U.S. patent application number 12/766850 was filed with the patent office on 2011-02-24 for lightweight vertical take-off and landing aircraft and flight control paradigm using thrust differentials.
Invention is credited to JOEBEN BEVIRT, David D. Craig, Jeffrey K. Gibboney, Matthew Peddie.
Application Number | 20110042510 12/766850 |
Document ID | / |
Family ID | 43604537 |
Filed Date | 2011-02-24 |
United States Patent
Application |
20110042510 |
Kind Code |
A1 |
BEVIRT; JOEBEN ; et
al. |
February 24, 2011 |
Lightweight Vertical Take-Off and Landing Aircraft and Flight
Control Paradigm Using Thrust Differentials
Abstract
An aerial vehicle adapted for vertical takeoff and landing using
the same set of engines for takeoff and landing as well as for
forward flight. An aerial vehicle which uses a rotating platform of
engines in fixed relationship to each other and which rotates
relative to the main body of the vehicle for takeoff and landing.
An aerial vehicle which is adapted to takeoff with the wings in a
vertical as opposed to horizontal flight attitude which takes off
in this vertical attitude and then transitions to a horizontal
flight path. An aerial vehicle which controls the attitude of the
vehicle during takeoff and landing by alternating the thrust of
engines, which are separated in at least two dimensions relative to
the horizontal during takeoff, and which may also control regular
flight in some aspects by the use of differential thrust of the
engines.
Inventors: |
BEVIRT; JOEBEN; (Santa Cruz,
CA) ; Craig; David D.; (Santa Cruz, CA) ;
Gibboney; Jeffrey K.; (Menlo Park, CA) ; Peddie;
Matthew; (Santa Cruz, CA) |
Correspondence
Address: |
MICHAEL A. GUTH
2-2905 EAST CLIFF DRIVE
SANTA CRUZ
CA
95062
US
|
Family ID: |
43604537 |
Appl. No.: |
12/766850 |
Filed: |
April 23, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61312188 |
Mar 9, 2010 |
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61247102 |
Sep 30, 2009 |
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61236520 |
Aug 24, 2009 |
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Current U.S.
Class: |
244/12.4 |
Current CPC
Class: |
B64C 29/0033
20130101 |
Class at
Publication: |
244/12.4 |
International
Class: |
B64C 29/00 20060101
B64C029/00 |
Claims
1. An aerial vehicle adapted for vertical takeoff and horizontal
flight, said aerial vehicle comprising: a main vehicle body; and a
wing and engine array, said wing and engine array comprising: a
first array of engines rotationally coupled to a first side of said
main vehicle body; a second array of engines rotationally coupled
to a second side of said main vehicle body; and one or more wings,
each of said wings having a first end and a second end, each of
said wings attached to said first array of engines on their first
end and attached to said second array of engines on said second
end, wherein said wing and engine array is adapted to rotate
relative to said main vehicle body as a single unit.
2. The aerial vehicle of claim 1 wherein said wing and engine array
is adapted to rotate from a first position adapted to vertical
take-off and landing to a second position adapted for regular
flight.
3. The aerial vehicle of claim 2 wherein the thrust of said first
array of engines and said second array of engines is pointed
downwards while said wing and engine array is in said first
position.
4. The aerial vehicle of claim 3 wherein the leading edges of said
one or more wings are facing upwards while said wing and engine
array is in said first position.
5. The aerial vehicle of claim 4 said wing and engine array
comprises two wings.
6. The aerial vehicle of claim 5 wherein said two wings comprise a
wing above said main vehicle body and a wing below said vehicle
body while said wing and engine array is in said second
position.
7. The aerial vehicle of claim 2 wherein said first array of
engines and said second array of engines combine to create a two
dimensional array of engines in a plane parallel to the ground
while said wing and engine array is said first position.
8. The aerial vehicle of claim 4 wherein said first array of
engines and said second array of engines combine to create a two
dimensional array of engines in a plane parallel to the ground
while said wing and engine array is said first position.
9. The aerial vehicle of claim 7 further comprising a control
system, said control system adapted to control the attitude of said
aerial vehicle during take-off and landing around a first control
axis parallel to the ground and a second control axis parallel to
the ground, wherein said first control axis and said second control
axis are perpendicular to each other.
