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Obstacle

About: Obstacle is a research topic. Over the lifetime, 9517 publications have been published within this topic receiving 94760 citations. The topic is also known as: impediment & barrier.


Papers
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Journal ArticleDOI
TL;DR: A path-planning method that has been developed for serial manipulators is adapted to cable-driven robots and guarantees finding a path, when it exists, no matter how cluttered the environment is.

86 citations

Journal ArticleDOI
TL;DR: In this article, two approaches for the Lp-theory of Navier-Stokes flow in the exterior of a moving or rotating obstacle are described, and the approaches are compared.
Abstract: In this paper we describe two recent approaches for the Lp-theory of the Navier-Stokes flow in the exterior of a moving or rotating obstacle.

86 citations

Posted Content
TL;DR: The proposed algorithm performs statistical hypothesis tests in disparity space directly on stereo image data, assessing freespace and obstacle hypotheses on independent local patches and outperforms all considered baselines in evaluations on both pixel and object level.
Abstract: Detecting small obstacles on the road ahead is a critical part of the driving task which has to be mastered by fully autonomous cars. In this paper, we present a method based on stereo vision to reliably detect such obstacles from a moving vehicle. The proposed algorithm performs statistical hypothesis tests in disparity space directly on stereo image data, assessing freespace and obstacle hypotheses on independent local patches. This detection approach does not depend on a global road model and handles both static and moving obstacles. For evaluation, we employ a novel lost-cargo image sequence dataset comprising more than two thousand frames with pixelwise annotations of obstacle and free-space and provide a thorough comparison to several stereo-based baseline methods. The dataset will be made available to the community to foster further research on this important topic. The proposed approach outperforms all considered baselines in our evaluations on both pixel and object level and runs at frame rates of up to 20 Hz on 2 mega-pixel stereo imagery. Small obstacles down to the height of 5 cm can successfully be detected at 20 m distance at low false positive rates.

86 citations

Journal ArticleDOI
TL;DR: PD hypokinesia compromises the approach and crossing phases of obstacle negotiation, both in the approaching and crossing phase.

86 citations

Journal ArticleDOI
TL;DR: In this article, it is shown how near-grazing systems, i.e. systems in which the impacts take place at low speed, can be described by discrete mappings.
Abstract: Impacting systems are found in a great variety of mechanical constructions and they are intrinsically nonlinear. In this paper it is shown how near-grazing systems, i.e. systems in which the impacts take place at low speed, can be described by discrete mappings. The derivation of this mapping for a harmonic oscillator with a stop is dealt with in detail. It is found that the resulting mapping for rigid obstacles is somewhat different from those presented earlier in the literature. The derivations are extended to systems with a compliant obstacle. We find that the map for impacts with a compliant obstacle is very similar to the one describing collisions with a rigid obstacle. A notable difference is a change of scale of the bifurcation parameter. We illustrate our findings in the limit of large damping, where the mechanism of period adding can be analysed exactly. The relevance of our results to experiments on practical impact systems is indicated.

85 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
20231,483
20223,389
2021407
2020817
2019873