scholarly journals Rendezvous in Cis-Lunar Space near Rectilinear Halo Orbit: Dynamics and Control Issues

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 68
Author(s):  
Giordana Bucchioni ◽  
Mario Innocenti
Keyword(s):  
Body Motion ◽  
Stable And Unstable Manifolds ◽  
Actuator Dynamics ◽  
Guidance And Control ◽  
Dynamics And Control ◽  
Critical Phases ◽  
Three Body ◽  
And Control ◽  
In Cis ◽  
Selection Of

The paper presents the development of a fully-safe, automatic rendezvous strategy between a passive vehicle and an active one orbiting around the Earth–Moon L2 Lagrangian point. This is one of the critical phases of future missions to permanently return to the Moon, which are of interest to the majority of space organizations. The first step in the study is the derivation of a suitable full 6-DOF relative motion model in the Local Vertical Local Horizontal reference frame, most suitable for the design of the guidance. The main dynamic model is approximated using both the elliptic and circular three-body motion, due to the contribution of Earth and Moon gravity. A rather detailed set of sensors and actuator dynamics was also implemented in order to ensure the reliability of the guidance algorithms. The selection of guidance and control is presented, and evaluated using a sample scenario as described by ESA’s HERACLES program. The safety, in particular the passive safety, concept is introduced and different techniques to guarantee it are discussed that exploit the ideas of stable and unstable manifolds to intrinsically guarantee some properties at each hold-point, in which the rendezvous trajectory is divided. Finally, the rendezvous dynamics are validated using available Ephemeris models in order to verify the validity of the results and their limitations for future more detailed design.

Modeling the Spatial Dynamics of Robotic Manipulators with Flexible Links and Joint Clearances

1993 ◽  
Vol 115 (4) ◽  
pp. 839-847 ◽  
Author(s):  
T. Kakizaki ◽  
J. F. Deck ◽  
S. Dubowsky
Keyword(s):  
Control System ◽  
Spatial Dynamics ◽  
Dynamic Effects ◽  
Nonlinear Functions ◽  
Detailed Model ◽  
Actuator Dynamics ◽  
Dynamics And Control ◽  
Joint Clearances ◽  
And Control ◽  
System Characteristics

A dynamic modeling method is presented for spatial elastic manipulators that can account for a number of their realistic properties, including bearing clearances, actuator dynamics, and control system characteristics. Forces in the bearing clearances are modeled by nonlinear functions of the links’ relative motions and the internal geometry of the connection, or by experimentally measured properties. A detailed model is given for a revolute connection with radial and axial clearances. Results obtained for a SCARA manipulator show that the combined dynamic effects of bearing clearances, link elasticity, and control system characteristics can significantly degrade the system’s performance.

Dynamics and control of three-body tethered system in large elliptic orbits

2018 ◽  
Vol 144 ◽  
pp. 397-404 ◽  
Author(s):  
Gefei Shi ◽  
Zhanxia Zhu ◽  
Zheng H. Zhu
Keyword(s):  
Elliptic Orbits ◽  
Dynamics And Control ◽  
Three Body ◽  
And Control

A Theoretical Study of the Internal Forces in a Hydraulic Vane Pump with Hypertrochoid Curve in the Inner Surface of its Stator

2012 ◽  
Vol 463-464 ◽  
pp. 301-304 ◽  
Author(s):  
M. Ebrahimi ◽  
S.A. Jazayeri
Keyword(s):  
Inertia Force ◽  
Fluid Viscosity ◽  
Vane Pump ◽  
Pump Design ◽  
Inner Surface ◽  
Dynamics And Control ◽  
Internal Forces ◽  
Line Pressure ◽  
And Control ◽  
Selection Of

In the latest our works, Performance of a fixed displacement- hydraulic balance vane pump, theoretically and practically was studied by application of the basic hypertrochoid curve in the inner surface of its stator. Also the effect of the inertia force of the vanes on the performance of the pump with this curve was studied. This study presents a theoretical analysis of the internal pressure distribution in the pump, and of the resulting forces and torques applied to its components. This analysis is essential to the study of the pump dynamics and control, the pump design, and selection of the pump bearings. These forces are shown to be a function of the line pressure, the shaft rotational speed, the fluid bulk modulus, the fluid viscosity, and the design geometry. These forces are composed of two components: a continuous component due to the exposure of chambers to the line port, and an intermittent component due to a hydraulic lock phenomenon.

scholarly journals Integrated Guidance and Control Using Model Predictive Control with Flight Path Angle Prediction against Pull-Up Maneuvering Target

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3143
Author(s):  
Jongho Park ◽  
Youngil Kim ◽  
Jong-Han Kim
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Flight Path ◽  
Actuator Dynamics ◽  
Guidance And Control ◽  
Maneuvering Target ◽  
Flight Path Angle ◽  
Short Period ◽  
Integrated Guidance And Control ◽  
And Control

Integrated guidance and control using model predictive control against a maneuvering target is proposed. Equations of motion for terminal homing are developed with the consideration of short-period dynamics as well as actuator dynamics of a missile. The convex optimization problem is solved considering inequality constraints that consist of acceleration and look angle limits. A discrete-time extended Kalman filter is used to estimate the position of the target with a look angle as a measurement. This is utilized to form a flight-path angle of the target, and polynomial fitting is applied for prediction. Numerical simulation including a Monte Carlo simulation is performed to verify the performance of the proposed algorithm.

