Periodically Cruising Hypersonic Vehicle With Active Cooling: An Optimal-Control Based Design Approach

Wang, Wenkai; Hou, Zhanqiang; Shan, Shangqiu; Chen, Lili

doi:10.1109/access.2019.2918848

Cited by 7 publications

(2 citation statements)

References 32 publications

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“…This is commonly achieved by optimally regulating the thrust produced by the UAV propellers, attack angle, and bank angle to realize autonomous flight based on energy maximization. Closely related works in this direction investigated the possibility of finding optimal "periodic" solutions to enhance endurance rather than steady-state optimal solutions; [27][28][29][30][31][32]. This interesting subject is part of the optimal periodic control theory, which was originally motivated by problems from chemical engineering, as some studies have found that cycling a chemical reactor can increase the average output compared to steady-state operation [33].…”

Section: Introductionmentioning

confidence: 99%

Optimal Periodic Control of Unmanned Aerial Vehicles Based on Fourier Integral Pseudospectral and Edge-Detection Methods

Elgindy¹

2023

Preprint

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This study describes the development of a novel numerical optimization framework to maximize the endurance of unmanned aerial vehicles (UAVs). We address the problem of numerically determining the optimal thrust and cruise angle of attack in a two-dimensional space for a UAV under certain initial, periodic, and bound constraints. The time horizon of the free final time optimal control problem (OCP) is first normalized, and the normalized OCP in integral form is discretized in physical space into a nonlinear programming problem (NLP) using Fourier collocation and quadrature based on equispaced points. Great attention in this work is placed on the accurate detection of jump discontinuities and resolving the thrust history effectively directly from the Fourier pseudospectral (FPS) data through a novel edge-detection method without any smoothing techniques. The numerical results demonstrate that the proposed method is simple, stable, and easy to implement.

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Section: Introductionmentioning

confidence: 99%

Optimal Periodic Control of Unmanned Aerial Vehicles Based on Fourier Integral Pseudospectral and Edge-Detection Methods

Elgindy¹

2023

Preprint

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“…In recent decades, hypersonic flight vehicles (HFVs) equipped with air-breathing supersonic combustion ramjet (scramjets) have been widely researched owing to their excellent advantages in flight speed, penetration ability, and costeffectiveness [1]- [4]. In order to reinforce the control performance, tremendous advanced control schemes have been resorted successively for HFVs dynamics, such as slidingmode control [5], robust control [6], fault-tolerant control [7], and adaptive backstepping control [8].…”

Section: Introductionmentioning

confidence: 99%

Fuzzy Adaptive Finite-Time Tracking for Hypersonic Flight Vehicles Using Switching Event-Triggered Methodology

Tang

et al. 2022

IEEE Access

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The problem of event-triggered fuzzy adaptive finite-time tracking for flexible hypersonic flight vehicles is considered in this work. A new switching event-triggered mechanism is devised to mitigate the unnecessary resources waste in the process of system communication and sampled data computation. Compared with the traditional event-triggered mechanism, an exponential term with regard to tracking error is introduced into the proposed switching event-triggered function, which significantly reduces the frequencies of data transmission. To evade singularity issue typical of traditional recursive finite-time design methods, we introduce a new piecewise switching controller whose continuity and differentiability are ensured everywhere via an appropriate design. Stability of the proposed design is proved using asymmetric barrier Lyapunov functions, which are devised to tackle the fact that the operating regions of the flight state variables are asymmetric in actual engineering. Finally, comparative simulations are designed to illustrate the effectiveness and superiority of the presented methodology.INDEX TERMS Switching event-triggered mechanism, singularity-free design, hypersonic flight vehicle, finite-time stability.

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A Promising Radiation Thermal Protection Coating Based on Lamellar Porous Ca‐Cr co‐Doped Y₃NbO₇ Ceramic

Chen

Zou

et al. 2023

Adv Funct Materials

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Dissipation of heat efficiently from a hot object via radiation while minimizing the inward heat conduction is the key requirement of radiation thermal protection. In this study, a Ca‐Cr co‐doped Y3NbO7 coating with lamellar porous structure is fabricated, which shows an ultra‐low thermal conductivity (<0.7 W m−1 K−1) and near‐unity emissivity (>0.9) across a broad wavelength range of ≈1–24 µm. This record high emissivity to thermal conductivity ratio (≈1.3) is experimentally and theoretically revealed from a multi‐scale perspective. The diffusoin‐mediated thermal conduction feature of niobates combined with lamellar porous structure of the coating reduces its thermal conductivity to an impressive 0.5 W m−1 K−1 at 25 °C, surpassing the theoretical amorphous limitation of 0.72 W m−1 K−1. Experiments and FDTD calculation results demonstrate that the intrinsic emissivity dips at shallow extinction wavelengths (1 and 8 µm) and strong phonon‐polariton resonances wavelengths (>13 µm) can be effectively compensated by the multiple scattering/absorption and gradual modulation of conical shape/effective refractive index induced by surface micro‐protrusion structures, respectively. Furthermore, the coating exhibits robust mechanical and thermal stability with a high bonding strength (18.3 MPa) and thermal expansion coefficient (≈11 × 10−6 K−1 at 1200 °C) comparable to YSZ, showing great potential in the radiation thermal protection field.

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Periodically Cruising Hypersonic Vehicle With Active Cooling: An Optimal-Control Based Design Approach

Cited by 7 publications

References 32 publications

Optimal Periodic Control of Unmanned Aerial Vehicles Based on Fourier Integral Pseudospectral and Edge-Detection Methods

Optimal Periodic Control of Unmanned Aerial Vehicles Based on Fourier Integral Pseudospectral and Edge-Detection Methods

Fuzzy Adaptive Finite-Time Tracking for Hypersonic Flight Vehicles Using Switching Event-Triggered Methodology

A Promising Radiation Thermal Protection Coating Based on Lamellar Porous Ca‐Cr co‐Doped Y₃NbO₇ Ceramic

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Periodically Cruising Hypersonic Vehicle With Active Cooling: An Optimal-Control Based Design Approach

Cited by 7 publications

References 32 publications

Optimal Periodic Control of Unmanned Aerial Vehicles Based on Fourier Integral Pseudospectral and Edge-Detection Methods

Optimal Periodic Control of Unmanned Aerial Vehicles Based on Fourier Integral Pseudospectral and Edge-Detection Methods

Fuzzy Adaptive Finite-Time Tracking for Hypersonic Flight Vehicles Using Switching Event-Triggered Methodology

A Promising Radiation Thermal Protection Coating Based on Lamellar Porous Ca‐Cr co‐Doped Y3NbO7 Ceramic

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A Promising Radiation Thermal Protection Coating Based on Lamellar Porous Ca‐Cr co‐Doped Y₃NbO₇ Ceramic