1,721,001 research outputs found
On the Use of Large Area Tactile Feedback for Contact Data Processing and Robot Control
No full textThe progress in microelectronics and embedded systems has recently enabled the realization of devices for robots functionally similar to the human skin, providing large area tactile feedback over the whole robot body.
The availability of such kind of systems, commonly referred to as extit{robot skins}, makes possible to measure the contact pressure distribution applied on the robot body over an arbitrary area.
Large area tactile systems open new scenarios on contact processing, both for control and cognitive level processing, enabling the interpretation of physical contacts.
The contents proposed in this thesis address these topics by proposing techniques exploiting large area tactile feedback for: (i) contact data processing and classification; (ii) robot control
Pressure Distribution Classification and Segmentation of Human Hands in Contact with the Robot Body
No full textThis paper deals with the problem of the recognition of human hand touch by a robot equipped with large area tactile
sensors covering its body. This problem is relevant in the domain of physical human-robot interaction for discriminating
between human and non-human contacts and to trigger and to drive cooperative tasks or robot motions, or to ensure a
safe interaction. The underlying assumption, used in this paper, is that voluntary physical interaction tasks involve hand
touch over the robot body, and therefore the capability of recognizing hand contacts is a key element to discriminate a
purposive human touch from other types of interaction.
The proposed approach is based on a geometric transformation of the tactile data, formed by pressure measurements
associated to a non uniform cloud of 3D points (taxels) spread over a non linear manifold corresponding to the robot
body, into tactile images representing the contact pressure distribution in 2D. Tactile images can be processed using
deep learning algorithms to recognize human hands and to compute the pressure distribution applied by the various
hand segments: palm and single fingers.
Experimental results, performed on a real robot covered with robot skin, show the effectiveness of the proposed
methodology. Moreover, to evaluate its robustness, various types of failures have been simulated. A further analysis
concerning the transferability of the system has been performed, considering contacts occurring on a different
sensorized robot part
Tactile Images Generation from Contacts Involving Adjacent Robot Links
No full textTactile data processing or classification is commonly performed using tactile images, i.e. two-dimensional representation of the applied contact. When tactile sensors cover the whole robot body, their relative spatial relations change depending on the robot posture. If the applied contact involves two adjacent links, the current relations among the tactile elements must be considered in order to generate a tactile image that preserves the contact shape. The goal of this paper is to propose a method for creating tactile images from pressure measurement acquired from a large area tactile system, where the relative displacement among the sensors fixed to different links change according to the robot posture. The proposed approach is experimentally validated using a Baxter robot equipped with distributed tactile sensors
Towards autonomous robotic skin spatial calibration: A framework based on vision and self-touch
No full textThis paper deals with the problem of estimating the pose of tactile elements (i.e. taxels) composing a robotic skin covering the whole body of a robot. This problem arises when a robot skin technology has to be integrated into an already existing robotic platform. To date, the integration process is done by hand and it is not possible to predict where the sensor will be placed on the robot body. This paper presents a novel approach based on a RGB-D camera and exploiting the motion capabilities of the robot for activating the skin sensors. The method uses the measurements of the camera to reconstruct the unknown robot body outer shape and to compute how the area can be touched by the robot. The taxels responses and the related contact centroids are used for estimating the position of the sensors. Our method is based on few assumptions and is a step towards a calibration procedure that can be executed autonomously by a robot. Experiments performed on the Baxter robotic platform demonstrate the effectiveness of the presented approach obtaining an average position error less than 2mm
Enabling natural human-robot physical interaction using a robotic skin feedback and a prioritized tasks robot control architecture
No full textThis paper describes a procedure aimed to integrate tactile sensors into a real robot in order to create a platform suitable for human-robot physical interaction experiments. Furthermore, a framework for human-robot physical interaction based on tactile feedback and prioritized tasks control is presented. The framework has been successfully tested by defining and executing three physical interaction tasks. A further experiment has been performed, simulating a human intervention during a task execution
Human hand recognition from robotic skin measurements in human-robot physical interactions
No full textThis paper presents the design and development of a novel tactile sensor system for clothes manipulation and perception using industrial grippers. The proposed system consists of a multi-modal tactile sensor and embedded re-programmable interface electronics. The sensing element features a matrix of capacitive pressure sensors, a microphone for acoustic measurements, and a proximity and ambient light sensor. The sensor is fully embedded and can be easily integrated at mechanical and electrical levels with industrial grippers. Tactile sensing design has been put on the same level of additional requirements, such as the mechanical interface, cable harness, and robustness against continuous and repetitive operations, just to name but a few. The performances of the different sensing modalities have been experimentally assessed using a test rig for tactile sensors and the system has been successfully integrated and tested on a real robotic gripper. Experiments have been performed in order to show the capabilities of the sensor for implementing tactile-based industrial gripper control
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
A Magnetorheological Elastomer‐Based Proportional Valve for Soft Pneumatic Actuators
Full text linkThe interest in soft pneumatic actuators has been growing rapidly in robotics, owing to the contact adaptability with the material softness. However, these actuators are mostly controlled by rigid electronic pneumatic valves, which can hardly be integrated into the robot itself, limiting its mobility and adaptability. Recent advances in soft or electronics‐free valve designs provide the potential to achieve an integrated soft robotic system with reduced weight and rigidity. Nevertheless, the challenge in valve response remains open. To enable dynamic control of a soft pneumatic actuator (SPA), a fast‐response proportional valve is needed. Herein, the potential of Ecoflex‐based magnetorheological elastomer (MRE) membrane to create a proportional valve that can be used in the control of a soft robot made from the same silicone material is explored. Experimental characterization shows that the proposed MRE valve (30 mm × 30 mm × 15 mm, 30 grams) can hold pressure up to 41.3 kPa and regulate the airflow in an analog manner. The valve is used to perform closed‐loop proportional–integral–differential (PID) control with 50 Hz on a SPA and is able to control the pressure within the actuator chamber with a root‐mean‐square error of 0.05 kPa
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