1,721,019 research outputs found
Un approccio meccatronico per la progettazione e lo sviluppo di sistemi di controllo in asservimento visivo
Full text linkModern robots and mechatronic systems are equipped with a large number of sensors which give them the possibility to accomplish complex tasks. In recent years the integration of robots and vision system has become critical to improve machinery productivity and versatility. Nevertheless, the most widely used approach is still the "look then move" fashion, in which the vision system simply supports a manipulator without taking part in the robot control task. An alternative technique that allows to merge the vision task and the control one is named "visual servoing" or "vision in the loop". Following this approach, a visual-feedback loop can be added to the standard manipulator control loop in order to drive the robot directly with the information coming from the vision system.
This further controller brings a lot of benefits including: (i) a general increase of the accuracy of the subsystem and its robustness towards environment noise and changes; (ii) the capability to follow fast moving objects; (iii) the possibility to adapt the system to different situations and tasks. On the contrary hand, designing and developing an efficient and robust visual control is tipically a difficult task as it involves various issues like computer vision lgorithms, control theory, robot kinematics and so on. The analysis carried out in this thesis aims to highlight the aspects common to all visual servoing tasks in order to provide a general solution schema for this kind of problems. Firstly, the image acquisition process and image elaboration techniques are presented, with particular attention to their application to "tracking" fast moving objects or scenes; secondly, visual servoing controller design is ntroduced and its kinematic and dynamic issues are studied; eventually, a software architecture for the mplementation of visually guided task is shown along with simple experimental applications used to evaluate the results of the work
A Formal High-level Modeling Approach to Develop Reliable Components in Vision-based Robotics
No full textA time-domain travelling-wave model including multi-population rate-equations for passively mode-locked quantum-dot lasers
No full textSimulation and design of high power gain guided quantum dot tapered lasers operating in passive mode-locking regime
No full textModelling passive mode-locking in quantum-dot lasers using a finite difference travelling-wave model with multi-population rate equations
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Time domain travelling wave model of QD-DFB lasers with inhomogeneously broadened gain material
Full text linkModelling differential transmission spectroscopy experiments in quantum dot optical amplifiers and saturable absorbers
No full textTime-Domain Traveling Wave Model of Quantum Dot DFB Lasers
No full textWe present a time-domain traveling wave model for the simulation of InAs/GaAs quantum dot DFB lasers. The optical susceptibility of the quantum dot (QD) active material is represented through a series of numerical filters that account for the interplay between homogeneous and inhomogeneous broadening of the gain spectrum of the self-assembled QDs. We also consider separate rate equations for electrons and holes for representing the different dynamics of carriers in the conduction and the valence band. We present examples of simulation results focusing in particular on the dynamic properties of the laser (modulation bandwidth, nonreturn-to-zero direct modulation, chirp, α-parameter, etc.) with the purpose of comparing these simulation results with the experimental ones found in the literatur
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