Cat3 3-axes ADCS using Reaction Wheels and Magnetorquers

89 Pages·2016·23.83 MB·English

3
Cat3 3-axes ADCS using Reaction
Wheels and Magnetorquers
A Degree’s Thesis submitted to the
Escola Te`cnica Superior d’Enginyeria de Telecomunicacio´ de Barcelona
Universitat Polite`cnica de Catalunya
by
Armand Molla` Garcia
In partial fulfilment
of the requirements for the degree in
ELECTRONIC SYSTEMS ENGINEERING
Advisor: Professor Adriano Camps
June 27, 2016
Abstract
Standardized CubeSats, with a mass between 1 and 10 Kg, and a volume defined by the
number of 10x10x10 cm3 cubic units that implement it, need compact and effective attitude
determination and control systems. For fast maneuvers, a reaction wheels system is the best
option. In the near future, University’s own CubeSat program with 3Cat3 mission, aims to
use this subsystem. The objective of this thesis is to continue developing this attitude control
systemimplementingthecontrolalgorithmsforcontrollingthemotors. Mostofthedevelopment
has been carried out using a test board from Texas Instruments before experimenting with
the final hardware. The boards which control the motors in the satellite are based on the
development board and the motors, from Maxon motors, are special for being able to work in
vacuumconditions. AcontrolsystemwithspeedfeedbackfromHalleffectsensorsandcurrent
sensors has been developed. FOC has been the algorithm used, with the aim of achieving a
smooth and precise performance. All the results have been obtained evaluating the motors’
behaviour under speed and acceleration tests. All motors and boards have been tested under
the same conditions to simulate slow speed variations, similar to the ones necessary to make
the satellite rotate in space.
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Resumen
LosCubeSatsestandarizados,conunamasadeentre1y10Kg,yunvolumendefinidoporel
nu´merodeunidadescu´bicasde10x10x10cm3 queloforman,necesitansistemasdecontroly
determinacio´n de actitud compactos y efectivos. Para maniobras ra´pidas, un sistema basado
en Reaction Wheels es la mejor opcio´n. En el futuro, el programa de CubeSats propio de la
universidad, con la misio´n 3Cat-3, pretende usar este subsistema. El objetivo de esta tesis
es continuar con el desarrollo de este sistema de control de actitud implementando los algo-
ritmos necesarios para controlar los motores. Gran parte del desarrollo se ha llevado a cabo
usando una placa de desarrollo de Texas Instruments, antes de experimentar con el hardware
definitivo. Las placas que controlan los motores en el sate´lite esta´n basadas en la placa de
desarrollo y, los motores, de Maxon motors, son espec´ıficos para poder funcionar en el vac´ıo.
Unsistemadecontrolconrealimentacio´ndelavelocidadcalculadausandosondasHallysen-
sores de corriente ha sido desarrollado. Se ha utilizado el algoritmo denominado FOC para
lograrunamayorsuavidadyprecisio´ndefuncionamiento. Todoslosresultadossehanobtenido
evaluando el comportamiento de los motores bajo test de velocidad y aceleracio´n. Todos los
motoresyplacassehantesteadobajolasmismascondicionesparasimularvariacioneslentas
de velocidad, similares a las necesarias para hacer rotar el sate´lite en el espacio.
ii
Resum
ElsCubeSatsestandarditzats,ambunamassad’entre1i10Kg, iunvolumdefinitpelnombre
d’unitats cu´biques de 10x10x10 cm3 que el formen, necessiten sistemes de control i determi-
nacio´ d’actitud compactes i eficac¸os. Per maniobres ra`pides, un sistema basat en Reaction
Wheels e´s la millor opcio´. En el futur, el programa de CubeSats propi de la universitat, amb
la missio´ 3Cat-3, prete´n utilitzar aquest subsistema. L’objectiu d’aquest tesi e´s continuar amb
el desenvolupament d’aquest sistema de control d’actitud implementant els algorismes nec-
essaris per controlar els motors. Gran part del desenvolupament s’ha dut a terme utilitzant
una placa de desenvolupament de Texas Instruments, abans d’experimentar amb el hardware
definitiu. Les plaques que controlen els motors en el sate`l•lit estan basades en la placa de
desenvolupament i, els motors, de Maxon motors, so´n espec´ıfics per poder funcionar en el
buit. Un sistema de control amb realimentacio´ de la velocitat calculada utilitzant sondes Hall i
sensors de corrent ha estat desenvolupat. S’ha utilitzat l’algorisme denominat FOC per acon-
seguirunamajor suavitatiprecisio´ defuncionament. Totselsresultats s’hanobtingutavaluant
el comportament dels motors sota tests de velocitat i acceleracio´. Tots els motors i plaques
s’han testejat sota les mateixes condicions per simular variacions lentes de velocitat, similars
a les necessa`ries per fer rotar el sate`l•lit a l’espai.
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To everyone who has supported me along this process.
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Acknowledgements
I am very grateful for the opportunity I have been given to work in the 3Cat-3 project in the
NanoSat Lab. I want to thank my advisor Professor Adriano Jose´ Camps Carmona and all the
laboratory members. Specially for the wide knowledge I have achieved and the challenging
experience that has made me give my best.
