scispace - formally typeset
Search or ask a question
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
More filters
Journal ArticleDOI
01 Dec 1998
TL;DR: In this article, the authors presented a new reliable methodology for robot navigation and obstacle avoidance based on the artificial potential field (APF) method, which is used extensively for obstacle avoidance.
Abstract: This paper presents a summary of the research aimed at developing a new reliable methodology for robot navigation and obstacle avoidance. This new approach is based on the artificial potential field (APF) method, which is used extensively for obstacle avoidance. The classical APF is dependent only on the separation distance between the robot and the surrounding obstacles. The new scheme introduces a variable, which is used to determine the importance that each obstacle has on the robot's future path. The importance variable is dependent on the obstacles position, both angle and distance, with respect to the robot. Simulation results are presented demonstrating the ability of the algorithm to perform successfully in simple environments.

28 citations

Proceedings ArticleDOI
10 Dec 2014
TL;DR: An on-road objects detection approach improved by previous work in defining the traffic area and new strategy in obstacle extraction from U-disparity is presented, which is effective and reliable when applied on different traffic video sequences from a public database.
Abstract: Vision systems provide a large functional spectrum for perception applications and, in recent years, they have demonstrated to be essential in the development of Advanced Driver Assistance Systems (ADAS) and Autonomous Vehicles. In this context, this paper presents an on-road objects detection approach improved by our previous work in defining the traffic area and new strategy in obstacle extraction from U-disparity. Then, a modified particle filtering is proposed for multiple object tracking. The perception strategy of the proposed vision-only detection system is structured as follows : First, a method based on illuminant invariant image is employed at an early stage for free road space detection. A convex hull is then constructed to generate a region of interest (ROI) which includes the main traffic road area. Based on this ROI, an U-disparity map is built to characterize on-road obstacles. In this approach, connected regions extraction is applied for obstacles detection instead of standard Hough Transform. Finally, a modified particle filter framework is employed for multiple targets tracking based on the former detection results. Besides, multiple cues, such as obstacle's size verification and combination of redundant detections, are embedded in the system to improve its accuracy. Our experimental findings demonstrates that the system is effective and reliable when applied on different traffic video sequences from a public database.

28 citations

Journal ArticleDOI
TL;DR: In this paper, a two-dimensional forward-looking sonar model with a 120° horizontal scan and a 110 meter radial range is modeled for obstacle detection and the product of bearing and range weighting functions form the gain factor for a dynamic obstacle avoidance behavior, and overall vehicle heading error incorporates this obstacle avoidance term to develop a path around detected objects.

28 citations

Journal ArticleDOI
01 Dec 2017
TL;DR: It can be concluded that a circle-shaped obstacle corresponds to a stronger guiding function and a larger area of “evading region” compared with a bar-shaped one, and induces a relatively higher bottleneck passing capacity in a walking passageway.
Abstract: The pedestrian flow with evading and surpassing behavior in a walking passageway is simulated based on a modified social force model in order to explore the influence of this behavior on evacuation efficiency, bottleneck passing capacity, and the macroscopic phenomenon. A pair of conjugated self-driven forces is introduced to enable a pedestrian to avoid a direct collision and keep a normal velocity magnitude while confronting an obstacle. The pedestrian avoiding time is used to define the triggering conditions of evading and surpassing behavior, and has been estimated through practical experiments. Simulation results show that in a passageway without spatial obstacles, the evading and surpassing behavior will increase the evacuation time under the condition that the pedestrian number is larger than a critical value. Moreover, when a spatial obstacle exists, both the rise of pedestrian numbers and the decline of bottleneck width would increase the evacuation time. Meanwhile, it is observed that compared with a bar-shaped obstacle, a circle-shaped obstacle corresponds to a larger bottleneck passing capacity and less evacuation time when the size of the spatial obstacle is above a critical value. In addition, a phenomenon of a triangle źevading regionź caused by the evading and surpassing behavior also can be observed before the spatial obstacle through simulation and experiments. Furthermore, it can be concluded that a circle-shaped obstacle corresponds to a stronger guiding function and a larger area of źevading regionź compared with a bar-shaped one, and induces a relatively higher bottleneck passing capacity in a walking passageway.

28 citations

Patent
19 Nov 2013
TL;DR: In this article, a ground collision avoidance system (GCAS) for an aircraft is disclosed, where a radio frequency (RF) sensor senses a location of an obstacle with respect to the aircraft moving along the ground.
Abstract: A ground collision avoidance system (GCAS) for an aircraft is disclosed. A radio frequency (RF) sensor senses a location of an obstacle with respect to the aircraft moving along the ground. An expected location of the obstacle with respect to the aircraft is determined from the sensed location and a trajectory of the aircraft. An alarm signal is generated when the expected location of the obstacle is less than a selected criterion.

28 citations


Network Information
Related Topics (5)
Nonlinear system
208.1K papers, 4M citations
79% related
Artificial neural network
207K papers, 4.5M citations
78% related
Fuzzy logic
151.2K papers, 2.3M citations
77% related
Software
130.5K papers, 2M citations
77% related
Optimization problem
96.4K papers, 2.1M citations
76% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
20231,483
20223,389
2021407
2020817
2019873