is nose
downward. FIG. 7C depicts in a top view an aircraft 310 having a
nose tip oriented in the forward direction with its left airfoil
312 and its right airfoil 313 both deflected more in the beginning
of a forward stroke (fore stroke) of the wings than the deflection
at the end of the forward stroke--which is depicted as smaller in
deflected angle, i.e., a smaller sweep angle of deflection. The
deflection grows smaller as the wing sweeps forward. Accordingly,
the wings each generate less thrust upward during the beginning of
the forward stroke than at the end of the forward stroke. FIG. 7D
depicts in a top view an aircraft 310 having a nose tip oriented in
the forward direction with its left airfoil 312 and its right
airfoil 313 both deflected less in the beginning of a backward
stroke (backstroke) of the wings than the deflection at the end of
the backward stroke which is depicted as larger in deflected angle,
i.e., a larger sweep angle of deflection. The deflection grows
larger as the wing sweeps backward. Accordingly, the wings each
generate less thrust upward during the beginning of the backward
stroke than at the end of the backward stroke. Accordingly, this
cyclic pitch control generates a backward pitching moment, i.e., a
pitching control authority about the vehicle in an angular
direction that is nose upward.
[0102] FIGS. 8A and 8B depict idealized instantaneous thrust
vectors 810-811, 830-831 for the left and right sides of a vehicle
such as in FIGS. 7A and 7B respectively, and an idealized average
cumulative thrust vector 820, 840 for the vehicle such as in FIGS.
7A and 7B respectively. Exemplary wing deflections are depicted for
each wing at four positions in a stroke. Accordingly, the vehicle
generates pitch moment to effect a forward (nose down) maneuver.
FIGS. 8C and 8D depict idealized instantaneous thrust vectors
850-851, 870-871 for the left and right sides of a vehicle such as
in FIGS. 7C and 7D respectively, and an idealized average
cumulative thrust vector 860, 880 for the vehicle such as in FIGS.
7C and 7D respectively. Exemplary wing deflections are depicted for
each wing at four positions in a stroke. Accordingly, the vehicle
generates pitch moment to effect a backward (nose up) maneuver.
[0103] FIG. 9 depicts an exemplary flapping drive assembly 900
including a motor 910, a gearing assembly 920, a left arm 924 and a
right arm 926 rotatably attached at a pin 928 of a drive gear 930,
where the pin is offset from the center of rotation of the drive
gear 930. When the drive gear is rotated 931, the exemplary left
rocker arm 924 and right rocker arm 926 are cyclically pushed and
pulled, and thereby cause the left mast receiver 934 and the right
mast receiver 932 to swing forward and backward.
[0104] FIG. 10A depicts, for a flapping drive assembly, the
disposition of a first capstan 1012 relative to the center of
rotation of a rotating element 1010 that may be a gear. The second
capstan (not shown in this view) is interposed between the first
capstan 1012 and the rotating element 1010, and both the first
capstan 1012 and second capstan are mounted about a shaft 1001 that
is offset from the center of rotation 1002 of a rotating element
1010. FIG. 10B depicts an exemplary flapping drive assembly and
mechanism 1000 comprising: (a) a rotating element 1010 having a
center of rotation and a plane of rotation; (b) a first capstan
1012 mounted about a shaft (not shown), the shaft attached to the
rotating element 1010 distal from the center of rotation and
substantially perpendicular to the plane of rotation; (c) a second
capstan 1018 mounted about the shaft; (d) a first arm 1032 mounted
to a third capstan 1022, a first linking member 1020 connecting the
third capstan 1022 with the first capstan 1012; (e) a second arm
1030 mounted to a fourth capstan 1024, a second linking member 1017
connecting the fourth capstan 1024 with the first capstan 1012; and
(f) a third linking member 1023 connecting the third capstan 1022
with the fourth capstan 1024. In some embodiments of the mechanism,
the third capstan 1022 of the mechanism may have a center of
rotation, the fourth capstan 1024 may have a center of rotation,
and the center of rotation of the rotating element 1010 may be
substantially collinear with both the center of rotation of the
third capstan 1022 and the center of rotation of the fourth capstan
1024. In some embodiments of the mechanism, the first linking
member 1020 may comprise a cord, the second linking member 1017 may
comprise a cord, and the third linking member 1023 may comprise a
cord. A left wing assembly 1028 is depicted engaging the first arm
1032 and a right wing assembly 1026 is depicted as engaging the
second arm 1030. Accordingly, a motor drives 1050 the offset
capstans to effect flapping of the two wing assemblies.
