Complex Systems Approach for Prevention of Unmanned

Systems’ Operator Unsafe Acts C. D. Bocaniala and V. V. S. S. Sastry

Department of Engineering Systems and ManagementCranfield University, Shrivenham, SN6 8LA, UK

{cbocaniala.cu, vsastry.cu}@defenceacademy.mod.uk

Unsafe acts

Motivation - local causal models

•  A command can only be given in certain  context

•  Causal modelso dependencies between

different flight mission’s phases and the associated UAS’ states

o can assist with validation of UAS’ operator commands

• Complex structureso computationally expensive to use them in their entirety

Motivation

• Complex systems: emergent behaviouro no single sub-set of its sub-systems can achieve individually

• How to manage emergence?• Survey of related literature

o identify the relatively independent parts of the systemo identify the way the parts connect/relate to each other 

•  Key challenge is to discover appropriate graph partitioning algorithms

 

The challenge is in identifying the relevant neighbourhood of a given sub-set of components

xPart algorithm

• compleX causal models PARTitioning

• Generic procedure• The proposed system

is encoded as a directed grapho vertices: system’s basic componentso edges: causal relationships between

components

• Edge disjoint sub-models separated by interfaces formed out of shared vertices.

• Two central propertieso each sub-model is causally

independent from the rest of the system

o each interface contains a minimal number of vertices

An exampleInitial causal model (cycles in red)

Partitioned causal model (shared/border components in yellow)

Local operational context

• An outcome of the causal independence property

If the UAS finds itself in a sub-set of states and/or deploying a command, that is (are) contained in one or more

neighboring partitions, including its (their) border

then that partition represents UAS’ local operational

context

Prevention of unsafe actst=1

t=2

Prevention of unsafe acts

 Work under progress

• Different generic UAS flight phases are similarly modeled (~100 vertices)

• Collected approx 60 UAS mishaps reported in different public domain sources

• Test the model using test scenarios similar to real mishaps (e.g., xPlane)