A New Classification and Aerial Manipulation Q-PRR Design

International audienceThis paper presents a new designation and classification of system with UAV and robot manipulator where a new nomenclature is recognized as being the first contribution in the bibliography of design and systems. Several papers deal a problem of manipulation with a different unmanned aerial vehicle, robot arms and also with different naming of their systems, where the difficulty for locate and finding items and a good paper with its title or even by keywords, multirotor equipped with n-DoF robotic arm is the expression among the most widely used to describe that system. Aerial manipulation formula is presented and proved with a large example in the literature

Planification de mission pour un système de lancement aéroporté autonome

Cette thèse de doctorat s inscrit dans le cadre des activités de recherche sur les systèmes de lancement aéroporté autonome. L originalité du travail est basée sur la planification de mission effectuée par un algorithme de type A*(A-étoile). Cet algorithme a été amélioré pour répondre aux besoins de la mission de largage d un lanceur. Il effectue la planification du chemin le plus court dans un espace tridimensionnel. Le meilleur chemin est choisi à partir de plusieurs points de passage générés dans la région de mission. Une région peut être une phase du vol ou une partie du profil de vol. Le chemin le plus court est identifié par rapport à la présence de différents obstacles dans l espace de recherche et son objectif consiste à atteindre un point désiré. Les obstacles ont différentes dimensions et orientations dans l espace. L étude de leur comportement est associée aux incertitudes en provenance de l environnement. Ils peuvent représenter des régions interdites au vol ou des conditions atmosphériques défavorables. L évolution de ces derniers n est pas prévisible à l avance, ce qui impose l addition d une fonctionnalité dans l algorithme. Il est possible de replanifier le chemin à partir d un point de passage appartenant à un chemin généré en fonction de la position détectée récemment de l obstacle en déplacement pour arriver dans la configuration finale désirée. Cette détection est possible grâce aux capteurs positionnés sur le premier étage de ce système de lancement représenté par un avion-porteur. Les points de passage que le véhicule aérien doit suivre pour atteindre les objectifs importants ne sont pas choisis d une manière aléatoire. Leur génération dans l espace de recherche du chemin est définie en rapport aux limitations dynamiques de l avion. Les modèles cinématique et dynamique du véhicule aérien qui décrivent son évolution sont aussi développés dans cette thèse. Ces modèles sont étudiés dans un système de coordonnées aérodynamiques. Le référentiel traite la présence du vent qui influe sur le comportement du véhicule. Cela nous permet de considérer d une manière prédictive plusieurs incertitudes en provenance de l environnement ou internes pour le véhicule. Les perturbations internes sont provoquées par le largage du lanceur. Le régime transitoire est relié à la perte de masse qui pour certaines missions peut atteindre le tiers de la masse totale du système de lancement. L algorithme de planification traite une autre prévision la possibilité que le largage ne soit pas réalisé. Cela peut arriver dans le cas où une tempête s est installée dans la région de lancement ou il y a plusieurs obstacles dont l évitement risque de consommer trop de carburant et d empêcher le retour sur le site d atterrissage. Les connexions entre les différents points de passage peuvent être souvent brutes et difficiles à réaliser par le véhicule aérien. Pour résoudre cette problématique dans le deuxième module développé sur la génération de trajectoire réalisable, nous utilisons l approche des polynômes de troisième ordre. Ces polynômes par rapport aux autres techniques diminuent le temps du calcul pour générer une trajectoire réalisable entre deux points de passage consécutifs. Le chemin réalisable est facile à suivre par le système. Pour le suivi de la trajectoire, nous avons introduit dans un troisième module la commande par mode glissant. Le principe de cette commande consiste le choix de la surface de commutation entre la trajectoire actuelle suivie par le véhicule et la trajectoire désirée déterminée par l algorithme de planification A-étoile et générée par les polynômes cartésiens de troisième ordre.This Ph.D. thesis deals with the systems of autonomous airborne launch vehicles. The originality of this work is based on the mission planning released by a graph-based A* (A-star) pathfinding algorithm. This algorithm was improved to respond to the specifications of this launching mission. It carries out the planning of the shortest path in a three-dimensional space. The optimal path is selected from the interconnections of several waypoints generated in the mission area. An area can be a specific mission phase or a part of the flight plan. The shortest path is identified according to the presence of various obstacles during the path search and its objective is to reach a desired point in the region. The obstacles have various dimensions and orientations in space. The study of their behavior is associated with disturbances coming from the environment. They could be forbidden flight regions or unfavorable atmospheric conditions. The evolution of the latter cannot be always predicted in advance, which still imposes an improvement that can be added in the operation of the algorithm. The path replanning is also possible. Starting from a safe waypoint from an already generated path according to a recently detected obstacle, a new path can be planned from this point considering the new obstacle coordinates to arrive at the desired final configuration. This detection will be taken into account by the sensors situated on the airborne launcher called a carrier to define the final necessary computing time. The waypoints which the airborne vehicle must follow to achieve the important mission goals are not selected in a random manner. Their generation in the search space is defined according to the dynamic limitations of the vehicle. The kinematic and dynamic models of the carrier are also developed in this thesis. These models are studied in an aerodynamic reference frame. This frame treats the presence of the wind which influences the vehicle evolution in space. That enables to consider in a predictive manner several uncertainties coming from the environment or internal for the vehicle. The internal disturbances are caused by the launching mode relied to a significant loss of mass which for certain missions can reach a half of the total mass of the launching system. The planning algorithm treats in a predictive manner the possibility that the launching is not executed. That can happen if in the launching region a storm is settled or there are several obstacles that avoidance is likely to consume the fuel of the carrier and to prevent the successful return on the landing site. The interconnections between the various waypoints can be often rough and difficult to execute by the airborne launcher. To solve these problems a second module has to be developed to generate a feasible trajectory using the polynomials of third order.. Compared to other techniques this one decreases the calculation time of the trajectory between two consecutive waypoints. The feasible path is easy to follow by the airborne launcher. For the trajectory tracking we introduced into a third module the sliding mode control. The functionality of this control is in the choice of switching surfaces between the current trajectory tracking by the vehicle and the desired trajectory defined by the A* algorithm waypoints and generated by the third order polynomials.EVRY-Bib. électronique (912289901) / SudocSudocFranceF