10. A method for flying an aerial vehicle, said method including
the steps of: rotating a wing and engine assembly relative to an
aircraft body into a vertical take-off position, wherein the
leading edges of the wings face upward, said wing and engine
assembly comprising a first array of engines rotationally coupled
to a first side of said main vehicle body; a second array of
engines rotationally coupled to a second side of said main vehicle
body; and one or more wings, each of said wings having a first end
and a second end, each of said wings attached to said first array
of engines on their first end and attached to said second array of
engines on said second end; directing thrust from the first array
of engines and the second array of engines to effect a take-off
from the ground; controlling the attitude of said aerial vehicle in
a first axis and a second axis during take-off by varying the
thrust of the engines, wherein said first axis and said second axis
are perpendicular to each other, and wherein said first axis and
said second axis are parallel to the ground.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 61/312,188 to Bevirt, filed Mar. 9, 2010, which is
hereby incorporated by reference in its entirety. This application
claims priority to U.S. Provisional Patent Application No.
61/247,102 to Bevirt, filed Sep. 30, 2009, which is hereby
incorporated by reference in its entirety. This application claims
priority to U.S. Provisional Patent Application No. 61/236,520 to
Bevirt, filed Aug. 24, 2009, which is hereby incorporated by
reference in its entirety.
BACKGROUND
[0002] 1. Field of the Invention
[0003] This invention relates to powered flight, and more
specifically to a take-off and flight control aircraft method using
thrust differentials.
[0004] 2. Description of Related Art
[0005] There are generally three types of vertical takeoff and
landing (VTOL) configurations: wing type configurations having a
fuselage with rotatable wings and engines or fixed wings with
vectored thrust engines for vertical and horizontal translational
flight; helicopter type configuration having a fuselage with a
rotor mounted above which provides lift and thrust; and ducted type
configurations having a fuselage with a ducted rotor system which
provides translational flight as well as vertical takeoff and
landing capabilities.
SUMMARY
[0006] An aerial vehicle adapted for vertical takeoff and landing
using the same set of thrust producing elements for takeoff and
landing as well as for forward flight. An aerial vehicle which is
adapted to takeoff with the wings in a vertical as opposed to
horizontal flight attitude which takes off in this vertical
attitude and then transitions to a horizontal flight path. An
aerial vehicle which controls the attitude of the vehicle during
takeoff and landing by alternating the thrust of motors, which are
separated in at least two dimensions relative to the horizontal
during takeoff, and which may also control regular flight in some
aspects by the use of differential thrust of the motors. An aerial
vehicle which uses a rotating platform of motors in fixed
relationship to each other and which rotates relative to the main
body of the vehicle for takeoff and landing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of an aerial vehicle in takeoff
configuration according to some embodiments of the present
invention.
[0008] FIG. 2 is a perspective view of an aerial vehicle in a
forward flight configuration according to some embodiments of the
present invention.
[0009] FIG. 3 is a top view of an aerial vehicle in takeoff
configuration according to some embodiments of the present
invention.
[0010] FIG. 4 is a front view of an aerial vehicle in takeoff
configuration according to some embodiments of the present
invention.
[0011] FIG. 5 is a side view of an aerial vehicle in takeoff
configuration according to some embodiments of the present
invention.
[0012] FIG. 6 is a top view of an aerial vehicle in forward flight
configuration according to some embodiments of the present
invention.
[0013] FIG. 7 is a front view of an aerial vehicle in forward
flight configuration according to some embodiments of the present
invention.
[0014] FIG. 8 is a side view of an aerial vehicle in forward flight
configuration according to some embodiments of the present
invention.
[0015] FIG. 9 is a sketch of the transition from take-off to
forward flight mode.
[0016] FIG. 10 is sketch of an aerial vehicle according to some
embodiments of the present invention.
[0017] FIG. 11 is a sketch of an aerial vehicle according to some
embodiments of the present invention.
DETAILED DESCRIPTION
[0018] In some embodiments of the present invention, as seen in
FIG. 1, an aerial vehicle 100 is seen in take-off configuration.
