Design of Long-Endurance Systems With Inherent Robustness to Partial Failures During Operations

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Jeremy Agte ◽  
Nicholas Borer ◽  
Olivier de Weck
Keyword(s):  
Prima Facie ◽  
Markov Analysis ◽  
System Availability ◽  
Baseline Design ◽  
Multidisciplinary Analysis ◽  
Design Variables ◽  
The Face ◽  
Aerial Vehicle ◽  
Component Failure Rates ◽  
Long Endurance

This article presents an integrated multistate method for the early-phase design of inherently robust systems; namely, those capable, as a prima facie quality, of maintaining adequate performance in the face of probabilistic system events or failures. The methodology merges integrated multidisciplinary analysis techniques for system design with behavioral-Markov analysis methods used to define probabilistic metrics such as reliability and availability. The result is a multistate approach that concurrently manipulates design variables and component failure rates to better identify key features for an inherently robust system. This methodology is demonstrated on the design of a long-endurance unmanned aerial vehicle for a three-month ice surveillance mission over Antarctica. The vehicle is designed using the multistate methodology and then compared to a baseline design created for the best performance under nominal conditions. Results demonstrated an improvement of 10–11% in system availability over this period with minimal impacts on cost or performance.

scholarly journals Development of a Flexible Framework Multi-Design Optimization Scheme for a Hand Launched Fuel Cell-Powered UAV

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2951
Author(s):  
Zaid O. Alrayes ◽  
Mohamed Gadalla
Keyword(s):  
Fuel Cell ◽  
Optimal Solution ◽  
Design Methods ◽  
Physical Models ◽  
Design Structure ◽  
Design Variables ◽  
Steady Level ◽  
Aerial Vehicle ◽  
Flexible Framework ◽  
Long Endurance

This paper presents different methods for the design of a hand-launchable, fixed wing, fuel cell-powered unmanned aerial vehicle (UAV) to maximize flight endurance during steady level flight missions. The proposed design methods include the development of physical models for different propulsion system components. The performance characteristics of the aircraft are modeled through empirical contributing analyses in which each analysis corresponds to an aircraft subsystem. The contributing analyses are collected to form a design structure matrix which is included into a multi-disciplinary analysis to solve for the design variables over a defined design space. The optimal solution is found using a comprehensive optimization tool developed for long endurance flight missions. Optimization results showed a significant improvement in UAV flight endurance that reached up to 475 min with take-off ratio equals to 59 min/kg. Wind tunnel and bench-top tests and HiL simulation tests are performed to validate the results obtained from the optimization tools. Validated optimization results showed an increase of the overall UAV flight endurance by 19.4% compared to classical approaches in design methods.

On the Measurement of the Palate in Idiots and Imbeciles

1876 ◽  
Vol 22 (98) ◽  
pp. 196-201 ◽  
Author(s):  
T. Claye Shaw
Keyword(s):  
Prima Facie ◽  
The Body ◽  
The Other ◽  
General Idea ◽  
Cranial Sutures ◽  
High Arched Palate ◽  
Other Hand ◽  
The Face

There is a general idea expressed in text-books, and more or less freely asserted in practice, but which I shall prove to be a fallacy, that a high-arched palate is so frequently met with in idiocy and imbecility that it may be taken as a sign of their existence. Indeed, when a case of this kind is brought forward the patient is made to open his mouth, under the conviction that a high palate will be found as certainly as a superficial alteration of the tongue in gastric disturbance. We shall see that the connection is an accidental one; and there is, in reality, no relationship between the development of the intellect and the height and width of the palate. If we consider that the bones of the cranium are developed in a different manner from those of the face, and that ossification at the base is complete long before that of the bones forming the palate, it is clear that there can be no primâ facie reason for thinking that because a person has an imperfect brain he should therefore have an imperfect palate; yet such an interdependence is held. It is quite true that a constitutional taint, such as rickets or syphilis, which affects the ossification of the bones generally and the cranial sutures, would probably affect the palatine bones, and hence it is that many idiots and imbeciles are found to have high or imperfect palates: but on the other hand some modifying taint may dwarf the height of the body, may affect the shape of the head to such an extent as to make an idiot of the microcephalic type, and yet leave the palate untouched, perfect in all conditions of width, height, number, quality, and regularity of teeth.

