Smooth and Safe Nearness-Diagram (SSND) Navigation for Autonomous Mobile Robots

2011 ◽  
Vol 403-408 ◽  
pp. 4718-4726 ◽  
Author(s):  
Muhannad Mujahed ◽  
Hussein Jaddu
Keyword(s):  
Mobile Robots ◽  
Autonomous Mobile Robots ◽  
Cluttered Environments ◽  
Heading Direction ◽  
Simulation Results ◽  
The Difference ◽  
Two Sides

This paper addresses further enhancements of the earlier developed Smooth Nearness-Diagram Navigation (SND) method for mobile robots moving in complex and cluttered environments. The enhanced method, entitled SSND, improves the safety of paths generated by the SND and solves the problem of trapping the robot in narrow corridors, where the difference in the number of threats on its sides is high. This is achieved by adjusting the difference in the number of obstacles on the two sides of the robot heading direction. The power of our method is demonstrated by simulation results.

Adaptive Shape Reconfiguration of a Decentralized Motile System Exploiting Molecular Dynamics and Stokesian Dynamics Methods

2004 ◽  
Vol 16 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Masahiro Shimizu ◽  
◽  
Akio Ishiguro ◽  
Masayasu Takahashi ◽  
Toshihiro Kawakatsu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Mobile Robots ◽  
Essential Role ◽  
Autonomous Mobile Robots ◽  
Global Information ◽  
Many Body ◽  
Stokesian Dynamics ◽  
Unstructured Environment ◽  
Simulation Results ◽  
Many Body Systems

This paper discusses a fully decentralized algorithm able to create a coherent swarm of autonomous mobile robots from the viewpoint of computational physics. To this end, we focus on Molecular Dynamics and Stokesian Dynamics, both of which are widely used to investigate many-body systems. To verify the feasibility of our approach, this idea has been implemented to a swarm of 2-D radio-connected autonomous mobile robots as a practical example. Simulation results indicate that the proposed algorithm can control the shape of the swarm appropriately based on the current situation without losing the coherence of the swarm nor exchanging global information among modules. Furthermore, we found that local interaction used to exploit Stokesian Dynamics plays an essential role to maintain the coherence of the swarm particularly in an unstructured environment.

scholarly journals Trajectory Planner CDT-RRT* for Car-Like Mobile Robots toward Narrow and Cluttered Environments

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4828
Author(s):  
Hyunki Kwon ◽  
Donggeun Cha ◽  
Jihoon Seong ◽  
Jinwon Lee ◽  
Woojin Chung
Keyword(s):  
Mobile Robots ◽  
Tree Structures ◽  
Cluttered Environments ◽  
Fast Growing ◽  
Efficient Generation ◽  
Simulation Results ◽  
Environmental Geometry ◽  
Trajectory Generator ◽  
Parent Node

In order to achieve the safe and efficient navigation of mobile robots, it is essential to consider both the environmental geometry and kinodynamic constraints of robots. We propose a trajectory planner for car-like robots on the basis of the Dual-Tree RRT (DT-RRT). DT-RRT utilizes two tree structures in order to generate fast-growing trajectories under the kinodynamic constraints of robots. A local trajectory generator has been newly designed for car-like robots. The proposed scheme of searching a parent node enables the efficient generation of safe trajectories in cluttered environments. The presented simulation results clearly show the usefulness and the advantage of the proposed trajectory planner in various environments.

An Obstacle-resistant Relay Node Placement in Constrained Environment

2019 ◽  
Author(s):  
Abhishek Verma ◽  
Virender Ranga
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Mobile Robots ◽  
Relay Node ◽  
Wireless Sensor ◽  
Relay Node Placement ◽  
Node Placement ◽  
Simulation Results ◽  
Additional Hardware ◽  
Shape And Size

Relay node placement in wireless sensor networks for constrained environment is a critical task due to various unavoidable constraints. One of the most important constraints is unpredictable obstacles. Handling obstacles during relay node placement is complicated because of complexity involved to estimate the shape and size of obstacles. This paper presents an Obstacle-resistant relay node placement strategy (ORRNP). The proposed solution not only handles the obstacles but also estimates best locations for relay node placement in the network. It also does not involve any additional hardware (mobile robots) to estimate node locations thus can significantly reduce the deployment costs. Simulation results show the effectiveness of our proposed approach.

Modulation instability in nonlinear chiral fiber

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Demissie Jobir Gelmecha ◽  
Ram Sewak Singh
Keyword(s):  
Theoretical Model ◽  
Numerical Simulations ◽  
Pulse Propagation ◽  
Modulation Instability ◽  
Constitutive Relations ◽  
Gain Spectrum ◽  
Circularly Polarized ◽  
Left Handed ◽  
Simulation Results ◽  
The Difference

AbstractIn this paper, the rigorous derivations of generalized coupled chiral nonlinear Schrödinger equations (CCNLSEs) and their modulation instability analysis have been explored theoretically and computationally. With the consideration of Maxwell’s equations and Post’s constitutive relations, a generalized CCNLSE has been derived, which describes the evolution of left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) components propagating through single-core nonlinear chiral fiber. The analysis of modulation instability in nonlinear chiral fiber has been investigated starting from CCNLSEs. Based on a theoretical model and numerical simulations, the difference on the modulation instability gain spectrum in LCP and RCP components through chiral fiber has been analyzed by considering loss and chirality into account. The obtained simulation results have shown that the loss distorts the sidebands of the modulation instability gain spectrum, while chirality modulates the gain for LCP and RCP components in a different manner. This suggests that adjusting chirality strength may control the loss, and nonlinearity simultaneously provides stable modulated pulse propagation.

scholarly journals Determining Shape and Size of Personal Space of a Human when Passed by a Robot

2021 ◽  
Author(s):  
Margot M. E. Neggers ◽  
Raymond H. Cuijpers ◽  
Peter A. M. Ruijten ◽  
Wijnand A. IJsselsteijn
Keyword(s):  
Mobile Robots ◽  
Humanoid Robot ◽  
Personal Space ◽  
Human Robot Interaction ◽  
Autonomous Mobile Robots ◽  
Robot Interaction ◽  
Human Comfort ◽  
Navigation Algorithms ◽  
Insight Into ◽  
Shape And Size

AbstractAutonomous mobile robots that operate in environments with people are expected to be able to deal with human proxemics and social distances. Previous research investigated how robots can approach persons or how to implement human-aware navigation algorithms. However, experimental research on how robots can avoid a person in a comfortable way is largely missing. The aim of the current work is to experimentally determine the shape and size of personal space of a human passed by a robot. In two studies, both a humanoid as well as a non-humanoid robot were used to pass a person at different sides and distances, after which they were asked to rate their perceived comfort. As expected, perceived comfort increases with distance. However, the shape was not circular: passing at the back of a person is more uncomfortable compared to passing at the front, especially in the case of the humanoid robot. These results give us more insight into the shape and size of personal space in human–robot interaction. Furthermore, they can serve as necessary input to human-aware navigation algorithms for autonomous mobile robots in which human comfort is traded off with efficiency goals.

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