The aircraft body 101 rotationally attached to the left inside duct
106 with a rotational coupling 116. The aircraft body 101 is also
attached to the right inside duct 107 with a rotational coupling.
The aircraft body 101 is adapted to rotate relative to the rotating
portion 120.
[0019] In the take-off configuration, the aerial vehicle 100 is
adapted to engage in controlled vertical take-off. The rotating
portion 120 has landing struts 121 which are adapted to support the
aircraft when on the ground. In some embodiments, the aerial
vehicle 100 has six thrust producing elements, which may be ducted
fans (propellers) driven by electric motors. A left inside duct
106, which is rotationally coupled to the aircraft body 101, is
attached to an upper left outside duct 105 and a lower left outside
duct 104. The left side ducts house fans 110, 111, 112 which may be
driven by electric motors. A right inside duct 107, which is
rotationally coupled to the aircraft body 101, is attached to an
upper right outside duct 109 and a lower right outside duct 108.
The right side ducts house fans 113, 114, 115 which may be driven
by electric motors.
[0020] In a vertical takeoff scenario, the power from the fans 110,
111, 112, 113, 114, 115 are varied in power output in order to
either change, or maintain, the attitude of the vehicle relative to
take-off axis 1 or take-off axis 2. For example, to effect an
attitude change around take-off axis 1, the relative power output
of the left side motors can be varied relative to the power output
of the right side motors. To effect an attitude change relative to
take-off axis 2, the relative power output of the upper motors can
be varied relative to the power output of the lower motors. In this
way, the aerial vehicle can be raised from the ground in a vertical
takeoff scenario while maintaining control in these two axes.
[0021] In some embodiments, the aerial vehicle may use a sensor
package adapted to provide real time attitude information to a
control system which is adapted to perform a vertical takeoff while
maintaining the horizontal attitude position of the rotating
portion 120 of the aerial vehicle 100. The control system may be
autonomous in keeping the attitude while an operator commands an
altitude raise while in takeoff mode. With the aerial vehicle
adapted to take off from a position wherein the leading edges of
the wings and the engines face skywards, no relative motion of the
engines and the wings is necessary to achieve vertical take off and
landing.
[0022] The spacing of the thrust producing elements in two
dimensions as viewed from above when the aerial vehicle is on the
ground ready for takeoff allows the engine power differentials to
control the aircraft in the two aforementioned axes, take-off axis
1 and take-off axis 2. Although six thrust producing elements are
illustrated here, the two dimensional spacing needed to affect two
dimensional control could be achieved with as few as three
engines.
[0023] Although the control of two axes has been discussed, in some
embodiments rotation around take-off axis 3 may also be controlled.
In some embodiments, the roll control during takeoff and landing
may be controlled using ailerons. In some embodiments, directional
vanes are placed behind the ducts, or within the ducts but behind
the fans, in order to control take-off axis 3.
[0024] As seen in FIG. 2, the aerial vehicle 100 has a forward
flight configuration wherein the rotating portion 120 is rotated
approximately 90 degrees relative to the aircraft body 101 compared
to the take-off configuration. An upper wing 102 is attached to the
top of the right upper duct 109 and the left upper duct 105. A
lower wing 103 is attached to the bottom of the right lower duct
108 and the left lower duct 104. The upper wing 102 and the lower
wing 103 are lifting airfoils which are adapted to provide
sufficient lift to support the mass of the aerial vehicle 100
during forward flight.
[0025] As seen, the aircraft body may be sized such the rotating
portion, including the wings and the ducted fan assemblies, is
adapted to rotate from a first take-off position to a second
forward flight position without physical interference with the
aircraft body in which the pilot may sit. Also seen is that in some
embodiments the wings are not attached to the aircraft body, but
are attached to the rotating group of fan assemblies.
