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.

Navigating vehicles through an unstructured environment with sonar

Abstract: A procedure to navigate a vehicle from a source to a destination through an unstructured environment using only a sonar sensor is described. The environment considered is a two-dimensional floor plan, consisting of line segments of arbitrary size that is extended into the third dimension. To ensure that a sonar-guided vehicle does not collide with an obstacle, it is necessary to consider an obstacle that produce the weakest echoes and determine the conditions under which these obstacles can be detected. In this environment, the smallest echo is produced by the line that defines the boundary between the two planes, or the edge; and distant edges become invisible. This physical principle then becomes the basis for the navigation strategy, indicating the necessary scanning pattern and maximum step size that guarantee that no collision will occur. The approach is illustrated with results produced by a vehicular robot equipped with a Polaroid sensor. A representative floor plan and the automatically determined path are shown; a blind alley was included to observe the behavior of the algorithm. >

Obstacle avoidance method and obstacle-avoidable mobile apparatus

Abstract: An obstacle avoidance method for mobile apparatus includes the steps of acquiring, by a mobile apparatus, information as to relative movement of an obstacle with respect to the mobile apparatus, calculating a travel path and a travel direction of the obstacle based on the information during its relative movement, setting a non-intrusion area having a configuration which is longer in the travel direction of the obstacle than in a direction perpendicular to the travel direction, and performing such travel control on the mobile apparatus as to avoid the non-intrusion area, by which obstacle avoidance operation is fulfilled. Thus, an obstacle avoidance method as well as an obstacle-avoidable mobile apparatus are provided which are capable of not only reducing collisions against obstacles and repetitions of avoidance operation, but also preventing impartment of uneasiness and oppression to persons in the obstacle avoidance operation for mobile apparatuses such as robots.

Artificial potentials with elliptical isopotential contours for obstacle avoidance

Abstract: Previous use of artificial potentials has demonstrated the need for an obstacle avoidance potential that closely models the obstacle, yet does not generate local minima in the workspace of the manipulator. However, none of the artificial potential functions proposed to date satisfy this criterion. In this paper we present a new obstacle avoidance potential, based on modified ellipses, that prevents the formation of local minima when added to spherically symmetric attractive wells. A modified form of this elliptical potential provides safe approach towards objects. We have implemented our potentials in a simulation and the results exhibit an improvement over existing potential schemes. The simulation also employs an algorithm that eliminates collisions with obstacles by calculating the repulsive forces exerted on links, based on the shortest distance to an object.

Obstacle detection device

Abstract: An obstacle detection device includes: an obstacle detection section (11) for successively emitting a beam having a predetermined spread angle to a plurality of different directions and receiving a reflected wave from an obstacle in each of the directions, thereby detecting an obstacle existing in the beam emission angle range of each direction; a distance calculation section (12) for calculating a value representing a distance between an obstacle in each direction and an automobile having the obstacle detection device according to the reception signal of reflected wave in each direction output from the obstacle detection section; an obstacle image creation section (14) for treating the distance for each direction calculated by the distance calculation section, as an image creation reference, thereby creating as an obstacle image a graphic spread in two-dimensional way in the emission angle range of the beam emitted in each direction, and creating and outputting image data for displaying the obstacle image; and a display section (15) for receiving image data created by the obstacle image creation section and displaying an image showing the positional relationship between the obstacle and the automobile.