thesis svendsen 2006

8/13/2019 Thesis Svendsen 2006

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HIN - HovedoppgaveMaster i teknologiPostboks 385, Postboks 3858505 NARVIK

Telefon: 76 96 60 00Telefax: 76 96 68 10

Tittel

Coordinated control of spacecraft in formation

Koordinert styring av romfarty i formasjon

Dato

12. juni 2006

Gradering

pen Ja

ForfattereLisa Maria Svendsen

Antall sider80

Vedlegg

1

Institutt for

Data-, elektro- og romteknologiStudieretning

Romteknologi

Veileder

Frsteamanuensis Dr. Ing. Per NicklassonOppdragsgiver

HiNOppdragsgivers kontaktperson

Frsteamanuensis Dr. Ing.Per Nicklasson

Sammendrag

Oppgaven omhandler modellering og styring av relative translasjon og rotasjon av toromfarty i formasjon i jordbane. En matematisk modell er utledet, en refert tilledersystemet og en refert til ECI systemet. En regulator for relative translasjon ogrelative rotasjon er utledet, en basert p ledersystemet og en basert p ECI systemet.Regulatordesignet er basert p en velocity error sliding surface regulator. Simulering avden utledede regulatoren for ledersystemet er utfrt.

Abstract

The project deals with modelling and control of relative translation and rotation of twoformation flying spacecraft in Earth orbit. A mathematical model of relative translationand rotation is derived. The model is referenced both in the leader-fixed system and in theEarth-fixed inertial coordinate system. Furthermore, a state feedback controller forregulation of relative translation and rotation based on the leader-fixed model, and one

based on the Earth-fixed model is derived. The tracking controllers are based on velocityerror sliding surface. Simulation of the propsed controller for the leader-fixed system is

performed.Norske stikkord

formasjonsflyvende romfartymatematisk modelleringrelative translasjon og rotasjonregulatordesign

Keywords

formation flying spacecraftmathematical modellingrelative translation and rotationcontrol design


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Master thesis project 2006for

Stud. Techn. Lisa Maria Svendsen

Coordinated control of spacecraft in formation

Spacecraft flying in formation are revolutionizing our way of performing space-basedoperations, and this new paradigm brings on several advantages in space missionaccomplishment, and new opportunities and applications for such missions. Spacecraftformation flying is a technology that includes two or more spacecraft in a tightly controlledspatial configuration, whose operations are closely synchronized. The distributed spacecraftstructure appears as a single sensing system for the user, whose physical size largely exceeds

the barriers imposed by a single body. The concept makes the way for new and betterapplications in space industry such as monitoring of the earth and its surrounding atmosphere,geodesy, deep space imaging and exploration, and in-orbit servicing and maintenance ofspacecraft. The replacement of traditional large and complex spacecraft with an array ofsimpler micro-satellites, introduces a multitude of advantages regarding mission cost and

performance. The major advantage of formation flying of spacecraft lies in flexibility andmodularity. The development of formation flying technologies for spacecraft applications willenable the use of a modular spacecraft structure where multiple distributed spacecraft could

be coordinated to act as one. The life span of the mission can be prolonged with thepossibility of adding new units to replenish or augment the formation. The initial instrumentbaseline can evolve by implementing new measurement concepts at a later time, withoutrequiring a complete replacement of all the spacecraft in the formation. This also entailssystem redundancy at a large scale, and not only in subsystems.

The advantages of using spacecraft formations come at a cost of increased complexity andtechnological challenges. Formation flying introduces a control problem with strict and time-varying boundaries on spacecraft reference trajectories, and collisions between spacecraftshould of course be avoided at all costs. The rise of spacecraft formation flying as a newtechnology has resulted in new areas of research, and the concept requires detailed knowledgeand tight control of relative distances, velocities and orientations for participating spacecraft.A challenge for tight spacecraft formation flying lies in the coordination of the spacecraft

motions relative to each other, to avoid inter-satellite interference and collisions and achievemission goals, while minimizing the required control efforts. In addition, tight spacecraftformations will be sensitive to perturbations due to external disturbances caused byatmospheric and solar drag, and variations in the gravity field of the Earth, and a solution tothe control problem must be able to suppress such perturbations.

This project assignment deals with modelling and control of relative translation and rotationof two formation flying spacecraft in Earth orbit. The work shall be substantiated withtheoretical analysis and system simulations in MATLAB.

Technical specifications for the system are chosen by the student in cooperation with the

supervisor.


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Problems:

1. Perform a study on previous work within modelling and control of relative translationaland rotational motion in leader-follower spacecraft formations. The papers (Kristiansen etal, 2005) and (Kristiansen & Nicklasson, 2005) are a recommended starting point

(preprint available from advisor).

2. Derive the mathematical model of relative translation and rotation in a leader-followerformation with two spacecraft. The model should be referenced in both the leader orbitcoordinate system (leader-fixed) and an Earth-fixed inertial coordinate system.

3. Suggest one state feedback controller for regulation of relative translation and rotationbased on the leader-fixed model, and one based on the Earth-fixed model. Assume that theleader spacecraft is perfectly controlled in a chosen orbit, and that the follower spacecrafthas continuous thrust about all axes and in all directions available at all times.

4. Perform a theoretical analysis of the stability in the closed loop system, and investigateadvantages and disadvantages using a leader-fixed vs. Earth-fixed model.

5. Perform simulations of the spacecraft formation in MATLAB, and present simulationresults to visualize the performance of the proposed controller for the leader-fixed model.

References:

R. Kristiansen, E. I. Grtli, P. J. Nicklasson and J. T. Gravdahl (2005).A model of relativeposition and attitude in a leader-follower spacecraft formation. Submitted to Mathematicaland Computer Modelling of Dynamical Systems.

Kristiansen, R. and P. J. Nicklasson (2005). Spacecraft formation flying: A review and newresults on state feedback control. Submitted to Acta Astronautica.

Extradition date: 16.01.2006

Submission date: 18.07.2006

Supervisor: Ass. Professor Dr. Ing. Per J. Nicklasson

Advisor: PhD student Raymond Kristiansen, M.Sc

Hgskolen i NarvikInstitutt for data, elektro og romteknologi

Veileder

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0 50 100 150 200 250 300 350-50

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Relative position and velocity

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thesis svendsen 2006

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