Monocular vision based autonomous navigation for a cost-effective MAV in GPS-denied environments

In this paper, we present a monocular vision based autonomous navigation system for Micro Aerial Vehicles (MAVs) in GPS-denied environments. The major drawback of monocular systems is that the depth scale of the scene can not be determined without prior knowledge or other sensors. To address this problem, we minimize a cost function consisting of a drift-free altitude measurement and up-to-scale position estimate obtained using the visual sensor. We evaluate the scale estimator, state estimator and controller performance by comparing with ground truth data acquired using a motion capture system. All resources including source code, tutorial documentation and system models are available online.

Optimal location of centre of gravity for swashplateless helicopter UAV and MAV

To investigate the use of centre of gravity location on reducing cyclic pitch control for helicopter UAV's (unmanned air vehicles) and MAV's (micro air vehicles). Low cyclic pitch is a necessity to implement the swashplateless rotor concept using trailing edge flaps or active twist using current generation low authority piezoceramic actuators. Design/methodology/approach – An aeroelastic analysis of the helicopter rotor with elastic blades is used to perform parametric and sensitivity studies of the effects of longitudinal and lateral center of gravity (cg) movements on the main rotor cyclic pitch. An optimization approach is then used to find cg locations which reduce the cyclic pitch at a given forward speed. Findings – It is found that the longitudinal cyclic pitch and lateral cyclic pitch can be driven to zero at a given forward speed by shifting the cg forward and to the port side, respectively. There also exist pairs of numbers for the longitudinal and lateral cg locations which drive both the cyclic pitch components to zero at a given forward speed. Based on these results, a compromise optimal cg location is obtained such that the cyclic pitch is bounded within ±5° for a BO105 helicopter rotor. Originality/value – The reduction in the cyclic pitch due to helicopter cg location is found to significantly reduce the maximum magnitudes of the control angles in flight, facilitating the swashplateless rotor concept. In addition, the existence of cg locations which drive the cyclic pitches to zero allows for the use of active cg movement as a way to replace the cyclic pitch control for helicopter MAV's.

Morphing fixed wing MAV modeling using VAM

The design and implementation of a morphing Micro Air Vehicle (MAV) wing using a smart composite is attempted in this research work. Control surfaces actuated by traditional servos are difficult to instrument and fabricate on thin composite-wings of MAVs. Piezoelectric Fiber Reinforced Composites (PFRCs) are the chosen smart structural materials in the current work for incorporation onto fixed-wing MAVs to simultaneously perform the dual functions of structural load-bearing and actuation of flexure, torsion and/or extension for morphing. Further, PFRC use can be extended towards shape control of a “fixed” wing MAV to meet changing performance requirements. Wings that can warp into desired shapes and/or have variable camber are well-known to exhibit improved efficiency in aerodynamic control. During an entire flight cycle, there are multiple optimal configurations, each of which suits a particular phase of the flight regime. Widely proposed methods of wing morphing include changes in camber, twist, sweep and span. However, camber change during flight is already established, in terms of its potential, as a major factor in improving the aerofoil efficiency and flow separation behavior. Hence, for this work, morphing with camber change is adopted with the goal to better tailor aerodynamic properties.

MAV para la comunicación en la escuela.