[0105] FIG. 11A depicts in exploded view an exemplary wing 1100
having two curved battens 1111, 1112, where a mast element 1120 is
inserted into a leading edge sleeve 1121 of a wing airfoil membrane
1101. The sleeve 1121 may be formed by drawing the airfoil membrane
back on itself and/or may include a tube for receiving the mast
element--a tube about which the airfoil may be wrapped and fixed.
Resilient washers 1122, 1123 may be deposed at the proximal and
distal portions of the mast element 1120 on each side of the
leading edge sleeve 1121. A root spar element 1130, or boom
element, is inserted into the root spar sleeve 1131 of the wing
airfoil membrane 1101. The boom sleeve 1131 may be formed by
drawing the airfoil back on itself and/or may include a tube for
receiving the mast element--a tube about which the airfoil may be
wrapped and fixed. Resilient washers 1132, 1133 may be deposed at
the proximal and distal portions of the root spar element 1130 on
each side of the boom sleeve 1131. The mast element 1120 and boom
element 1130 engage a corner element 1140, or arm fitment, that is
configured to be received by an arm socket element (not shown).
FIG. 11B depicts an assembled exemplary wing 1100. The membrane may
be made of extruded polyethylene foam sheet, e.g., having 1/32 inch
thickness such as packing foam sheets. The battens 1111, 1112, mast
element 1120, boom element 1130, and sleeve tubes 1121, 1131 may be
made of carbon filaments. The wing 1100 may further include a
pocket made from overlapping the membrane proximate to the root
spar, or boom, and interposing between the layers of membrane a
layer of foam fabric. The foam fabric may damp vibrations and
reduce acoustical effects of flapping.
[0106] FIG. 12 depicts an exemplary flapping drive assembly and
mechanism 1200 comprising a left flapping drive assembly 1210 and a
right flapping drive assembly 1220, similar to combining a pair of
the embodiments of FIG. 10B, where each right and left flapping
drive assemblies has four capstans, but one arm for a wing
assembly. The embodiment of FIG. 12 depicts a left wing assembly
1230 engaging the arm of a left portion 1211 of the flapping drive
assembly 1200, where the arm 1211 of the left assembly 1210 engages
the third capstan 1212 of the left assembly 1210. The embodiment of
FIG. 12 also depicts a right wing assembly 1231 engaging the arm
1213 of the right assembly 1220, where the arm 1213 of the right
assembly 1220 engages the fourth capstan 1212 of the right assembly
1220. In this exemplary embodiment, a processor such as a central
processing unit (CPU), having load instructions, maintains
synchronization between the left and right motor by monitoring
inputs from wing position sensors 1240, 1241. Pitch control
authority may be generated by differential front and rear engine
throttling. Yaw control authority may be generated by differential
forestroke and rearstroke throttling, and roll control authority
may be generated by differential midstroke and endstroke
throttling, and done so with a wing-mounted spring, e.g., a luffing
spring attached to the root spar, or boom. Accordingly, servos to
adjust the angles of deflection of the wings are not required for
this exemplary embodiment.
[0107] FIG. 13 depicts an exemplary assembly for limiting root
spar, or boom, travel 1300. Two servos 1310, 1320 are used, each
controlling by a string, or a cord, fed via eyelets 1370-1379, and
a pulley system 1330 the position of boom stops, 1360-1363, to
allow for differential deflection of each airfoil (not shown). Each
boom stop is affixed to a rocker-like pulley element that may be in
tension, and the drawing back on the string opens the angle between
opposing boom stops. A pair of boom stops are disposed on each of
the arms of the flapping assembly so that the boom stops rotate
with the flapping arm to limit the travel of the proximal end of
the boom. Accordingly, roll and yaw authority may be generated
during mast flapping by the positioning of the boom stops.
Aerodynamic forces tend to cause the boom to stop on the trailing
boom stop of the stroke, i.e., the aftward boom stop during a
forward stroke and the forward boom stop during a backward stroke.
