U.S. patent application number 11/290975 was filed with the patent office on 2007-05-31 for aerodynamic control of a hypersonic entry vehicle.
This patent application is currently assigned to The Boeing Company. Invention is credited to Henry August.
Application Number | 20070120019 11/290975 |
Document ID | / |
Family ID | 38086523 |
Filed Date | 2007-05-31 |
United States Patent
Application |
20070120019 |
Kind Code |
A1 |
August; Henry |
May 31, 2007 |
AERODYNAMIC CONTROL OF A HYPERSONIC ENTRY VEHICLE
Abstract
A hypersonic vehicle having in one or more embodiments a control
surface that is movable to a deployed position. The control surface
is movable in a pivotal manner that establishes a gap between the
leading edge of the control surface and the outer surface of the
vehicle to provide a flow path. The gap allows a boundary layer
along the outer surface of the vehicle to pass through the flow
path with out separation from the outer surface, to further improve
the effectiveness of the control surface.
Inventors: |
August; Henry; (Chatsworth,
CA) |
Correspondence
Address: |
HARNESS DICKEY & PIERCE, PLC
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Assignee: |
The Boeing Company
|
Family ID: |
38086523 |
Appl. No.: |
11/290975 |
Filed: |
November 30, 2005 |
Current U.S.
Class: |
244/158.9 |
Current CPC
Class: |
B64G 1/62 20130101 |
Class at
Publication: |
244/158.9 |
International
Class: |
B64G 1/62 20060101
B64G001/62 |
Claims
1. An aerodynamic vehicle comprising: a body having a portion with
a generally conical outer surface shape; one or more control
surfaces positioned on the body's outer surface; and one or more
arm portions configured to couple a leading edge of one of the one
or more control surfaces to the body; each said control surface
being moveable between a stowed position in which the control
surface is substantially flush with the body's outer surface and
the one or more arm portions are inside the body, and at least one
deployed position in which a trailing edge of the control surface
is separated from and deflected at an angle from the body's outer
surface and the arm portions are extended at least partially to
establish a gap between a portion of the outer surface of the body
substantially parallel to the leading edge of the control surface
and the leading edge of the control surface, to enable a first
boundary layer flow along the body's outer surface to pass
through.
2. The aerodynamic vehicle of claim 1, wherein the gap has a height
for allowing a portion of the first boundary layer along the body's
outer surface to pass through the gap such that substantially no
separation of the first boundary layer along the body's outer
surface occurs, and a second boundary layer along each said control
surface attaches at a point substantially near the leading edge of
each said control surface.
3. The aerodynamic body of claim 1, further comprising an actuator
structure that is configured to move each said control surface to
one or more positions of varying deflection angle relative to the
outer surface of the body for steering the vehicle.
4. The aerodynamic vehicle of claim 2, wherein the actuator
structure is configured to adjust the gap height between the body
surface and the leading edge of each said control surface.
5. The aerodynamic vehicle of claim 1, wherein the gap allows a
portion of the first boundary layer flow along the outer surface of
the body to pass through the gap under the leading edge of the
control surface so as to inhibit separation of the first boundary
layer along the body's outer surface.
6. The aerodynamic vehicle of claim 1 wherein the gap is configured
to substantially alleviate the influence of a local shock at the
body/control surface juncture such that the first boundary layer
along the body's outer surface remains attached.
7. The aerodynamic vehicle of claim 1 wherein the gap has an
effective height for allowing a portion of the first boundary layer
flow along the body's outer surface to pass through the gap without
suffering a local shock, such that a second boundary layer along
the control surface attaches itself substantially near the leading
edge of the control surface.
8. An atmospheric entry vehicle adapted to travel through a fluid
medium comprising: a body having an outer surface; at least one
moveable member, each coupled to the body at a leading edge of the
member by one or more arm portions, where in one position of one of
the at least one moveable member a gap is provided by the one or
more arm portions between the leading edge of said moveable member
and a portion of said outer body surface substantially parallel to
the leading edge that defines a fluid flow path; and a control
surface associated with the at least one moveable member that is
adapted to direct the atmospheric entry vehicle in a predetermined
direction.
9. The atmospheric entry vehicle of claim 8, wherein the gap
between the body surface and the leading edge of the control
surface defines a flow path through which a first boundary layer
flow along the body surface passes, such that the gap substantially
alleviates the influence of a local shock at the body/control
surface juncture to permit a boundary layer along the control
surface to attach near the leading edge of the control surface.