[0026] FIG. 9 illustrates the transition from vertical takeoff to
horizontal flight according to some embodiments of the present
invention. As seen, the aerial vehicle first engages in vertical
takeoff while maintaining attitude control using an onboard sensor
package and by varying the power output of the motors to maintain
attitude in a desired range, and may also use ailerons or vanes
behind the fans for control in take-off axis 3. As the aerial
vehicle is raised to a desired altitude, the transition to
horizontal flight begins. With the use of differential power output
control of the motors, the rotating portion, which includes the
wings and the motors/fans/ducts, is pitched forward, which alters
the wings from their skyward facing position to a more horizontal,
normal flying position. This forward pitching of the rotating
portion, which then begins to direct thrust rearward, also causes
the vehicle to begin to accelerate forward horizontally. With the
increase in horizontal velocity coupled with the wing airfoils
attitude change to a more horizontal position, lift is generated
from the wing airfoils. Thus, as the rotating portion is
transitioned to a more horizontal position and their vertical
thrust is reduced, lift is begun to be generated from the wing
airfoils and the altitude of the aerial vehicle is maintained using
the lift of the wings. In this fashion, the aerial vehicle is able
to achieve vertical takeoff and transition to horizontal flight
without relative motion of the motors to the wings, and using
differential control of the power of the motors to achieve some, if
not all, of the attitude changes for this maneuver. When landing
the craft, these steps as described above are reversed.
[0027] Although not illustrated, in some embodiments the aerial
vehicle 100 may have control surfaces such as rudders, elevators,
and/or other control surfaces, which may be mounted to the aircraft
body. In some embodiments, the aerial vehicle 100 may have ailerons
on one or more of its wings which are adapted for roll control.
[0028] The vehicle may be adapted to turn using a simultaneous roll
and pitch up, which is affected by the ailerons with regard to
roll, and by differentially throttling the motors with regard to
pitch. Namely, upper motors may be throttled down relative to the
lower motors to achieve an upward change in pitch used in
conjunction with the roll of the vehicle to turn the vehicle.
[0029] The control system adapted for attitude control during
takeoff using differential control of the thrust elements, which
may be electric motors with ducted fans in some embodiments, is
also adapted to be used during traditional, more horizontal flight.
Although the aerial vehicle may have rudders and elevators in some
embodiments, the aerial vehicle and its control system are adapted
to use differential control of the thrust elements to vary pitch
and yaw during forward flight, and in some embodiments, to control
roll as well.
[0030] When the pilot gives a pitch command, the onboard control
system then executes a pitch change using a combination of engine
thrust differentiation, and also through the use of the ailerons on
both sides of the wing in common mode. The pitch change will be
executed primarily or fully by differential throttling of the upper
and lower motors. A pitch command may be given by the pilot by
pulling or pushing a control stick, or by pulling back or pushing
on a steering yoke, for example.
[0031] When the pilot gives a roll command, the onboard control
system then executes a roll of the aerial vehicle using a
combination of aileron control and differential thrusting of
counter-rotating motors on the aerial vehicle.
[0032] When the pilot gives a yaw command, the onboard control
system then executes a yaw change of the aerial vehicle using
engine thrust differentiation. The yaw change will be executed by
differential throttling of the right side and left side motors.
[0033] An aerial vehicle 100 according to some embodiments of the
present invention thus allows for attitude control of the vehicle
during VTOL and regular flight using the same or similar control
system parameters, including thrust differentiation of the various
thrust producing elements. In some embodiments, the thrust control
may involve the reduction or increase of electrical power sent to
the motors controlling a propeller or ducted fan assembly. In some
embodiments, the thrust control may involve the change of pitch of
the propeller/fan blades. In some embodiments, thrust control may
use a combination of pitch control and electrical power input
control.
[0034] In some embodiments of the present invention, the aerial
vehicle may be designed for use as a commuter vehicle. In such a
scenario, safety, reliability, compactness, and noise become
important design considerations.
[0035] In some embodiments, reliability may be enhanced by the use
of two motors on a single shaft driving each of the ducted fan
assemblies. The use of two sets of windings wherein one set of
windings is used for driving the ducted fan, and the second is a
redundant set of windings which may be used in the case of a
winding failure, greatly enhances reliability.
[0036] In some embodiments, the electric motors of the aerial
vehicle are powered by rechargeable batteries. The use of multiple
batteries driving one or more power busses enhances reliability, in
the case of a single battery failure. In some embodiments, the
batteries may be spread out along the rotating portion, and there
may be one battery for each of the motor/ducted fan assemblies. In
some embodiments, the battery or batteries may reside in part or
fully within the aircraft body, with power routed out to the motors
through the rotational couplings.
