A Coupled Rotor/Wing Optimization Procedure for High Speed Tilt-Rotor Aircraft

Tilt-rotor unmanned aerial vehicles have attracted increasing attention due to their ability to perform vertical take-off and landing and their high-speed cruising abilities, thereby presenting broad application prospects. Considering portability and applications in tasks characterized by constrained or small scope areas, this article presents a compact tricopter configuration tilt-rotor unmanned aerial vehicle with full modes of flight from the rotor mode to the fixed-wing mode and vice versa. The unique multiple modes make the tilt-rotor unmanned aerial vehicle a multi-input multi-output, non-affine, multi-channel cross coupling, and nonlinear system. Considering these characteristics, a control allocation method is designed to make the controller adaptive to the full modes of flight. To reduce the cost, the accurate dynamic model of the tilt-rotor unmanned aerial vehicle is not obtained, so a full-mode flight strategy is designed in view of this situation. An autonomous flight test was conducted, and the results indicate the satisfactory performance of the control allocation method and flight strategy.

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Modelling and vibration of a non-classical tilt-rotor wing system

The Aeronautical Journal ◽

10.1017/s000192400000453x ◽

2007 ◽

Vol 111 (1119) ◽

pp. 285-295 ◽

Cited By ~ 3

Author(s):

O. Song ◽

H. D. Kwon ◽

L. Librescu

Keyword(s):

Cross Section ◽

Point Of View ◽

Vertical Position ◽

Aircraft Wing ◽

Tilt Rotor ◽

Mass Moment ◽

Rotor Wing ◽

Mass Size ◽

Mass Moment Of Inertia ◽

Tiltrotor Aircraft

Abstract Problems related with the mathematical modelling and eigenvibration of a tiltrotor aircraft-wing system built up of anisotropic composite materials are investigated. The wing-mounted rotor that can tilt from the vertical position to a horizontal one is modelled and analysed from the vibrational point of view. In this sense, its behaviour is analysed as a function of the mass size, mass moment of inertia, tilt angle and spin speed of the spinning rotor and of its location along the wing span. While the rotor is considered to be rigid, the aircraft wing is modelled as a thin-walled beam that features a doubly-symmetric cross-section contour and incorporates the elastic coupling between flap-lag-transverse shear, on one hand, and between extension-twist, on the other hand. Numerical simulations are provided and pertinent conclusions are outlined.

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Large Motion Visualization and Estimation for Fluid-Structure Simulations

Volume 6: 11th International Conference on Multibody Systems, Nonlinear Dynamics, and Control ◽

10.1115/detc2015-46239 ◽

2015 ◽

Author(s):

Tzu-Sheng Shane Hsu ◽

Timothy Fitzgerald ◽

Vincent Phuc Nguyen ◽

Balakumar Balachandran

Keyword(s):

Objective Function ◽

High Speed ◽

Flexible Structures ◽

Three Dimensional ◽

Optimization Procedure ◽

Fluid Structure Interactions ◽

Displacement Fields ◽

Fluid Structure ◽

Computational Implementation

Studies of fluid-structure interactions associated with flexible structures such as flapping wings require the capture and quantification of large motions of bodies that may be opaque. As a case study, motion capture of a free flying insect is considered by using three synchronized high-speed cameras. A solid finite element (FE) representation is used as a reference body and successive snapshots in time of the displacement fields are reconstructed via an optimization procedure. One of the original aspects of this work is the formulation of an objective function and the use of shadow matching and strain-energy regularization. With this objective function, the authors penalize the shape differences between silhouettes of the captured images and the FE representation of the deformed body. A similar method with a three-dimensional voxel cloud (VC) reconstruction is also illustrated. Challenges faced in implementing the VC method are discussed and the current computational implementation will also be covered.

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Integrated Modified Repetitive Control With Disturbance Observer of Piezoelectric Nanopositioning Stages for High-Speed and Precision Motion

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.4042879 ◽

2019 ◽

Vol 141 (8) ◽

Cited By ~ 4

Author(s):

Zhao Feng ◽

Jie Ling ◽

Min Ming ◽

Xiaohui Xiao

Keyword(s):

Disturbance Observer ◽

High Speed ◽

External Disturbance ◽

Repetitive Control ◽

Optimization Procedure ◽

Tracking Performance ◽

Hysteresis Nonlinearity ◽

Control Scheme ◽

The Stability ◽

Precision Motion

The tracking performance of piezoelectric nanopositioning stages is vital in many applications, such as scanning probe microscopes (SPMs). Although modified repetitive control (MRC) can improve tracking performance for commonly used periodic reference input, it is sensitive to unexpected disturbances that deteriorate tracking precision, especially for high-speed motion. In order to achieve high-speed and precision motion, in this paper, a new composite control scheme by integrating MRC with disturbance observer (DOB) is developed. To simplify controller implementation, the hysteresis nonlinearity is treated as external disturbance and the proposed method is designed in frequency domain. The stability and robust stability are analyzed, and an optimization procedure to calculate the controller parameters is employed to enhance the performance to the maximum extent. To validate the effectiveness of the proposed method, comparative experiments are performed on a piezoelectric nanopositioning stage. Experimental results indicate that the hysteresis is suppressed effectively and the proposed method achieves high-speed and precision tracking with triangular waves references up to 25 Hz and improves the disturbance rejection ability with disturbances under different frequencies and robustness to model uncertainty through comparing with feedback controllers and MRC, respectively.