10. The atmospheric entry vehicle of claim 9, wherein the gap
allows a portion of the first boundary layer flow along the outer
surface of the body to pass through the gap under the leading edge
of the control surface so as to substantially alleviate separation
of the first boundary layer along the body's outer surface.
11. The atmospheric entry vehicle of claim 10, wherein the first
boundary layer flow propagates through the gap between the body and
the leading edge of the control surface, such that substantially no
separation of the first boundary layer flow along the body surface
results.
12. The atmospheric entry vehicle of claim 8, wherein the body has
a portion having a generally conical surface, and the at least one
control surface is conformal in shape to the generally conical body
surface.
13. The atmospheric entry vehicle of claim 12, wherein the at least
one control surface comprises four control surfaces arranged in a
cruciform pattern around the body's outer surface.
14. The atmospheric entry vehicle of claim 13 wherein the
arrangement of four control surfaces allows adjacent deflected
control surfaces to generate variable moments about the vehicle's
center of gravity to control pitch and yaw attitude for controlling
maneuverability of the atmospheric entry vehicle.
15. The atmospheric entry vehicle of claim 8 wherein the gap has an
effective height that allows at least a portion of a first boundary
layer along the body's outer surface to pass through the gap such
that the first boundary layer remains substantially attached to the
body's outer surface of the vehicle.
16. The atmospheric entry vehicle of claim 15 wherein the gap
alleviates turbulence caused separation of the first boundary layer
from the body, to enable attachment of the second boundary layer at
or near the leading edge of the control surface.
17. The atmospheric entry vehicle of claim 16 wherein the
attachment of the second boundary layer near the leading edge of
the control surface enhances the effective area of the control
surface to further improve the maneuverability of the vehicle.
18. The atmospheric entry vehicle of claim 15 wherein the effective
height is in the range of about 0.125 inch to about 1.0 inch.
19. A method for controlling flight of an aerodynamic vehicle
entering an atmosphere at hypersonic speeds, comprising: securing
at least one control surface to an aerodynamically shaped body
portion for the vehicle; and controllably moving the control
surface from a stowed position in which one or more arm portions
coupling the control surface to the body portion are enclosed in
the body portion, to a deployed position in which the control
surface projects outwardly as extended by the one or more arm
portions extending from the body portion to assist in steering the
vehicle and to cause a gap to be formed between a leading edge of
the control surface and an adjacent surface of the body portion
substantially parallel to the leading edge, the gap enabling a
first boundary layer along the body portion to pass therethrough
and thus avoid separation of the first boundary layer as the
control surface is deployed.
20. The method of claim 19, further comprising: providing a
plurality of control surfaces secured to the body portion and
spaced apart around the body portion; controllably deploying the
control surfaces in independent fashion to steer the vehicle.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to atmospheric entry vehicles,
and more specifically to aerodynamic control of a capsule.
BACKGROUND OF THE INVENTION
[0002] In the pursuit of space exploration, scientists have
recently contemplated planetary landing missions to planets such as
Mars. A vehicle for such a mission would require aerodynamic
control during its atmospheric entry at hypersonic speeds. During
the vehicle's entry into the atmosphere, the vehicle's flight needs
to be controlled so that the vehicle can be steered to sites where
safe landings can be executed.
SUMMARY OF THE INVENTION
[0003] The various embodiments in the present specification relate
to the aerodynamic control, steering and aerobraking of an
atmospheric entry vehicle, which comprises a body having a
generally tapered shape, and one or more moveable members. In one
embodiment, the vehicle includes a body having a generally conical
outer surface shape, and one or more control surfaces positioned on
the body's outer surface. Each of the one or more control surfaces
are moveable between a stowed position in which the control surface
is substantially flush with the body's outer surface, and at least
one deployed position in which the control surface is deflected at
an angle from the body surface. In the deployed position, the
control surface establishes a gap between the outer surface of the
body and the leading edge of the control surface, through which a
boundary layer flow along the body's outer surface passes through.
The gap has a height which allows a portion of the boundary layer
along the body's outer surface to pass through, such that
substantially no separation of the boundary layer along the body's
outer surface occurs, and the boundary layer along the control
surface attaches at a point substantially near the leading edge of
the control surface.
[0004] In one or more embodiments, the vehicle includes an actuator
structure that is configured to move the control surface to one or
more positions of varying deflection angle relative to the outer
surface of the body for steering the vehicle. A control system is
also included for controlling the actuator structure for each
control surface, for controlling the deployment of one or more
control surfaces to steer the vehicle.