Aerodynamic and structural design for the development of a MALE UAV

2018 ◽  
Vol 90 (7) ◽  
pp. 1077-1087 ◽  
Author(s):  
Pericles Panagiotou ◽  
Efstratios Giannakis ◽  
Georgios Savaidis ◽  
Kyros Yakinthos
Keyword(s):  
Structural Design ◽  
Design Procedure ◽  
Unmanned Aircraft ◽  
Content Type ◽  
Parameterized Design ◽  
Detail Design ◽  
Aerial Vehicle ◽  
Structural Parts ◽  
Long Endurance ◽  
Structural Aspects

Purpose The purpose of this paper is to present the preliminary design of a medium altitude long endurance (MALE) unmanned aerial vehicle (UAV), focusing on the interaction between the aerodynamic and the structural design studies. Design/methodology/approach The classic layout theory was used, adjusted for the needs of unmanned aircraft, including aerodynamic calculations, presizing methods and CFD, to estimate key aerodynamic and stability coefficients. Considering the structural aspects, a combination of layout, finite element methods and custom parameterized design tools were used, allowing automatic reshapes of the skin and the internal structural parts, which are mainly made of composite materials. Interaction loops were defined between the aforementioned studies to optimize the performance of the aerial vehicle, maximize the aerodynamic efficiency and reduce the structural weight. Findings The complete design procedure of a UAV is shown, starting from the final stages of conceptual design, up to the point where the detail design and mechanical drawings initiated. Practical implications This paper presents a complete view of a design study of a MALE UAV, which was successfully constructed and flight-tested. Originality/value This study presents a complete, synergetic approach between the configuration layout, aerodynamic and structural aspects of a MALE UAV.

Optimisation Studies for an Efficient Aerodynamic Configuration of a Blended Wing Unmanned Aerial Vehicle

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
M.K. Padmanabhan ◽  
G. Santhoshkumar ◽  
Praveen Narayan ◽  
N. Jeevaraj ◽  
M. Dinesh ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Focal Point ◽  
Lift Coefficient ◽  
Innovative Design ◽  
Aerodynamic Efficiency ◽  
Payload Capacity ◽  
Aerial Vehicle ◽  
Computational Fluid Dynamics Cfd ◽  
The Cost ◽  
Long Endurance

There are various configurations and parameters that contribute to the Design of Unmanned Aerial Vehicles for specific applications. This paper deals with an innovative design of an unmanned aerial vehicle for a specified class of UAVs that require demands such as long endurance, minimized landing space with vertical take-off and landing (VTOL) capabilities. The focal point of this design is superimposing the high endurance blended wing design into tri-copter to address these parameters. The preliminary calculations are initially performed for the blended wing VTOL vehicle based on the required payload capacity and endurance. Superimposing the tri-copter will decrease the aerodynamic efficiency of the vehicle. Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical methods and algorithms to solve complex problems involving fluid flow which will effectively employed to reduce the cost and time during the conceptual and preliminary design stages. CFD analysis was carried out to estimate the major parameters like lift, drag, lift coefficient (CL) and drag coefficient (CD) for various Angle of Attack (AoA) for configurations of blended wing vehicle with and without tri-copter system in the cruise condition. Thus, the vehicle design and propulsion system is effectively optimized using this drag estimation.

Intellectually Virtuous Inquirer and the Practical Value of Truth

2021 ◽  
Vol 58 (4) ◽  
pp. 54-59
Author(s):  
Sergei M. Levin ◽  
Keyword(s):  
Prima Facie ◽  
Epistemic Value ◽  
Practical Reasons ◽  
Circular Reasoning ◽  
Duncan Pritchard ◽  
Different Types ◽  
The Face

