-
[show abstract]
[hide abstract]
ABSTRACT: In this overview paper we present current work on safety analysis for physical Human-Robot Interaction (pHRI) and motion control methods for robotic co-workers. In particular, we introduce the analysis tools for investigating the potential injury a human would suffer during robot-human impacts. Furthermore, we outline our concept for establishing a procedure towards standardized crash testing in robotics with automobile crash-test dummies. Since it is only possible to investigate blunt impacts with these devices, we developed a drop testing setup for analyzing soft-tissue injury in robotics from a biomechanics perspective. In the second part of the paper, some of our methods for task preserving and task relaxing motion schemes are described, which enable collision avoidance in real-time. The algorithms are well suited to work in an integrated fashion with the soft robotics control developed for the DLR Lightweight Robot III (LWR-III). In addition, it is shown how the torque sensing capabilities of the robot can be used to support reactive motion schemes. Finally, an overview of our human-friendly control architecture for the LWR-III is given, which unifies the rich bundle of developed methods for this manipulator.
Intelligent Robots and Systems (IROS), 2010 IEEE/RSJ International Conference on; 11/2010
-
Applied Physics Letters 10/2009; 95(17):179902-179902-1. · 3.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Current-induced domain wall (DW) displacements in an array of ultrathin Pt/Co/AlOx wires with perpendicular magnetic anisotropy have been directly observed by wide field Kerr microscopy. DWs in all wires in the array were driven simultaneously and their displacement on the micrometer scale was controlled by the current pulse amplitude and duration. At the lower current densities where DW displacements were observed (j≤1.5×10<sup>12</sup> A / m <sup>2</sup>) , the DW motion obeys a creep law. At higher current density (j=1.8×10<sup>12</sup> A / m <sup>2</sup>) , zero-field average DW velocities up to 130±10 m / s were recorded.
Applied Physics Letters 01/2009; · 3.84 Impact Factor
-
A. Manchon,
C. Ducruet,
L. Lombard,
S. Auffret,
B. Rodmacq,
B. Dieny,
S. Pizzini, J. Vogel,
V. Uhlir,
M. Hochstrasser,
G. Panaccione
[show abstract]
[hide abstract]
ABSTRACT: Extraordinary Hall effect and x-ray spectroscopy measurements have been performed on a series of Pt / Co /M Ox trilayers ( M= Al , Mg, Ta, etc.) in order to investigate the role of oxidation in the onset of perpendicular magnetic anisotropy at the Co /M Ox interface. It is observed that varying the plasma oxidation time modifies the magnetic properties of the Co layer, inducing a magnetic anisotropy crossover from in plane to out of plane. We focused on the influence of plasma oxidation on Pt/Co/AlOx perpendicular magnetic anisotropy. The interfacial electronic structure is analyzed via x-ray photoelectron spectroscopy measurements. It is shown that the maximum of out-of-plane magnetic anisotropy corresponds to the appearance of a significant density of Co–O bondings at the Co/AlOx interface.
Journal of Applied Physics 09/2008; · 2.17 Impact Factor
-
A. Manchon,
S. Pizzini, J. Vogel,
V. Uhlîr,
L. Lombard,
C. Ducruet,
S. Auffret,
B. Rodmacq,
B. Dieny,
M. Hochstrasser,
G. Panaccione
[show abstract]
[hide abstract]
ABSTRACT: X-ray spectroscopy measurements have been performed on a series of Pt/Co/AlOx trilayers to investigate the role of Co oxidation in the perpendicular magnetic anisotropy at the Co/AlOx interface. It is observed that varying the degree of oxidation modifies the magnetic properties of the Co layer, inducing a magnetic anisotropy crossover from in plane to out of plane. The microscopic structural properties are analyzed via x-ray photoelectron spectroscopy measurements. It is shown that increasing the oxidation time enhances the amount of interfacial oxide, which may be at the origin of perpendicular magnetic anisotropy.
Journal of Applied Physics 03/2008; 103(7):07A912-07A912-3. · 2.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Soft x-ray resonant magnetic scattering has been used to investigate the element-selective microscopic magnetization reversal behavior of room temperature perpendicular exchange coupled ferromagnetic/antiferromagnetic (F/AF) systems and to study the role of the interfacial coupling strength on it. Different nucleation processes and domain size distributions along the decreasing and increasing branches of the reversal have been found. The size of the magnetic domains during reversal depends on both the F anisotropy and F/AF coupling strength, decreasing when one of them increases. Evidence of the exchange bias (coercivity enhancement) being induced by pinned (unpinned) uncompensated AF interfacial spins is also shown.
Applied Physics Letters 01/2007; · 3.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In content-based image retrieval (CBIR) performance characterization is easily being neglected. A major difficulty lies in
the fact that ground truth and the definition of benchmarks are extremely user and application dependent. This paper proposes
a two-stage CBIR framework which allows to predict the behavior of the retrieval system as well as to optimize its performance.
