1,720,978 research outputs found
Non-Invasive Optical Sensors to Measure Pilots’ Forces on Aircraft Control Inceptors
No full textThe document presents an innovative type of sensor that can be used to measure forces on aircraft control inceptors. The measures can be applied both to in-flight and on simulators and allow for measure not only the total force applied on the inceptor’s grip but also their distribution over the inceptor grip without altering the ergonomics of the input device. The sensor aims also to provide a reliable way to quantify the workload to which a pilot is subjected during specific mission task elements. The sensor working principle is based on an optical measure making it not sensible to typical temperature-drift problems that affect classical electro-mechanical systems. A prototype of the sensor embedded in the yoke of an aircraft flight simulator has been designed, built, and tested. The results of an experiment involving several experienced pilots to assess the workload will be reported
A Methodology for Preliminary Performance Estimation of a Hybrid-Electric Tilt-Wing Aircraft for Emergency Medical Services
Full text linkThis paper aims to provide a simple methodology
to preliminary size a hybrid-electric propulsion system for
large scale piloted, optionally piloted or unmanned tilt-wing
aircraft. In this work, the author refers to three mission
profile representative of an Emergency Medical Service (EMS)
operation and estimate the performance of the aircraft along
the mission. Thus, based on some assumptions on battery
technology, architecture of the hybrid system and mission safety
requirements, a methodology for preliminary performance estimation
is described and results for a baseline architecture are
presented. Based on present and near future battery technology
(in terms of charge/discharge rates and energy density), the
present study shows how safety requirements can strongly
affect the overall size of the power-plant system and impact
the feasibility of hybrid-electric technology in aeronautical
applications
Implementation of a comprehensive real-time flight simulator for XV-15 tilt-rotor aircraft
Full text linkThis paper presents a tilt-rotor flight simulation platform implementing a real-time simulation of the Bell XV-15 aircraft for teaching and research purposes. The mathematical model of the tilt-rotor aircraft is implemented in MATLAB/Simulink© including simplified models of aircraft dynamics, actuators, sensors, and Flight Control Computer. The implemented tilt-rotor mathematical model is interfaced with flight control hardware, i.e. a flight stick and a rudder pedal, used by the pilot to set input commands. Instead, the graphics environment is provided by FlightGear, an open-source and cross-platform software widely used in research activities. Another contribution of the paper is the design and implementation of a Stability Control and Augmentation System to enhance aircraft stability and improve handling qualities. The developed simulator is tested with several simulations validating the developed mathematical model and the effectiveness of the Stability Control and Augmentation System. The result is a tilt-rotor flight simulation platform executable on a commercial laptop with real-time performance for research and teaching activities
Comprehensive Analysis and Configuration of a Control Loading Solution for a Rotary Wing Flight Simulator
Full text linkThis paper presents the design methodologies of a Control Loading System (CLS) drive model for the Research and Didactics Simulator (ReDSim) of the Zurich University of Applied Sciences (ZHAW). The analysis of the CLS hardware and interface software is presented. The CLS drive model is intended as an irreversible flight control system of a rotary wing aircraft’s collective control, with trim system and force feedback capabilities, mainly as a function of the lever’s position. The CLS motor’s control parameters are set to fit the application’s performance requirements. The drive model is developed in MATLAB/Simulink and is integrated with the XV-15 tiltrotor model of the ReDSim. Two different system identification techniques, the Least Squares and a convex relaxation-based Set-Membership approach, are used to estimate the parameters of the CLS hardware and consequently assess its fidelity to a model of reference. The implementation in the ReDSim has been rated by the pilot according to the Cooper-Harper handling qualities rating scale
Design and Integration of a Tilt-Rotor Flight Simulation Platform
Full text linkThis paper introduces a tilt-rotor flight simulation platform for research and teaching purposes implementing a real-time simulation of the Bell XV-15 aircraft. The mathematical model of the XV-15 aircraft has been implemented including simplified models for the aerodynamics of the whole aircraft, rotors, and engine dynamics. Hence, the simulation is performed in a graphic environment to reproduce the simulated flight and to interact with it using commands given by the pilot. The simulation platform is implemented using MATLAB/Simulink®, while the input commands are set using USB peripherals, i.e., a flight stick and a pedal board. Instead, the visualization environment is performed using FlightGear, an open-source and cross-platform software that is widely used in research. The result is a portable tilt-rotor simulator to be executed on a commercial pc, while ensuring real-time performance. The tilt-rotor flight simulator is also validated by a licensed helicopter pilot returning positive feedback regarding the flight experience
Mathematical modelling of gimballed tilt-rotors for real-time flight simulation
Full text linkThis paper introduces a novel gimballed rotor mathematical model for real-time flight simulation of tilt-rotor aircraft and other vertical take-off and landing (VTOL) concepts, which improves the previous version of a multi-purpose rotor mathematical model developed by ZHAW and Politecnico di Torino as part of a comprehensive flight simulation model of a tilt-rotor aircraft currently implemented in the Research and Didactics Simulator of ZHAW and used for research activities such as handling qualities studies and flight control systems development. In the novel model, a new formulation of the flapping dynamics is indroduced to account for the gimballed rotor and better suit current tilt-rotor designs (XV-15, V-22, AW-609). This paper describes the mathematical model and provides a generic formulation as well as a specific one for 3-blades proprotors. The method expresses the gimbal attitude but also considers the variation of each blade’s flapping due to the elasticity of the blades, so that the rotor coning angle can be represented. A validation of the mathematical model is performed against the available literature on the XV-15 Tilt-rotor aircraft and a comparison between the previous model is provided to show the improvements achieved. The results show a good correlation between the model and the reference data and the registered performance allow real-time flight simulation with pilot and hardware in the loop
Implementation of a Comprehensive Mathematical Model for Tilt-Rotor Real-Time Flight Simulation
Full text linkThis paper aims at describing the effort performed by the joint research group of Politecnico di Torino and ZHAW
(Zurich University of Applied Sciences) in achieving a novel implementation of a mathematical model for real-time
flight simulation of tilt-rotors and tilt-wings aircraft. The focus is on the description of the current stage of the project,
the achievements of the first version of the model, on-going improvements and future developments.
The first part of the work describes the initial development of the overall simulation model: relying on several NASA
reports on the Generic Tilt Rotor Simulator (GTRS), the mathematical model is revised and the rotor dynamic
model is improved in order to enhance computational performance. In particular, the model uses the conventional
mathematical formulation for non-dynamic inflow modelling based on Blade Element Momentum Theory. A novel
but simple numerical method is used to ensure the convergence of the non-linear equation in every tested condition.
The resulting simulation model and its development and implementation in the MATLAB/Simulink® environment is
described.
The second part of the work deals with the integration of the model in the ZHAW Research and Didactics Simulator
(ReDSim), the replacement of the pilot controls by the introduction of a center stick and the corresponding adjustment
of the force-feel system to suitable values for the tilt-rotor model. Subsequently, several pilot tests are carried
out and preliminary feedbacks about the overall behaviour of the system are collected. Limits and weaknesses
of the first release of the model are investigated and future necessary improvements are assessed, such as the
development of a novel generic prop-rotor mathematical model.
The third part introduces the novel multi-purpose rotor mathematical model which was developed to improve the
overall tilt-rotor simulation model. The multi-purpose rotor model implements non-approximated flapping dynamics
and inflow dynamic based on Pitt-Peters formulation. The validation of the novel rotor model is carried out with
available data of both the XV-15 Research Aircraft and the UH-60 Helicopter
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