Special thanks to former students Mr. Albert Bolet and Mr. Jordi Macia` for their invaluable
help and advice regarding the Reaction Wheels system they started developing.
Finally, thanks to all the 3Cat team members for their support when any difficulty came up
and, of course, for the great working atmosphere in the NanoSat Lab.
Revision history and approval record
Revision Date Purpose
0 16/05/2016 Document creation
1 30/05/2016 Project Advisor first revision
2 20/06/2016 Project Advisor second revision
3 26/06/2016 Project Advisor final revision
Document Distribution List
Name e-mail
Armand Molla` Garcia [email protected]
Adriano Jose´ Camps Carmona [email protected]
Written by: Armand Molla` Garcia Reviewed by: Adriano Camps Carmona
Date 16/05/2016 Date 26/06/2016
Name Armand Molla` Garcia Name Adriano Jose´ Camps Carmona
Position Project Author Position Project Advisor
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Contents
List of Figures ix
List of Tables xi
List of Acronyms xi
1 Introduction 1
2 State of the art of Reaction Wheels 3
2.1 BLDC Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Hall effect sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3 Clarke and Park transforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 BLDC motor control implementations . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4.1 PID controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.4.2 Field Oriented Control (FOC) . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 Methodology and Project Development 12
3.1 System overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.1 RW as part of the ADCS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.1.1 General overview . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.1.2 The Masterboard and its link with the RW . . . . . . . . . . . . . 13
3.1.2 RW functioning and their interaction with the magnetorquers . . . . . . . 14
3.1.2.1 RW actions and behaviour . . . . . . . . . . . . . . . . . . . . . 14
3.1.2.2 Momentum unloading . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2 Development hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2.1 F28069M Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2.2 TI DRV8312 Motor Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2.3 Motor Anaheim BLY17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.3 Satellite final hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.3.1 Motor controllers PCBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.3.2 Maxon EC32 Flat and flywheel . . . . . . . . . . . . . . . . . . . . . . . . 17
3.3.3 Hardware general configuration . . . . . . . . . . . . . . . . . . . . . . . . 18
3.4 Final implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.4.1 Software design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.4.2 PCBs modifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.4.3 How to command the motor controllers . . . . . . . . . . . . . . . . . . . 21
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4 Results 23
4.1 Development kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1.1 Kit parameters identification . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1.2 Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.2 Satellite motors and PCBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2.1 Maxon motors’ parameters identification . . . . . . . . . . . . . . . . . . . 25
4.2.2 Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5 Budget 29
6 Conclusions and Future Development 30
Bibliography 32
A Critical Design Review Document 34
B PCBs schematics 39
B.1 Motor PCBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
B.2 FTDI board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
C Scilab code 43
D F28069M Code 45
D.1 MAIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
D.1.1 main.c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
D.1.2 main.h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
D.2 user.h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
D.3 hal.c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
E Results Complement 68
E.1 Inertia units transformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
E.2 Inertia histograms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
F Anaheim BLY17 motor datasheet 71
G Maxon EC32 Flat motor datasheet 75
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List of Figures
2.1 Maryland Aerospace ADCS module including RW with a price of 25.000 US
dollars [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Aspect of UPC nanosat lab RW system . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Athree-phasesynchronousmotorwithaonepermanentmagnetpairpolerotor
[2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.4 A three-phase inverter [2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.5 Hall effect sensors output signals . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.6 Reference frames transformations [3] . . . . . . . . . . . . . . . . . . . . . . . . 7
2.7 Block diagram for a closed speed loop with PI controller [2] . . . . . . . . . . . 8
2.8 FOC flow diagram overview [4] . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.9 Insta-SPIN MOTION Control with Mechanical Sensor and and FAST Software
Sensor [5] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.10 Applied Torque Disturbance Comparison . . . . . . . . . . . . . . . . . . . . . . 11
2.11 SpinTAC Move Curve Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.12 S-curve representation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.1 BlockdiagramoftheentireAttitudeDeterminationandControlSystem(ADCS)
system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2 Serial Peripheral Interface (SPI) link between motor control boards and Mas-
terboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.3 VariationoftheangularvelocityoftheReactionWheels(RW)startingat0rpm
-simulated with Matlab by Aleix Caldero´n in his degree thesis-. . . . . . . . . . 14
3.4 Development DRV8312-C2-KIT by Texas Instruments [6] . . . . . . . . . . . . . 16
3.5 Final Printed Circuit Board (PCB) design (a) and the dimensions reduction it
supposed (b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.6 Maxon EC32 Flat, the flywheel currently used and a flywheel design proposal . 17
3.7 Preliminary RW system design . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.8 Flow diagram of the software’s functioning mechanism . . . . . . . . . . . . . . 19
3.9 Connections done to simulate a low resolution encoder. . . . . . . . . . . . . . 20
3.10 Hardware modifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.11 Different speed (top) and acceleration (middle) references and the motor’s
speed evolution (bottom). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1 Slow speed progression at 1rpm/s . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.2 Speed progression with different accelerations . . . . . . . . . . . . . . . . . . 24
4.3 Slow speed progression at 1.5rpm/s . . . . . . . . . . . . . . . . . . . . . . . . 26
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