Synthesis Of Subsonic Airplane Design

La conception architecturale est souvent realisee grâce aux habitudes professionnelles et a l'experience des concepteurs, qui leur permettent d'identifier les parametres de conception pertinents a prendre en compte pour commencer l'etude et de faire les choix qu'impliquent une demarche sequentielle de determination d'architecture. Ces decisions sont difficiles a prendre car les concepteurs ne disposent pas forcement d'elements suffisants pour comparer les differentes alternatives. Ainsi, ils procedent souvent par essai-erreur, jusqu'a l'obtention d'une configuration operationnelle, mais qui n'est pas necessairement optimale. Ces iterations sont, de plus, couteuses en temps. Nous proposons un systeme d'aide a la decision en conception preliminaire, permettant de partir de plusieurs concepts de solution pertinents, pour arriver a une architecture validee et predimensionnee en objectivant les choix de conception. Les grandes etapes sont : (i) l'ecriture du probleme de conception preliminaire sous forme de Probleme par Satisfaction de Contraintes (PSC), (ii) la recherche exhaustive des architectures solutions, (iii) l'exploitation et la reduction de l'espace des solutions pour aider a la decision. C'est seulement ensuite qu'un choix est a faire parmi ces solutions, qui n'ont pas ete arbitrairement restreintes par des choix initiaux. Les etapes (i) et (iii) necessitent une analyse prealable du probleme de conception. Il faut, d'une part, le limiter aux seules caracteristiques necessaires et suffisantes pour la conception architecturale, que nous nommons caracteristiques structurantes. D'autre part, il faut exprimer les objectifs de conception et les criteres de qualification de la conception, qui permettent de hierarchiser les architectures-solutions obtenues et ainsi aider au choix final parmi elles. Nous proposons pour cela une demarche systematique d'analyse et structuration du probleme de conception, basee sur quatre etapes, depuis l'analyse du besoin jusqu'a une approche physique, en passant par des approches fonctionnelle et organique du produit a concevoir. Des tableaux systematiques sont proposes. Notre approche est confrontee avec la demarche 'classique' d'un groupe de concepteurs, pour une meme conception architecturale. L'utilisation du systeme d'aide a la decision permet une amelioration de la satisfaction des objectifs de conception, le choix du concept de solution le plus performant, l'obtention d'architectures-solutions valides et respectant toutes les contraintes enoncees. On dispose ainsi d'elements dimensionnels pour poursuivre en conception detaillee sans subir les iterations engendrees par le processus essai-erreur.

https://tel.archives-ouvertes.fr/tel-00008800/document

Formulation préalable d'un problème de conception, pour l'aide à la décision en conception préliminaire

Configurations, flight mechanisms, and applications of unmanned aerial systems: A review

An avoidance algorithm is proposed in this paper which works by generating avoiding waypoints, within the original predefined waypoints, when the vehicle finds obstacles obstructing its flightpath. The approach developed here bases the search for avoidance path on the utilization of ellipsoid geometry as a restricted zone containing the obstacle. The restricted ellipsoid zone is established by considering the identified obstacle geometry information, and further the ellipsoid becomes the basis for computing the new waypoints for avoiding the obstacle. These avoiding waypoints determined by computing the contact points between the ellipsoid and planes the normal vector of which are corresponded to the vehicle velocity vector. The information about geometry and dimension of the ellipsoid are computed from the information about obstacle geometry, which is assumed to be available, either from mission database or predicted from UAV’s ground detection system. In the development process, the algorithm is constructed in MATLAB environment and then simulated and analyzed in some scenarioed cases representing possible situations when an UAV has to avoid obstacles during its flight. This algorithm is intended to be integrated into the guidance system of UAV.

UAV Obstacle Avoidance Algorithm Based on Ellipsoid Geometry

In this paper we are studying the application of techniques to solve constraint satisfaction problems (CSP) for designing mechanical systems. After presenting the CSP method and the several ways to solve it, we introduce an optimization point of view for CSP. Then, we propose a quick overview of CSP application in product engineering. An example in mechanical system optimization is given via the case study of the optimal design of a bolt coupling. The case is modelled as a Constraint Satisfaction Problem on real variables. Finally, numerical results illustrate the resolution process with a CSP approach.

