U.S. patent application number 09/922167 was filed with the patent office on 2003-02-06 for autonomous control of a parafoil recovery system for uavs.
This patent application is currently assigned to Lockheed Martin Corporation. Invention is credited to Nicolai, Leland M., Ramsey, William R. JR., Robinson, Douglas J..
Application Number | 20030025038 09/922167 |
Document ID | / |
Family ID | 25446615 |
Filed Date | 2003-02-06 |
United States Patent
Application |
20030025038 |
Kind Code |
A1 |
Nicolai, Leland M. ; et
al. |
February 6, 2003 |
Autonomous control of a parafoil recovery system for UAVs
Abstract
A parafoil system for autonomously controlling the gliding
descent of a payload/UAV from a launch point to a predetermined
recovery area and manipulating the parafoil to execute a soft
landing in the recovery area, a sensing means associated with the
system for determining wind speed and direction, as well as
altitude, heading and position of the system, a means housed within
the system for processing information received from the sensing
means to determine the gliding flight path from the launch point to
a predetermined recovery area and the execution of a flare maneuver
to achieve a soft landing, control surface means on the parafoil
canopy, mechanical means coupling the information processing means
with the control surface means for adjusting the control surface
means to accomplish the steering to the recovery area during
gliding flight and the flare maneuver during landing, and a power
source in the payload/UAV.
Inventors: |
Nicolai, Leland M.;
(Castaic, CA) ; Robinson, Douglas J.; (Little
Rock, CA) ; Ramsey, William R. JR.; (Altadena,
CA) |
Correspondence
Address: |
KOESTNER BERTANI LLP
18662 MacArthur Boulevard
Suite 400
Irvine
CA
92612
US
|
Assignee: |
Lockheed Martin Corporation
|
Family ID: |
25446615 |
Appl. No.: |
09/922167 |
Filed: |
August 6, 2001 |
Current U.S.
Class: |
244/152 |
Current CPC
Class: |
B64C 2201/104 20130101;
G05D 1/105 20130101; B64D 17/025 20130101; B64D 17/343 20130101;
B64C 39/024 20130101; B64C 2201/128 20130101; B64C 2201/141
20130101; B64C 2201/185 20130101; B64C 2201/187 20130101 |
Class at
Publication: |
244/152 |
International
Class: |
B64D 017/14; B64D
017/18; B64D 017/34 |
Claims
What I claim is :
1. A system for autonomously controlling the glide path and flare
landing of a parafoil recovery system for the recovery of an
airborne payload from a launch point to a predetermined recovery
area, comprising: a parafoil canopy coupled to said payload, said
parafoil canopy having a flexible leading edge and a flexible
trailing edge, said trailing edge having a control surface; sensing
means associated with said system for determining wind speed and
direction, as well as altitude, heading and position of said
system, means housed within said payload of the said recovery
system for continuously processing information received from said
sensing means to determine the glide flight path from the launch
point to said recovery area and flare landing maneuver to enable a
soft landing, control surface means on said trailing edge of the
said recovery system; mechanical means coupling said information
processing means with said control surface means relative to the
trailing edge of said parafoil recovery system power source means
in said payload, whereby adjustment of said control surface means
is performed on a continuous basis throughout the gliding flight of
said recovery system from launch to said recover area.
2. The gliding path and flare maneuver controlling system of claim
1, wherein said mechanical means comprises spool means on said
payload and control lines wrapped about said spool means and
attached at one end to said trailing edge control surfaces.
3. The gliding path and flare maneuver controlling means of claim
2, and further comprising motors functionally coupled with said
processing means and said spool means, for driving said spools in
one of a forward winding rotation or a rearward unwinding rotation,
whereby as said flight path is determined, adjustments to said
control surfaces are made on a continuing basis until the payload
impacts the recovery area.
4. The gliding flight path and flare maneuver controlling means of
claim 3, wherein said control surfaces comprise said flexible
trailing edge of said parafoil canopy.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an apparatus for the
parachute recovery of a payload. More particularly to an autonomous
steering of a parafoil recovery system to a recovery area and the
soft landing of the payload.
[0003] 2. Description of the Related Art
[0004] Current parachute recovery systems use an uncontrolled round
(or ballistic) parachute. The parachute descends at a vertical
speed depending on the relation of the size of the parachute to the
weight of the payload. The system also has a horizontal speed and
direction equal to that of the surface wind. The round parachute
system drifts with the wind and impacts the ground at a random
orientation. This ground impact usually results in damage to the
payload due to the vertical descent rate and the horizontal speed
which causes the payload to tumble and/or slam into rocks, trees,
etc. In addition, since the round parachute is difficult to steer
and drifts with the wind, the ground impact location is random.
[0005] Clearly there is a need for a parachute recovery system that
can be steered to a precise recovery area and then execute a soft
landing, all autonomously.
[0006] The related art teaches several parachute recovery systems
for the controlled steering of the system to a predetermined
recovery area, but none include the soft landing offered by the
present invention. For example U.S. Pat. No. 5,201,482 to Ream,
U.S. Pat. No. 5,620,153 to Ginsberg and U.S. Pat. No. 5,899,415 to
Conway all use parafoils (or ram air parachutes) for controlling
the glide path of the recovery system. These systems all rely on
human piloting of the parafoil (i.e.; non-autonomous). U.S Pat. No.
