1,401 research outputs found
Stability and Transparency Analysis of a Teleoperation Chain For Microscale Interaction.
International audienceMicroscale teleoperation with haptic feedback requires scaling gains in the order of 104 107. These high gains impose a trade-off between stability and transparency. Due to the conservative approach used in most designs, transparency is reduced since damping is added to the system to guarantee stability. Starting from the fact that series, negative feedback and parallel connection of passive systems is a passive system, a new approach is addressed in this work. We propose here a complete teleoperation chain designed from the ground up for full transparency and stability, including a novel self-sensing probe and a high fidelity force-feedback haptic interface. By guaranteeing the passivity of each device and assuming that the human operator and the environment are passive systems, a homothetic direct coupling can be used without jeopardizing the stability and provides best transparency. The system is experimentally demonstrated in the complex case of a probe interacting with a water droplet under human control, while accurately transcribing the interaction back to operator
A framework for robotized teleoperated tasks
"Premio al mejor artĂculo presentado en ROBOT 2011" atorgat pel Grupo de RobĂłtica, VisiĂłn y Control de la Universidad de Sevilla, la Universidad Pablo Olavide i el Centro Avanzado de TecnologĂas Aeroespaciales.Teleoperation systems allow the extension of the
human operator’s sensing and manipulative capability into a
remote environment to perform tasks at a distance, but the
time-delays in the communications affect the stability and
transparency of such systems. This work presents a teleoperation
framework in which some novel tools, such as nonlinear
controllers, relational positioning techniques, haptic guiding
and augmented reality, are used to increase the sensation
of immersion of the human operator in the remote site.
Experimental evidence supports the advantages of the proposed
framework.Award-winningPostprint (published version
Miniaturized modular manipulator design for high precision assembly and manipulation tasks
In this paper, design and control issues for the development of miniaturized manipulators which are aimed to be used in high precision assembly and manipulation tasks are presented. The developed manipulators are size adapted devices, miniaturized versions of conventional robots based on well-known kinematic structures. 3 degrees of freedom (DOF) delta robot and a 2 DOF pantograph mechanism enhanced with a rotational axis at the tip and a Z axis actuating the whole mechanism are given as examples of study. These parallel mechanisms are designed and developed to be used in modular assembly systems for the realization of high precision assembly and manipulation tasks. In that sense, modularity is addressed as an important design consideration. The design procedures are given in details in order to provide solutions for miniaturization and experimental results are given to show the achieved performances
Complexity, rate, and scale in sliding friction dynamics between a finger and textured surface.
Sliding friction between the skin and a touched surface is highly complex, but lies at the heart of our ability to discriminate surface texture through touch. Prior research has elucidated neural mechanisms of tactile texture perception, but our understanding of the nonlinear dynamics of frictional sliding between the finger and textured surfaces, with which the neural signals that encode texture originate, is incomplete. To address this, we compared measurements from human fingertips sliding against textured counter surfaces with predictions of numerical simulations of a model finger that resembled a real finger, with similar geometry, tissue heterogeneity, hyperelasticity, and interfacial adhesion. Modeled and measured forces exhibited similar complex, nonlinear sliding friction dynamics, force fluctuations, and prominent regularities related to the surface geometry. We comparatively analysed measured and simulated forces patterns in matched conditions using linear and nonlinear methods, including recurrence analysis. The model had greatest predictive power for faster sliding and for surface textures with length scales greater than about one millimeter. This could be attributed to the the tendency of sliding at slower speeds, or on finer surfaces, to complexly engage fine features of skin or surface, such as fingerprints or surface asperities. The results elucidate the dynamical forces felt during tactile exploration and highlight the challenges involved in the biological perception of surface texture via touch
ERGOS: Multi-degrees of Freedom and Versatile Force-Feedback Panoply
International audienceThis paper deals with the design of a generic force feedback devices technology. System compactness, accessible number of degrees of freedom, morphology, resolution of the physical variables, frequency bandwidth are the main criteria the ERGOS technology answers to. This technology is successfully applied in two various fields: virtual bowed string instrument and nano-manipulator, applications presented in this paper
Active haptic perception in robots: a review
In the past few years a new scenario for robot-based applications has emerged. Service
and mobile robots have opened new market niches. Also, new frameworks for shop-floor
robot applications have been developed. In all these contexts, robots are requested to
perform tasks within open-ended conditions, possibly dynamically varying. These new
requirements ask also for a change of paradigm in the design of robots: on-line and safe
feedback motion control becomes the core of modern robot systems. Future robots will
learn autonomously, interact safely and possess qualities like self-maintenance. Attaining
these features would have been relatively easy if a complete model of the environment
was available, and if the robot actuators could execute motion commands perfectly
relative to this model. Unfortunately, a complete world model is not available and robots
have to plan and execute the tasks in the presence of environmental uncertainties which
makes sensing an important component of new generation robots. For this reason,
today\u2019s new generation robots are equipped with more and more sensing components,
and consequently they are ready to actively deal with the high complexity of the real
world. Complex sensorimotor tasks such as exploration require coordination between the
motor system and the sensory feedback. For robot control purposes, sensory feedback
should be adequately organized in terms of relevant features and the associated data
representation. In this paper, we propose an overall functional picture linking sensing
to action in closed-loop sensorimotor control of robots for touch (hands, fingers). Basic
qualities of haptic perception in humans inspire the models and categories comprising the
proposed classification. The objective is to provide a reasoned, principled perspective on
the connections between different taxonomies used in the Robotics and human haptic
literature. The specific case of active exploration is chosen to ground interesting use
cases. Two reasons motivate this choice. First, in the literature on haptics, exploration has
been treated only to a limited extent compared to grasping and manipulation. Second,
exploration involves specific robot behaviors that exploit distributed and heterogeneous
sensory data
Physically Interacting With Four Dimensions
Thesis (Ph.D.) - Indiana University, Computer Sciences, 2009People have long been fascinated with understanding the fourth
dimension. While making pictures of 4D objects by projecting them to 3D can help reveal basic geometric features, 3D graphics images by themselves are of limited value. For example, just as 2D shadows of 3D curves may have lines crossing one another in the shadow, 3D graphics projections of smooth 4D topological surfaces can be interrupted where one surface intersects another.
The research presented here creates physically realistic models for
simple interactions with objects and materials in a virtual 4D world.
We provide methods for the construction, multimodal exploration, and interactive manipulation of a wide variety of 4D objects. One basic achievement of this research is to exploit the free motion of a
computer-based haptic probe to support a continuous motion that
follows the \emph{local continuity\/} of a 4D surface, allowing collision-free exploration in the 3D projection. In 3D, this interactive probe follows the full local continuity of the surface as though we were in fact \emph{physically touching\/} the actual static 4D object.
Our next contribution is to support dynamic 4D objects that can move, deform, and collide with other objects as well as with themselves. By combining graphics, haptics, and collision-sensing physical modeling, we can thus enhance our 4D visualization experience. Since we cannot actually place interaction devices in 4D, we develop fluid methods for interacting with a 4D object in its 3D shadow image using adapted reduced-dimension 3D tools for manipulating objects embedded in 4D. By physically modeling the correct properties of 4D surfaces, their bending forces, and their collisions in the 3D interactive or haptic controller interface, we can support full-featured physical exploration of 4D mathematical objects in a manner that is otherwise far beyond the real-world experience accessible to human beings
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