Structured μ-Synthesis of Robust Attitude Control Laws for Quad-Tilt-Wing Unmanned Aerial Vehicle

Panza, Simone; Lovera, Marco; Sato, Masayuki; Muraoka, Koji

doi:10.2514/1.g005080

Cited by 5 publications

(3 citation statements)

References 28 publications

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“…Meanwhile, vectored-thrust (horizontal thrust) UAVs, as fully actuated systems, can produce thrust in the body xy-plane without generating moments (as opposed to planar rotors). One way to achieve vectored-thrust is to attach one or more rotors on servomotors to actively adjust their tilt angle [13][14][15][16]. This technique increases the number of moving parts and thus decreases reliability.…”

Section: Introductionmentioning

confidence: 99%

Frequency-dependent control for wind disturbance rejection of a fully actuated UAV

Bannwarth,

Kazemi,

Stol

2024

Robotica

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In this paper, an $\textrm{H}_{{\infty }}$ dynamic output feedback controller is experimentally implemented for the position regulation of a fully actuated tilted-rotor octocopter unmanned aerial vehicle (UAV) to improve wind disturbance rejection during station-keeping. To apply the lateral forces, besides the standard tilt-to-translate (attitude-thrust) movement, tilted-rotor UAVs can generate vectored (horizontal) thrust. Vectored-thrust is high-bandwidth but saturation-constrained, while attitude-thrust generates larger forces with lower bandwidth. For the first time, this paper emphasizes the frequency-dependent allocation of weighting matrices in $\textrm{H}_{{\infty }}$ control design based on the physical capabilities of the fully actuated UAV (vectored-thrust and attitude-thrust). A dynamic model of the tilted-rotor octocopter, including aerodynamic effects and rotor dynamics, is presented to design the controller. The proposed $\textrm{H}_{{\infty }}$ controller solves the frequency-dependent actuator allocation problem by augmenting the dynamic model with weighting transfer functions. This novel frequency-dependent allocation utilizes the attitude-thrust for low-frequency disturbances and vectored-thrust for high-frequency disturbances, which exploits the maximum potential of the fully actuated UAV. Several wind tunnel experiments are conducted to validate the model and wind disturbance rejection performance, and the results are compared to the baseline PX4 Autopilot controller on both the tilted-rotor and a planar octocopter. The $\textrm{H}_{{\infty }}$ controller is shown to reduce station-keeping error by up to 50% for an actuator usage 25% higher in free-flight tests.

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Section: Introductionmentioning

confidence: 99%

Frequency-dependent control for wind disturbance rejection of a fully actuated UAV

Bannwarth,

Kazemi,

Stol

2024

Robotica

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“…The UAV improved mobility and trajectory tracking capabilities. A quad tilt-wing UAV was designed and studied in [ 7 , 8 ]. Its rotors and wings can tilt together to reduce the impact caused by the wing occlusion effect.…”

Section: Introductionmentioning

confidence: 99%

Thrust Vectoring Control of a Novel Tilt-Rotor UAV Based on Backstepping Sliding Model Method

Zhang

Wang

2023

Sensors

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In this paper, a control method of a novel tilt-rotor UAV with a blended wing body layout is studied. The novel UAV is capable of vertical take-off and landing and has strong stealth capabilities that can be applied to carrier-borne reconnaissance aircraft. However, the high aspect ratio of blended wing body UAVs leads to a wingtip or oar-tip touchdown problem when adopting the conventional position-attitude control (CPAC) scheme with a large crosswind disturbance. Moreover, when the UAV is subject to interference during reconnaissance, aerial photography, and landing missions, the conventional scheme cannot provide both attitude stability and track accuracy. First, a direct thrust vectoring control (DTVC) scheme is proposed. The control authority of the rotor tilt mechanism was added to enable the decoupling of the attitude and trajectory and to improve the response rate and response bandwidth of the flight trajectory. Second, considering the problems of strong couplings and parameter uncertainties and the nonlinear features and mismatched perturbations that are inevitable in the tilt-rotor, we designed a robust UAV controller based on the backstepping sliding mode control method and determined the stability of the control system through the Lyapunov function. Finally, in the case of crosswire interference during vertical takeoff and landing and the aerial photography missions of the UAV, the numerical simulation of the CPAC scheme and the DTVC scheme was carried out, respectively, and the Monte Carlo random test method was introduced to conduct the statistical test of the landing accuracy. The simulation results show that the DTVC scheme improves the landing accuracy and speed compared to the CAPC scheme and decouples the position control loop from the attitude control loop, finally enabling the UAV to complete the flight control in the VTOL phase.

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“…Sato and Muraoka have addressed the QTW problem and shown the effectiveness of the gainscheduled controllers to address the dynamic change in the aerodynamic characteristics on an actual QTW-UAV [12]- [14]. For The QTW-UAV, the controller design method has been continuously developed [15], [16]. In this study, a design method for structural parameters of the electric QTW-UAV is developed.…”

Section: Introductionmentioning

confidence: 99%

On Structural Parameter Optimization Method for Quad Tilt-Wing UAV Based on Indirect Size Estimation of Domain of Attraction

Yamaguchi

Hara

2022

IEEE Access

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To deal with the flexibility in the electric aircraft design, this study develops a structural parameter optimization method. The quad tilt-wing aircraft exhibits rotary-wing flight and fixed-wing flight modes by tilting its wings. This study focuses on the domain of attraction, which is a class of state vectors that converge to a static equilibrium point after infinite time. The method indirectly estimates the size of domain of attraction of an aircraft by calculating the radius of a sphere that is encompassed by the domain. In addition, after investigating the relationship between change in structural parameters and the size of the domain of attraction, the structural parameters that maximize the size of the domain are surveyed. The effectiveness of the proposed method is demonstrated for the optimization of the quad tilt-wing aircraft. The quad tilt-wing aircraft exhibits rotary-wing flight and fixed-wing flight modes by tilting its wings. As the characteristics of the dynamics of the quad tilt-wing aircraft demonstrate a significant nonlinear change depending on the tilt angle of the wing, we propose a method to optimize the structural parameters for an easy control of the aircraft. Simulation results show that the optimization scheme identifies the parameters that enable the aircraft to perform agile control to address a disturbance moment. Further, although the same controller is used in the original and optimized aircraft, the optimized aircraft can handle a disturbance in a shorter time when compared with the original aircraft.

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Structured μ-Synthesis of Robust Attitude Control Laws for Quad-Tilt-Wing Unmanned Aerial Vehicle

Cited by 5 publications

References 28 publications

Frequency-dependent control for wind disturbance rejection of a fully actuated UAV

Frequency-dependent control for wind disturbance rejection of a fully actuated UAV

Thrust Vectoring Control of a Novel Tilt-Rotor UAV Based on Backstepping Sliding Model Method

On Structural Parameter Optimization Method for Quad Tilt-Wing UAV Based on Indirect Size Estimation of Domain of Attraction

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