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.

Autonomous vehicle obstacle avoidance method based on arc path

Abstract: The invention discloses an autonomous vehicle obstacle avoidance method based on an arc path. The autonomous vehicle obstacle avoidance method comprises the following steps of: S1, acquiring the position of a vehicle at any moment through a positioning system; S2, judging whether an obstacle exists in a specific region of a detection range or not, and if so, measuring the distance between the vehicle and the obstacle; S3, selecting a manner of advancing toward a target or walking around the obstacle by the vehicle according to an obstacle distribution condition to realize collision-free navigation towards a fixed target point in an unknown environment; and S4, adding a turning route selection mechanism in the manner of walking around the obstacle, and determining an optimal obstacle avoidance driving route according to the information of the obstacle. The autonomous vehicle obstacle avoidance method disclosed by the invention sufficiently utilizes the advantages of a BUG obstacle avoidance algorithm, and the vehicle is only required to have a detection range of 180 degrees; a physical size and a driving character of the vehicle are also considered and the problem that a four-wheeled vehicle in a non-360-degree detection range cannot use the BUG algorithm is solved; continuous and smooth by-pass movements by navigation obstacle avoidance is realized through a transition path track generated at a turning point.

Obstacle and Boundary Determination from Scattering Data

Abstract: In this paper, we are concerned with the identification of complex obstacles from the scattering data for the acoustic problem. The complex obstacle is characterized by its shape and the boundary values of the impedance coefficient. We establish pointwise formulas which can be used to reconstruct the shape of the obstacle and give explicitly the values of the surface impedance as a function of the far field. In addition, these formulas enable us to distinguish and recognize the coated and the noncoated parts of the obstacle.

The downstream flow beyond an obstacle

Abstract: This paper is concerned with theoretical predictions, given the upstream conditions from a rigid obstacle of arbitrary shape, of the downstream flow beyond the obstacle for an incompressible inviscid fluid sheet under the action of gravity. The fluid sheet flows upstream over a level bottom, continues to flow over (or under) an obstacle leading to a downstream region over a level bottom. In the absence of surface tension, a nonlinear st., ady-state solution of the problem is used to predict the downstream values of the free-surface wave height for the full range of the far-upstream Froude number. The general results obtained are then applied to a special case of fluid flowing over a stationary hump leading to a supercritical flow far downstream and detailed numerical comparison is made with available experimental results, with very good agreement.

Particle Grid Tracking System Stereovision Based Obstacle Perception in Driving Environments

Abstract: This paper presents an occupancy grid tracking system based on particles, and the use of this system for dynamic obstacle detection in driving environments. The particles will have a dual nature they will denote hypotheses, as in the particle filtering algorithms, but they will also be the building blocks of our modeled world. The particles have position and speed, and they can migrate in the grid from cell to cell depending on their motion model and motion parameters, but they will also be created and destroyed using a weighting-resampling mechanism specific to particle filter algorithms. An obstacle grid derived from processing a stereovision-generated elevation map is used as measurement information, and the measurement model takes into account the uncertainties of the stereo reconstruction. The dynamic occupancy grid is used for improving the quality of the stereovision-based reconstruction as oriented cuboids. The resulted system is a flexible, real-time tracking solution for dynamic unstructured driving environments, and a useful tool for extracting intermediate dynamic information that can considerably improve object detection and tracking.

Mobile robot obstacle avoidance navigation method and system

Abstract: The invention discloses a mobile robot obstacle avoidance navigation method and system. The method includes the following steps that: a global map of a home environment is established; the starting point and destination of the movement of a robot are set; the movement path of the robot is planned according to the A* algorithm; the position of a obstacle is marked in the global map; the movement path of the robot is re-planned according to the A* algorithm; the robot is controlled to move according to the planned path; and the robot arrives at the destination and stops moving. With the mobile robot obstacle avoidance navigation method and system of the invention adopted, unknown environment can be detected, so that the information of unknown obstacles can be obtained, and the estimation function is adopted to plan the shortest and most economical path, and therefore, the equipment cost of the obstacle avoidance navigation of the robot can be decreased; the position and movement attitude of the robot can be monitored in real time, and the walking attitude of the robot can be adjusted and controlled in real time, and the accuracy and effectiveness of the obstacle avoidance navigation of the robot can be ensured.