A unique, beneficial feature of rotorcraft is their flexibility in aircraft-to-ground interfacing. For a variety of reasons, hard landings can occur when the descent rate of the aircraft is larger than intended. The resulting impact can result in vehicle damage, structural failure, injuries, etc. To reduce these risks, an attractive solution is the implementation of a robotic legged landing gear (RLLG) system. The system softens a hard landing by acting as a shock absorber with a relatively large stroke, allowing the aircraft to decelerate over a much larger distance compared with a tradition landing gear system. This paper explores the mitigation of rotorcraft hard landings via RLLG through a comprehensive multibody dynamics simulation tool. The purpose of this study is to demonstrate the efficacy of the RLLG as a robust solution to reduce loads during hard landings for multiple landing configurations. The results show that when using RLLG in place of conventional landing gear, peak loads are reduced by approximately 70–90%, depending on the landing conditions. Through Monte Carlo simulation, robotic landing gear system performance is shown to be robust to uncertain conditions.

References

References
1.
Sharp
,
C. S.
,
Shakernia
,
O.
, and
Sastry
,
S. S.
,
2001
, “
A Vision System for Landing an Unmanned Aerial Vehicle
,”
IEEE
International Conference on Robotics and Automation
,
Seoul, South Korea
, pp.
1720
1727
.
2.
Sykora
,
B.
,
2009
, “
Rotorcraft Visual Situational Awareness, Solving the Pilotage Problem for Landing in Degraded Visual Environments
,”
American Helicopter Society 65th Annual Forum
,
AHS, Ontario, CA
.
3.
Taylor
,
T.
,
2009
, “
Rotorcraft Visual Situational Awareness (VSA): Solving the Pilotage Problem for Landing in Degraded Visual Environments
,”
Proc. SPIE
,
7328
, p.
73280G-1
.
4.
Templeton
,
T.
,
2007
,
Autonomous Vision-Based Rotorcraft Landing and Accurate Aerial Terrain Mapping in an Unknown Environment
,
University of California at Berkeley
,
Berkeley, CA
.
5.
Takahashi
,
M. D.
,
Abershitz
,
A.
,
Rubinets
,
R.
, and
Whalley
,
M. S.
,
2013
, “
Evaluation of Safe Landing Area Determination Algorithms for Autonomous Rotorcraft Using Site Benchmarking
,”
J. Am. Helicopter Soc.
,
58
(
3
), pp.
1
13
.
6.
Coltman
,
J. W.
,
Bolukbasi
,
A. O.
, and
Laananen
,
D. H.
,
1985
,
Analysis of Rotorcraft Crash Dynamics for Development of Improved Crashworthiness Design Criteria
,
Simula, Inc.
,
Tempe, AZ
.
7.
Shanahan
,
D. F.
, and
Mastroianni
,
G. R.
,
1984
, “
Spinal Injury in a U.S. Army Light Observation Helicopter
,”
Aviat. Space Environ. Med.
,
55
(
1
), pp.
32
40
.
8.
Iseler
,
L.
, and
De Maio
,
J.
,
2002
,
An Analysis of U.S. Civil Rotorcraft Accidents by Cost and Injury (1990–1996)
,
National Aeronautics and Space Administration AMES Research Center
,
Moffett Field, CA
.
9.
Couch
,
M.
, and
Lindell
,
D.
,
2010
,
Study on Rotorcraft Safety and Survivability
,
Defense Acquisition University
,
Fort Belvoir, VA
.
10.
Shanahan
,
D. F.
,
1993
,
Basic Principles of Helicopter Crashworthiness
,
Army Aeromedical Research Laboratory
,
Fort Rucker, AL
.
11.
Standard Military
,
1988
,
MIL_STD_1290 (A) Light Fixed and Rotary-Wing Aircraft Crash Resistance
,
Department of Defense
,
Washington, DC
.
12.
Tho
,
C. H.
,
Sparks
,
C. E.
,
Sareen
,
A. K.
,
Smith
,
M. R.
, and
Johnson
,
C.
,
2004
, “
Efficient Helicopter Skid Landing Gear Dynamic Drop Simulation Using LS-DYN
,”
J. Am. Helicopter Soc.
,
49
(
4
), pp.
483
492
.
13.
Airoldi
,
A.
, and
Lanzi
,
L.
,
2005
, “
Multi-Objective Genetic Optimization for Helicopter Skid Landing Gears
,”
AIAA
Paper No. 2005-2310.
14.
Chernoff
,
M.
,
1962
, “
Analysis and Design of Skid Gears for Level Landing
,”
J. Am. Helicopter Soc.
,
7
(
1
), pp.
33
39
.
15.