Veritism is the thesis that the truth is the fundamental epistemic good. According to Duncan Pritchard, the most pressing objections to veritism are the trivial truths objection and the trivial inquiry problem. The former states that veritism entails that trivial truths are as important as deep and important truths. The latter is a problem that a veritist must prefer trivial inquiry that generates many trivial truths to the serious inquiry with the hope but no guarantee to discover some deep and important truth. Both objections arise from the inability of veritism prima facie to properly rate the different types of truths. Pritchard's solution is to approach the truth from the perspective of the intellectually virtuous inquirer who would prefer weighty truth over trivial truth. In my commentary, I criticise the proposed solution as circular reasoning. The necessary virtue for an intellectually virtuous inquirer is that they would prefer the weighty truth over the trivial one and at the same time, the weighty truth is superior because it is the goal for intellectually virtuous inquirer. I suggest another path to substantiate veritism in the face of the two sibling objections. I argue that truth is the fundamental epistemic good as it makes the epistemic realm practically valuable more than any other epistemic good. The weighty truths are preferable to the trivial ones because the practical value of the deep and important truths is usually higher. The suggested path goes away from the attempts to prove the epistemic value of truth only within the epistemic realm, yet I argue it does not compel the intellectually virtuous inquirer to seek the truth only for the sake of practical reasons.

The aerodynamic optimisation of a low-Reynolds paper plane with adjoint method

2020 ◽  
pp. 1-15
Author(s):  
Y. Zhang ◽  
X. Zhang ◽  
G. Chen
Keyword(s):  
Adjoint Method ◽  
Low Cost ◽  
Aerodynamic Performance ◽  
Discrete Adjoint ◽  
Design Variables ◽  
Limited Variation ◽  
Aerial Vehicle ◽  
Paper Plane ◽  
Drag Ratio ◽  
Lift To Drag Ratio

ABSTRACT The aerodynamic performance of a deployable and low-cost unmanned aerial vehicle (UAV) is investigated and improved in present work. The parameters of configuration, such as airfoil and winglet, are determined via an optimising process based on a discrete adjoint method. The optimised target is locked on an increasing lift-to-drag ratio with a limited variation of pitching moments. The separation that will lead to a stall is delayed after optimisation. Up to 128 design variables are used by the optimised solver to give enough flexibility of the geometrical transformation. As much as 20% enhancement of lift-to-drag ratio is gained at the cruise angle-of-attack, that is, a significant improvement in the lift-to-drag ratio adhering to the preferred configuration is obtained with increasing lift and decreasing drag coefficients, essentially entailing an improved aerodynamic performance.

Solar UAV design framework for a HALE flight

2019 ◽  
Vol 91 (7) ◽  
pp. 927-937
Author(s):  
Hoyon Hwang ◽  
Jaeyoung Cha ◽  
Jon Ahn
Keyword(s):  
User Interfaces ◽  
Minimum Weight ◽  
Lift Coefficient ◽  
Aircraft Design ◽  
Design Framework ◽  
Night Time ◽  
Simple Method ◽  
Content Type ◽  
Aerial Vehicle ◽  
Long Endurance

Purpose The purpose of this paper is to present the development of an optimal design framework for high altitude long endurance solar unmanned aerial vehicle. The proposed solar aircraft design framework provides a simple method to design solar aircraft for users of all levels of experience. Design/methodology/approach This design framework consists of algorithms and user interfaces for the design of experiments, optimization and mission analysis that includes aerodynamics, performance, solar energy, weight and flight distances. Findings The proposed sizing method produces the optimal solar aircraft that yields the minimum weight and satisfies the constraints such as the power balance, the night time energy balance and the lift coefficient limit. Research limitations/implications The design conditions for the sizing process are given in terms of mission altitudes, flight dates, flight latitudes/longitudes and design factors for the aircraft configuration. Practical implications The framework environment is light and easily accessible as it is implemented using open programs without the use of any expensive commercial tools or in-house programs. In addition, this study presents a sizing method for solar aircraft as traditional sizing methods fail to reflect their unique features. Social implications Solar aircraft can be used in place of a satellite and introduce many advantages. The solar aircraft is much cheaper than the conventional satellite, which costs approximately $200-300m. It operates at a closer altitude to the ground and allows for a better visual inspection. It also provides greater flexibility of missions and covers a wider range of applications. Originality/value This study presents the implementation of a function that yields optimized flight performance under the given mission conditions, such as climb, cruise and descent for a solar aircraft.

