AUTOMATIC TAKE-OFF OR LANDING PATH FOLLOWING IN TURBULENT AIR FOR UAS - AN EKF BASED PROCEDURE

By using the Extended Kalman Filter (EKF) an accurate take-off or landing flight path following in turbulent air is performed. The tuned up procedure employs simultaneously two different EKF: the first one estimates gust disturbances, the second one affords to determine the necessary controls displacements for rejecting those ones. In particular, the first filter, by using instrumental measurements gathered in turbulent air, estimates wind components. The second one obtains command laws able to follow the desired flight path. To perform this task aerodynamic coefficients have been modified by adding entirely new derivatives or synthetic increments to basic ones whose might the kind of change required to reject disturbances. Such a procedure leads to a set of unknown stability and control parameters containing the required displacements of the controls. The modified aircraft parameters are determined by augmenting the aircraft’s state. The filter estimates the new set of aircraft stability derivatives by using measurements made by the desired take-off or landing flight path parameters. Once the unknown stability and control derivatives have been determined, the obtained control displacements are used to perform an accurate path following in turbulent air. Obviously, the obtained control laws are adaptive since they depend by either the characteristics of the disturbance or the desired flight path. The proposed procedure requires low computational power, therefore it is particularly suited for UAS, besides being simple to implement on board it may be successfully employed on low cost platforms

Gain scheduling automatic landing system by modeling Ground Effect

Taking ground effect into account a longitudinal automatic landing system is designed. Such a system will be tested and implemented on board by using the Preceptor N3 Ultrapup aircraft which is used as technological demonstrator of new control navigation and guidance algorithms in the context of the “Research Project of National Interest” (PRIN 2008) by the Universities of Bologna, Palermo, Ferrara and the Second University of Naples. A general mathematical model of the studied aircraft has been built to obtain non–linear analytical equations for aerodynamic coefficients both Out of Ground Effect and In Ground Effect. To cope with the strong variations of aerodynamic coefficients In Ground Effect a modified gain scheduling approach has been employed for the synthesis of the controller by using six State Space Models. Stability and control matrices have been evaluated by linearization of the obtained aerodynamic coefficients. To achieve a simple structure of the control system, an original landing geometry has been chosen, therefore it has been imposed to control the same state variables during both the glide path and the flare

An Algorithm for Parameter Identification of UAS from Flight Data

The aim of the present work is to realize an identification algorithm especially devoted to UAS (unmanned aerial systems). Because UAS employ low cost sensor, very high measurement noise has to be taken into account. Therefore, due to both modelling errors and atmospheric turbulence, noticeable system noise has also to be considered. To cope with both the measurement and system noise, the identification problem addressed in this work is solved by using the FEM (filter error method) approach. A nonlinear mathematical model of the subject aircraft longitudinal dynamics has been tuned up through semi-empirical methods, numerical simulations and ground tests. To take into account model nonlinearities, an EKF (extended Kalman filter) has been implemented to propagate the state. A procedure has been tuned up to determine either aircraft parameters or the process noise. It is noticeable that, because the system noise is treated as unknown parameter, it is possible to identify system affected by noticeable modelling errors. Therefore, the obtained values of process noise covariance matrix can be used to highlight system failure. The obtained results show that the algorithm requires a short computation time to determine aircraft parameter with noticeable precision by using low computation power. The present procedure could be employed to determine the system noise for various mechanical systems, since it is particularly devoted to systems which present dynamics that are difficult to model. Finally, the tuned up off-line EKF should be employed to on-line estimation of either state or unmeasurable inputs like atmospheric turbulence

Diseño de una red que permita acceder a los servicios telemáticos, aplicando arquitectura DMZ como seguridad, bajo plataforma LINUX y Virtualización, en radio Fe-Nandaime

La información es el elemento principal a proteger, resguardar y recuperar dentro de las redes empresariales. Por el enorme número de amenazas y riesgos que existen a lo largo del mundo, la infraestructura de red y recursos informáticos de una organización deben estar protegidos bajo un esquema de seguridad que reduzca los niveles de vulnerabilidad y sobre todo que permita una eficiente administración del riesgo

An experimental investigation on air quality inside WindJet aircraft

ABSTRACT In order to improve the passengers and crew comfort during the flight, the aim of the present paper is a study of the cabin air quality through experimental measures on randomly selected flight segments of an Italian airline company, WindJet. Carbon dioxide, ultrafine particles, temperature and relative humidity have been measured by using low cost high efficiency instrumental equipments. Exploring ways to improve aircraft cabin air quality, WindJet and University of Palermo are investigating equipment, filters and components of the ventilation system. In this paper, after description of both ventilation systems for aircrafts of WindJet and the instrumental equipments used to measure environmental characteristics on board, obtained results are shown