Optimization of mechanical system: Contribution of constraint satisfaction method

Dans le cadre de cette these, le processus de conception d'un avion est vu comme un probleme de satisfaction ou d'optimisation sous contraintes, avec des contraintes issues des besoins exprimes par les utilisateurs, des reglementations et des limitations technologiques. L'objectif de cette these est d'etudier comment les techniques de programmation par contraintes et de propagation de contraintes sur des variables a domaines discrets ou continus peuvent aider au processus de conception, plus particulierement dans l'etape conceptuelle. Dans cette these, nous proposons un cadre de representation et de resolution du probleme de conception base sur la programmation par contraintes et une representation objet. Dans ce cadre, nous avons propose une approche probabiliste pour prendre en compte les parametres incertains, puis une approche a base d'approximation par reseaux de neurones pour prendre en compte les connaissances existantes sous forme de tableaux de valeurs ou de codes de calcul.

Utilisation des techniques de programmation par contraintes pour la conception d'avions

A path following flight control is developed to be implemented in a small UAV system. The path following control is designed such that the UAV is able to follow smooth flight-paths within its maneuvering capabilities. Payload space, weight, and power source constraints dictate the system to be designed with limited application of sensors and actuators, while it is still required to be able to perform its mission within a predefined measures. The control scheme is intended to be able to steer the UAV flight close to a predefined path and control its heading angle accordingly. The controller principally works by driving the cross-track and course angle errors of the UAV flight, relative to the desired path, to zero, through performing Bank to Turn (BTT) maneuvers. The system generates corrective commands based on the error information and transforms it into a heading change via roll maneuver. The roll maneuver controller is designed using LQR technique such that it can provide an appropriate roll dynamics of the UAV. Simulation results will be presented and analyzed to investigate the performance of the proposed system

Path following system of small unmanned autonomous vehicle for surveillance application

A small UAV is being developed in the Faculty of Mechanical and Aerospace Enginnering, ITB, Indonesia. The UAV system is designed for surveillance missions in a rural area. The limitation of payload space, weight, and power source demands the system to be designed with limited application of sensors and actuators, while it is still required to be able to perform its mission within a predefined measures. In this paper, the development of a waypoints following system, as a part of the UAV autonomous system, is discussed. The system is developed using the principle of the VOR-hold system (VOR stands for VHF Omni-directional Radio Range). The developed waypoint following system plays a key role in keeping the flight path of the UAV during its mission. The implementation of a state feedback for this hold system is studied so that the UAV can track the desired flight path and reject any disturbance which can cause path drifting.

http://ieeexplore.ieee.org/iel5/5256114/5276086/05276112.pdf

The development of an autonomous control system for a small UAV: Waypoints following system

Flight Test of GL-1 Glider Half Scale Prototype

Sailplaning or gliding is one branch of aero sports activities in Indonesia under Federation of Aero Sport Indonesia (FASI). Until now, the most common sailplane used in Indonesia is still Schweitzer SGS 1-26, which is a single seated metal-fabric sailplane designed in 1955 and produced until 1979. The development of a new national glider to replace the Schweitzer SGS 1-26 had been conducted since 2013 and resulted in a design named GL-1. The EASA CS-22 had been chosen as certification basis for GL-1 as there is no equivalent yet in Indonesian CASR. A preliminary design of internal cockpit arrangement and control mechanism has been conducted. This study shows that the control mechanism using a combination of cable and push-pull rod arrangement satisfy the required control surface movement and limited sailplane interior space.

https://iopscience.iop.org/article/10.1088/1757-899X/645/1/012005/pdf

T. Mulyanto

Papers

Utilisation des techniques de programmation par contraintes pour la conception d'avions

Path following system of small unmanned autonomous vehicle for surveillance application

The development of an autonomous control system for a small UAV: Waypoints following system

Flight Test of GL-1 Glider Half Scale Prototype

Preliminary Design of GL-1 Sailplane Cockpit Arrangement and Control Mechanism Based on EASA CS-22 Requirements