[0037] In some embodiments, the aerial vehicle is adapted to be
able to absorb the failure of one ducted fan assembly and still
have sufficient power to engage in both forward flight and also
vertical take-off and landing. Given the spacings of the motors,
the loss of thrust by one of the thrust producing elements will
still allow for attitude control of the vehicle using thrust
differentials. The control system of the vehicle may be adapted to
sense the failure of one or more thrust producing elements and
modify the control paradigms accordingly.
[0038] In some embodiments, the vehicle may have multiple sensor
packages adapted to provide attitude, altitude, position, and other
information. The sensor packages may be duplicates of each other,
allowing for failure of a sensor package in a redundant fashion. In
other embodiments, there may be a variety of different types of
sensors which are integrated using a common filter, and which also
may be able to absorb the loss of one or more of the single sensor
types without loss, or without complete loss, of functionality of
the vehicle.
[0039] Although ducted fans assemblies are illustrated in the
embodiments shown herein, it is understood that other types of
thrust producing elements may be used. In some embodiments, ducted
fan assemblies may be chosen to enhance safety and to reduce noise
of the vehicle.
[0040] In some embodiments, the aerial vehicle may have an
emergency safety system such as a ballistic parachute. In the case
of absolute failure of the power or control systems, the ballistic
parachute may be deployed to allow for an emergency landing.
[0041] In an exemplary embodiment, a vehicle is made primarily from
composite materials. The total weight, including the pilot, may be
600 pounds. The weight may be allocated as 200 pounds for the
batteries, 150-200 pounds for the pilot, and 200-250 pounds for the
remaining aircraft structure less the battery weight. With a six
ducted fan/six motor system, the nominal engine load would be 100
pounds per duct. The six ducts may be identical in size, each with
an interior diameter of 42 inches. With a 10 horsepower engine per
duct, the disc loading is 10 pounds per foot squared. The specific
thrust (pounds of thrust/horsepower) is targeted for a range of
8-12.5.
[0042] In this exemplary embodiment, the length of the upper and
lower wings is 14 feet, with a chord length of 18 inches. The
system may have a stall speed of 70 miles per hour. The system is
designed to have a ground parking envelope maximum of 8 feet by 18
feet, which is geared in part to allow it to fit in a parking
space.
[0043] The range of the vehicle may be 100 miles, with a flight
speed of 100 miles per hour. The range may be achieved using a 15
kWhr battery.
[0044] In some embodiments of the present invention, as seen in
FIG. 10, an aerial vehicle may have two sets of thrust producing
elements, one on each side of the aircraft body. The thrust
producing elements may be ducted fans driven by electric motors.
The thrust assemblies are adapted to rotate from a first position
wherein the thrust is primarily downward to a second position
adapted for forward flight, with the thrust primarily rearward.
With the spacing of the thrust elements as seen, attitude control
can be achieved using thrust differentiation both during vertical
take-off (the position shown in the figure) as well as during
forward flight, as the thrust elements are spaced in two dimensions
relative to the direction of motion in both take-off and forward
flight modes.
[0045] In some embodiments of the present invention, as seen in
FIG. 11, an aerial vehicle may have four thrust producing elements
spread out over two wings. The wings may be set at different
heights, thus the thrust elements are spaced in two dimensions in
forward flight mode as well as during vertical take-off mode
(pictured). The thrust producing elements may be ducted fans driven
by electric motors. The thrust assemblies are adapted to rotate
from a first position wherein the thrust is primarily downward to a
second position adapted for forward flight, with the thrust
primarily rearward. With the spacing of the thrust elements as
seen, attitude control can be achieved using thrust differentiation
both during vertical take-off (the position shown in the figure) as
well as during forward flight, as the thrust elements are spaced in
two dimensions relative to the direction of motion in both take-off
and forward flight modes.
[0046] As evident from the above description, a wide variety of
embodiments may be configured from the description given herein and
additional advantages and modifications will readily occur to those
skilled in the art. The invention in its broader aspects is,
therefore, not limited to the specific details and illustrative
examples shown and described. Accordingly, departures from such
details may be made without departing from the spirit or scope of
the applicant's general invention.
* * * * *