A handlebar-like structure 1380 may be added that may be rotated
1382, via a pitch servo 1381, to extend or retract, in conjunction
with the mast flapping motion, the boom stops on each wing. The
handlebar-like structure 1340, 1350 may be used to generate pitch
authority during flapping by continually repositioning the boom
stops during strokes. FIG. 14A depicts in a side view the exemplary
assembly 1400 of FIG. 13 where the pair of strings or cords 1410,
1412 are shown threaded through an eyelet 1414 at end of an arm of
the handlebar-like structure 1416. The servo shown may be disposed
proximate to the flapping motor and the flapping drive assembly. A
boom stop 1363 may be mounted on a pulley element that itself is
mounted in tension to a support structure. FIG. 14B depicts a
rotation 1430 of the handlebar element 1416 by the pitch servo 1318
causing the strings to allow the boom stops 1363, 1362 to retract,
for a particular portion of the stroke. That is, the stings would
draw on the boom stop pulleys as the mast rotates (out of the page
in this illustration). FIG. 14C depicts a rotation 1431 of the
handle bar element by the pitch servo 1318 causing the strings to
draw on the boom stops 1362, 1363 to extend the angle between each
for a particular portion of the stroke.
[0108] In a view orthogonal to the plane of a mast and root spar,
or boom, FIG. 15A depicts the motion of a string 1510 to rotate the
position of a first boom stop 1520 by rotating a first pulley
element (obstructed in this view by a second pulley element 1530)
about a pivot point on a support structure. Also depicted in FIG.
15A is a second string 1511 that does not move in this example,
leaving the second boom stop 1521 in a stationary position--at this
position in a stroke--as the tension in the string balances the
tension in the mounted second pulley element 1530. FIG. 15B depicts
in a bottom up view of FIG. 13 where the boom stops 1360-1363 are
extended to a relatively high deflecting angle of the boom. FIG.
15C depicts the bottom up view of FIG. 13 where the flapping motion
of the arms has caused the wings to change relative angles in the
stroke, and that the boom stop 1360-1363 remain extended as the
same angle as in FIG. 15B. That is, the pitch actuator may be at a
neutral position so as to not affect the deflection angle during a
stroke of the exemplary embodiment of FIG. 14A.
[0109] FIG. 16 depicts a wing assembly 1600 and the pair of pulley
elements 1610, 1612 for the boom stops 1614, 1616. With the
application of the two strings, each that may be under the control
of a bi-directional servo (not shown), each pulley element may be
placed in tension and each boom stop may be angularly positioned
independent of the other. FIG. 17A depicts an example where each
boom stop 1710, 1720 is positioned to allow a relatively large
deflection angle for both the forward stroke and the backward
stroke. With the stops opened wide, a flapping wing such as this
has a relatively low angle of attack and generates relatively low
thrust. In contrast, FIG. 17B depicts an example where each boom
stop 1711, 1721 is positioned to allow a relatively small
deflection angle for both the forward stroke and the backward
stroke. With the stops open to a narrow position, a flapping wing
such as this has a relatively high angle of attack and generates
relatively high thrust with an accompanying relatively larger
magnitude of downwash. FIGS. 18A-18C depict yaw control 1800
effected by modulating the boom stops left or right to generate a
net yawing moment. FIG. 18A depicts stops 1810, 1812 in a neutral
position as to the yaw channel. That is, a flapping arm would have
the same boom angle of deflects in the forward stroke as in the
backward stroke, i.e., the thrust vector would be aligned with the
"upward" direction of the aircraft. FIG. 18B depicts stops 1814,
1816 biased to the right where the flapping of the wing and
movement of the boom between the two stops--to one stop during the
forward stroke and to the other stop during the rearward
stroke--would generate a thrust vector having a right-oriented
component. Accordingly, during flapping, the vehicle effecting
stops biased to the right would execute a nose left command. FIG.
18C depicts stops 1818, 1820 biased to the left where the flapping
of the wing and movement of the boom between the two stops--to one
stop during the forward stroke and to the other stop during the
rearward stroke--would generate a thrust vector having a
left-oriented component. Accordingly, during flapping, the vehicle
effecting stops biased to the left would execute a nose right
command.
