scholarly journals Dynamic analysis and motion control of spinning tether system during its Earth to Mars flight

2021 ◽  
Vol 5 (1) ◽  
pp. 27-34
Author(s):  
H. Lu ◽  
C. Wang ◽  
Yu. M. Zabolotnov
Keyword(s):  
Dynamic Analysis ◽  
Motion Control ◽  
Center Of Mass ◽  
Angular Speed ◽  
Artificial Gravity ◽  
Jet Engines ◽  
Interplanetary Trajectory ◽  
Material Points ◽  
Spinning Tether ◽  
Interplanetary Mission

The dynamic analysis and motion control of a spinning tether system for an interplanetary mission to Mars is considered. The space system consists of two spacecraft connected by a tether with thrusts to control its movement. The movements of the tether system in the sphere of action of the Earth, on the interplanetary trajectory and in the sphere of action of Mars are consistently analyzed. In near-Earth orbit, the transfer of the system into rotation with the help of jet engines installed on the end spacecrafts is considered. The spin of the system is used to create artificial gravity during the interplanetary flight. The tether system spins in the plane perpendicular to the plane of the orbital motion of the center of mass of the system. To describe spatial motion of the system, a mathematical model is used, in which the tether is represented as a set of material points with viscoelastic unilateral mechanical connections. When calculating the movement of the system, an approach based on the method of spheres of action is used. Spacecrafts are considered as material points. The level of gravity and spin of tether system is controlled by thrusters. The structure of the controller for controlling the angular speed of rotation of the tether system is proposed. The simulation results are presented to confirm the effectiveness of the proposed control algorithm, which provides a given level of artificial gravity for th e interplanetary mission under consideration.

scholarly journals Hyperbolic Center of Mass for a System of Particles in a Two-Dimensional Space with Constant Negative Curvature: An Application to the Curved 2-Body Problem

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 531
Author(s):  
Pedro Pablo Ortega Palencia ◽  
Ruben Dario Ortiz Ortiz ◽  
Ana Magnolia Marin Ramirez
Keyword(s):  
Negative Curvature ◽  
Dimensional Space ◽  
Center Of Mass ◽  
Simple Expression ◽  
Two Dimensional ◽  
Constant Negative Curvature ◽  
Euclidean Case ◽  
System Of Particles ◽  
Material Points ◽  
The One

In this article, a simple expression for the center of mass of a system of material points in a two-dimensional surface of Gaussian constant negative curvature is given. By using the basic techniques of geometry, we obtained an expression in intrinsic coordinates, and we showed how this extends the definition for the Euclidean case. The argument is constructive and serves to define the center of mass of a system of particles on the one-dimensional hyperbolic sphere LR1.

Dynamic Analysis on a Cable-Driven Interventional Active Catheter Using Kane's Method Combined with Screw Theory

2014 ◽  
Vol 527 ◽  
pp. 140-145
Author(s):  
Da Xu Zhao ◽  
Bai Chen ◽  
Guo Zhong Shou ◽  
Yu Qi Gu
Keyword(s):  
Mathematical Model ◽  
Dynamic Analysis ◽  
Motion Control ◽  
Screw Theory ◽  
Driving Forces ◽  
Structure Design ◽  
Kinematics And Dynamics ◽  
Existing Problems ◽  
Blind Area ◽  
The Mathematical Model

In view of the existing problems of traditional interventional catheters, particularly poor activity, operation difficulty and mass blind area, a novel interventional catheter with a cable-driven active head-end is proposed, and a prototype was built to verify the performance. This paper deals with the kinematics and dynamics of the cable-driven prototype, a dynamic model based on Kanes method combined with screw theory was presented in this paper. According the mathematical model and the prototypes structure, the analysis of kinematics and dynamics of active head-end-end is done in the environment of Mathematica. The needed driving forces of every joint when the system moving along planned trajectory are calculated. The results can provide a basis for the structure design and motion control of the interventional active catheter.

Dynamic Analysis of Slider Mechanisms With Consideration of Frictional Effect in the Slider

2018 ◽  
Author(s):  
Jianyou Han ◽  
Yang Cao ◽  
Penghao Li
Keyword(s):  
Dynamic Analysis ◽  
Friction Force ◽  
Center Of Mass ◽  
Frictional Effect ◽  
Hinge Point ◽  
Shear Mechanism ◽  
Dynamic Analyses ◽  
Rotation Motion ◽  
Application Scope

This paper deals with dynamic analysis of three methods for the slider in mechanisms. Three methods are introduced under three conditions (the influence of friction force is considered, the slider’s center of mass is not coincide with the hinge point, the slider and its guide have rotation motion). The dynamic analyses of the crank slider mechanism and the flying shear mechanism are given as examples by a developed software based on Visual C++ environment, and application scope of the three methods is concluded at the end of the paper. These results are useful for analyzing and designing mechanisms with sliders, such as choosing suitable slider materials or actuators.

