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.

Efficient Obstacle Rearrangement for Object Manipulation Tasks in Cluttered Environments

Abstract: We present an algorithm that produces a plan for relocating obstacles in order to grasp a target in clutter by a robotic manipulator without collisions. We consider configurations where objects are densely populated in a constrained and confined space. Thus, there exists no collision-free path for the manipulator without relocating obstacles. Since the problem of planning for object rearrangement has shown to be NP-hard, it is difficult to perform manipulation tasks efficiently which could frequently happen in service domains (e.g., taking out a target from a shelf or a fridge).Our proposed planner employs a collision avoidance scheme which has been widely used in mobile robot navigation. The planner determines an obstacle to be removed quickly in real time. It also can deal with dynamic changes in the configuration (e.g., changes in object poses). Our method is shown to be complete and runs in polynomial time. Experimental results in a realistic simulated environment show that our method improves up to 31% of the execution time compared to other competitors.

Autonomous off-road navigation using stereo-vision and laser-rangefinder fusion for outdoor obstacles detection

Abstract: During the last decade, ground mobile robots that are able to drive autonomously in off-road environments have received a great deal of attention. Autonomous navigation in unstructured environments faces many new challenges compared to structured urban environments, these challenges increase the complexity of the localization, obstacle detection, path planning and navigation commands. Accordingly this paper presents a fusion system for stereo-vision and laser-rangefinder outdoor obstacle detection, which is implemented as an application for autonomous off-road navigation. The test platform is an electric golf-cart that is modified mechanically and electrically to operate in driver-less mode. This vehicle is equipped with binocular camera, laser-rangefinder, electronic compass and on-board embedded computer, which operates using Robotic Operating System (ROS) architecture. The proposed architecture gathers the data from all different sensors, in order to make navigation decisions from one point to another, avoiding obstacles in the path. Experimental results indicate the high performance of the proposed approaches, they show that the perception from the stereo-vision detection enhances the laser-rangefinder detection, which consequently makes a better decision in maneuvering the obstacle and returns back to the original path.

Two-dimensional incompressible viscous flow around a small obstacle

Abstract: In this article we study the asymptotic behavior of incompressible, ideal, time-dependent two dimensional flow in the exterior of a single smooth obstacle when the size of the obstacle becomes very small. Our main purpose is to identify the equation satisfied by the limit flow. We will see that the asymptotic behavior depends on γ, the circulation around the obstacle. For smooth flow around a single obstacle, γ is a conserved quantity which is determined by the initial data. We will show that if γ = 0, the limit flow satisfies the standard incompressible Euler equations in the full plane but, if γ≠ 0, the limit equation acquires an additional forcing term. We treat this problem by first constructing a sequence of approximate solutions to the incompressible 2D Euler equation in the full plane from the exact solutions obtained when solving the equation on the exterior of each obstacle and then passing to the limit on the weak formulation of the equation. We use an explicit treatment of the Green's ...

The obstacle problem for nonlinear integro-differential operators

Abstract: We investigate the obstacle problem for a class of nonlinear equations driven by nonlocal, possibly degenerate, integro-differential operators, whose model is the fractional $p$-Laplacian operator with measurable coefficients. Amongst other results, we will prove both the existence and uniqueness of the solutions to the obstacle problem, and that these solutions inherit regularity properties, such as boundedness, continuity and Holder continuity (up to the boundary), from the obstacle.