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16 pages, 17925 KB

Open AccessArticle

Linear Disturbance Observer-Enhanced Continuous-Time Predictive Control for Straight-Line Path-Following Control of Small Unmanned Aerial Vehicles

by Weiwei Qi, Mingbo Tong, Xubo Li, Qi Wang and Wei Song

Aerospace 2024, 11(11), 902; https://doi.org/10.3390/aerospace11110902 - 2 Nov 2024

Cited by 1 | Viewed by 1186

Abstract

This paper studies the straight-line path-following problem on the lateral plane for fixed-wing unmanned aerial vehicles (FWUAVs) which are susceptible to uncertainties. Firstly, based on the natural frame’s location on the prescribed reference paths, the command yaw angle (which is the basis for yaw angle control system design) is solved analytically by combining it with the errors of path following, attack angle, sideslip angle, attitude angles, and geometric parameters of the prescribed reference paths. Secondly, by considering complicated dynamic characteristics, a linear extended state observer is designed to estimate uncertainties such as nonlinearities, couplings, and unmodeled dynamics whose estimated values are incorporated into the continuous-time predictive controllers for feedback compensation. Finally, numerical simulations are conducted to demonstrate the advantages of the proposed method, including reduced tracking errors and enhanced robustness in the closed-loop system, as compared to the conventional nonlinear dynamic inversion and sliding mode control approaches. Full article

(This article belongs to the Section Aeronautics)

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27 pages, 16525 KB

Open AccessArticle

Attitude Control of a Mass-Actuated Fixed-Wing UAV Based on Adaptive Global Fast Terminal Sliding Mode Control

by Laohu Yuan, Jinxin Zheng, Xiaoguang Wang and Le Ma

Drones 2024, 8(7), 305; https://doi.org/10.3390/drones8070305 - 8 Jul 2024

Cited by 4 | Viewed by 1553

Abstract

Compared with traditional control methods, moving mass control (MMC) enhances the aerodynamic efficiency and stealth performance of fixed-wing unmanned aerial vehicles (FWUAVs), thereby facilitating their broader application in military and civilian fields. Nevertheless, this approach increases system complexity, nonlinearity, and coupling characteristics. To address these challenges, a novel attitude controller is proposed using adaptive global fast terminal sliding mode (GFTSM) control. Firstly, a dynamic model is established based on aerodynamics, flight dynamics, and moving mass dynamics. Secondly, to improve transient and steady-state responses, prescribed performance control (PPC) is adopted, which enhances the controller’s adaptability for mass-actuated aircraft. Thirdly, a fixed-time extended state observer (FTESO) is utilized to solve the inertial coupling issue caused by mass block movement. Additionally, the performance of the entire control system is rigorously proven through the Lyapunov function. Finally, numerical simulations of the proposed controller are compared with those of PID and linear ADRC in three different conditions: ideal conditions, fixed aerodynamic parameters, and nonlinear aerodynamic parameter changes. The results indicate that the controller effectively compensates for the system’s uncertainty and unknown disturbances, ensuring rapid and accurate tracking of the desired commands. Full article

(This article belongs to the Section Drone Design and Development)

