Unmanned Systems Special Report. February 2023 - 16

TECH BRIEFS
of terminology and classification
is due to the emergence and rapid
development of unmanned systems
in a wide variety of disciplines across
numerous organizations around the
world. This is characteristic of how
fast the technology is outpacing the
language, law and, even in some cases,
the application of these systems.
There are several industries fueling
the development of UAS including, but
not limited to, telecommunications,
home security, personal navigation, and
hobby. These activities are dominated
by an evolution of achieving lower
cost and higher reliability with each
new generation. This is especially true
for Small Unmanned Aircraft Systems
(SUAS). In fact, these systems are
beginning to saturate the market
as the parts become smaller, more
durable, and mobile. While there is a
healthy supply of UAS, the demand
is unrealized because there are still
many unexplored applications.
This work was done by Brandon
B. Barnes, Captain, USMC, for the
Air Force Institute of Technology.
For more information, download the
Technical Support Package (free white
paper) at mobilityengineeringtech.
com/tsp under the Vehicles &
Robotics category. AFIT-0007
Enhancing Fault Isolation and Detection for Electric
Powertrains of UAVs
A method for rapidly understanding, isolating, and informing response to faults in a
complex system.
Ames Research Center, Mountain View, CA
N
ASA's System-Wide Safety (SWS)
project is developing innovative
data solutions to assure safe, rapid, and
repeatable access to a transformed
National Airspace System. The
increasing number of electric propulsion
systems that will enter the airspace
will require systems that ensure high
safety standards in the low-altitude
airspace. One element that can help
ensure safety is proper diagnosis of
failures via Fault Detection and Isolation
(FDI). NASA Ames has developed a
fault isolation approach for electric
powertrains of unmanned aerial vehicles.
The approach leverages a combination
of Failure Mode and Effect Analysis
(FMEA) and Bayesian Networks (BN)
to create a dependability structure
within a diagnostic frameworkmapping
fault and failure events
from the FMEA within a BN.
This framework helps the fault
isolation process by identifying the
probability of occurrence of specific
fault or root causes given evidence
observed through sensor signals.
The tool developed through this work
merges information from the electric
propulsion system design phase with
diagnostic tools. Information from the
FMEA from the system design phase
is embedded within BN. Each node
16 FEBRUARY 2023
in the network can represent either a
fault, failure mode, root cause or effect,
and the causal relationships between
different elements are described
through the connecting edges.
This novel approach can help FDI,
producing a framework capable of
isolating the cause of sub-system
level fault and degradation. This
system: Identifies and quantifies the
effects of the identified hazards,
the severity and probability of their
effects, their root cause, and the
likelihood of each cause; Uses a
Bayesian framework for FDI; Based
on the FDI output, estimates health
of the faulty component and predicts
the remaining useful life (RUL) by also
UNMANNED SYSTEMS SPECIAL REPORT
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Unmanned Systems Special Report. February 2023

Table of Contents for the Digital Edition of Unmanned Systems Special Report. February 2023

Unmanned Systems Special Report. February 2023 - Cov1
Unmanned Systems Special Report. February 2023 - Cov2
Unmanned Systems Special Report. February 2023 - 1
Unmanned Systems Special Report. February 2023 - 2
Unmanned Systems Special Report. February 2023 - 3
Unmanned Systems Special Report. February 2023 - 4
Unmanned Systems Special Report. February 2023 - 5
Unmanned Systems Special Report. February 2023 - 6
Unmanned Systems Special Report. February 2023 - 7
Unmanned Systems Special Report. February 2023 - 8
Unmanned Systems Special Report. February 2023 - 9
Unmanned Systems Special Report. February 2023 - 10
Unmanned Systems Special Report. February 2023 - 11
Unmanned Systems Special Report. February 2023 - 12
Unmanned Systems Special Report. February 2023 - 13
Unmanned Systems Special Report. February 2023 - 14
Unmanned Systems Special Report. February 2023 - 15
Unmanned Systems Special Report. February 2023 - 16
Unmanned Systems Special Report. February 2023 - 17
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