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Undergraduate Thesis · Northwestern Polytechnical University · Completed

Design and Implementation of a Digital Twin System for Quadrotor UAV Formation Flight

四旋翼无人机编队飞行数字孪生系统的设计与实现

An undergraduate thesis developing an Unreal Engine and AirSim digital twin for quadrotor formation control, remote interaction, and flight-data collection.

HuiShan Lai

Northwestern Polytechnical University · Xi'an, China

Twenty-five quadrotor UAVs generated in the AirSim digital twin environment with three onboard sensor views
A 25-UAV scale test in the Unreal Engine and AirSim simulation environment.

Abstract

This undergraduate thesis develops a digital twin environment for exploring quadrotor UAV formation flight before deploying control logic to physical aircraft.

The project uses Unreal Engine 4 and Microsoft AirSim to combine a physics-based simulation, multi-UAV generation, controller and Python API input, remote PX4 communication, sensor recording, and a shared flight-data store. The resulting system supports both global formation observation and individual-aircraft views.

Functional testing demonstrated formation generation, multiple viewpoints, environmental controls, data recording, database export, and Windows–Linux remote interaction. The work also documents the practical limits of the prototype: large formations reduced rendering performance, occasional API disconnections disrupted follower aircraft, and the implemented formation controller remained a simplified follow-and-avoidance design.

Language note: the thesis and defense slides are in Chinese. This page provides an English project overview for the archive, with a browser-friendly PDF plus the original DOCX and PPTX files.

2022
completion year
25
UAV scale test
5
system objectives
UE 4.27
simulation engine

Project scope

Five objectives for a usable digital twin

The thesis treats the simulator as an integrated engineering environment rather than a single formation-control demonstration.

01

Global formation view

Visualize the overall evolution of a quadrotor formation together with status information and operator controls.

02

Individual aircraft view

Inspect a selected UAV through first-person, follow, ground-observer, and chase-camera perspectives.

03

Shared data layer

Record images, timestamps, positions, and quaternions in a consistent data structure for later analysis.

04–05

External interaction

Support remote control and information exchange, then expose recorded metadata through XML-compatible exports.

System

Simulation, control, and data in one loop

The simulator connects vehicle, sensor, environment, physics, rendering, and data modules to controller hardware and a decision layer.

Chinese system architecture diagram connecting a UAV, flight controller, radio controller, decision engine, simulator, physics, sensors, rendering, environment, and data collection
Original system architecture from the Chinese thesis. The simulator integrates UAV, sensor, environment, physics, rendering, and data-collection models.

Unreal Engine and AirSim

A photorealistic environment and high-frequency vehicle simulation provide the core digital-twin workspace.

Formation generation

AirSim settings and Python APIs generate multiple vehicles and coordinate a primary UAV with follower aircraft.

Human and API control

An Xbox controller supports direct flight, while msgpack-RPC exposes takeoff, landing, switching, and automated movement.

Remote flight interface

PX4 and QGroundControl run in an Ubuntu client connected to the Windows-hosted AirSim environment.

Sensor recording

AirSim records camera frames together with vehicle names, timestamps, positions, and orientation quaternions.

Database and metadata

Recorded truth data is imported into an Access database and can be exported as XML with an accompanying schema.

Implementation

Prototype stack

The final implementation moved from an early Unity direction to Unreal Engine because AirSim integration was more stable there at the time.

Engine
Unreal Engine 4.27.2
Simulator
Microsoft AirSim
Control API
Python · msgpack-RPC
Flight stack
PX4 · QGroundControl
Hosts
Windows 11 · Ubuntu 20.04
Data
AirSim logs · Access · XML/XSD
Three simulated quadrotor UAVs aligned in formation on a sports field
Three-UAV formation generated in the AirSim environment.
Recorded AirSim data in an Access database with vehicle names, positions, quaternions, and image references
The shared data table links each UAV state record to its captured image.

Evaluation

Functional validation and practical limits

The evaluation is an engineering verification of implemented functions, not a controlled user study or a validation against physical UAV telemetry.

Objectives

Five functional goals completed

The thesis reports completion of the two visual scenes, shared database, interaction interface, and metadata directory.

Scale test

Twenty-five UAVs generated

The environment could instantiate 25 vehicles, but rendering load and communication stability made one-to-three UAV tests more reliable.

Remote link

Windows host, Linux client

PX4 commands from Ubuntu controlled a UAV in the Windows AirSim host, demonstrating cross-system interaction.

Split-screen remote communication test with AirSim on Windows and PX4 plus QGroundControl in an Ubuntu virtual machine
Remote-control test: the AirSim host runs on Windows while PX4 and QGroundControl operate from an Ubuntu client.
  • Formation controlAvailable from both host and client by controlling the primary UAV and allowing followers to track it.
  • Environment controlsFully available on the Windows host; the Linux client requires API-mediated changes.
  • Data recordingDirect on the host and available remotely through API calls from the client.
  • Vehicle switchingSupported on the host; constrained on the PX4 client because changing the bound primary aircraft can break the connection.

Evidence boundary: this thesis establishes a working simulation prototype and documents its engineering behavior. It does not claim high-fidelity correspondence with a physical multi-UAV system, robust large-scale formation control, or experimentally measured performance gains.

Archive context

Why the Chinese thesis belongs here

The original language is part of the work's history, not a barrier to presenting it. Keeping the Chinese title and source files preserves the academic record, while the English overview makes the engineering contribution legible to a broader audience.

As an undergraduate project, it also records an earlier stage of the research trajectory represented by this archive: building interactive simulation systems, connecting virtual environments to external services, and being explicit about what a prototype can and cannot demonstrate.

Authors

HuiShan LaiNorthwestern Polytechnical University

Undergraduate thesis citation

Lai, Hui Shan. “四旋翼无人机编队飞行数字孪生系统的设计与实现 [Design and Implementation of a Digital Twin System for Quadrotor UAV Formation Flight].” Undergraduate thesis, Northwestern Polytechnical University, July 2022.

@misc{lai2022quadrotor,
  author       = {Lai, Hui Shan},
  title        = {四旋翼无人机编队飞行数字孪生系统的设计与实现
                  [Design and Implementation of a Digital Twin System for
                  Quadrotor UAV Formation Flight]},
  howpublished = {Undergraduate thesis, Northwestern Polytechnical University},
  address      = {Xi'an, China},
  month        = jul,
  year         = {2022}
}