[0005] A method for controlling an atmospheric entry vehicle is
also provided. The method includes providing an aerodynamically
shaped body portion for the vehicle, securing at least one control
surface to the body portion, and controllably moving the control
surface from either a stowed position, in which the control surface
has no affect on the vehicle, to a deployed position in which the
control surface projects outwardly from the body portion to assist
in steering the vehicle. The process of controllably moving the
control surface to the deployed position causes a gap to be formed
between a leading edge of the control surface and an adjacent
surface of the body portion, wherein the gap enables a boundary
layer along the body portion to pass therethrough and thus avoid
separation of the boundary layer as the control surface is
deployed.
[0006] Further areas of applicability of the present invention will
become apparent from the detailed description provided hereinafter.
It should be understood that the detailed description and specific
examples, while indicating various preferred embodiments of the
invention, are intended for purposes of illustration only and are
not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The present invention will become more fully understood from
the detailed description and the accompanying drawings,
wherein:
[0008] FIG. 1 is a perspective view of an atmospheric entry vehicle
in accordance with one embodiment of the present invention;
[0009] FIG. 2 is a side elevation view of an atmospheric entry
vehicle having one of its control surfaces deflected;
[0010] FIG. 3 is an illustration of the hypersonic flow along the
surface of a first embodiment of an atmospheric entry vehicle and
control surface;
[0011] FIG. 4 is a side elevation view of a second embodiment of an
atmospheric entry vehicle having a deflected control surface;
and
[0012] FIG. 5 is a perspective view of a third embodiment of the
present invention.
[0013] Corresponding reference numerals indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0014] The following description of the various specific
embodiments is merely exemplary in nature and is in no way intended
to limit the present disclosure, its application, or uses.
[0015] According to various aspects of the invention, there are
provided specific embodiments of an atmospheric entry vehicle
having one or more control surfaces that provide improved
effectiveness for steering the vehicle as it experiences flight at
hypersonic speeds. One embodiment of an atmospheric entry vehicle
adapted to travel through a fluid medium is generally shown as 100
in FIG. 1. The atmospheric entry vehicle 100 comprises a body 104
having an outer surface 108, and at least one moveable member 112
coupled to the body 104. A control surface 116 associated with the
movable member 112 is movable relative to the vehicle 100 to
provide for direction control of the vehicle. It should be noted
that the control surface 116 may comprise a separate surface
component that is attached to the movable member 112, or
alternatively, the control surface 116 associated with the moveable
member 112 may be integrally formed with the moveable member 112.
In the first embodiment, the control surface 116 generally
comprises a trailing edge control surface or flap that conforms to
the shape of the outer surface 108 of the vehicle 100. The control
surface 116 and movable member 112 are adapted to be variably
deployed into the orientation shown in FIG. 1, to generate a moment
for maneuvering the atmospheric entry vehicle during hypersonic
speeds or lesser speeds, as well as for aerobraking.
[0016] Referring to FIG. 1, the outer body surface 108 has a
generally tapered shaped. The atmospheric entry vehicle 100 can
encompass a variety of shapes or contours, and may include a
conical shape such as that shown in FIG. 1. The moveable member 112
and control surface 116 are pivotally coupled to the vehicle 100 in
a manner such that outward movement of the control surface 116 is
permitted. The outward deploying movement of the control surface
116 establishes a deflection angle relative to the vehicle 100 from
the juncture point where the leading edge 118 of the control
surface 116 adjoins the outer surface 108, to the trailing edge of
the control surface. When the moveable member 112 is in a first
stowed position, the control surface 116 is generally flush with a
portion of the vehicle's outer surface 108. At hypersonic speed, a
first local boundary layer 110 is developed over the juncture 120
(shown in FIG. 2) where the leading edge 118 of the control surface
116 adjoins the outer surface 108 of the vehicle 100. In at least
one deployed position, the control surface 116 also develops a
second local boundary layer 140 along a portion of its outer
surface 108.
[0017] In FIG. 1, the vehicle 100 comprises at least two deployable
control surfaces 116, but may include four control surfaces or any
other suitable number of control surfaces 116 to provide for
steering. At least two of the control surfaces 116 are generally
opposite each other, such that the opposing control surfaces 116
provide for aerobraking when simultaneously deployed. When the
moveable member 112 is deployed to extend away from the outer
surface 108 of the vehicle 100 (at an angle .delta. relative to the
surface of the vehicle), the fluid flow acting on the control
surface 116 creates a control force 126 that generates a moment 128
about the vehicle's center of gravity for directing the vehicle 100
in a predetermined direction. The deploying of the control surface
116 into the hypersonic flow along a Newtonian line-of-sight
direction causes this local control force and associated moment
about the vehicle's 100 center of gravity, the magnitude of which
increases as the deflection angle of the control surface 116
increases. The arrangement of two or more variably deployable
control surfaces 116 allows the control surfaces 116 to generate
variable moments about the vehicle's 100 center of gravity for
controlling maneuverability of the atmospheric entry vehicle 100.
