1,720,984 research outputs found
Optimal Sensor Positioning for Large Scale Metrology Applications
No full textAs it strongly affects the system performance in measuring 3D point coordinates, beacon positioning represents a challenging issue in large scale metrology applications based on wireless sensor networks. This paper presents a software-assisted procedure for efficient placement of ultrasonic beacons in a wireless distributed network-based system for medium-large sized object measurements. A regular grid-based strategy and a genetic algorithm-based approach to the deployment problem are presented. The resulting network configurations are compared in terms of overall costs, sensor availability and measurement precision. The genetic algorithm outperforms the regular deployment solution, optimizing the objective functions and providing additional capabilities to represent a realistic working environment. The novelty here is the approach to the "pre-processing" phase of a sensor network deployment, involving working environment constraints, system functional characteristics, measurand geometry, and measurement task definition in the three-dimensional network desig
Fluorescent Oil Flow Visualization Technique Applied to 2D Airfoils at Very Low Reynolds Numbers
No full text
Flight Control System Design for a Micro Aerial Vehicle
No full textPurpose - The purpose of this paper is to present an original design procedure for a flight control system. Design/methodology/approach - An optimization process, based on a genetic algorithm (GA), is used to meet the frequency domain handling qualities requirements in the longitudinal plane for an unconventional platform characterized by nonlinear aerodynamics. The parameters are implemented in the search process as fitness functions related to the expected magnitude of bandwidth and delay for an existing micro aerial vehicle. The bandwidth and the delay of the longitudinal short-term attitude response are estimated before and after the inclusion of the flight control system in the simulation model, and the parameters are compared with the expected handling qualities levels. A qualitative analysis of handling qualities levels is also performed by implementing the augmented aircraft in a simulator with a realistic visual environment. Findings - The results show that an optimal search process based on a GA can implement the handling qualities requirements with a computational procedure that is straightforward. Research limitations/implications - Even if the requisites for bandwidth and delay implemented in the search process are general in use as no specific aircraft response type is taken as a reference for the estimation of handling qualities requirements, only future experimental work will provide insight for the definition of specific Level 1 boundaries for micro aerial vehicles in remotely piloted flight. Originality/value - The virtual environment is useful to test remote piloting with unconventional onboard visual cues. This is important in applications in which technical limitations may preclude complete real time data link during flight tests in the first development phase of the vehicl
- …