El proyecto propone introducir en el aula los medios audiovisuales con la intención de ofrecer al alumnado otras formas de comunicación y expresión, que potencien su capacidad crítica y fomenten una actitud más activa en la sociedad. Los objetivos son: combinar recursos lingüísticos y no lingüísticos para interpretar mensajes con diferentes intenciones comunicativas; comprender las posibilidades del lenguaje, imagen y sonido como elementos de representación y expresión de ideas, sentimientos y vivencias; conocer las técnicas específicas de los distintos lenguajes; y potenciar la capacidad crítica. La experiencia de carácter interdisciplinar se lleva a cabo fundamentalmente en las áreas de Conocimiento del Medio, Educación Artística y Lengua Española. Como punto de partida se trabajan en el aula algunas nociones básicas relativas a la imagen (percepción, línea, punto, forma, color, iluminación, encuadre, relación imagen y texto, etc.) y sus soportes (cámara fotográfica, radio, vídeo, etc.). Así, entre las actividades realizadas, destacan: análisis de elementos que integran formas de comunicación verbal y no verbal (programas de televisión, anuncios publicitarios, documentales, etc.), composiciones plásticas y visuales, realización de fotografías, añadir textos a las imágenes y viceversa, y elaboración de guiones, diaporamas y vídeos. La valoración de la experiencia es muy positiva por el alto grado de adecuación entre proyecto y memoria y los buenos resultados obtenidos..

Posibilidades de uso de los MAV.

Consiste en el estudio y aprovechamiento de la información actual, ofrecida a través de los medios de comunicación. Se divide en dos subproyectos: Proyecto A y Proyecto B. Se pretende despertar el interés por los problemas sociales de hoy, y por las posibilidades que ofrecen la imagen y el texto sobre la realidad. Asimismo, se espera estar al tanto de los contenidos de los temas esenciales de las asignaturas de Lengua y Literatura Española, y Expresión Artística, para ponerlos en práctica en la programación escolar. La metodología se basará en recogida y catalogación de datos, análisis y comentario de los mismos, y finalmente, elaboración de un guión de trabajo. Entre las actividades, señalar: lectura y visionado de noticias, confección de periódicos, etc. No figura memoria del proyecto..

El empleo de los MAV en un centro de EGB : aula de ciencias sociales : taller de imagen.

Ejemplar fotocopiado

Survey of Spring Oats for Barley Yellow Dwarf Viruses in Illinois

During the spring of 1987, 1,215 samples of spring oats (Avena sativa L.) were collected in Madison, Champaign, Woodford, Warren, and DeKalb counties, Illinois. At each site on each of three sampling dates, 45 samples were collected (regardless of symptoms) in a W pattern in I ha and tested for the PAY, MAV, RPV, and RMV serotypes of barley yellow dwarf virus (BYDV) by direct doubleantibody sandwich enzyme-linked immunosorbent assay (ELISA). RMV was not detected at any location. PAY and RPV were detected at all locations, as early as 17 April in Champaign County. The incidences of P A V and RPV from all plants sampled ranged from 2 to 64% and from 2 to 88%, respectively. Highest incidences of both strains were in May samples [rom Woodford County. MAV was detected in lower incidences (2-16%) only in samples from the central region of the state (Champaign, Woodford, and Warren counties). The presence of MA V serotypes was confirmed in triple-antibody sandwich ELISA with the MA V -specific MAFF2 monoclonal antibody from L. Torrance. In the last previous survey for BYDV in Illinois during 1967-1968 (1), about 75% of the isolates were PAY and about 20% were RPV; single isolates of RMV and MAV were found. Twenty years later, 55% were PAY, 39% were RPV, and 6% were MAV.

Aerial SLAM with a single camera using visual expectation

Micro aerial vehicles (MAVs) are a rapidly growing area of research and development in robotics. For autonomous robot operations, localization has typically been calculated using GPS, external camera arrays, or onboard range or vision sensing. In cluttered indoor or outdoor environments, onboard sensing is the only viable option. In this paper we present an appearance-based approach to visual SLAM on a flying MAV using only low quality vision. Our approach consists of a visual place recognition algorithm that operates on 1000 pixel images, a lightweight visual odometry algorithm, and a visual expectation algorithm that improves the recall of place sequences and the precision with which they are recalled as the robot flies along a similar path. Using data gathered from outdoor datasets, we show that the system is able to perform visual recognition with low quality, intermittent visual sensory data. By combining the visual algorithms with the RatSLAM system, we also demonstrate how the algorithms enable successful SLAM.