scholarly journals Stepwise fusion algorithm with dual correction for multi-sensor navigation

2018 ◽  
Vol 15 (3) ◽  
pp. 172988141877993 ◽  
Author(s):  
Rong Wang ◽  
Zhi Xiong ◽  
Jianye Liu ◽  
Yuxuan Cao
Keyword(s):  
High Altitude ◽  
Unmanned Aerial Vehicle ◽  
Error Estimation ◽  
Attitude Determination ◽  
Vehicle Navigation ◽  
Fusion Algorithm ◽  
Aerial Vehicle ◽  
Determination System ◽  
Long Endurance ◽  
Sensor Navigation

In high-altitude, long-endurance unmanned aerial vehicles, a celestial attitude determination system is used to enhance the inertial navigation system (INS)/global positioning system (GPS) to achieve the required attitude performance. The traditional federal filter is not applicable for INS/GPS/celestial attitude determination system information fusion because it does not consider the mutually coupled relationship between the horizontal reference error in the celestial attitude determination system and the navigation error; this limitation results in reduced navigation accuracy. This article proposes a novel stepwise fusion algorithm with dual correction for multi-sensor navigation. Considering the horizontal reference error, the celestial attitude determination system measurement model is constructed and the issues involved in applying the federal filter are discussed. Then, preliminary error estimation and horizontal reference compensation are added to the navigation architecture. In addition, a sequential update strategy is derived to estimate the attitude error with the compensated celestial attitude determination system based on the preliminary estimation. A stepwise correction filtering algorithm with interactive preliminary and sequential updates that can effectively fuse celestial attitude determination system measurements with the INS/GPS is constructed. High-altitude, long-endurance unmanned aerial vehicle navigation in a remote sensing task is simulated to verify the performance of the proposed method. The simulation results demonstrate that the horizontal reference error is effectively compensated, and the attitude accuracy is significantly improved after stepwise error estimation and correction. The proposed method also provides a novel multi-sensor integrated navigation architecture with mutually coupled errors; this architecture is beneficial in unmanned aerial vehicle navigation applications.

Self-Powered Solar Aerial Vehicles: Towards Infinite Endurance UAVs

2020 ◽  
Vol 08 (02) ◽  
pp. 95-117 ◽  
Author(s):  
Farbod Khoshnoud ◽  
Ibrahim I. Esat ◽  
Clarence W. de Silva ◽  
Jason D. Rhodes ◽  
Alina A. Kiessling ◽  
...  
Keyword(s):  
Solar Energy ◽  
Optimal Solution ◽  
Power Demand ◽  
Aerial Vehicles ◽  
Duty Cycles ◽  
Dynamics And Control ◽  
Aerial Vehicle ◽  
Self Powered ◽  
And Control ◽  
Long Endurance

A self-powered scheme is explored for achieving long-endurance operation, with the use of solar power and buoyancy lift. The end goal is the capability of “infinite” endurance while complying with the Unmanned Aerial Vehicle (UAV) dynamics and the required control performance, maneuvering, and duty cycles. Nondimensional power terms related to the UAV power demand and solar energy input are determined in a framework of Optimal Uncertainty Quantification (OUQ). OUQ takes uncertainties and incomplete information in the dynamics and control, available solar energy, and the electric power demand of a solar UAV model into account, and provides an optimal solution for achieving a self-sustained system in terms of energy. Self-powered trajectory tracking, speed and control are discussed. Aerial vehicles of this class can overcome the flight time limitations of current electric UAVs, thereby meeting the needs of many applications. This paper serves as a reference in providing a generalized approach in design of self-powered solar electric multi-rotor UAVs.

Design concept of a high-altitude long-endurance unmanned aerial vehicle

1999 ◽  
Vol 2 (1) ◽  
pp. 19-44 ◽  
Author(s):  
Zdobysław Goraj ◽  
Andrzej Frydrychiewicz ◽  
Jacek Winiecki
Keyword(s):  
High Altitude ◽  
Unmanned Aerial Vehicle ◽  
Design Concept ◽  
Aerial Vehicle ◽  
Long Endurance
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