Control Moment Gyro Actuator for Small Satellite Applications by Reimer Berner Thesis presented at the University of Stellenbosch in partial fulfilment of the requirements for the degree of Master of Science in Electrical & Electronic Engineering Department of Electrical & Electronic Engineering University of Stellenbosch Private Bag X1, 7602 Matieland, South Africa Study leader: Prof W.H. Steyn April 2005
119
Embed
Control Moment Gyro actuator for small satellite ... · Control Moment Gyro Actuator for Small Satellite Applications R. Berner Department of Electrical & Electronic Engineering University
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Control Moment Gyro Actuator for Small SatelliteApplications
by
Reimer Berner
Thesis presented at the University of Stellenboschin partial fulfilment of the requirements for the
degree of
Master of Science in Electrical & Electronic Engineering
Department of Electrical & Electronic EngineeringUniversity of Stellenbosch
I, the undersigned, hereby declare that the work contained in this thesis is my own originalwork and that I have not previously in its entirety or in part submitted it at any universityfor a degree.
Control Moment Gyro Actuator for Small Satellite Applications
R. Berner
Department of Electrical & Electronic EngineeringUniversity of Stellenbosch
Private Bag X1, 7602 Matieland, South Africa
Thesis: M Sc Eng (E & E)
April 2005
The aim of the thesis is to design a Control Moment Gyro (CMG) actuator which can beused in small satellite applications. The hardware and software of the CMG has to bedesigned according to specifications given. A satellite fitted with these CMGs has to beable to do a 30 degree rotation within 10 seconds.
A mathematical model of a satellite fitted with six CMGs was designed for simulationpurposes. This model was then extended to include a 3-axis control algorithm which con-trol the angular momentum vectors of the CMGs. An imaging sequence, which describesthe attitude and angular rate of the satellite at any point in time, was also implementedinto the design to produce a smooth attitude function during pointing maneuvers. Thisimaging sequence is used as input to the 3-axis control algorithm to ensure high precisionpointing of the satellite.
The CMG was tested on an air bearing table and the results of the tests were comparedto the mathematical simulations. The results of these tests were as expected and thefunctionality of the CMG was verified.
iii
Uittreksel
Control Moment Gyro Actuator for Small Satellite Applications
R. Berner
Departement Elektriese & Elektroniese IngenieursweseUniversiteit van Stellenbosch
Privaatsak X1, 7602 Matieland, Suid Afrika
Tesis: M Sc Ing (E & E)
April 2005
Die doel van die tesis is om ’n Beheer Moment Giro (BMG) aktueerder te ontwerp wat opklein satelliete gebruik kan word. Die hardeware en sagteware van die BMG is ontwerpvolgens gegewe spesifikasies. ’n Satelliet wat met hierdie BMGs toegerus is, moet ’n 30grade rotasie binne 10 sekondes afhandel.
’n Wiskundige model van ’n satelliet met ses BMGs was ontwerp vir simulasie doeleindes.Hierdie model is uitgebrei om ’n 3-as beheer algoritme in te sluit wat die hoekmomen-tum vektore van die BMGs beheer. ’n Beeldafneem sekwensie wat die posisie en diehoeksnelheid van die satelliet op enige gegewe oomblik beskryf, is ook geïmplementeerin die ontwerp om sodoende ’n gladde rotasie funksie te verkry wanneer die satelliet inverskillende rigtings moet mik. Hierdie beeldafneem sekwensie dien as intree tot die 3-asbeheerder om sodoende die satelliet akkuraat te kan rig.
Die BMG is getoets op ’n luglaertafel en die resultate van die toetse is vergelyk met diewiskundige simulasies. Die resultate van hierdie toetse is soos verwag en die funksionaliteitvan die BMG is bevestig.
iv
Acknowledgements
I would like to thank the following for their help and assistance in the successful completionof this thesis:
• Thank You Almighty God for Your guiding hand in my life.
• Prof. W.H. Steyn for his guidance and support throughout this thesis.
• Xandri Farr for all his help, and the design and layout of the microcontroller pcb.
• Mnr. J. Treurnicht and Corne van Daalen for their help on the air bearing table.
• Mnr. J. Blom and the SMD group for the mechanical design of the CMG.
• Eckhardt Kuhn, who helped with all the practical tests.
• My parents for their support and my education.
• All my friends for encouragement during the writing of my thesis.