Stephens
,
B. E.
, and
Evans
,
W. L.
,
1999
, “
Application of Skid Landing Gear Dynamic Drop Simulation
,”
American Helicopter Society 55th Annual Forum
,
AHS
,
Montreal, Canada
.
16.
Littell
,
J.
,
2011
, “
Full-Scale Crash Test of an MD-500 Helicopter
,”
67th American Helicopter Society Annual Forum
,
AHS
,
Virginia Beach, VA
.
17.
Caprile
,
C.
,
Airolid
,
A.
, and
Janszen
,
G.
,
1999
, “
Multi-Body Simulation of a Helicopter Landing With Skid Landing Gear in Various Attitudes and Soil Conditions
,”
25th European Rotorcraft Forum
,
Rome, Italy
, p.
G-12
.
18.
Kellas
,
S.
,
Jackson
,
K. E.
, and
Littell
,
J. D.
,
2010
, “
Full-Scale Crash Test of an MD-500 Helicopter With Deployable Energy Absorbers
,”
American Helicopter Society 66th Annual Forum and Technology Display
,
AHS
,
Phoenix, AZ
.
19.
Jackson
,
K. E.
, and
Yvonne
,
T. F.
,
2008
, “
Comparison of ALE and SPH Simulations of Vertical Drop Tests of a Composite Fuselage Section Into Water
,”
10th International LS-DYNA Users Conference
,
Dearborn, MI
,
Document ID No. 20080022946
.
20.
Kim
,
H.
, and
Kirby
,
B. P. D.
,
2006
, “
Investigation of External Airbags for Rotorcraft Crashworthiness
,”
J. Aircr.
,
43
(
3
), pp.
809
816
.
21.
Airoldi
,
A.
, and
Janszen
,
G.
,
2005
, “
A Design Solution for a Crashworthy Landing Gear With a New Triggering Mechanism for the Plastic Collapse of Metallic Tubes
,”
Aerosp. Sci. Technol.
,
9
(
5
), pp.
445
455
.
22.
Fagan
,
C. H.
, and
Lynn
,
R. R.
,
1973
, “
Energy Absorbing Landing Gear
,”
U.S. Patent No. 3,716,208
, Feb. 13.
23.
Gentile
,
D. M.
,
1998
, “
Emergency Soft-Landing System for Rotor-Type Aircraft
,”
U.S. Patent No. US5836544 A
, Nov. 17.
24.
Logan
,
A. H.
, and
Wagner
,
R. A.
,
1985
, “
For Use in an Aircraft
,” U.S. Patent No. US4519559 A, May 28.
25.
Mikulowski
,
G.
, and
Holnicki-Szulc
,
J.
,
2004
, “
Adaptive Aircraft Shock Absorbers
,”
Third European Conference on Structural Control
,
Jadwisin
, Sept. 2–5.
26.
Sandy
,
D. F.
, and
Furnes
,
K. M.
,
1999
, “
Energy Absorbing Landing Gear/Tail Skid
,”
U.S. Patent No. US5927646 A
, Jul. 27.
27.
Carter
, Jr.
J. W.
,
1999
, “
Crashworthy Landing Gear Shock
,” U.S. Patent No. US5944283 A, Aug. 31.
28.
Shwayder
,
W.
,
1985
, “
Helicopter Landing Skid Shoe Pad
,” U.S. Patent No. US4544116 A, Oct. 1.
29.
Smith
,
M. R.
, and
Cheng-Ho Tho
,
S. C.
,
2011
, “
Crash Attenuation System for Aircraft
,”
U.S. Patent No. US7954752 B2
, Jun. 7.
30.
Manivannan
,
V.
,
Langley
,
J. P.
,
Costello
,
M. F.
, and
Ruzzene
,
M.
,
2013
, “
Rotorcraft Slope Landings With Articulated Landing Gear
,”
AIAA
Paper No. 2013-5160.
31.
Leylek
,
E.
,
Ward
,
M.
, and
Costello
,
M.
,
2012
, “
Flight Dynamic Simulation for Multibody Aircraft Configurations
,”
J. Guid. Control Dyn.
,
35
(
6
), pp.
1828
1842
.
32.
Goyal
,
S.
,
Pinson
,
E. N.
, and
Sinden
,
F. W.
,
1994
, “
Simulation of Dynamics of Interacting Rigid Bodies Including Friction I: General Problem and Contact Model
,”
Eng. Comput.
,
10
(
3
), pp.
162
174
.
33.
Goyal
,
S.
,
Pinson
,
E. N.
, and
Sinden
,
F. W.
,
1994
, “
Simulation of Dynamics of Interacting Rigid Bodies Including Friction II: Software System Design and Implementation
,”
Eng. Comput.
,
10
(
3
), pp.
175
195
.
34.
1990, Operators Manual: Helicopter, Observation OH-6A, Headquarters, Department of the Army
.
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