1,720,969 research outputs found
Human-Robot Assembly Task with Holographic Projections for Inexperienced Operators
No full textIn the age of flexible and fast-evolving industrial scenarios, the operator is often required to learn and perform different tasks during the same working shift. Making the collaboration between a human and a robot easier becomes then crucial. In this paper, we propose an exploratory study to analyze the advantages of using a mixed-reality interface to support the operator during the learning phase of a new task in collaboration with a robot. To highlight the benefits of the proposed solution, we compared the use of the holographic instructions against the more traditional textual guidelines. The results showed that the proposed mixed-reality interface reduces the variability of the cycle-time and of the operator's learning rate. From a subjective perspective, the holographic learning method turned out to be more intuitive and effective than the textual one
Comportamento vegetativo e produttivo di alcune cultivar di susino autoradicate e innestate
No full textIdentification of Robot Forward Dynamics via Neural Network
No full textIn recent years machine learning techniques have received an increasing interest, since they can be successfully applied to several application domains, among which robotics. In this field, neural networks can be used to approximate the dynamic model of the manipulator, which is highly non-linear and often affected by some uncertainties regarding the dynamic parameters. These parameters are typically not provided by the manufacturer or partially unknown. In this work, we propose the use of neural networks to perform the black-box identification of the robot forward dynamics. This consists in performing a one step ahead prediction of the robot joint positions, velocities and accelerations based on the knowledge of the joint positions, velocities at the previous time step and the actuation torques. To this purpose, we analyzed both static and dynamic neural networks structures with different combinations of hyper-parameters. We tested the performance by comparing the predicted output with both simulated data and those acquired on a real industrial manipulator, ABB IRB 140
A Dynamic Task Allocation Strategy to Mitigate the Human Physical Fatigue in Collaborative Robotics
No full textIn human-robot collaboration, the mitigation of human physical workload is a crucial factor to avoid musculoskeletal disorders that might jeopardize the operator’s safety and job performance. In this work, we propose a novel, non-invasive method to estimate online the muscle fatigue experienced by the worker during the task execution. The estimation process relies on a sophisticated musculoskeletal model of the human upper body and on a 3D vision system used to track human motions in real-time. Based on this estimate, we develop a strategy that dynamically allocates the task activities to the human and to the robot with the aim of minimizing his/her muscular fatigue, thus improving the quality of the cooperation. The proposed approach has been experimentally validated in a collaborative industrial use case and compared to a static allocation strategy
A particle filter technique for human pose estimation in case of occlusion exploiting holographic human model and virtualized environment
No full textIn a collaborative scenario, robots working side by side with humans might rely on vision sensors to monitor the activity of the other agent. When occlusions of the human body occur, both the safety of the cooperation and the performance of the team can be penalized, since the robot could receive incorrect information about the ongoing cooperation. In this work, we propose a novel particle filter algorithm that, by merging the data acquired through a RGB-D camera and a MR headset, estimates online the human wrist position. This algorithm allows to significantly reduce the uncertainty of the human pose estimation, in case of both static and dynamic occlusions. To this purpose, the proposed particle filter is integrated with a detailed virtual model of the real workspace. Moreover, additional constraints describing the boundaries of the motion of the human upper body are included in a virtualized framework. The results showed that the proposed technique entails significant improvements, determining a relevant reduction of the estimation error and of the uncertainty of the estimate
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
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