Multiple nutrient transporters enable cells to mitigate a rate-affinity tradeoff

Eukaryotic genomes often encode multiple transporters for the same nutrient. For example, budding yeast has 17 hexose transporters (HXTs), all of which potentially transport glucose. Using mathematical modelling, we show that transporters that use either facilitated diffusion or symport can have a rate-affinity tradeoff, where an increase in the maximal rate of transport decreases the transporter's apparent affinity. These changes affect the import flux non-monotonically, and for a given concentration of extracellular nutrient there is one transporter, characterised by its affinity, that has a higher import flux than any other. Through encoding multiple transporters, cells can therefore mitigate the tradeoff by expressing those transporters with higher affinities in lower concentrations of nutrients. We verify our predictions using fluorescent tagging of seven HXT genes in budding yeast and follow their expression over time in batch culture. Using the known affinities of the corresponding transporters, we show that their regulation in glucose is broadly consistent with a rate-affinity tradeoff: as glucose falls, the levels of the different transporters peak in an order that mostly follows their affinity for glucose. More generally, evolution is constrained by tradeoffs. Our findings indicate that one such tradeoff often occurs in the cellular transport of nutrients

Effects and cost of implementing a gender-sensitive reproductive health program in Bolivia

The Integral Health Coordination Program (Programa de Coordinación en Salud Integral or PROCOSI), a network of 24 Bolivian NGOs, and the Population Council’s Frontiers in Reproductive Health (FRONTIERS) program evaluated the effects of interventions on clinic clients and their partners, and estimated the costs of incorporating a gender perspective into service delivery. Results show that sexual and reproductive health service organizations can implement action plans to change organizational policies and service delivery practices and to improve their infrastructure and equipment to make them more convenient for clients. The results further show that the intervention made modest but important changes in partner dynamics. No evidence was found that the incorporation of a gender perspective had an effect on the demand for sexual and reproductive health services. In the context of the current study, if change in unmet need is posited as the measure of success, then the question for program managers is whether this expenditure is justified to achieve the resulting changes in unmet need

Optimal Power Flow in Direct Current Networks Using the Antlion Optimizer

This document presents a solution method for optimal power flow (OPF) problem in direct current (DC) networks by implementing a master-slave optimization methodology that combines an antlion optimizer (ALO) and a power flow approach based on successive approximation (SA ). In the master stage, the ALO determines the optimal amount of power to be delivered by all the distributed generators (DGs) in order to minimize the total power losses in the distribution lines of the DC network. In slave stage, the power flow problem is solved considering constant power loads and power outputs of DGs as constants. To validate the effectiveness and robustness of the proposed model, two additional comparative methods were implemented: particle swarm optimization (PSO) and black hole optimization (BHO). Two distribution test feeders (21 and 69 nodes) were simulated under different scenarios of distributed power generation. The simulations, conducted in MATLAB 2018$b$, show that the proposed method (ALO) presents a better balance between power loss minimization and computational time required to find the optimal solution regardless of the size of the DC network

Hacinamiento, causas y efectos, en el rendimiento académico de los estudiantes en el Instituto Nacional Francisco Menéndez, 2019

Se realizó un estudio acerca de la importancia de la educación como ente social, ya que es el que da paso a tener contacto a los jóvenes con una sociedad ya construida, es decir, la educación culturiza y tiene incidencia en la construcción social. Pero la educación se puede ver interrumpida por otros factores o problemas de la misma sociedad, y el objetivo de realizar esta investigación, es ver los efectos que pueda tener el Hacinamiento de los hogares de los estudiantes en su rendimiento académico. El hacinamiento como problema contemporáneo de las sociedades actuales cada vez se va agravando y creciendo, ya que en el país, existe una alta densidad poblacional a causas de muchos factores y sumando el déficit de vivienda que ningún Gobierno resuelve, el problema de Hacinamiento cada vez va ir impactando en la vida de las personas y sus relaciones sociales

The beginning of grape cultivation in the Iberian Peninsula: a reappraisal after the Huelva (southwestern Spain) archaeological finds and new radiocarbon datings

This paper provides a brief chronological overview of the oldest pottery found in the deepest anthropogenic stratum thus far investigated at the ancient city of Huelva, along with the oldest ceramics related to vineyards of the neighbouring agricultural countryside at La Orden-Seminario. It also compiles ten AMS radiocarbon dates of diverse organic materials of the referred stratum carried out by four different labs. The main conclusion of the study is that the Phoenicians introduced grape cultivation in the Iberian Peninsula pref</p