6,122,572 to Yavnai, teaches an autonomous command and control unit
for a powered airborne vehicle that uses a programmable decision
unit capable of managing and controlling the execution of a mission
by using subsystems and a data base capable of holding and
manipulating data including prestored data and data acquired by and
received from the various subsystems. U.S. Pat. No. 6,144,899 to
Babb et al. discloses a recoverable airborne winged instrument
platform for use in predicting and monitoring weather conditions.
The platform is taken aloft by balloon mean, accurately determines
its present position and uses the data to execute a predetermined
flight plan and ultimately guide its descent to a predetermined
landing site. This is achieved by installing the instrument package
payload in the aerodynamic exterior housing of the recoverable
airborne instrument platform.
[0007] Against this background of known technology, the applicant
has developed a novel system of components for autonomously
managing and controlling a parafoil recovery system to a
preselected recovery area and then executing a soft landing.
OBJECTS AND SUMMARY OF THE INVENTION
[0008] It is therefore an object of the present invention to
provide a novel system for the autonomous control of the gliding
descent of a parafoil recovery system to steer to a predetermined
recovery area, while overcoming many of the disadvantages and
drawbacks of similar configurations known in the art.
[0009] Another object of the present invention is to autonomously
manipulate the parafoil recovery system to execute a soft landing
(i.e.; reduce the vertical and horizontal speeds at ground impact
relative to an uncontrolled parafoil landing) at the recovery
site.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic diagram depicting the parafoil and the
attached payload of the present invention;
[0011] FIG. 2 is a schematic diagram depicting the control hardware
in the payload of the present invention;
[0012] FIG. 3 is a functional diagram of the control system
contained in the payload of the present invention;
[0013] FIG. 4 is a block diagram showing the chronology of
functions performed by the autonomous control embodied by the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The following description is provided to enable any person
skilled in the art to make and use the invention and sets forth the
best modes contemplated by the inventor of executing his invention.
Various modifications, however will be readily apparent to those
skilled in the art, since the generic principles of the present
invention have been defined herein specifically to provide a
control system for a parafoil that replicates a human operator as
the payload, and which encompasses many long sought after features
that make the present invention most desirable when used in the
parachute recovery of payloads.
[0015] Referring to the schematic diagram of FIG. 1, the parafoil
recovery system includes the rectangular shaped, ram-air filled
parafoil canopy 12, leading edge 11, railing edge 22 and sides 18
and 18" of said canopy, the main risers 13 that connect the canopy
leading edge and sides to the payload, the brake line risers 14R
and 14L that connect the outer portion (left and right) of the
trailing edge to the brake reel motors 20R and 20L, the payload 10
(shown here as an unmanned aerial vehicle UAV), and the payload
attitude lines 16R and 16L which control the attitude (nose up or
nose down) of the payload during descent.
[0016] Referring to FIG. 2 (a schematic diagram of the hardware
items in the payload), the parafoil main risers 13 are collected at
the parafoil release mechanisms 15R and 15L (releases the payload
from the parafoil upon ground impact so that the payload is not
dragged across the ground by surface winds) which are connected to
the payload attach points 21R and 21L, and the reel motors 20R and
20L which connect to brake line risers 14R and 14L and reel the
brake line risers in or out to control the outer portion of the
canopy trailing edge.
[0017] FIG. 3 shows a functional diagram of the control system
which consists of the IVMC (integrated vehicle management computer)
30, the right and left reel motors 20R and 20L, the GPS antenna 34,
the AGL (height above ground level) sensors 35, and the 28 vdc
power supply 36. The IVMC contains the motor controller 31, the
computer 32, the GPS receiver 33, and the heading indicator
(compass) 37.
[0018] FIG. 4 schematically illustrates the step-by-step method by
which the control system is executed. The parafoil is deployed from
the payload and stabilized in an equilibrium glide in blocks 41 and
42. The main risers are rigged and reel motors are adjusted before
launch so that all lines are of the proper length to give this
equilibrium glide. In block 43 the location of the recovery system
is determined using GPS and a flight plan developed to steer to the
stored coordinates of the recovery area. This plan is continually
updated to account for winds as the system glides to the recovery
area.. When over the recovery area a signal is sent to one reel to
adjust the parafoil trailing edge for a spiral flight path in block
44. The spiral flight path permits the computer to determine the
wind speed and direction in block 45. The wind direction is needed
since the parafoil recovery system always wants to land into the
wind in order to reduce the horizontal speed and eliminate the
possibility of a sideways or tail first ground impact. In block 46
the computer determines the last spiral and the appropriate time to
come out of the spiral for landing into the wind. At 50 feet above
ground level the recovery system is prepared for landing by
reverting to a very accurate altimeter (.+-.1 foot accuracy). At a
TBD altitude AGL a signal is sent to both reel motors in block 50
to reel in the brake lines and apply partial brakes in order to
flare the parafoil and reduce the vertical descent speed from
.about.27 ft/sec to .about.5 ft/sec. In block 51 the computer
determines the ground speed using GPS and determines the extent of
the braking (from none to full) to reduce the horizontal speed to 5
ft/sec or less. The payload impacts the ground nose first and
slides to a stop.
* * * * *