The design of the control surfaces 116 establishes a gap 124
through which the local boundary layer flow 110 passes through to
further provide for improved effectiveness of the control surface
116.
[0018] Referring to FIG. 2, an atmospheric entry vehicle is shown
with a control surface 116' which does not include a gap. When the
control surface 116' is deployed, the local boundary layer 110'
over the body surface 108' at juncture 120' shown in FIG. 2 is
likely to separate and reattach near the mid-chord of the control
surface 116'. At hypersonic speed, a local shock may be generated
at the juncture 120' when deploying the control surface 116'. Due
to the imposed adverse pressure gradient 142', the approaching
boundary layer 140' may separate and reattach on the control
surface 116' near mid-chord where the heat load experienced by the
control surface 116' is further aggravated. The separation of the
boundary layer 140' from the control surface 116' can degrade the
effectiveness of the control surface 116'. The effects of the local
shock and separation of the boundary layer 140' result in a higher
heat load and disruption of fluid flow across the control surface
116'.
[0019] In the first embodiment shown in FIG. 3, movement of the
movable member 112 and the associated control surface 116 outwardly
towards a deployed position establishes the gap 124 between the
body's outer surface 108 and the leading edge 118 of the control
surface 116, which gap forms a fluid flow path. The gap 124
generally comprises a curved space between the leading edge 118 of
the control surface 116 (which generally conforms to the conical
shape of the vehicle body), and the conical outer surface 108 of
the vehicle. It should be noted that at least a portion of the
vehicle may comprise a generally conical outer surface. In other
embodiments, some portions of the vehicle may comprise areas that
have much less curvature in the contour of the outer surface, and
may even have generally flat portions. In such cases, the gap may
comprise a generally rectangular space between the leading edge of
the control surface and the generally parallel outer surface of the
vehicle.
[0020] A portion of the boundary layer flow 110 along the vehicle
body's outer surface 108 passes through the gap 124. This
substantially alleviates the influence of a local shock at the
body/control juncture 120 to inhibit separation of boundary layer
110 from the outer surface 108, and to permit attachment of the
boundary layer 140 at or near the leading edge 118 of the control
surface 116. The atmospheric entry vehicle 100 may further comprise
an actuator structure 150 coupled to the control surface 116 for
deploying each individual control surface 116. A control system 152
preferably controls one or more actuator structures 150 to
independently variably deploy the one or more control surfaces 116
at various angles relative to the outer surface 108 of the vehicle
100 to provide for steering.
[0021] Referring to FIG. 4, a second embodiment of an atmospheric
entry vehicle 200 is shown that comprises an outer body surface 208
having a generally tapered shape. At least one moveable member 212
and at least one control surface 216 is pivotally coupled to the
vehicle 200 in a manner such that an outward deploying movement of
the control surface 216 is permitted. The outward movement of the
control surface 216 establishes a deflection angle relative to the
vehicle 200. When the moveable member 212 is in a first stowed
position, the control surface 216 is in a shielded position behind
the vehicle 200 (from a Newtonian line-of-sight). At hypersonic
speed, a local boundary layer 210 is established over the outer
surface 208 of the vehicle 200. When the moveable member 212 is
deployed (at an angle .delta. relative to the stowed position of
the control surface 216), the fluid flow acting on the control
surface 216 creates a control force 226 that generates a moment 228
about the vehicle's center of gravity for directing the vehicle 200
in a predetermined direction. In at least one deployed position,
the control surface 216 also develops a local boundary layer 240
along the control surface 216.
[0022] In the second embodiment, movement of the movable member 212
and associated control surface 216 outwardly towards a deflected
position establishes a gap between the body's outer surface 208 and
a leading edge 218 of the control surface 216. In at least one
deployed position of the moveable member 212, a space or gap 224 is
provided between the leading edge 218 of the control surface 216
and the outer body surface 208, which gap defines a fluid flow
path. The boundary layer flow 210 along the vehicle body's outer
surface 208 passes through this gap 224. This substantially
alleviates the influence of a local shock at the juncture 220 to
inhibit separation of the boundary layer 210 from the outer surface
208, and to permit attachment of the boundary layer 240 at or near
the leading edge 218 of the control surface 216.
