Topic
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 published on a yearly basis
Papers
More filters
••
13 Oct 1998
TL;DR: The presented approach differs from previous ones in the selective use of precalculated lookup tables, and these are the key to efficiency, and they especially allow the use of any-shaped robot contours.
Abstract: This paper presents an efficient approach for reactive collision avoidance taking into account both vehicle dynamics and nonholonomic constraints of a mobile robot. Motion commands are generated by searching the space of actuating variables. Vehicle dynamics are considered by restricting the search space to values which are reachable within the next time step. The final selection among admissible configurations is done by an objective function which trades off speed, goal-directedness and remaining distance until an obstacle is hit when moving along the chosen path. The presented approach differs from previous ones in the selective use of precalculated lookup tables. These are the key to efficiency, and they especially allow the use of any-shaped robot contours. Furthermore, obstacle information from different sources can easily be considered without preprocessing. Extensive experiments on different robots have shown robust operation in dynamic and unprepared indoor environments with speed up to 1 m/s.
75 citations
••
TL;DR: In this paper, the authors considered reshaping a scattering obstacle virtually by using transformation optics in acoustic and electromagnetic scattering, and derived stability estimates for scattering amplitude in terms of the diameter of a small obstacle, which implies that the limiting case for minification corresponds to a perfect cloaking.
Abstract: We consider reshaping a scattering obstacle virtually by using transformation optics in acoustic and electromagnetic scattering. Among the general virtual reshaping results, the virtual minification and virtual magnification are particularly studied. Stability estimates are derived for scattering amplitude in terms of the diameter of a small obstacle, which implies that the limiting case for minification corresponds to a perfect cloaking, i.e., the obstacle is invisible to detection.
75 citations
••
01 Sep 2016TL;DR: In this article, the performance comparison of ultrasonic and infrared measurement techniques across obstacles of different types of materials was presented, based on the data acquired from the sensors, correlation analysis of the measured distance with actual distance performed.
Abstract: In robotics, Ultrasonic sensors and Infrared sensors are commonly used for distance measurement. These low-cost sensors fundamentally address majority of problems related to the obstacle detection and obstacle avoidance. In this paper, the performance comparison of ultrasonic and infrared measurement techniques across obstacles of different types of materials presented. The Vehicle model integrated with the sensors, moving with constant velocity towards different types of obstacles for capturing the distance parameter. Based on the data acquired from the sensors, correlation analysis of the measured distance with actual distance performed. This analysis will be very much useful, to select the right sensor - Ultrasonic sensor / Infrared sensor or a combination of both sensors, while developing the algorithm for addressing obstacle detection problems. The detection range and inherent properties of sensors (reflection/ absorption etc.) also were tested in this experiment.
75 citations
•
14 Mar 2013TL;DR: In this article, an obstacle detecting unit detects an obstacle for a user wearing a head mounted display from an image of the outside world, and an obstacle replacing unit replaces the detected obstacle with a virtual object.
Abstract: An obstacle detecting unit detects an obstacle for a user wearing a head mounted display from an image of the outside world. A distance calculating unit calculates the distance from a detected obstacle to the user wearing the head mounted display. An obstacle replacing unit replaces the detected obstacle with a virtual object. A virtual object synthesizing unit generates a virtual object at a position within a virtual space displayed on the head mounted display, in which the position is determined according to the distance to the obstacle.
74 citations
•
27 Jun 2006TL;DR: In this paper, a system and method for displaying obstacles in a conformal perspective view is presented, which consists of a display screen for graphical display of data, at least one obstacle data source, one or more graphics processors for receiving obstacle data from the at least 1 obstacle data sources, and for providing input to the display screen.
Abstract: A system and method for displaying obstacles in a conformal perspective view. The system comprises a display screen for graphical display of data, at least one obstacle data source, one or more graphics processors for receiving obstacle data from the at least one obstacle data source, and for providing input to the display screen. The display screen displays obstacles in a 3-dimensional graphical representation of real space. The display size of the obstacles varies based on the distance to the obstacles. Obstacles located beyond a selected distance are displayed as semi-transparent line objects and obstacles located within the selected distance are displayed as semi-transparent polygons.
74 citations