[0110] FIG. 19 depicts an alternate means of boom travel control
1900 where a cord or string is controlled by a servo (not shown)
and fed, via eyelets 1911, 1912 on a yoke 1910, to the boom 1920,
and fixed at a distal portion of the boom. FIGS. 20A and 20B
depicts control of the orientation of the boom 2024 during flapping
2010, 2020, and the orientation of the boom 2024 may be effected by
rotating the cord 2030 or string to position the boom for a
backward stoke, as in FIG. 20A, and by rotating the cord 2022 or
string to position the boom 2024 for a backward stroke. The
positioned deflection angle may be effected during a stroke and
thus may effect control authority for pitch (e.g., via cyclic
modulation), yaw, and roll based on a continually changing servo
position commands.
[0111] A structural element termed a yang may be attached to the
wing-boom structure via a ball joint a multiple axis joint and may
dispose generally parallel to the boom. The boom or the yang may
engage a yoke and the luffing of the membrane can be affected by
the motions of the yoke. FIG. 21A depicts a three-axis servo boom
and/or yang assembly 2100 as another means of boom travel control
where a boom (or yang) restraining yoke 2110 may increase or reduce
luffing, i.e., the affects of the wing membrane slack, for both
wings during a stroke to generate pitch control authority via a
first servo and gearing assembly 2120; effect a differential amount
of luff between the wings during a stroke to generate roll control
authority via a second servo and gearing assembly 2130; and
optionally effect a bias in boom travel via a third servo and
gearing assembly 2140 to generate a luff differential for yaw
control. Accordingly, the assembly 2100 provides multiple axes of
orientation for the yoke to the body of the aircraft to adjust wing
membrane luff during strokes to effect three axes of control.
[0112] FIG. 21B depicts an exemplary aircraft having a flapping
mechanism 2100 as described in FIG. 10B (1000), and the root spar,
or boom, control mechanism as described in FIG. 21A (2100). In the
embodiment of FIG. 21B, the boom 2161 of each wing 2160 engage the
yoke 2110. Also depicted above the flapping mechanism are a power
and processing module 2170. The vehicle may include an optional
stand 2180. FIG. 22 depicts a portion of an exemplary aircraft 2200
having a flapping mechanism as described in FIG. 9 (900), and the
root spar, or boom, control mechanism as described in FIG. 21A,
where the root spars 2161, 2262 engage the yoke 2110. The FIG. 23
depict a portion of an exemplary aircraft 2300 having a flapping
mechanism as described in FIG. 9 (900), and another embodiment of
the root spar, or boom, control mechanism as described in FIG. 21A
(2100), where the root spars 2161, 2262 engage the yoke 2110. FIG.
24A depicts the positionable yoke 2110 tilted toward the left
airfoil 2410 and away from the right airfoil 2420. The masts of
each wing remain in the flapping plane and so the luffing, or wing
slack effect, of the left airfoil 2410 enhances as the membrane is
looser than the right airfoil 2420, and accordingly the left
airfoil 2410 generates less thrust than the right airfoil 2420.
FIG. 24B depicts the gimbaled yoke tilted toward the right airfoil
2420 and away from the left airfoil 2410. The masts of each wing
remain in the flapping plane and so the luffing of the right
airfoil 2420 is more than the luffing of the left airfoil 2410, and
accordingly the right airfoil 2420 generates less thrust than the
left airfoil 2410. FIGS. 24A and 24B illustrate a roll control
authority for this exemplary embodiment. The control gimbal having
a yoke may directly move the trailing edge ends of the root spars
to manipulate the luff in the wing.
[0113] FIG. 25A depicts a boom yang system 2500 where separate boom
yang 2510 engages the yoke 2110 and provides structural support
2511 for a variable boom stop lever 2512. Decoupling yaw control
from the pitch and roll control provided by the multiple axis yoke
positing assembly may be accomplished by allowing the root spar
2520 to move freely between adjustable boom stops 2521, 2522, and
having a yang 2510 or other structural element connect the movement
of the yoke arms 2111, 2112 of the yoke 2110 with the orientation
of the wing at a multiple-axis joint 2550. Accordingly, the roll
control may be effected by the side tilt position of the yoke of a
two-axis gimbal of servo assembly--similar to the assembly of FIG.
