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In this work, lead magnesium niobate-lead titanate (1−x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 ((1−x)PMN-xPT) thin films with PT-fractions of 6.5 to 20% were fabricated on Pt(111)-coated Si wafers by multi-target reactive sputtering using four metallic targets (Pb, Mg, Nb, Ti). In order to increase the dielectric strength, co-doping with Mn was performed by co-sputtering of MnO targets. The electrocaloric temperature...
In this work, lead magnesium niobate-lead titanate (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3(PMN-PT) thin films with PT-fractions of 6.5 to 20% were fabricated on Pt(111)-coated Si wafers for the first time by multitarget reactive sputtering using four metallic targets (Pb, Mg, Nb, Ti).
In this work, lead magnesium niobate-lead titanate (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3(PMN-PT) thin films with PT-fractions of 6.5 to 20% were fabricated on Pt(111)-coated Si wafers for the first time by multitarget reactive sputtering using four metallic targets (Pb, Mg, Nb, Ti).
Large area film deposition was performed by means of multitarget reactive magnetron sputtering from 200 mm diameter metallic targets (Pb, Ti, Zr) onto Cu-coated Kapton HN substrates. High-power pulse sputtering has been employed for the Zr-target (or alternatively for the Ti-target). Film composition profiles were evaluated by XPS and RBS. Piezoelectric properties were investigated by PFM.
We consider the problem of computing trajectories for a team of of coordinated unmanned aerial vehicles (UAVs) in large and complex 2D and 2.5D environments to guarantee the detection of any evading target. Our approach is based on the coordination of 2D sweep lines that move through the environment to clear it from all contamination, representing the possibility of a target being located in an area,...
The goal of the paper is to present the foreseen research activity of the European project “SHERPA” whose activities will start officially on February 1th 2013. The goal of SHERPA is to develop a mixed ground and aerial robotic platform to support search and rescue activities in a real-world hostile environment, like the alpine scenario that is specifically targeted in the project. Looking into the...
In this work, we investigate the composition profile of nanocrystalline Pb(Zr, Ti)O3 (PZT) thin films deposited by means of reactive magnetron sputtering from 200 mm diameter metallic targets (Pb, Ti, Zr). High-power pulse sputtering has been employed for alternatively the Zr- or Ti-target. Composition analysis and profiling was performed by means of X-ray photoelectron spectroscopy (XPS) and Rutherford...
We address the problem of searching for moving targets in large outdoor environments represented by height maps. To solve the problem we present a complete system that computes from an annotated height map a graph representation and search strategies based on worst-case assumptions about all targets. These strategies are then used to compute a schedule and task assignment for all agents. We improve...
In this paper we present an approach for a pursuit-evasion problem that considers a 2.5d environment represented by a height map. Such a representation is particularly suitable for large-scale outdoor pursuit-evasion, captures some aspects of 3d visibility and can include target heights. In our approach we construct a graph representation of the environment by sampling strategic locations and computing...
Teleoperation is a difficult task, particularly when controlling robots from an isolated operator station. In general, the operator has to solve ??nearly blindly?? the problems of mission planning, target identification, robot navigation, and robot control at the same time. The goal of the proposed system is to support teleoperated navigation with real-time mapping. We present a novel scan matching...
In this paper, we address the problem of creating an objective benchmark for comparing SLAM approaches. We propose a framework for analyzing the results of SLAM approaches based on a metric for measuring the error of the corrected trajectory. The metric uses only relative relations between poses and does not rely on a global reference frame. The idea is related to graph-based SLAM approaches in the...
C&C Technologies in Lafayette, LA in cooperation with the Naval Research Laboratory (NRL) Mapping, Charting and Geodesy Branch at Stennis Space Center, MS and Autonomous Surface Vehicles, Ltd. in W. Sussex, UK, is implementing a multiyear development program of an unmanned semi-submersible (USS) vehicle. Originally sponsored by the National Oceanic and Atmospheric Administration (NOAA), the goal...
We consider the problem of Decentralized Simultaneous Localization And Mapping (DSLAM) for pedestrians in the context of Urban Search And Rescue (USAR). In this context, DSLAM is a challenging task. First, data exchange fails due to cut off communication links. Second, loop-closure is cumbersome due to the fact that firefighters will intentionally try to avoid performing loops when facing the reality...
To autonomously navigate on rough terrain is a challenging problem for mobile robots, requiring the ability to decide whether parts of the environment can be traversed or have to be bypassed, which is commonly known as Obstacle Negotiation (ON). In this paper, we introduce a planning framework that extends ON to the general case, where different types of terrain classes directly map to specific robot...
One primary goal in rescue robotics is to deploy a team of robots for coordinated victim search after a disaster. This requires robots to perform sub- tasks, such as victim detection, in real-time. Human detection by computationally cheap techniques, such as color thresholding, turn out to produce a large number of false-positives. Markov Random Fields (MRFs) can be utilized to combine the local evidence...
To autonomously navigate on rough terrain is a challenging problem for mobile robots, requiring the ability to decide whether parts of the environment can be traversed or have to be bypassed, which is commonly known as obstacle negotiation (ON). In this video we show the robot's ability to map, detect and negotiate obstacles. The first part shows the robot exploring a test arena, that contains a pallet...
We consider the problem of jointly performing SLAM by humans and robots in Urban Search And Rescue (USAR) scenarios. In this context, SLAM is a challenging task. First, places are hardly re-observable by vision techniques since visibility might be affected by smoke and fire. Second, loop-closure is cumbersome due to the fact that fire fighters will intentionally try to avoid performing loops when...
To coordinate a team of robots for exploration is a challenging problem, particularly in large areas as for example the devastated area after a disaster. This problem can generally be decomposed into task assignment and multi-robot path planning. In this paper, we address both problems jointly. This is possible because we reduce significantly the size of the search space by utilizing RFID tags as...
Robot search and rescue is a time critical task, i.e. a large terrain has to be explored by multiple robots within a short amount of time. The efficiency of exploration depends mainly on the coordination between the robots and hence on the reliability of communication, which considerably suffers under the hostile conditions encountered after a disaster. Furthermore, rescue robots have to generate...
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