In particular, it is possible to maximize precision, recall, or jointly precision and recall. The framework is based on the
detection of high-level concepts in images. These concepts correspond to vocabulary users can query the database with. Performance
optimization is carried out on the basis of the user query, the performance of the concept detectors, and an estimated distribution
of the concepts in the database. The optimization is transparent to the user and leads to a set of internal parameters that
optimize the succeeding retrieval. Depending only on the query and the desired concept, precision and recall of the retrieval
can be increased by up to 40%. The paper discusses the theoretical and empirical results of the optimization as well as its
dependency on the estimate of the concept distribution.
12/2001: pages 51-55;
-
[show abstract]
[hide abstract]
ABSTRACT: The majority of today's content based image retrieval systems rely
on low-level image descriptors which limit their capability to support
meaningful interactions with the users. Even though relevance feedback
helps, most of the current interaction paradigms are far from the
semantic representations which most people use to categorize and
describe image content. Therefore we propose a concept called
"vocabulary-supported image retrieval" which aims to enable the user to
access an image database in a more natural way. In particular this paper
develops a technique to predict the system's performance with respect to
the user query. This allows the system to translate the user query into
an internal query which may satisfy predefined criteria such as
precision and recall rates. In addition, given the performance
parameters of the system's sub-components, the feasibility and the
success of the retrieval process can be evaluated beforehand and
optimized dynamically online
Image Processing, 2001. Proceedings. 2001 International Conference on; 11/2001
-
[show abstract]
[hide abstract]
ABSTRACT: Magnetic properties of amorphous Er 1-x Fe x alloys with x≊0.7 have been studied. Macroscopic characterization has been performed by measuring temperature‐ and field‐dependent magnetization. Applying a magnetic field the compensation temperature first decreases, but increases again at larger fields. This ‘‘exotic’’ behavior has been interpreted in terms of the sperimagnetic character of both subnetworks. The suggested scheme has been checked by measuring x‐ray circular magnetic dichroism at the Er M 5 ‐edge. Using this atom‐sensitive technique we have been able to detect temperature‐induced as well as field‐induced flips of the Er‐subnetwork with respect to the direction of the applied field. © 1996 American Institute of Physics.
Journal of Applied Physics 05/1996; · 2.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We have investigated the relationship between deposition process and mechanical properties of metal+carbon coatings of three different metals. We used a conventional sputtering system, equipped with planar magnetrons, whose configuration can be scaled up easily to an industrial batch coater. Metal as well as carbide targets were compared and acetylene was used as a reactive gas. The films were deposited onto substrates made of a high‐speed steel. Internal stresses were determined by measuring mechanically the flexture of a thin disk. The variation of the mechanical properties, internal stress, and hardness were completely different for the three metals.
Journal of Vacuum Science & Technology A Vacuum Surfaces and Films 02/1987; · 1.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Dimigen and Hübsch discovered that carbon‐rich metal/carbon coatings that are deposited with a process combining reactive magnetron sputtering with plasma activated chemical vapor deposition show promising tribological properties. We investigated some of these for metal/carbon compounds of chromium, tungsten, and titanium of different stoichiometry. Friction coefficients against high‐carbon low‐alloy steel were measured in a three pin‐on‐disk configuration. Three‐body wear resistance was evaluated using a modification of the three pin‐on‐disk equipment, where a polishing powder suspension was fed continuously into the tribocontact. The results showed a strong dependence of the tribological properties on composition. The variation in the three‐body wear resistance of tungsten carbon compounds agreed with Rabinowicz’s model for the dependence on Vickers hardness.
Journal of Vacuum Science & Technology A Vacuum Surfaces and Films 12/1986; · 1.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Performance improvements to cutting tools through the use of ion plated coatings are discussed as they relate to the quality of tools used, the specific geometry, and the material type of tool to be coated, as well as variations inherent in the coating process. Current state of the art for mass producing coated tools and the difficulties in quality assurance of tools having different geometries and end purposes is reviewed. Numerous examples are given showing the important aspects of tool condition on tool performance, such as surface roughness, presence of burrs, oxide layers, internal segregation, and heat treatment residues. Extensive data on coated tool life, types of failure, and performance as well as the range of tool material types presently considered suitable for coating are given.
Journal of Vacuum Science & Technology A Vacuum Surfaces and Films 12/1986; · 1.25 Impact Factor
-
pages 614-642;
-
[show abstract]
[hide abstract]
ABSTRACT: Coated metal-cutting tools that did not perform to expectations were analysed for the reasons of their premature failure. These tools investigated stem from two sources: regular users of coated tools who noticed a premature failure of a single tool or a production lot or first users who were disappointed not to obtain the expected performance gains. Optical microscopy, adhesion tests, metallography, scanning electron microscopy, energy-dispersive X-ray analysis, Auger spectroscopy, secondary ion mass spectrometry and drilling with reference tools were used as methods of investigation. Reasons for premature failure are related to the following: substrate material selection, metallurgy and heat treatment; tool manufacturing with respect to edge finish, surface finish and presence of Beilby layers; the various steps of the coating process (pretreatment, heating, etching, coating and conditioning); end user. Coating wear (intrinsic) is not treated in this analysis. The method is demonstrated with 11 case studies.
Thin Solid Films 153:219-231. · 1.89 Impact Factor