A novel aerial manipulation design, modelling and control for geometric com compensation

International audienceThis paper presents the design and modelling of a new Aerial manipulating system, that resolve a displacement of centre of gravity of the whole system with a mechanical device. A prismatic joint between the multirotor and a robotic arm is introduced to make a centre of mass as close as to the geometric centre of the whole system. This paper details also the geometric and dynamic modelling of a coupled system with a Lagrange formalism and control law with a Closed Loop Inverse Kinematic Algorithm (CLIKA). This dynamic inverse control is validated in a Simulink environment showing the efficiency of our approach

Missile trajectory shaping using sampling-based path planning

International audienceThis paper presents missile guidance as a complex robotic problem: a hybrid non-linear system moving in a heterogeneous environment. The proposed solution to this problem combines a sampling-based path planner, Dubins' curves and a locally-optimal guidance law. This algorithm aims to find feasible trajectories that anticipate future flight conditions, especially the loss of manoeuverability at high altitude. Simulated results demonstrate the substantial performance improvements over classical midcourse guidance laws and the benefits of using such methods, well-known in robotics, in the missile guidance field of research

UAV Downwash-Based Terrain Classification Using Wiener-Khinchin and EMD Filters

This work was partially funded by FCT Strategic Program UID/EEA/00066/203 of the Center of Technologies and System (CTS) of UNINOVA - Institute for the Development of new Technologies.Knowing how to identify terrain types is especially important in the autonomous navigation, mapping, decision making and detect landings areas. A recent area is in cooperation and improvement of autonomous behavior between robots. For example, an unmanned aerial vehicle (UAV) is used to identify a possible landing area or used in cooperation with other robots to navigate in unknown terrains. This paper presents a computer vision algorithm capable of identifying the terrain type where the UAV is flying, using its rotors’ downwash effect. The algorithm is a fusion between the frequency Wiener-Khinchin adapted and spatial Empirical Mode Decomposition (EMD) domains. In order to increase certainty in terrain identification, machine learning is also used. The system is validated using videos acquired onboard of a UAV with an RGB camera.authorsversionpublishe

K0.8Ag0.2Nb4O9AsO4

The title compound, potassium silver tetra­niobium nona­oxide arsenate, K0.8Ag0.2Nb4O9AsO4, was prepared by a solid-state reaction at 1183 K. The structure consists of infinite (Nb2AsO14)n chains parallel to the b axis and cross-linked by corner sharing via pairs of edge-sharing octa­hedra. Each pair links together four infinite chains to form a three-dimensional framework. The K+ and Ag+ ions partially occupy several independent close positions in the inter­connected cavities delimited by the framework. K0.8Ag0.2Nb4O9AsO4 is likely to exhibit fast alkali-ion mobility and ion-exchange properties. The Wyckoff symbols of special positions are as follows: one Nb 8e, one Nb 8g, As 4c, two K 8f, one Ag 8f, one Ag 4c, one O 8g, one O 4c

Synthesis of Zinc Phosphonated Poly(ethylene imine) and Its Fire-Retardant Effect in Low-Density Polyethylene

A novel oligomeric intumescent fire-retardant chelate, zinc phosphonated poly(ethylene imine) (Zn-PEIP), with a variable Zn2+ loading, was synthesized. The chemical structure of Zn-PEIP was confirmed by FTIR, 13C NMR, and 31P NMR spectroscopies. The thermal behavior and fire retardancy of low-density polyethylene (LDPE) containing 25 wt % Zn-PEIPs with different amounts of Zn2+ were investigated by thermogravimetric analysis (TGA), limiting oxygen index (LOI) measurements, and cone calorimetry. The TGA results showed that higher concentrations of Zn2+ improved the thermal stability and increased the residue yield of LDPE. However, the data from the LOI and cone calorimetry tests showed that there is an optimum concentration of Zn2+ for the best fire-retardancy performance of LDPE. This behavior is ascribed to the high cross-link density resulting from zinc bridges, preventing normal swelling of the intumescent system. The surface morphology of the char was characterized by digital photography and scanning electron microscopy (SEM). This confirmed the optimum intumescence and coherent and strong barrier layer formation at an intermediate Zn2+ loading

Copmmande hierarchisee d'un robot rigide

SIGLEINIST T 70641 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc