Truck & Off-Highway Engineering - April 2022 - 18

Predicting mobility in
MILITARY
OPERATIONAL
SCENARIOS
MODELING & SIMULATION FEATURE
Department of Defense's High Performance Computing
Modernization Program's (HPCMP) CREATE Ground
Vehicles (CREATE-GV) development program. Many of
the commercial vendors that participated in these efforts
are actively developing compliant models as well.
Modern methods such as NG-NRMM can significantThe
approach predicts land
and amphibious vehicle mobility
through coordinated interoperation
of GIS software and multibody, physicsbased,
vehicle dynamics M&S software.
A DEM simulation by Advanced Science
and Automation is shown.
Localization (GPS)
Foliage
Ceiling Clearance
Obstacles
Ground Clearance
ly improve the ability to make more accurate mobility
predictions and assessments that hold the promise of
reducing prediction errors by an order of magnitude.
The vision is to reach a point where nearly all virtual
prototyping and operational effectiveness can be determined
upfront, leading to the rapid fielding of new
technologies with a clear understanding of the operational
capability of the technology. The goal of M&S
investments is to minimize the need to build physical
prototypes and to fill the gaps in our mobility M&S
capabilities especially for autonomous operations.
Operational mobility readiness demands that Allied
Terrain (Topology & Soil)
Trafficability
Further work and investment are needed to improve computational efficiency so
that it runs faster but still can model and accurately simulate off-road - including
autonomous - mobility.
The need for a standard
By definition, NG-NRMM is not a specific computer code but any M&S
solution that is compliant with NG-NRMM standards and benchmarks,
and hence needs to be specified in a NATO STANREC
(STANdardization RECommendation). It is defined as a land-vehicle
mobility M&S open architectural specification that is applicable to all
land-vehicle geometric scales, implements GIS-based M&S methods
and mobility metrics, promotes modularity, interoperability and portability
and embraces scalable M&S at multiple levels of resolution.
It also includes M&S verification and validation maturity scales and
practical benchmarks, along with standards and databases for terramechanics
experimental data measurement methods that support the
terramechanics models and a soils database that should be applied to
all physics-based simulations of operational land and amphibious mobility
among the alliance. The STANREC was recently completed and
promulgated in July 2021 as NATO's M&S standard for mobility of offroad
vehicle systems. Efforts currently are underway to have the NGNRMM
methodology approved as a U.S. Army standard.
Looking to the future
The U.S. Army is developing a tool that will be compliant with NGNRMM
standards and benchmarks, called Mercury, which is part of the
18 April 2022
nations take full advantage of mobility modeling summarized
by the recommended NG-NRMM methodologies.
The future of analytical soft-soil mobility analysis
clearly rests with the NG-NRMM approach as it holds
the promise of allowing manufacturers, planners and
users the ability to model virtually any platform, over
any soil and terrain type.
Although there has been significant progress in the
NG-NRMM methodology development, further work
and investment are needed to increase computational
efficiency so that it runs faster but still is able to model
and accurately simulate off-road - including autonomous
- mobility. The near-term solution would
be based on physics-based models such as BekkerWong
rather than empirical assessment. The far-term
solution would rely on more-advanced Discrete
Element Method (DEM) models and Finite Element
Models (FEM) requiring HPC. The NG-NRMM would
include larger-scale terrains with variable resolutions
dependent on the area covered. There would be a
necessary tradeoff between computational efficiency
and model fidelity.
Future off-road vehicle mobility may involve many
different classes and sizes of vehicles such as wheeled/
tracked vehicles, small robots, legged robots, humanoid
robots and other emerging technologies traversing
a variety of environments that may include on-road,
urban, off-road and building interiors. The mobility performance
metric maps generated using this technology
are key requisites for consideration of military missions
that could succeed or fail depending on how accurately
the performance maps are generated.
Dr. David Gorsich of the U.S. Army Ground Vehicle Systems
Center, and Michael Letherwood, P.E., and Dr. Jean Dasch
of Huntington Ingalls Industries wrote this article for SAE
Truck & Off-Highway Engineering. Distribution A. Approved
for public release; distribution unlimited. OPSEC #: 6066
TRUCK & OFF-HIGHWAY ENGINEERING
BOTH IMAGES: U.S. ARMY
Truck & Off-Highway Engineering - April 2022

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