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17 pages, 1286 KB

Open AccessEditor’s ChoiceArticle

On the Dynamics of Flexible Wings for Designing a Flapping-Wing UAV

by Renan Cavenaghi Silva and Douglas D. Bueno

Drones 2024, 8(2), 56; https://doi.org/10.3390/drones8020056 - 7 Feb 2024

Cited by 4 | Viewed by 4521

Abstract

The increasing number of applications involving the use of UAVs has motivated the research for design considerations that increase the safety, endurance, range, and payload capability of these vehicles. In this article, the dynamics of a flexible flapping wing is investigated, focused on designing bio-inspired UAVs. A dynamic model of the Flapping-Wing UAV is proposed by using 2D beam elements defined in the absolute nodal coordinate formulation, and the flapping is imposed through constraint equations coupled to the equation of motion using Lagrange multipliers. The nodal coordinate trajectories are obtained by integrating the equation of motion using the Runge–Kutta algorithm. The imposed flapping is modulated using a proposed smooth function to reduce transient vibrations at the start of the motion. The results shows that wing flexibility yields significant differences compared to rigid-wing models, depending on the flapping frequency. Limited amplitude of oscillation is obtained when considering a non-resonant flapping strategy, whereas in resonance, the energy levels efficiently increase. The results also demonstrate the influence of different flapping strategies on the energy dissipation, which are relevant to increasing the time of flight. The proposed approach is an interesting alternative for designing flexible, bio-inspired, flapping-wing UAVs. Full article

(This article belongs to the Special Issue Conceptual Design, Modeling, and Control Strategies of Drones-II)

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17 pages, 5197 KB

Open AccessArticle

Curved-Line Path-Following Control of Fixed-Wing Unmanned Aerial Vehicles Using a Robust Disturbance-Estimator-Based Predictive Control Approach

by Weiwei Qi, Mingbo Tong, Qi Wang, Wei Song and Hunan Ying

Appl. Sci. 2023, 13(20), 11577; https://doi.org/10.3390/app132011577 - 23 Oct 2023

Cited by 1 | Viewed by 1931

Abstract

In this research, the design of a robust curved-line path-following control system for fixed-wing unmanned aerial vehicles (FWUAVs) affected by uncertainties on the latitude plane is studied. This is undertaken to enhance closed-loop system robustness under unknown uncertainties and derive the control surface deflection angle directly used to control FWUAVs, which has rarely been studied in previous works. The system is formed through the mass center position control (MCPC) and yaw angle control (YAC) subsystems. In the MCPC, the desired yaw angle, which is treated as the reference signal for the YAC subsystem, is calculated analytically using path-following errors, current flow angles, and the yaw angle. In the YAC, a disturbance estimator is designed to estimate uncertainties such as nonlinearities, couplings, time variations, model parameter perturbations, and unmodeled dynamics. Predictive functional controllers are designed to target nominal systems in the absence of uncertainties, such that the estimations of the uncertainties can be incorporated through feedback for closed-loop system robustness enhancement. The simulation results show that higher path-following precision and stronger robustness for the FWUAVs based on the proposed approach can be achieved using only rough model parameters compared with the conventional nonlinear dynamic inversion, which requires detailed model information. Full article

(This article belongs to the Topic Design, Simulation and New Applications of Unmanned Aerial Vehicles)

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27 pages, 10809 KB

Open AccessArticle

Aerodynamic Performance Analysis of VTOL Arm Configurations of a VTOL Plane UAV Using a Computational Fluid Dynamics Simulation

by Gesang Nugroho, Yoshua Dwiyanson Hutagaol and Galih Zuliardiansyah

Drones 2022, 6(12), 392; https://doi.org/10.3390/drones6120392 - 2 Dec 2022

Cited by 15 | Viewed by 14036

Abstract

A vertical take-off and landing plane (VTOL plane) is a fixed-wing unmanned aerial vehicle (FWUAV) configuration with the ability to take off and land vertically. It combines the benefits of fixed-wing and multirotor configurations, which gives it a high cruising range and independence from a runway. This configuration requires arms as mountings for the VTOL’s motors. This study discusses the design of a VTOL Plane with various VTOL arm configurations, and a computational fluid dynamics (CFD) simulation was conducted to find out which configuration performs the best aerodynamically. The VTOL arm configurations analyzed were a quad-plane, a twin-tail boom, a tandem wing, and a transverse arm. The interpreted performances were the lift and drag performances, stall conditions, flight efficiency, stability, and maneuverability. The relative wind directions toward the longitudinal axis of the UAV, which are the sideslip angle and the angle of attack, were varied to simulate various flying conditions. The results showed that the twin tail-boom is the most advantageous based on the interpreted performances. Full article

(This article belongs to the Topic Design, Simulation and New Applications of Unmanned Aerial Vehicles)

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