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Implementation of Underground Water for Wireless Optical Communication System using CDMA

International Innovative Research Journal of Engineering and Technology ◽

10.32595/iirjet.org/v6i4.2021.147 ◽

2021 ◽

Vol 6 (4) ◽

pp. 10-20

Author(s):

Umar Sabhapathy ◽

◽

Lenin Anselm Wilson ◽

Keyword(s):

High Speed ◽

Peak Power ◽

Estimation Error ◽

Optimization Procedure ◽

Propagation Distance ◽

Channel Estimation Error ◽

Optical Cdma ◽

Optical Wireless ◽

Data Propagation ◽

Code Division Multiple

Optical wireless communications is a powerful and cost-effective approach for high-speed wireless links that have been tightly guarded For underwater optical wireless communication, the following three optical code division multiple access (CDMA) techniques have been used. systems are associated, investigated, and presented in this paper, such as AC-biased optical CDMA (ACO-CDMA), symmetrically-SCO-OFDM (clipped optical OFDM), and unipolar CDMA (U-CDMA). Peak power constraints, light source bandwidth tag, there are so many factors to recognize, such turbulence, fading underwater signals, and channel estimation error. Advocate for a bit loading algorithm and a simplified modulation index that determines signal magnitude is being used to minimize the achievable data propagation distance. In this optimization procedure, the signal-to-noise ratio and the clipping distortion triggered by the peak power limitation are balanced (SNR). The SNR and clipping effects of the three compared CDMA techniques are represented in this paper. When the transmitted bit index is greater than the channel bandwidth, ACO-OFDM outperforms SCO- and UCDMA, according to the determined model. U-CDMA, on the other end, has a longer propagation distance but needs less transmitted power.

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Modeling and Control of Negative-Buoyancy Tri-Tilt-Rotor Autonomous Underwater Vehicles Based on Immersion and Invariance Methodology

Applied Sciences ◽

10.3390/app8071150 ◽

2018 ◽

Vol 8 (7) ◽

pp. 1150 ◽

Cited By ~ 5

Author(s):

Tao Wang ◽

Chao Wu ◽

Jianqin Wang ◽

Tong Ge

Keyword(s):

High Speed ◽

Autonomous Underwater Vehicles ◽

Underwater Vehicle ◽

Underwater Vehicles ◽

Error Model ◽

Nonlinear Controller ◽

Tilt Rotor ◽

Immersion And Invariance ◽

Attitude Error ◽

Negative Buoyancy

Spot hover and high speed capabilities of underwater vehicles are essential for ocean exploring, however, few vehicles have these two features. Moreover, the motion of underwater vehicles is prone to be affected by the unknown hydrodynamics. This paper presents a novel negative-buoyancy autonomous underwater vehicle equipped with tri-tilt-rotor to obtain these two features. A detailed mathematical model is derived, which is then decoupled to altitude and attitude subsystems. For controlling the underwater vehicle, an attitude error model is designed for the attitude subsystem, and an adaptive nonlinear controller is proposed for the attitude error model based on immersion and invariance methodology. To demonstrate the effectiveness of the proposed controller, a three degrees of freedom (DOF) testbed is developed, and the performance of the controller is validated through a real-time experiment.

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A DESIGN OPTIMIZATION PROCEDURE FOR MINIMIZING DRIVE SYSTEM WEIGHT OF HIGH SPEED PROP-ROTORS

Engineering Optimization ◽

10.1080/03052159508941356 ◽

1995 ◽

Vol 23 (3) ◽

pp. 239-254 ◽

Cited By ~ 5

Author(s):

ADITI CHATTOPADHYAY ◽

THOMAS R. McCARTHY ◽

JOHN F. MADDEN

Keyword(s):

Design Optimization ◽

High Speed ◽

Optimization Procedure ◽

Drive System

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Coupled and Trimmed Aerodynamic and Aeroacoustic Simulations for Airbus Helicopters' Compound Helicopter RACER

Journal of the American Helicopter Society ◽

10.4050/jahs.64.032003 ◽

2019 ◽

Vol 64 (3) ◽

pp. 1-14 ◽

Cited By ~ 2

Author(s):

Constantin Öhrle ◽

Felix Frey ◽

Jakob Thiemeier ◽

Manuel Keßler ◽

Ewald Kräamer

Keyword(s):

High Speed ◽

Flight Mechanics ◽

Main Rotor ◽

Noise Emission ◽

Tool Chain ◽

Aeroacoustic Noise ◽

Rotor Wing ◽

Compound Helicopter ◽

Cost Efficient ◽

Cruise Flight

In recent years, various helicopter manufacturers increasingly have been focusing on the development of new high-speed rotorcraft configurations, one of them being the compound helicopter RACER (rapid and cost-efficient rotorcraft) of Airbus Helicopters (AH). However, these new configurations encounter new aeromechanic challenges, in terms of aerodynamic interactions, flight mechanics stability, rotor dynamics, or aeroacoustic noise emission, to name only a few. To support AH at the minimization of risk of RACER's first flight, the Institute of Aerodynamics and Gas Dynamics provides high-fidelity coupled and trimmed aerodynamic and aeroacoustic simulations of the complete helicopter by the application of a multidisciplinary tool chain. In its first part, the work focuses on the description of this advanced tool chain and on important features for the analysis of this new configuration. In the second part, exemplary simulation results for a hover and a high-speed cruise flight condition are shown, and the main aerodynamic interactions between the different components are identified. As expected for this configuration, numerous interactions are found for both flight cases, e.g., main rotor–propeller interaction in hover or main rotor–wing interaction in high-speed flight. Finally, aeroacoustic results are shown for hover with a close look at the propellers' contribution.

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