Trajectory Following with a MAV under Rotor Fault Conditions

Lately, a novel multirotor aerial vehicle capable of handling single rotor failures was presented. When a rotor fails, physically reconfiguring one of the remaining rotors of an hexarotor allows to compensate for maneuverability limitations. In this work, experimental results show the per- formance of the vehicle in a trajectory-following task in both nominal and fault conditions.Fil: Pose, Claudio Daniel. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; ArgentinaFil: Francisco Presenza. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; ArgentinaFil: Mas, Ignacio Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Giribet, Juan Ignacio. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; Argentina. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina11th International Micro Air Vehicle Competition and ConferenceMadridEspañaUniversidad Politécnica de MadridConsejo Superior de Investigaciones Científica

Trajectory following with a MAV under Rotor Fault Conditions

Lately, a novel multirotor aerial vehicle capable of handling single rotor failures was presented. When a rotor fails, physically reconfiguring one of the remaining rotors of a hexarotor allows to compensate for maneuverability limitations. In this work, experimental results show the performance of the vehicle in a trajectory-following task in both nominal and fault conditions.Fil: Pose, Claudio Daniel. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Presenza, Juan Francisco. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Mas, Ignacio Agustin. Instituto Tecnológico de Buenos Aires. Departamento de Física - Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Giribet, Juan Ignacio. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin

Sistema de navegación, guiado y control para un VANT multirotor

Se presenta el diseño del sistema de navegación, guiado y control para un vehículo aéreo no tripulado capaz de volar en forma autónoma. La estabilización del vehículo, un helicóptero de seis rotores, se consigue a través de un lazo de control que estima la inclinación del mismo en dos ejes, ejerciendo empuje vertical y torques de control regulando las velocidades de giro de los motores. Este lazo, implementado en un microcontrolador de 32 bits a bajo nivel, estima la inclinación en base a una unidad de mediciones inerciales, la cual, junto con un magnetómetro, un receptor GPS y una cámara, permiten llevar a cabo la navegación del helicóptero, utilizando un algoritmo de navegación integrada. Este algoritmo, es implementado en una computadora embebida de nivel superior, la cual además, se encarga de la ejecución de un algoritmo de guiado, y de las comunicaciones e interacción con la estación terrena. La interfaz con el usuario es implementada en una estación de tierra multifuncional.Facultad de Ingenierí

Sistema de navegación, guiado y control para un VANT multirotor

Se presenta el diseño del sistema de navegación, guiado y control para un vehículo aéreo no tripulado capaz de volar en forma autónoma. La estabilización del vehículo, un helicóptero de seis rotores, se consigue a través de un lazo de control que estima la inclinación del mismo en dos ejes, ejerciendo empuje vertical y torques de control regulando las velocidades de giro de los motores. Este lazo, implementado en un microcontrolador de 32 bits a bajo nivel, estima la inclinación en base a una unidad de mediciones inerciales, la cual, junto con un magnetómetro, un receptor GPS y una cámara, permiten llevar a cabo la navegación del helicóptero, utilizando un algoritmo de navegación integrada. Este algoritmo, es implementado en una computadora embebida de nivel superior, la cual además, se encarga de la ejecución de un algoritmo de guiado, y de las comunicaciones e interacción con la estación terrena. La interfaz con el usuario es implementada en una estación de tierra multifuncional.Facultad de Ingenierí

Design of a flight controller to achieve improved fault tolerance

In the last years, multirotor aerial vehicles have gained popularity both as consumer products and in professional applications. Safety is one of the main concerns during operation, and different approaches to fault tolerance have been proposed and continue to be developed. For a control system to be able to handle off-nominal situations, failures must be properly detected and identified; therefore, a fault detection and identification algorithm is required. Also, the control loop has to be accordingly modified to cope with each particular failure in the best way possible. These algorithms usually run on the vehicle’s low-level flight computer, imposing on it a large additional computational load. In this work, a fault detection and identification module is used to evaluate its impact in terms of additional processing time on a flight computer based on the Cortex-M3 microcontroller. While a highly optimized version of the algorithm is able to run, it still suggests potential hardware limitations for expanding the system capabilities. The evaluation of the same module on an improved flight computer design based on a Cortex-M7 micro-processor shows a significantly reduced footprint in the overall performance, allowing for the addition of an augmented method for faster failure detection

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

The best interests of the child and truth and reconciliation commissions

Abstract: Adults can act on behalf of children and in the best interests of children, but unless children themselves are consulted and engaged, the process will fall short and undermine the potential to pursue the most relevant and most durable solutions

The real face of La Vida Loca : child protection, the Maras and their link with the civil conflict in El Salvador

Abstract: In the past years, as Washington has focused its attention on the Middle East, it has virtually ignored a dangerous phenomenon close to home. With the United States preoccupied elsewhere, the gangs have grown in power and numbers; today, local officials estimate their size at 70,000 – 100,000 members. The maras now present the most serious challenge to peace in the region since the end of Central America’s civil wars

Multirotor fault tolerance based on center-of-mass shifting in case of rotor failure

This work carries out an analysis on fault tol-erance in multirotor vehicles, particularly for an hexarotorone, where such feature is achieved by shifting the center ofmass in case of a motor failure. It will be shown that, foran hexarotor vehicle, for each of the possible motor failures,there exists an optimal fixed position for the center of mass, inorder to keep independent control of four degrees of freedom,and to obtain the best maneuverability. The performance ofthis solution will be compared with a previous design based onmotor reconfiguration in case of a motor failure.Fil: Pose Claudio. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; ArgentinaFil: Giribet, Juan Ignacio. Universidad de San Andrés; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaInternational Conference on Unmanned SystemsAtenasGreciaIEEE RA

Validación Experimental de la Tolerancia a Fallas en un Hexa-rotor con Brazos Inclinados

Recently, some work has emerged re-carrying the advantages of flying with multicopters with inclined rotors, that is, rotors that do not point in the direction of the vertical of the vehicle. In particular, it was shown that in order to achieve a hexa-rotor vehicle capable of tolerating faults in one of its rotors, it is necessary that they be inclined. So far, experimental validations of these results have considered partial failures in the rotors. More precisely, cases have been analyzed in which one of the rotors loses thrust capacity. However, the theoretical results admit a total failure of the rotors, that is, one of the rotors stops completely. In this work we experimentally validate the total failure of a rotor and show how a hexa-rotor vehicle is capable of maintaining its maneuverability in the face of the total loss of one of its rotors.Recientemente, han surgido algunos trabajos re-portando las ventajas de volar con multicópteros con rotores inclinados, es decir, rotores que no apunten en la dirección de la vertical del vehículo. En particular, se demostró que para lograr un vehículo hexa-rotor capaz de tolerar fallas en uno de sus rotores es necesario que estos estén inclinados. Hasta el momento, las validaciones experimentales de estos resultados han considerado fallas parciales en los rotores. Más precisamente, se han analizado casos en los cuales uno de los rotores pierde capacidad de empuje. Sin embargo, los resultados teóricos admiten una falla total de los rotores, es decir, que uno de los rotores se detenga completamente. En este trabajo validamos experimentalnente la falla total de un rotor y mostramos como un vehículo hexa-rotor es capaz de mantener su capacidad de maniobra ante la pérdida total de uno de sus rotores