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 and safe on-line motion planning in dynamic environments

Abstract: This paper presents a new on-line planner for dynamic environments that is based on the concept of Velocity Obstacles (VO). It addresses the issue of motion safety, i.e. avoiding states of inevitable collision, by selecting a proper time horizon for the velocity obstacle. The proper choice of the time horizon ensures that the boundary of the velocity obstacle coincides with the boundary of the set of inevitable collision states. This time horizon is determined by the minimum time it would take the robot to avoid collision, either by stopping or by passing the respective obstacle. The planner generates a near-time optimal trajectory to the goal by selecting at each time step the velocity that minimizes the time-to-go and is out of the velocity obstacle. The planner takes into account the shape, velocity, and path curvature of the obstacle's trajectory. It is demonstrated for on-line motion planning in very crowded static and dynamic environments.

Obstacle detection in a road scene based on motion analysis

Abstract: This paper deals with the problem of obstacle detection in traffic applications. The proposed device allows a driver to receive the current road and vehicle environment information. The perception of the environment is performed through a fast processing of image sequences acquired from a single camera mounted on a vehicle. This approach is based on frame motion analysis. The road motion is first computed through a fast and robust wavelets analysis. Finally, we detect the areas that have a different motion thanks to a Bayesian modelization. Results shown in this paper prove that the proposed method permits the detection of any obstacle on all type of road in various image conditions.

Behavior of a mobile robot navigated by an "iterated forecast and planning" scheme in the presence of multiple moving obstacles

Abstract: This paper investigates behavior of a single mobile robot which is navigated by an "iterated forecast and planning" scheme in an environment where multiple obstacles are moving around. This navigation scheme, which was previously proposed by the authors, searches a feasible path for a robot in (x,y,t) space by a heuristic method. The movement of each obstacle is then forecasted under the assumption that it moves with a piecewise constant velocity. The planning algorithm is iterated frequently to accommodate the actual changes in the obstacles' velocity. This paper examines various kinds of the behavior obtained by different experimental conditions in the computer simulations. >

Multimodal obstacle detection and collision avoidance for micro aerial vehicles

Abstract: Reliably perceiving obstacles and avoiding collisions is key for the fully autonomous application of micro aerial vehicles (MAVs), Limiting factors for increasing autonomy and complexity of MAVs are limited onboard sensing and limited onboard processing power. In this paper, we propose a complete system with a multimodal sensor setup for omnidirectional obstacle perception. We developed a lightweight 3D laser scanner and visual obstacle detection using wide-angle stereo cameras. Detected obstacles are aggregated in egocentric grid maps. We implemented a fast reactive collision avoidance approach for safe operation in the vicinity of structures like buildings or vegetation.

Toward an Autonomous Sailing Boat

Abstract: Among autonomous surface vehicles, sailing robotics could be a promising technology for long-term missions and semipersistent presence in the oceans. Autonomy of such vehicles in terms of energy will be achieved by renewable solar and wind power sources. Autonomy in terms of sailing decision will be achieved by innovative perception and navigation modules. The main contribution of this paper is to propose a complete hardware and software architecture for an autonomous sailing robot. The hardware architecture includes a comprehensive set of sensors and actuators as well as a solar panel and a wind turbine. For obstacle detection, a segmentation is performed on data coming from an omnidirectional camera coupled with an inertial measurement unit and a sonar. For navigation and control of the vehicle, a potential-based reactive path-planning approach is proposed. The specific sailboat kinematic constraints are turned into virtual obstacles to compute a feasible and optimal heading in terms of cost of gybe and tack maneuver as well as safety relative to obstacle danger. Finally, field test experiments are presented to validate the various components of the system.