Unmanned Aerial Vehicle Pitch Control under Delay Using Deep Reinforcement Learning with Continuous Action in Wind Tunnel Test

Nonlinear flight controllers for fixed-wing unmanned aerial vehicles (UAVs) can potentially be developed using deep reinforcement learning. However, there is often a reality gap between the simulation models used to train these controllers and the real world. This study experimentally investigated t...

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Bibliographic Details
Main Authors: Daichi Wada, Sergio A. Araujo-Estrada, Shane Windsor
Format: Article
Language:English
Published: MDPI AG 2021-09-01
Series:Aerospace
Subjects:
Online Access:https://www.mdpi.com/2226-4310/8/9/258
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spelling doaj-2ae47fa24b9f4382a808cdfd046e5d052021-09-25T23:33:19ZengMDPI AGAerospace2226-43102021-09-01825825810.3390/aerospace8090258Unmanned Aerial Vehicle Pitch Control under Delay Using Deep Reinforcement Learning with Continuous Action in Wind Tunnel TestDaichi Wada0Sergio A. Araujo-Estrada1Shane Windsor2Aeronautical Technology Directorate, Japan Aerospace Exploration Agency, Tokyo 181-0015, JapanDepartment of Aerospace Engineering, University of Bristol, Bristol BS8 1TR, UKDepartment of Aerospace Engineering, University of Bristol, Bristol BS8 1TR, UKNonlinear flight controllers for fixed-wing unmanned aerial vehicles (UAVs) can potentially be developed using deep reinforcement learning. However, there is often a reality gap between the simulation models used to train these controllers and the real world. This study experimentally investigated the application of deep reinforcement learning to the pitch control of a UAV in wind tunnel tests, with a particular focus of investigating the effect of time delays on flight controller performance. Multiple neural networks were trained in simulation with different assumed time delays and then wind tunnel tested. The neural networks trained with shorter delays tended to be susceptible to delay in the real tests and produce fluctuating behaviour. The neural networks trained with longer delays behaved more conservatively and did not produce oscillations but suffered steady state errors under some conditions due to unmodeled frictional effects. These results highlight the importance of performing physical experiments to validate controller performance and how the training approach used with reinforcement learning needs to be robust to reality gaps between simulation and the real world.https://www.mdpi.com/2226-4310/8/9/258attitude controldeep reinforcement learningfixed-wing aircraftunmanned aerial vehiclewind tunnel test
collection DOAJ
language English
format Article
sources DOAJ
author Daichi Wada
Sergio A. Araujo-Estrada
Shane Windsor
spellingShingle Daichi Wada
Sergio A. Araujo-Estrada
Shane Windsor
Unmanned Aerial Vehicle Pitch Control under Delay Using Deep Reinforcement Learning with Continuous Action in Wind Tunnel Test
Aerospace
attitude control
deep reinforcement learning
fixed-wing aircraft
unmanned aerial vehicle
wind tunnel test
author_facet Daichi Wada
Sergio A. Araujo-Estrada
Shane Windsor
author_sort Daichi Wada
title Unmanned Aerial Vehicle Pitch Control under Delay Using Deep Reinforcement Learning with Continuous Action in Wind Tunnel Test
title_short Unmanned Aerial Vehicle Pitch Control under Delay Using Deep Reinforcement Learning with Continuous Action in Wind Tunnel Test
title_full Unmanned Aerial Vehicle Pitch Control under Delay Using Deep Reinforcement Learning with Continuous Action in Wind Tunnel Test
title_fullStr Unmanned Aerial Vehicle Pitch Control under Delay Using Deep Reinforcement Learning with Continuous Action in Wind Tunnel Test
title_full_unstemmed Unmanned Aerial Vehicle Pitch Control under Delay Using Deep Reinforcement Learning with Continuous Action in Wind Tunnel Test
title_sort unmanned aerial vehicle pitch control under delay using deep reinforcement learning with continuous action in wind tunnel test
publisher MDPI AG
series Aerospace
issn 2226-4310
publishDate 2021-09-01
description Nonlinear flight controllers for fixed-wing unmanned aerial vehicles (UAVs) can potentially be developed using deep reinforcement learning. However, there is often a reality gap between the simulation models used to train these controllers and the real world. This study experimentally investigated the application of deep reinforcement learning to the pitch control of a UAV in wind tunnel tests, with a particular focus of investigating the effect of time delays on flight controller performance. Multiple neural networks were trained in simulation with different assumed time delays and then wind tunnel tested. The neural networks trained with shorter delays tended to be susceptible to delay in the real tests and produce fluctuating behaviour. The neural networks trained with longer delays behaved more conservatively and did not produce oscillations but suffered steady state errors under some conditions due to unmodeled frictional effects. These results highlight the importance of performing physical experiments to validate controller performance and how the training approach used with reinforcement learning needs to be robust to reality gaps between simulation and the real world.
topic attitude control
deep reinforcement learning
fixed-wing aircraft
unmanned aerial vehicle
wind tunnel test
url https://www.mdpi.com/2226-4310/8/9/258
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