13 research outputs found
Learning of Generalized Manipulation Strategies in Service Robotics
This thesis makes a contribution to autonomous robotic manipulation. The core is a novel constraint-based representation of manipulation tasks suitable for flexible online motion planning. Interactive learning from natural human demonstrations is combined with parallelized optimization to enable efficient learning of complex manipulation tasks with limited training data. Prior planning results are encoded automatically into the model to reduce planning time and solve the correspondence problem
Heuristic-free Optimization of Force-Controlled Robot Search Strategies in Stochastic Environments
In both industrial and service domains, a central benefit of the use of
robots is their ability to quickly and reliably execute repetitive tasks.
However, even relatively simple peg-in-hole tasks are typically subject to
stochastic variations, requiring search motions to find relevant features such
as holes. While search improves robustness, it comes at the cost of increased
runtime: More exhaustive search will maximize the probability of successfully
executing a given task, but will significantly delay any downstream tasks. This
trade-off is typically resolved by human experts according to simple
heuristics, which are rarely optimal. This paper introduces an automatic,
data-driven and heuristic-free approach to optimize robot search strategies. By
training a neural model of the search strategy on a large set of simulated
stochastic environments, conditioning it on few real-world examples and
inverting the model, we can infer search strategies which adapt to the
time-variant characteristics of the underlying probability distributions, while
requiring very few real-world measurements. We evaluate our approach on two
different industrial robots in the context of spiral and probe search for THT
electronics assembly.Comment: 7 pages, 5 figures, accepted to the 2022 IEEE/RSJ International
Conference on Intelligent Robots and Systems (IROS 2022), Kyoto, Japan For
code and data, see https://github.com/benjaminalt/dps
LapSeg3D: Weakly Supervised Semantic Segmentation of Point Clouds Representing Laparoscopic Scenes
The semantic segmentation of surgical scenes is a prerequisite for task automation in robot assisted interventions. We propose LapSeg3D, a novel DNN-based approach for the voxel-wise annotation of point clouds representing surgical scenes. As the manual annotation of training data is highly time consuming, we introduce a semi-autonomous clustering-based pipeline for the annotation of the gallbladder, which is used to generate segmented labels for the DNN. When evaluated against manually annotated data, LapSeg3D achieves an F1 score of 0.94 for gallbladder segmentation on various datasets of ex-vivo porcine livers. We show LapSeg3D to generalize accurately across different gallbladders and datasets recorded with different RGB-D camera systems
LapSeg3D: Weakly Supervised Semantic Segmentation of Point Clouds Representing Laparoscopic Scenes
The semantic segmentation of surgical scenes is a prerequisite for task
automation in robot assisted interventions. We propose LapSeg3D, a novel
DNN-based approach for the voxel-wise annotation of point clouds representing
surgical scenes. As the manual annotation of training data is highly time
consuming, we introduce a semi-autonomous clustering-based pipeline for the
annotation of the gallbladder, which is used to generate segmented labels for
the DNN. When evaluated against manually annotated data, LapSeg3D achieves an
F1 score of 0.94 for gallbladder segmentation on various datasets of ex-vivo
porcine livers. We show LapSeg3D to generalize accurately across different
gallbladders and datasets recorded with different RGB-D camera systems.Comment: 6 pages, 5 figures, accepted at the 2022 IEEE/RSJ International
Conference on Intelligent Robots and Systems (IROS 2022), Kyoto, Japa
A low complex and efficient coexistence approach for non-coherent multiband impulse radio UWB
When bringing a high data rate multiband impulse radio UWB system to the market it has to coexist with other already existing UWB technologies such as multiband OFDM UWB. This paper analyzes the interference impact of a multiband OFDM UWB system on a non-coherent multiband impulse radio UWB system. It is shown that the impact can be so dominant that communication within the impulse based multiband UWB system gets worse. For this reason a static as well as a dynamic coexistence approach are considered. The dynamic approach uses an efficient, robust and easy to realize pixel based interference detection algorithm in conjunction with an adapted bandplan array. In comparison to the static approach, the dynamic coexistence approach allows higher data rates during data transmission phases without significant losses in bit error rate performance
Microlocal analysis of quantum fields on curved spacetimes: Analytic wavefront sets and Reeh-Schlieder theorems
We show in this article that the Reeh-Schlieder property holds for states of
quantum fields on real analytic spacetimes if they satisfy an analytic
microlocal spectrum condition. This result holds in the setting of general
quantum field theory, i.e. without assuming the quantum field to obey a
specific equation of motion. Moreover, quasifree states of the Klein-Gordon
field are further investigated in this work and the (analytic) microlocal
spectrum condition is shown to be equivalent to simpler conditions. We also
prove that any quasifree ground- or KMS-state of the Klein-Gordon field on a
stationary real analytic spacetime fulfills the analytic microlocal spectrum
condition.Comment: 31 pages, latex2
Identification of Novel Rodent Herpesviruses, Including the First Gammaherpesvirus of Mus musculusâ–¿
Rodent herpesviruses such as murine cytomegalovirus (host, Mus musculus), rat cytomegalovirus (host, Rattus norvegicus), and murine gammaherpesvirus 68 (hosts, Apodemus species) are important tools for the experimental study of human herpesvirus diseases. However, alphaherpesviruses, roseoloviruses, and lymphocryptoviruses, as well as rhadinoviruses, that naturally infect Mus musculus (house mouse) and other Old World mice are unknown. To identify hitherto-unknown rodent-associated herpesviruses, we captured M. musculus, R. norvegicus, and 14 other rodent species in several locations in Germany, the United Kingdom, and Thailand. Samples of trigeminal ganglia, dorsal root ganglia, brains, spleens, and other organs, as well as blood, were analyzed with a degenerate panherpesvirus PCR targeting the DNA polymerase (DPOL) gene. Herpesvirus-positive samples were subjected to a second degenerate PCR targeting the glycoprotein B (gB) gene. The sequences located between the partial DPOL and gB sequences were amplified by long-distance PCR and sequenced, resulting in a contiguous sequence of approximately 3.5 kbp. By DPOL PCR, we detected 17 novel betaherpesviruses and 21 novel gammaherpesviruses but no alphaherpesvirus. Of these 38 novel herpesviruses, 14 were successfully analyzed by the complete bigenic approach. Most importantly, the first gammaherpesvirus of Mus musculus was discovered (Mus musculus rhadinovirus 1 [MmusRHV1]). This virus is a member of a novel group of rodent gammaherpesviruses, which is clearly distinct from murine herpesvirus 68-like rodent gammaherpesviruses. Multigenic phylogenetic analysis, using an 8-kbp locus, revealed that MmusRHV1 diverged from the other gammaherpesviruses soon after the evolutionary separation of Epstein-Barr virus-like lymphocryptoviruses from human herpesvirus 8-like rhadinoviruses and alcelaphine herpesvirus 1-like macaviruses