21A but without the yaw servo gear box, and the pitch control may
be effected by the fore and aft tilt position of the yoke. A third
(yaw) servo is used to control the orientation of the boom stops
2521, 2522 attached to a lever 2512 by pulling or releasing a
lever, e.g., via a cable 2513. FIG. 25B depicts an embodiment of
the lever 2512, that may be mounted to the yang structure 2511 in
tension, and actuated via a cable 2513 attached to the boom yang
structure 2511. FIG. 25C depicts the cable 2513 pulling the lever
2512 to shorten the boom 2590 travel distance of the boom stops.
FIG. 25D depicts the cable 2513 releasing the lever 2512 to allow
the travel distance of the boom 2590 to lengthen.
[0114] FIG. 26 is an exemplary top level block diagram of the
control and propulsion system of an aircraft embodiment 2600. A
central processing unit (CPU) 2602, having addressable memory and
drawing from an onboard power supply 2608 comprising a battery,
generates voltage commands to at least one drive motor, i.e., a
thrust or flapping, motor 2610. The commands may be pulse width
modulated (PWM). A Hall sensor may be disposed at the crankshaft so
that flapping frequency may be derived and provided to the CPU
2602. In some embodiments there are three control servos 2612,
2614, 2616 and so, FIG. 26 depicts the CPU 2602 generating commands
to a pitch bi-directional servo 2612, a roll bi-directional servo
2614, and a yaw bi-directional servo 2616. Position sensors 2624,
2626, 2628 can feed back to the CPU 2602 each servo position 2612,
2614, 2616. Angular rate measuring devices such as two, two-axis
gyroscopes 2618, 2620 may be used to provide yaw angular rate,
pitch angular rate, and roll angular rate. The CPU 2602 may provide
external command signals from a radio controller 2622 by an uplink
and the CPU 2602 may provide status or other information via a
downlink. Generally, the CPU 2602 may communicate with an external
node via a transceiver. Electrical and/or electronic elements may
be powered via an onboard power supply and or local chemical
battery elements 2608.
[0115] FIG. 27 is a top level functional block diagram 2700 of a
flapping frequency controller where the command flapping frequency,
F.sub.C, 2702 and the derived flapping frequency F.sub.est 2704 are
differenced to generate a flapping frequency error, .epsilon. 2706.
The flapping frequency error 2706 is integrated and multiplied by a
gain, K.sub.I, 2708 and the flapping frequency error 2706 is
multiplied by a gain, K.sub.P 2710. These two products are
combined, along with the product of the flapping frequency
multiplied by a gain, K.sub.FF, 2712 to generate a command, e.g., a
main motor voltage command, to the drive or thrust motor for
flapping. The flapping frequency controller, along with gains or
steps to generate gains, may be expressed in machine-readable
language, stored in memory accessible by the aircraft processor,
and executed to generate the flapping motor voltage commands.
[0116] FIG. 28 is an exemplary top level block diagram of a servo
controller 2800 where a position command, d.sub.c, 2802 is
differenced from the measured position, d.sub.MEAS, 2804 to
generate a servo position error, d.sub..epsilon., 2806 and then the
servo position error is multiplied by a servo gain K.sub..delta.,
2808 to generate servo motor voltage command, u 2810. Per servo
channel, the servo controller 2800, along with gains or steps to
generate gains, may be expressed in machine-readable language,
stored in memory accessible by the aircraft processor, and executed
to servo motor voltage commands for one or more servos.
[0117] FIG. 29 is an exemplary top level block diagram of an
angular rate controller 2900 that may be implemented for roll,
pitch, or yaw rate control. A biased angular rate 2902 measurement
may be generated by differencing the filtered gyro rate 2904
measurement and a gyro rate bias based on one or more gyro readings
stored at throttle-up, i.e., before the wings start flapping. An
angular error rate, e, 2906 may be generated by differencing the
angular rate command and the biased angular rate 2902 measurement.
The servo position command, .delta..sub.C, 2908 may be generated by
combining the product of the angular rate command and a feed
forward gain, K.sub.FF, 2910 with the product of the angular error
rate 2906 and a proportional rate gain, K.sub.P 2912.
