1,720,971 research outputs found
SensHB.Q: A Cost-Effective Force-Sensitive Handlebar to Control Omnidirectional Robots and Wheelchairs
Full text linkThis paper details the design and development of SensHB.Q, a force-sensitive handlebar intended for caregivers driving electric-powered wheelchairs, particularly those with omnidirectional mobility. The same interface can also be used in the future to operate other omnidirectional motorized systems, such as mobile robots, hospital beds, and industrial trolleys. The primary objective was to develop an intuitive, cost-effective device. To achieve this, the interface mimics the way we naturally interact with objects by applying forces and torques to achieve desired movements. SensHB.Q measures the forces and torques applied by the driver and converts them into commands for the motorized system. The idea is that the driver applies small forces and torques, and the motorized platform then takes care of the traction forces needed to perform the desired motion. In terms of cost-effectiveness, SensHB.Q uses a mechanism that only employs uniaxial load cells to measure the forces applied by the driver, thus avoiding the need for costly multiaxial load cells. This paper first presents the concept of SensHB, followed by a discussion of its functional and executive design. Second, the study elaborates on the electronic control unit of the device and presents experimental tests comparing the force/torque measurements of SensHB.Q with those of an off-the-shelf, six-axis force/torque sensor. Finally, SensHB.Q is integrated and tested on the omnidirectional motorized wheelchair MoviWE.Q, which was developed at Politecnico di Torino. These preliminary tests, which are performed with a limited number of participants, are used to test whether it is possible to drive an omnidirectional motorized system using the developed force-sensitive interface
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
On the suspension design of paquitop, a novel service robot for home assistance applications
Full text linkThe general and constant ageing of the world population that has been observed in the last decade has led robotics researchers community to focus its aims to answer the ever-growing demand for health care, housing, care-giving, and social security. Among others, the researchers at Politecnico di Torino are developing a novel platform to enhance the performance offered by present-day issues, and to assess many others which were not even taken into consideration before they have been highlighted by the pandemic emergency currently in progress. This situation, in fact, made dramatically clear how important it is to have reliable non-human operators whom one can trust when the life of elderly or weak patients is endangered by the simple presence of other people. The platform, named Paquitop, features an innovative architecture conceived for omni-directional planar motion. The machine is designed for domestic, unstructured, and variously populated environments. Therefore, the mobile robot should be able to avoid or pass over small obstacles, passing through the capability to achieve specific person tracking tasks, and arriving to the need of operating with an high dynamic performance. Given its purpose, this work addresses the design of the suspension system which enables the platform to ensure a steady floor contact and adequate stability in every using condition. Different configurations of such system are then presented and compared through use-case simulations
Data-Driven Analysis of Locomotion for a Class of Articulated Mobile Robots
Full text linkIn the recent past, the use of autonomous vehicles is becoming of relevant interest in several fields of application. In many cases, the use of articulated structures is preferred to single chassis robots for their peculiar modularity. Such vehicles are often built as an active front module and a rear one that is pulled passively or that can contribute to the vehicle traction when required. Understanding whether this contribution is convenient or not is the main matter of this paper. Two different mobile robots of different scales and purposes are taken into consideration. A dynamic model is presented and analyzed. An experimental validation of the model parameters is also presented in order to make it exploitable as a reliable analysis tool. At last, a simple yet effective actuation law is tested for both the considered robots to evaluate whether the contribution of the back module is beneficial or not to the whole machine maneuverability
Modeling and Parametric Analysis of Quasi-Translational Parallel Continuum Manipulators
Full text linkTranslational Parallel Manipulators proved to be effective mechanisms in different application fields, from industries to haptic devices. The introduction of intrinsic flexibility within these mechanisms looks promising at increasing the safety of robots that are adopted in collaborative work-spaces. This paper focuses on the analysis of different types of Parallel Continuum Manipulator to find the better geometric structure to achieve quasi-translational motions. Therefore, the goal is to look for new flexible architectures that could be used instead of mechanisms composed by rigid links to improve safety in factories, in alignment with the United Nations Sustainable Development Goal 9: build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation
Surface phase transitions of Ge(111)c(2x8) studied by electron energy loss spectroscopy
No full textWe report the results of an electron energy loss spectroscopy (EELS) investigation of the Ge(111)c(2 x 8) surface at different temperatures, covering the three different phases previously observed for this system (c(2 x 8)[-](1 x 1)[-] surface premelting). In order to discriminate between bulk and surface losses, we used different primary beam energies (50-500 eV). Four loss features are revealed to be affected by the temperature. Results are discussed on the basis of a comparison with previous optical spectroscopy data and of the dielectric theory of EELS applied to a slab geometry
Preliminary observations for functional design of a mobile robotic manipulator
No full textThis paper presents the first steps approached for the functional design of a mobile robotic manipulator conceived for home assistance. The main characteristic of the mobile platform is that of owning an innovative architecture conceived to enhance the dynamics performance offered by the present-day solutions for omni-directional planar motions. The mobile robot, named Paquitop.arm, is aimed at working in a domestic unstructured environment and it has been designed to mainly perform monitoring activities. The variety of tasks to whom it can be devoted significantly increases if an on-board manipulation ability is installed. Due to that, it is worth investigating what aspects could be to be considered while designing such a mobile manipulator. The manuscript approaches a simplified kinematics analysis to define the most relevant parameters necessary for implementation of a commercial robot arm on the customized mobile platform Paquitop
Modelling and Experimental Validation of Articulated Mobile Robots with Hybrid Locomotion System
Full text linkIn recent years, autonomous vehicles and mobile robots are starting to become a trend also in several new fields of application. In some cases, they are articulated vehicles with an active front module and a rear one that is pulled passively or that can contribute to the vehicle traction when required. Although modelling of mobile robots is not a novelty, most of the available studies are limited to kinematic or very basic dynamic models. In order to correctly simulate mobile robots with fast dynamics or operating off-road, this study proposes a dynamic model of such systems derived taking into account lateral and longitudinal slip in the wheels. The model is then validated experimentally using a small articulated robot
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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