[0023] In a third embodiment shown in FIG. 5, an aerodynamic body
or capsule 300 is provided that has a generally conically shaped
outer body surface 308. The aerodynamic capsule or body 300
comprises one or more control surfaces 316 circumferentially
positioned along the body's outer surface 308. The one or more
control surfaces 316 preferably include at least four control
surfaces spaced around the vehicle's conical surface 308 in a
cruciform pattern. The deployment of the control surface 316 into a
hypersonic flow along a Newtonian line-of-sight direction causes a
local control force 326 to be formed that generates a predetermined
moment 328 about the body's center of gravity, the magnitude of
which increases as the deflection angle of the control surface 316
increases. The arrangement of four control surfaces 316 allows
adjacent deployed control surfaces 316 to generate variable moments
in various selected directions about the body's center of gravity
to control pitch and yaw attitude for controlling maneuverability
of the capsule body 300. The design of the control surfaces 316
provides for improved control surface effectiveness during
aerobraking and maneuvering phases to allow for fuel saving
aerocapture techniques that enhance the longevity of capsule
300.
[0024] The one or more control surfaces 316 are moveable between a
first stowed position in which the control surfaces 316 are
positioned substantially flush with the body surface 308, and at
least a second position in which the control surfaces 316 are
deployed at an angle .delta. from the body surface 308. In the
second position, the control surfaces 316 form a space between a
leading edge 318 of the control surface 316 and the body surface
308 that defines a gap 324 through which a first boundary layer
flow 310 along the body surface passes through. The one or more
control surfaces 316 are pivotally coupled to the aerodynamic body
300 via arm portions 336 and 338. The aerodynamic capsule 300
further comprises a conventional independent actuator structure
(not shown) for each control surface that is configured to move the
control surface 316 to one or more positions of varying deployment
angles relative to the outer surface 308 of the body. The one or
more control surfaces 316 have first and second opposing edge
portions 332 and 334 that are coupled to the first and second arm
portions 336 and 338. The opposite ends of the arm portions 336 and
338 are pivotally coupled to the capsule 300 near edge 308A. Each
independent actuator structure is preferably connected to a drive
mechanism, and is operative to pivotally move its respective
control surface 316 via the arm portions 336 and 338 to a deployed
position relative to the capsule body's outer surface 308. The
pivotal coupling permit the control surfaces 316 to be deployed in
a manner such that each control surface 316 may pivot generally
about a hinge line, but may alternatively move outwardly in a
rotational manner that does involve a fixed pivot point. For
example, the arm portions 336 and 338 may comprise a dog leg shape
(as shown in FIG. 3) that allows the control surface 316 to be
deployed to establish the gap 324 between the control surface 316
and the outer capsule surface 308. Thus, the deployment of the
control surface 316 establishes a stand-off region between the
leading edge 318 of the control surface 316 and the body's outer
surface 308.
[0025] The actuator structure moves the control surfaces 316 to a
position that is generally flush with the outer surface 308 of the
body to close the gap 324. The actuator structure can also be
configured to adjust the angle of deflection of the control surface
316, as well as the height of the gap 324. The height of gap 324
allows a portion of the boundary layer flow 310 along the outer
surface 308 of the body 300 to pass through the gap 324 under the
leading edge 318 of the control surface 316. The height of gap 324
inhibits the separation effects of the boundary layer 310 along the
body's outer surface 308, such that the boundary layer remains
substantially attached to the outer surface 308. The gap 324 is
configured to substantially alleviate the influence of a local
shock that may cause turbulence at the body/control juncture 320
such that the boundary layer 310 remains attached to the outer
surface 308. In one preferred form, the gap height is preferably in
the range of about 0.125 inch (3.175 mm) to about 1.0 inch (25.4
mm), and is more preferably in the range of about 0.250 (6.35 mm)
to about 0.750 (19.05 mm). This substantially alleviates the
influence of a local shock at the juncture 320 to inhibit
separation of the boundary layer 310 from the outer surface 308,
and to permit attachment of a second boundary layer 340 at or near
the leading edge 318 of the control surface 316. The attachment of
the second boundary layer near the leading edge enhances the
effective area of the control surface 316 to further improve the
maneuverability of the vehicle.
[0026] The description of the invention is merely exemplary in
nature and, thus, variations that do not depart from the gist of
the invention are intended to be within the scope of the invention.
Such variations are not to be regarded as a departure from the
spirit and scope of the invention.
* * * * *