scholarly journals Time-Continuous Real-Time Trajectory Generation for Safe Autonomous Flight of a Quadrotor in Unknown Environment

2021 ◽  
Vol 11 (7) ◽  
pp. 3238
Author(s):  
Yonghee Park ◽  
Woosung Kim ◽  
Hyungpil Moon
Keyword(s):  
Analytical Solution ◽  
Numerical Method ◽  
Trajectory Generation ◽  
Local Minima ◽  
Computationally Efficient ◽  
Cluttered Environment ◽  
Order Polynomial ◽  
Path Planner ◽  
Global And Local ◽  
Global Trajectory

In this paper, we present an efficient global and local replanning method for a quadrotor to complete a flight mission in a cluttered and unmapped environment. A minimum-snap global path planner generates a global trajectory that comprises some waypoints in a cluttered environment. When facing unexpected obstacles, our method modifies the global trajectory using geometrical planning and closed-form formulation for an analytical solution with 9th-order polynomial. The proposed method provides an analytical solution, not a numerical one, and it is computationally efficient without falling into a local minima problem. In a simulation, we show that the proposed method can fly a quadrotor faster than the numerical method in a cluttered environment. Furthermore, we show in experiments that the proposed method can provide safer and faster trajectory generation than the numerical method in a real environment.

Convergence and approximate calculation of average degree under different network sizes for decreasing random birth-and-death networks

2018 ◽  
Vol 32 (15) ◽  
pp. 1850159
Author(s):  
Yin Long ◽  
Xiao-Jun Zhang ◽  
Kui Wang
Keyword(s):  
Analytical Solution ◽  
Numerical Method ◽  
Power Law ◽  
Approximate Calculation ◽  
Approximate Expression ◽  
Network Size ◽  
Average Degree ◽  
Large Network ◽  
Network Link ◽  
Theoretical Results

In this paper, convergence and approximate calculation of average degree under different network sizes for decreasing random birth-and-death networks (RBDNs) are studied. First, we find and demonstrate that the average degree is convergent in the form of power law. Meanwhile, we discover that the ratios of the back items to front items of convergent reminder are independent of network link number for large network size, and we theoretically prove that the limit of the ratio is a constant. Moreover, since it is difficult to calculate the analytical solution of the average degree for large network sizes, we adopt numerical method to obtain approximate expression of the average degree to approximate its analytical solution. Finally, simulations are presented to verify our theoretical results.

A Biologically Inspired Autonomous Robot Control Based on Behavioural Coordination in Evolutionary Robotics

2011 ◽  
pp. 107-129 ◽  
Author(s):  
José A. Fernández-León ◽  
Gerardo G. Acosta ◽  
Miguel A. Mayosky ◽  
Oscar C. Ibáñez
Keyword(s):  
Mobile Robots ◽  
Autonomous Vehicle ◽  
Trajectory Generation ◽  
Real Life ◽  
Evolutionary Robotics ◽  
Knowledge Based ◽  
Planning And Control ◽  
Life Problems ◽  
Path Planner ◽  
And Control

This work is intended to give an overview of technologies, developed from an artificial intelligence standpoint, devised to face the different planning and control problems involved in trajectory generation for mobile robots. The purpose of this analysis is to give a current context to present the Evolutionary Robotics approach to the problem, which is now being considered as a feasible methodology to develop mobile robots for solving real life problems. This chapter also show the authors’ experiences on related case studies, which are briefly described (a fuzzy logic based path planner for a terrestrial mobile robot, and a knowledge-based system for desired trajectory generation in the Geosub underwater autonomous vehicle). The development of different behaviours within a path generator, built with Evolutionary Robotics concepts, is tested in a Khepera© robot and analyzed in detail. Finally, behaviour coordination based on the artificial immune system metaphor is evaluated for the same application.

Global and local minima of protonated acetonitrile clusters

2020 ◽  
Vol 44 (40) ◽  
pp. 17558-17569 ◽  
Author(s):  
Alhadji Malloum ◽  
Jeanet Conradie
Keyword(s):  
Hydrogen Bonds ◽  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Local Minima ◽  
Energy Surfaces ◽  
Global And Local

Potential energy surfaces of protonated acetonitrile clusters have been explored to locate global and local minima energy structures. The structures are stabilized by strong hydrogen bonds, anti-parallel dimers, dipole–dipole and CH⋯N interactions.

scholarly journals ON ONE NUMERICAL METHOD FOR THE COMPUTING OF SEDIMENTATION OF THE SURFACE OF THE SOIL MASSIVE CAUSED BY THE CONSTRUCTION OF THE SHELL LINING OF THE TUNNEL

2018 ◽  
Vol 14 (1) ◽  
pp. 78-91
Author(s):  
Sergey B. Kosytsyn ◽  
Vladimir Y. Akulich
Keyword(s):  
Analytical Solution ◽  
Numerical Method ◽  
Strain State ◽  
Soil Mass ◽  
Stress Strain ◽  
Stress Strain State ◽  
The Earth ◽  
Surrounding Soil

The distinctive work is aimed at the geotechnical forecast of the influence of the construction of the tunnel on the change in the stress-strain state of the surrounding soil mass, namely, the precipitations that arise on the surface of the earth. The work assumes both a numerical and an analytical solution with subsequent com-parative analysis

Vision Object-Oriented Augmented Sampling-Based Autonomous Navigation for Micro Aerial Vehicles

Drones ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 107
Author(s):  
Xishuang Zhao ◽  
Jingzheng Chong ◽  
Xiaohan Qi ◽  
Zhihua Yang
Keyword(s):  
Autonomous Navigation ◽  
Object Oriented ◽  
Micro Aerial Vehicles ◽  
Cluttered Environments ◽  
Structure Information ◽  
Safety Issues ◽  
Cluttered Environment ◽  
Aerial Vehicles ◽  
Planning Algorithm ◽  
Global Trajectory

Autonomous navigation of micro aerial vehicles in unknown environments not only requires exploring their time-varying surroundings, but also ensuring the complete safety of flights at all times. The current research addresses estimation of the potential exploration value neglect of safety issues, especially in situations with a cluttered environment and no prior knowledge. To address this issue, we propose a vision object-oriented autonomous navigation method for environment exploration, which develops a B-spline function-based local trajectory re-planning algorithm by extracting spatial-structure information and selecting temporary target points. The proposed method is evaluated in a variety of cluttered environments, such as forests, building areas, and mines. The experimental results show that the proposed autonomous navigation system can effectively complete the global trajectory, during which an appropriate safe distance could always be maintained from multiple obstacles in the environment.

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