[0118] FIG. 30 is an exemplary top level block diagram of an
angular rate controller 3000 that may be implemented for roll,
pitch, or yaw rate control. A biased angular rate measurement 3002
may be generated by differencing the filtered gyro rate measurement
3004 and a gyro rate bias based on one or more gyro readings stored
at throttle-up, i.e., before the wings start flapping. A digital
integrator may integrate over time the angular error rate, e, 3006.
An angular error rate, e, 3006 may be generated by differencing the
angular rate command and the biased angular rate measurement. The
servo position command, .delta..sub.C, 3008 may be generated by
combining the product of the angular rate command and a feed
forward gain, K.sub.FF, 3010 with the product of the angular error
rate and a proportional rate gain, K.sub.P, 3012 and along with the
product of the integrated angular error rate multiplied by a gain,
K.sub.I 3014.
[0119] FIG. 31 depicts an exemplary wing having mast, root spar and
a membrane. having a mast fold-over portion 3100 and a root spar
fold-over portion 3120, and first batten 3130. FIG. 32 depicts in
cross sectional view the wing of FIG. 31 where a first batten 3130
is a rod-shaped filament disposed on the membrane surface, the
second batten 3140 is parallelepiped-shaped. FIG. 33 depicts in a
an edge on view of FIG. 31 depicting rotatability of the membrane
about the mast. FIG. 34 depicts in a cross section view of wing
FIG. 31 where the membrane 3103 wrapped around a 3400 tube within
which is disposed the mast, or root-to-wingtip spar. The
overlapping surfaces of the membrane may be joined in part by an
epoxy or heat treatment. FIG. 35 depicts another means of
attachment where a separate piece of material 3500, that may be the
same material as the membrane, is used to attach the tube 3400 to
the membrane 3103. FIG. 36 depicts another means of attachment
where the membrane edge 3610 has a t-shape portion 3611 when viewed
edge on, and the t-shaped portion, or orthogonal edge surface, is
inserted within the mast tube 3620 along a slit, and may be held in
place by pressure of the mast element of fixed via heat or epoxy.
FIG. 37 depicts an exemplary airfoil having two battens a membrane
fold-over portions. FIG. 38 depicts an exemplary airfoil having two
battens and membrane fold-over portions, where the battens have
membrane overlays, 3810, 3811. FIG. 39 depicts the airfoil of FIG.
37 having two battens 3710, 3711 and two fold-over regions 3720,
3721, and where the membrane material is a foam membrane. FIG. 40
depicts an airfoil without battens and no membrane fold-overs. FIG.
41 depicts an airfoil having two battens, membrane fold-overs and
an arcuate cutout region 4100 between the mast 4110 and the root
spar 4120. FIG. 42, depicts an angular airfoil planform of reduced
surface area when compared with other examples, and without
fold-over regions or battens. FIG. 43 depicts an airfoil made of a
foam membrane having two curving battens 4310, 4311, and membrane
fold-overs. FIG. 44 depicts a fixture 4400 for making an airfoil
with the mast 4410 and root spar 4420 attached to the fixture 440,
and the tubes 4430 and 4440 available. FIG. 45 depicts a membrane
blank 4500 having a filament grid fixed to a working surface. FIG.
46 depicts the fixture of FIG. 44 positioned over the membrane
blank. FIG. 47 depicts a cutting of the membrane and fold-over step
along the mast and root spar. FIG. 48 depicts the battens 5011,
5012 applied to the surface of the membrane and a cut step for the
remainder of the planform. FIG. 49 depicts a removal of an
exemplary airfoil 5110 from the blank 4500.
[0120] One of ordinary skill in the art will appreciate that the
elements, components, steps, and functions described herein may be
further subdivided, combined, and/or varied, and yet, still remain
within the spirit of the embodiments of the invention. Accordingly,
it should be understood that various features and aspects of the
disclosed embodiments may be combined with, or substituted for one
another in order to form varying modes of the invention, as
disclosed by example. It is intended that the scope of the present
invention herein disclosed by examples should not be limited by the
particular disclosed embodiments described above. Accordingly, the
invention has been disclosed by way of example and not limitation,
and reference should be made to the following claims to determine
the scope of the present invention.
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