scholarly journals Center-of-Gravity Variation-Driven Spherical UAV System and Its Control Law

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Donghoon Kim ◽  
Sungwook Yang
Keyword(s):  
Tracking Control ◽  
Center Of Gravity ◽  
Path Tracking ◽  
Variation Principle ◽  
Control Law ◽  
Control Torque ◽  
Numerical Studies ◽  
The Moment ◽  
The One ◽  
Control Surfaces

Most of the spherical unmanned aerial vehicles (SUAVs) use control surfaces, which are functions of aileron and an elevator, to generate control torque. The work proposes a new conceptual design of an SUAV system controlled through center-of-gravity (CG) variations with its path-tracking control law designed for the system. Compared to the one using control surfaces, the concept suggested is beneficial in the aspect of the expandability of building lighter and smaller SUAVs, especially. A CG variation principle by actuating a pendulum type of a moving part is considered as a methodology for both translational and rotational motion control of an SUAV. Since variations of the moment-of-inertia (MOI) elements which resulted from the motion of the moving part affect the performance of the suggested method, the variations of MOI analysis are performed for all angular ranges of the moving part. As a result, certain angular ranges for the moving part to prevent the degradation of the path-tracking performance by the effect of the MOI changes are found. By considering the findings, numerical studies are performed for hovering, ascent, descent, and horizontal tracking missions. The applicability of the proposed SUAV system and the corresponding controller to achieve the path-tracking missions is demonstrated through the numerical simulation.

On the Backward Path Tracking Control of N-Trailer Systems

2021 ◽  
Vol 1 (1) ◽  
pp. 13-20
Author(s):  
Julius Kolb ◽  
Gunter Nitzsche ◽  
Sebastian Wagner ◽  
Klaus Röbenack
Keyword(s):  
Tracking Control ◽  
Path Tracking ◽  
Stability Conditions ◽  
Control Law ◽  
Exact Linearization ◽  
Lateral Control ◽  
General Stability ◽  
Articulated Vehicles ◽  
Articulated Vehicle ◽  
Wheeled Vehicles

This paper considers the lateral control of articulated wheeled vehicles in backward motion. The parameterized articulated vehicle is composed of a car-like truck and N passive trailers, resulting in one single steerable axle. First a nonlinear path tracking control law based on exact linearization of an offset model is reviewed and the general stability conditions of such systems is presented. Second, a stability analysis for some vehicle cases is performed and verified in simulation. The possible application of this path tracking control law in real world articulated vehicles is discussed, and its limitations are shown.

Backward Path Tracking of Mobile Robot with Two Trailers

2014 ◽  
Vol 716-717 ◽  
pp. 1512-1517
Author(s):  
Yu Ma ◽  
Yong Zhang ◽  
Jin Cheng ◽  
Qin Jun Zhao
Keyword(s):  
Mobile Robot ◽  
Tracking Control ◽  
Path Tracking ◽  
Control Law ◽  
Control Laws ◽  
New Approach ◽  
Smooth Control ◽  
The Social ◽  
Continuous Progress ◽  
Nonlinear Smooth

With the social development and the continuous progress of science and technology, the mobile robots can greatly improve efficiency, reduce costs, many of these applications can be attributed to the backward path tracking control problem. A controller for backward path tracking of mobile robot with two trailers is addressed in this paper. The paper presents a new approach to stabilizing the system in backward motion by controlling the orientation angles of the two trailers. Nonlinear smooth control laws for orientations of the trailers with asymptotic stability in backward motion are then proposed. The result simulated in Simulink illustrates the effectiveness of the control law and the controller.

The Munich conference of Minister-Presidents of German lands in 1947

2020 ◽  
Vol 2020 (10-2) ◽  
pp. 86-98
Author(s):  
Ivan Popov
Keyword(s):  
The State ◽  
State Governments ◽  
The West ◽  
Constitutional Development ◽  
The Moment ◽  
The One

The paper deals with the organization and decisions of the conference of the Minister-Presidents of German lands in Munich on June 6-7, 1947, which became the one and only meeting of the heads of the state governments of the western and eastern occupation zones before the division of Germany. The conference was the first experience of national positioning of the regional elite and clearly demonstrated that by the middle of 1947, not only between the allies, but also among German politicians, the incompatibility of perspectives of further constitutional development was existent and all the basic conditions for the division of Germany became ripe. Munich was the last significant demonstration of this disunity and the moment of the final turn towards the three-zone orientation of the West German elite.

scholarly journals On the Two-phase Fractional Stefan Problem

2020 ◽  
Vol 20 (2) ◽  
pp. 437-458 ◽  
Author(s):  
Félix del Teso ◽  
Jørgen Endal ◽  
Juan Luis Vázquez
Keyword(s):  
Free Boundary ◽  
Stefan Problem ◽  
Free Boundary Problems ◽  
Classical Problem ◽  
Nonlocal Diffusion ◽  
Two Phase ◽  
Boundary Problems ◽  
Numerical Studies ◽  
The One ◽  
Evolution Type

AbstractThe classical Stefan problem is one of the most studied free boundary problems of evolution type. Recently, there has been interest in treating the corresponding free boundary problem with nonlocal diffusion. We start the paper by reviewing the main properties of the classical problem that are of interest to us. Then we introduce the fractional Stefan problem and develop the basic theory. After that we center our attention on selfsimilar solutions, their properties and consequences. We first discuss the results of the one-phase fractional Stefan problem, which have recently been studied by the authors. Finally, we address the theory of the two-phase fractional Stefan problem, which contains the main original contributions of this paper. Rigorous numerical studies support our results and claims.

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