scholarly journals Neural Extended State Observer Based Intelligent Integrated Guidance and Control for Hypersonic Flight

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2605
Author(s):  
Liang Wang ◽  
Ke Peng ◽  
Weihua Zhang ◽  
Donghui Wang
Keyword(s):  
State Observer ◽  
Lyapunov Theory ◽  
Extended State Observer ◽  
Control Surface ◽  
Extended State ◽  
Actuator Dynamics ◽  
Guidance And Control ◽  
Hypersonic Flight ◽  
Integrated Guidance And Control ◽  
And Control

Near-pace hypersonic flight has great potential in civil and military use due to its high speed and low cost. To optimize the design and improve the robustness, this paper focuses on the integrated guidance and control (IGC) design with nonlinear actuator dynamics in the terminal phase of hypersonic flight. Firstly, a nonlinear integrated guidance and control model is developed with saturated control surface deflection, and third-order actuator dynamics is considered. Secondly, a neural network is introduced using an extended state observer (ESO) design to estimate the complex model uncertainty, nonlinearity and disturbance. Thirdly, a command-filtered back-stepping controller is designed with flexible designed sliding surfaces to improve the terminal performance. In this process, hybrid command filters are implemented to avoid the influences of disturbances and repetitive derivation, meanwhile solving the problem of unknown control direction caused by nonlinear saturation. The stability of the closed-loop system is proved by the Lyapunov theory, and the controller parameters can be set according to the relevant remarks. Finally, a series of numerical simulations are presented to show the feasibility and validity of the proposed IGC scheme.

Dynamics and Control of a Translating Flexible Beam With a Prismatic Joint

1992 ◽  
Vol 114 (3) ◽  
pp. 422-427 ◽  
Author(s):  
Sivakumar S. K. Tadikonda ◽  
Haim Baruh
Keyword(s):  
Rigid Body ◽  
The Other ◽  
Body Motion ◽  
Rigid Base ◽  
Flexible Beam ◽  
Positioning Control ◽  
Dynamics And Control ◽  
And Control ◽  
Tip Mass ◽  
Free Beam

The complete dynamic model of a translating flexible beam, with a tip mass at one end and emerging from or retracting into a rigid base at the other, is presented. The model considers the effect of elastic and translational motions of the beam on each other. The properties of the eigenfunctions of a fixed-free beam are exploited to obtain closed-form expressions for several domain integrals that arise in the model. It is shown that neglecting the effect of elastic motion on the rigid body motion leads to inaccuracies in positioning control. Issues associated with the feedback control of such a beam are discussed.

Editorial Dynamics and Control of Aerospace and Vertical Transportation Systems

2014 ◽  
Vol 706 ◽  
pp. 1-5
Author(s):  
José M. Balthazar ◽  
Paulo Batista Gonçalves ◽  
Stefan Kaczmarczyk ◽  
André Fenili ◽  
Marcos Silveira ◽  
...  
Keyword(s):  
Nonlinear Dynamics ◽  
Transportation Systems ◽  
Special Issue ◽  
Science And Engineering ◽  
International Conference ◽  
Dynamics And Control ◽  
Vibration Problems ◽  
And Control ◽  
New Strategies ◽  
Selection Of

This Special Issue presents a selection of papers initially presented at the 11th International Conference on Vibration Problems (ICOVP-2013), held from 9 to 12 September 2013 in Lisbon, Portugal. The main topics of this Special Issue are linear and, mainly, nonlinear dynamics, chaos and control of systems and structures and their applications in different field of science and engineering. According to the goal of the Special Issue, the selected contributions are divided into three major parts: “Vibration Problems in Vertical Transportation Systems”, “Nonlinear Dynamics, Chaos and Control of Elastic Structures” and “New Strategies and Challenges for Aerospace and Ocean Structures Dynamics and Control”.

scholarly journals Analysis of a Unibody Stub Axle-Hub Design for an ATV

2021 ◽  
Author(s):  
Urooj Ahmad ◽  
Subhrat Praharaj
Keyword(s):  
Dynamic Performance ◽  
Material Design ◽  
Vehicle Performance ◽  
Ground Vehicle ◽  
Dynamics And Control ◽  
Suspension Geometry ◽  
The Cost ◽  
And Control ◽  
Control Behaviour ◽  
Selection Of

This paper aims to design and model a unibody hub and stub axle Wheel assembly to withstand rough terrain conditions while adhering to design optimization objectives of weight, costs, and manufacturability. For any ground vehicle, its dynamics and control behaviour are majorly governed by the design of its wheel assembly since it experiences all the major loads an ATV faces. We aimed to design and fabricate a unibody hub and stub axle that is lightweight and more durable in comparison to the present form of design in which the hub and stub axle is manufactured and assembled separately. The advantages of this unibody design are lesser components, easy replacement, and easy manufacturing. This report also considers the simulation of this unibody using FEM through Ansys, considering all the loads acting on the unibody. Also, the cost and strength comparison of different materials is done for the selection of the best material. Design is done in such a way to consider all the parameters such as performance, reliability, manufacturability, serviceability, weight, and cost. The model achieves a significant reduction in unsprung mass, improving the dynamic performance of the ATV, without requiring a change in suspension geometry. We also analyze the improvement in vehicle performance in shifting from the classic independent stub through hub design to this integrated unibody design.

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