Robust visual servoing in 3d reaching tasks

This paper describes a novel approach to the problem of reaching an object in space under visual guidance. The approach is characterized by a great robustness to calibration errors, such that virtually no calibration is required. Servoing is based on binocular vision: a continuous measure of the end-effector motion field, derived from real-time computation of the binocular optical flow over the stereo images, is compared with the actual position of the target and the relative error in the end-effector trajectory is continuously corrected. The paper outlines the general framework of the approach, shows how visual measures are obtained and discusses the synthesis of the controller along with its stability analysis. Real-time experiments are presented to show the applicability of the approach in real 3-D applications

A Vision-Based Learning Method for Pushing Manipulation

We describe an unsupervised on-line method for learning of manipulative actions that allows a robot to push an object connected to it with a rotational point contact to a desired point in image-space. By observing the results of its actions on the object\u27s orientation in image-space, the system forms a predictive forward empirical model. This acquired model is used on-line for manipulation planning and control as it improves. Rather than explicitly inverting the forward model to achieve trajectory control, a stochastic action selection technique [Moore, 1990] is used to select the most informative and promising actions, thereby integrating active perception and learning by combining on-line improvement, task-directed exploration, and model exploitation. Simulation and experimental results of the approach are presented

A Vision-Based Learning Method for Pushing Manipulation

We describe an unsupervised on-line method for learning of manipulative actions that allows a robot to push an object connected to it with a rotational point contact to a desired point in image-space. By observing the results of its actions on the object's orientation in imagespace, the system forms a predictive forward empirical model. This acquired model is used on-line for manipulation planning and control as it improves. Rather than explicitly inverting the forward model to achieve trajectory control, a stochastic action selection technique [Moore, 1990] is used to select the most informative and promising actions, thereby integrating active perception and learning by combining on-line improvement, task-directed exploration, and model exploitation. Simulation and experimental results of the approach are presented. I. INTRODUCTION Active perception can broadly be defined as the process of information gathering, organization and interpretation by the active and purposive control of..

A Direct Approach to Vision Guided Manipulation

This paper describes a method for robotic manipulation that uses direct image-space calculation of optical flow information for continuous real-time control of manipulative actions. State variables derived from optical flow measurements are described. The resulting approach is advantageous since it robustifies the system to changes in optical parameters and also simplifies the implementation needed to succeed in the task execution. Two reference tasks and their corresponding experiments are described: the insertion of a pen into a "cap" (the capping experiment) and the rotational point-contact pushing of an object of unknown shape, mass and friction to a specified goal point in the image-space. I. INTRODUCTION The visual system of an agent, either natural or artificial, has to cope with motion in at least two ways: it should be able to detect, measure and interpret the motion of external objects, and it must be able to use dynamic visual information to control, plan and coordinate its..

A direct approach to vision guided manipulation

Abstract|This paper describes a method for robotic manipulation that uses direct image-space calculation of optical ow information for continuous real-time control of manipulative actions. State variables derived from optical ow measurements are described. The resulting approach is advantageous since it robusti es the system to changes in optical parameters and also simpli es the implementation needed to succeed in the task execution. Two reference tasks and their corresponding experiments are described: the insertion of a pen into a \cap " (the capping experiment) and the rotational point-contact pushing of an object of unknown shape, mass and friction to a speci ed goal point in the image-space. I

Raccomandazioni cliniche in odontostomatologia

L’Organizzazione Mondiale della Sanità considera la salute orale come parte integrante, non solo dello stato di salute generale, ma anche della qualità della vita di ciascun individuo. In tale ottica, in accordo e con il sostegno del mondo professionale e della comunità scientifica di questo settore, le raccomandazioni cliniche in odontostomatologia contenute nel presente volume forniscono indicazioni e definiscono standard di intervento per la prevenzione e la cura delle più comuni patologie del cavo orale nonché per l’identificazione di percorsi terapeutici appropriati a supporto degli operatori pubblici e privati. Esse costituiscono, inoltre, uno strumento utile per mantenere alto il livello di qualità delle cure in questo periodo storico, nel quale, se da un lato crescono le opportunità tecniche di cura e la potenziale domanda delle stesse, dall’altro la riduzione delle risorse economiche a disposizione dei cittadini tende a limitare l’accesso all’offerta professionale privata e, al contempo, i processi di razionalizzazione dell’allocazione dei fondi nel SSN rendono più difficile l’accesso alle strutture pubbliche. L’individuazione di raccomandazioni cliniche chiaramente definite e rese pubbliche può facilitare la condivisione degli obiettivi e dei percorsi terapeutici tra odontoiatra e paziente, migliorare la comunicazione e, in ultima analisi, accrescere la fiducia sia nei riguardi del proprio specifico professionista che del “sistema delle cure” più in generale. La revisione delle “Raccomandazioni cliniche in odontostomatologia” si è resa necessaria in considerazione del cambiamento dell’evidenza scientifica, dell’immissione in commercio di nuovi materiali e dell’utilizzo di nuove tecnologie, specie in ambito protesico. Come per la precedente, alla realizzazione di questa edizione ha contribuito un ampio gruppo di docenti ed esperti delle singole branche odontoiatriche insieme alle più importanti e rappresentative Associazioni professionali e ai componenti della Commissione Albo Odontoiatri (CAO) nazionale