1,720,965 research outputs found
Studio ed ottimizzazione di sistemi di automazione flessibile
Full text linkNowadays, the market is characterized by products which are increasingly varied and with short life cycles. To adapt to this environment and to remain competitive on an international level, many companies are adopting the use of flexible assembly systems (FAS). These systems must also guarantee a high productivity at a low unit cost, which requires the development of new technology for modern assembly systems.
In addition to flexibility of the product, that is the possibility to manage different components with the same automation, there is a strong need on an industrial level to arrange hardware and software in order to increase the flexibility of layout of robotized cells, with features of being able to reconfigure the workplace in a short period of times.
Infact, with each amendment to the layout of the work-cell, for example to substitute components with different obstacles, the integration of further modules and subsystems, it is necessary to complete certain operations like the redefinition of the via point, the redefinition of the work cycle and the recalibration of the sensors utilized. Furthermore, it is necessary to pay a great deal of attention to the problem of collisions of the robot, given the presence of potentially new obstacles. All of these operations require specialized personnel, time, and subsequently an interruption in production.
In this PhD Thesis, focusing on the flexibility of layout, some solutions have been studied and implemented in order to achieve more rapid and more intuitive operations of updating of the configuration of a robotized cell, without needing to use highly specialized personnel.
The solutions developed regard the rapid procedures for the calibration of industrial television-cameras, tools for a three-dimensional overview of the workplace and the importation of such in the environment of commercial CAD. A robotic simulator allows off-line navigation of the manipulator in the acquired geometry, the off-line memorization of the robot trajectories and via points, in addition to handling of data of the work cycle in real time inside of the CAD space.
In the face of some studies conducted in the Rehabilitation And Robotics (ROAR) laboratory at Columbia University in the city of New York, NY, USA, under the supervision of Prof. S. K. Agrawal, a shoe device is described which is able to provide feedback of audio and tactile sensory information nature giving spacial-time measurements of the walk which could be utilized to estimate the position of the operator inside of a robotic cell for safety applications.
In conclusion, for rapid and intuitive movement of industrial robots, the design and making of a impugnable device based on MEMS sensors is presented
Sophia-3: a semi-adaptive cable-driven rehabilitation device with tilting working plane
No full textSophia-3 (String Operated Planar Haptic Interface for Armrehabilitation) is a planar cable-driven device with a tilting working plane.
It represents the first application of the adaptive cable-driven design paradigm recently introduced by the authors, featuring a moving pulley-block that allows the robot to achieve excellent force capabilities despite the low number of cables.
This work presents the design, kinematics and control of the device, and results of experimental validation on healthy subject
Design and construction of a variable-aperture gripper for flexible automated assembly
No full textThe growing market demand for a wide variety of product models and small batch production makes flexible
robotized production systems an emerging need in industry. Today, in manufacturing applications, general
purpose grippers are not very considered, and robot end effectors are properly designed for the specific task with
a strongly limited versatility. Flexibility is thus usually obtained by using a different tool for each family of parts:
a tool changing system allows the robot to rapidly replace the tool on the end effector; tools are stored in a tool
magazine allocated in the workcell. However, such systems are expensive and their use can affect the working
cycle-time. This paper presents the design and testing of a variable-aperture, cost-effective gripper, capable of
adapting its aperture (grasp width) to different handling demands, without affecting the working-cycle time of
the production system. The solution proposed consists of (1) an electrically-actuated mechanism, which allows
it to satisfy flexibility requirements, by regulating the aperture in hidden time; (2) a pneumatically-actuated
mechanism to achieve high performance in open/close operations. Simulations and preliminary tests showed
that this type of design can be a suitable solution to increase flexibility in robotized workcells without increasing
the cycle time
Emotion Rendering in Plantar Vibro-Tactile Simulations of Imagined Walking Styles
No full textThis paper investigates the production and identification of emotional states of a walker using plantar vibro-tactile simulations. In a first experiment, participants were asked to render, according to imagined walking scenarios, five emotions (aggressive, happy, neutral, sad, and tender) by manipulating the parameters of synthetic footstep vibrations simulating various combinations of surface materials and shoes. Results allowed to identify, for the involved emotions and vibration conditions, the mean values and ranges of variation of two parameters, vibration amplitude and temporal distance between consecutive steps. Results were in accordance with those reported in previous studies on real walking, suggesting that the plantar vibro-tactile expression of emotions in walking is independent of the real or imagined motor activity. In a second experiment, participants were asked to identify the emotions portrayed by walking vibrations synthesized by setting the synthesis engine parameters to the mean values found in the first experiment. Results showed that the involved algorithms were successful in conveying the emotional information at a level comparable with previous studies. Results of both experiments revealed strong similarities with those of an analogous study on footstep sounds suggesting that emotionally expressive walking styles are consistently produced and recognized at auditory and plantar vibro-tactile level
Trajectory planning of a suspended cable driven parallel robot with reconfigurable end effector
No full textIn this paper, a new suspended cable driven parallel robot (CDPR) with reconfigurable end effector is presented. This robot has been conceived for pick and place operations in industrial environments. For such applications, the possibility to change the configuration of the cables at the end-effector level is a promising way to avoid collisions with obstacles in the approaching phases, while reducing at the same time the duration of motion in the remaining part of the trajectory. An optimized trajectory planning algorithm is proposed, which implements a pick and place operation in the operational space with dynamic on-line reconfiguration of the end effector. The results on a simplified scenario demonstrate the ability of the system to obtain reduced movement times together with obstacle avoidance
Optimized trajectory planning of pick and place operations to be performed by cable-driven parallel robots
No full text
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
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