Dynamic Analysis and Structure Optimization of Linear Vibration Screen

2013 ◽  
Vol 364 ◽  
pp. 42-45
Author(s):  
Yong Yan Wang ◽  
Xiao Liang Liu ◽  
Wen Bin Wei ◽  
Nan Qin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Analysis ◽  
Center Of Mass ◽  
Structure Optimization ◽  
Element Model ◽  
Linear Vibration ◽  
Ansys Software ◽  
Structural Modifications ◽  
The Finite Element Model

Simulation of simplified the part structures of vibration screen by ANSYS software, and then establishes the finite element model of the linear vibration screen. Modal analysis and harmonic analysis of finite element model, and then according to the analysis results corresponding local structural modifications and adjust the center of mass of the modified vibration screen. Last verified the rationality of structure optimization.

Comparison of Discharge Coefficient Measurements and Correlations for Several Orifice Designs With Cross-Flow and Rotation Around Several Axes

2008 ◽  
Author(s):  
M. Hu¨ning
Keyword(s):  
Gas Turbines ◽  
Computer Network ◽  
Cross Flow ◽  
Angular Speed ◽  
Jet Engines ◽  
Component Design ◽  
Engine Design ◽  
Contour Plots ◽  
Secondary Air ◽  
Temperature Levels

Gas turbines and jet engines consist of a network of connected cavities beside the main gas path, called secondary air system. These cavities, which are often surrounded by stationary and high angular speed rotating walls are exposed to varying pressure and temperature levels of air or oil contaminated air and are connected to each other by orifices or restrictors. It is vital to control the secondary flow, to enable a reliable and efficient engine design, which meets component durability with a minimum of parasitic air consumption. It is essential to understand the flow physics as well as network inter-dependency in order to minimise the flow consumption and yet, meeting engine operating requirements, as well as practical parts component design or manufacturing needs. In this connexion computer network codes containing model conceptions, which can accurately predict orifice flows, are essential. In an effort to provide usable further insight into flows across restrictors such as orifices this publication compares test results, CFD calculations and orifice loss calculation models from the open literature with the aid of transformation laws and contour plots. The influence of different geometric features is incorporated into a model for the calculation of discharge coefficients.

scholarly journals Influence of Satellite Motion Control System Parameters on Performance of Space Debris Capturing

Aerospace ◽  
2020 ◽  
Vol 7 (11) ◽  
pp. 160
Author(s):  
Mahdi Akhloumadi ◽  
Danil Ivanov
Keyword(s):  
Control System ◽  
Motion Control ◽  
Control Algorithm ◽  
Space Debris ◽  
Equations Of Motion ◽  
Center Of Mass ◽  
Attitude Motion ◽  
System Parameters ◽  
Thrust Vector ◽  
Rendezvous And Docking

Relative motion control problem for capturing the tumbling space debris object is considered. Onboard thrusters and reaction wheels are used as actuators. The nonlinear coupled relative translational and rotational equations of motion are derived. The SDRE-based control algorithm is applied to the problem. It is taken into account that the thrust vector has misalignment with satellite center of mass, and reaction wheels saturation affects the ability of the satellite to perform the docking maneuver to space debris. The acceptable range of a set of control system parameters for successful rendezvous and docking is studied using numerical simulations taking into account thruster discreteness, actuators constrains, and attitude motion of the tumbling space debris.

Leveraging synergetic information resources for angular motion control of unmanned spacecraft

2021 ◽  
pp. 127-141
Author(s):  
Vladimir S. KOVTUN ◽  
Aleksandr N. PAVLOV ◽  
Boris V. SOKOLOV ◽  
Dmitry A. PAVLOV ◽  
Valentin N. VOROTYAGIN
Keyword(s):  
Motion Control ◽  
Transitive Closure ◽  
Angular Rate ◽  
Center Of Mass ◽  
Control Process ◽  
Measured Data ◽  
Binary Relations ◽  
Spacecraft Control ◽  
Rate Vector ◽  
Unmanned Spacecraft

A key condition for accomplishing a mission of an unmanned spacecraft consists in providing it with resources. Resources can be replenished through synergetic observations of processes in cases where measured data are partially or fully missing or lacking for some of the controlled objects by means of measuring parameters of the processes characterizing the operation of other controlled objects. As an example, the paper discusses provisioning of resources for the process of controlling the motion about the center of mass by means of synergetic observations in cases where no inertial instrument was available for measuring the angular rate vector in the system controlling the motion of the geostationary communications satellite Yamal-200. Specifically, the observation is based on the operation of transitive closure of the binary relation defined on the base set of processes in the onboard systems and ground assets for radio interactions with the onboard systems of the unmanned spacecraft. Key words: unmanned spacecraft, control process, measuring data, binary relations, transitive closure, provision of resources.

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