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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
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Proceedings ArticleDOI
01 May 2020
TL;DR: In this paper, an on-board vision-based approach for avoidance of moving obstacles in dynamic environments is presented, which relies on an efficient obstacle detection and tracking algorithm based on depth image pairs, which provides the estimated position, velocity and size of the obstacles.
Abstract: In this paper, we present an on-board vision-based approach for avoidance of moving obstacles in dynamic environments. Our approach relies on an efficient obstacle detection and tracking algorithm based on depth image pairs, which provides the estimated position, velocity and size of the obstacles. Robust collision avoidance is achieved by formulating a chance-constrained model predictive controller (CC-MPC) to ensure that the collision probability between the micro aerial vehicle (MAV) and each moving obstacle is below a specified threshold. The method takes into account MAV dynamics, state estimation and obstacle sensing uncertainties. The proposed approach is implemented on a quadrotor equipped with a stereo camera and is tested in a variety of environments, showing effective on-line collision avoidance of moving obstacles.

24 citations

01 Jan 2006
TL;DR: The lawnmower will be an autonomous platform with several integral safety features including obstacle avoidance, collision sensing, and unsafe handling awareness, and the robot is a robust outdoor platform designed to operate continuously for several hours.
Abstract: robot is designed to test the practicality of constructing an autonomous lawn care system. It will also allow experimentation with several technologies and help to investigate their practical applications. The first prototype of this platform will use an RF emitting wire as a containment field, random walk programming to control obstacle and field limit boundary reactions, and a linear motor controller implemented in software. The lawnmower will be an autonomous platform with several integral safety features including obstacle avoidance, collision sensing, and unsafe handling awareness. The robot is a robust outdoor platform designed to operate continuously for several hours. Future versions will be weatherproofed and will include an automatic recharging system. The sensor package includes an ultrasound sensor for obstacle avoidance, bump sensors to detect collisions, two RF field strength detectors, and one digital compass to permit plow navigation programming. Keywordslawnmower, mower, robot, RF.

24 citations

Proceedings ArticleDOI
G. DeMuth1, S. Springsteen1
05 Jun 1990
TL;DR: A neural network that limits the closest point of approach of an autonomous underwater vehicle (AUV) with respect to a navigation obstacle is described, and the AUV simulation successfully avoided collision with all obstacles during test runs.
Abstract: A neural network that limits the closest point of approach of an autonomous underwater vehicle (AUV) with respect to a navigation obstacle is described. Neural network inputs consist of beam outputs from a forward-looking sonar, and differences between current and desired values for AUV course and speed are inputs to normal navigation and control. The neural network outputs are AUV rudder angle and propulsion power: basic vehicle maneuvering characteristics are incorporated in the model. Obstacle avoidance is accomplished using a proximity detector for avoiding static obstacles and a rate detector for avoiding moving obstacles. The detections are made using 2D masked binary filters implemented as multilayer neural networks in the classification mode. Adaptive training is not used: instead. neuron weights are defined by the desired AUV response. The AUV simulation successfully avoided collision with all obstacles during test runs. >

24 citations

Patent
21 Sep 2016
TL;DR: In this paper, the authors proposed a UAV autonomous obstacle avoidance method, which consists of starting equipped distance sensors in a plurality of directions and resolving the distance sensing data into a distance, and changing a course of a drone into a preset course when the distance is less than a preset distance, so as to avoid an obstacle.
Abstract: The invention relates to a UAV autonomous obstacle avoidance method and a UAV autonomous obstacle avoidance device. The UAV autonomous obstacle avoidance method comprises the steps of: starting equipped distance sensors in a plurality of directions; receiving distance sensing data transmitted by the distance sensors; and resolving the distance sensing data into a distance, and changing a course of a UAV into a preset course when the distance is less than a preset distance, so as to avoid an obstacle. In addition, the invention further provides multi-functional control equipment for executing the UAV autonomous obstacle avoidance method. According to the scheme provided by the invention, the distance is generated according to the distance sensing data of the plurality of distance sensors, and an obstacle avoidance action is generated through comparing the distance with the preset distance; the provided UAV autonomous obstacle avoidance method is reliable, real-time and accurate, can effectively prevents UAV body damage, and can ensure that other items are not damaged in the flight process.

24 citations

Journal ArticleDOI
TL;DR: Practical time-varying output formation tracking problems with collision avoidance, obstacle dodging and connectivity maintenance for high-order multi-agent systems are investigated, and the practical time-Varyingoutput formation tracking error is controlled within an arbitrarily small bound.
Abstract: Practical time-varying output formation tracking problems with collision avoidance, obstacle dodging and connectivity maintenance for high-order multi-agent systems are investigated, and the practical time-varying output formation tracking error is controlled within an arbitrarily small bound. The outputs of followers are designed to track the output of the leader with unknown control input while retaining the predefined time-varying formation. Uncertainties are considered in the dynamics of the followers and the leader. Firstly, distributed extended state observers are developed to estimate the uncertainties and the leader’s unknown control input. A strategy of obstacle dodging is given by designing an ideal secure position for the followers which are in the threatened area of the obstacles. By constructing collision avoidance, obstacle dodging and connectivity maintenance artificial potential functions, corresponding negative gradient terms are calculated to achieve the safety guarantee. Secondly, a practical time-varying output formation tracking protocol is proposed by using distributed extended state observers and the negative gradient terms. Additionally, an approach is presented to determine the gain parameters in the protocol. The stability of the closed-loop multi-agent system with the protocol is analyzed by using Lyapunov stability theory. Finally, a simulation experiment is provided to illustrate the effectiveness of the obtained methods.

24 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
20231,483
20223,389
2021407
2020817
2019873