The settling times at the end of slew 1 and slew 3 are assumed to be ∆tSET12 = ∆tSET34 =
5 seconds. The demanded angular accelerations for each slew are chosen as aS1 = aS2 =
aS3 = aS4 = 0.005 rad/s2 and the time ∆tPM = 0.5ρS2/ |ωoIMG|. This simulation uses
the three-axis quaternion feedback controller from Section 4.2.3. A faster settling time
is chosen for this simulation, since the commanded angles are very small. A 5% settling
time of ts = 0.1 seconds is used with a damping ratio of ζ = 0.9. The undamped natural
frequency ωn = 3/ζts = 33.33 rad/s and the integral time constant T = 10/ζωn = 0.333
seconds. The controller gains are calculated as:
k = ω2n + 2ζωn/T = 1291
c = 2ζωn + 1/T = 63
The generated quaternion demand and the orbit-referenced body rate demands are shown
in Figure 5.2 and Figure 5.3 respectively. The settling periods at the end of Slew 1 and
Slew 3 are clearly visible in both figures. In Figure 5.3 the body rates of the satellite
for the different slew maneuvers can be seen. During Slew 1 and Slew 3 the body rate
ramps to a maximum value and then reduces linearly to 0. This behaviour is expected
since both slews are performed with an angular acceleration for the first half of the slew,
followed by an angular deceleration.
Chapter 5 — Control Demand for Imaging Sequence 56
Slew 2 starts with an acceleration phase until the required imaging rate is obtained and
then continues at a constant rate. This rate is maintained during Slew 3 until the end of
the imaging period, where after the rate reduces at a constant deceleration to 0.
0 20 40 60 80 100 120−0.15
−0.1
−0.05
0
0.05
0.1
0.15
0.2
0.25Quaternion Demand
time (s)
q1q2q3
Slew 1 &SettlingTime
Slew 2
Slew 3 &SettlingTime
Slew4
ImagingPeriod
Figure 5.2: Quaternion Demand for Imaging Sequence
The commanded torque for the imaging sequence and the corresponding gimbal rate is
shown in Figure 5.4 and Figure 5.6 respectively. The maximum torque needed is 0.12 Nm
and the maximum gimbal rate is 2.2 deg/s. The errors between the commanded Euler
angles and the measured Euler angles are also depicted. These angle errors are very small,
especially during imaging (Slew 2 and Slew 3) when accuracy is most important. The
maximum error during imaging is less than 0.001 degrees.
From these simulation results one can see that the maneuvers are quite accurate when
using the Moving Demand approach since the reference angle and rate demand are con-
tinuously known.
Chapter 5 — Control Demand for Imaging Sequence 57
0 20 40 60 80 100 120−2.5
−2
−1.5
−1
−0.5
0
0.5
1
1.5
2
2.5Orbit Referenced Rate Demand
time (s)
wxwywz
Slew 1 &SettlingTime
Slew 2
Slew 3 &SettlingTime
Slew 4
ImagingPeriod
Figure 5.3: Body Rate Demand for Imaging Sequence
0 20 40 60 80 100 120
−0.1
−0.05
0
0.05
0.1
0.15Torque Command
Nm
time (s)
Tx
Ty
Tz
Imaging Period
Figure 5.4: Simulation Result for Imaging Sequence - Torque Command
Chapter 5 — Control Demand for Imaging Sequence 58
0 20 40 60 80 100 120−20
−15
−10
−5
0
5
10
15
20
25
30Euler Angles
Deg
rees
time (s)
PitchRollYaw
Imaging Period
Figure 5.5: Simulation Result for Imaging Sequence - Euler Angles
0 20 40 60 80 100 120−2.5
−2
−1.5
−1
−0.5
0
0.5
1
1.5
2
2.5Gimbal Rate
Deg
rees
/s
time (s)
Delta dotx
Delta doty
Delta dotz
Imaging Period
Figure 5.6: Simulation Result for Imaging Sequence - Gimbal Rate
Chapter 5 — Control Demand for Imaging Sequence 59
0 20 40 60 80 100 120−6
−4
−2
0
2
4
6x 10
−3 Euler Angle Error
degr
ees
time (s)
Pitch ErrorRoll ErrorYaw Error
Imaging Period
Figure 5.7: Simulation Result for Imaging Sequence - Euler Angle Error
Chapter 6
Measurements and Results
The Control Moment Gyro module designed in Chapter 3 is tested on an air bearing table
and the measurements are compared to the simulation results of Chapters 2, 4 and 5 to
verify the functionality of the CMG design. Communications between the CMG module
and the PC is done via an RF link to minimize external forces. The CMG module with
battery, RF link and rate gyro is mounted on a cart with three carbon nozzles which are
used to levitate the system. This whole setup will be referred to as the CMG system. The
air bearing table, levitating cart and CMG setup are further described in Appendix C.
6.1 Calibration
6.1.1 Gimbal Accuracy
The step size of the gimbal is measured by means of a laser pointer. The laser pointer
was attached to the gimbal, pointing horizontally onto a wall. After a rotation of 100
steps, the distance covered on the wall was measured. The typical geometry are shown
in Figure 6.1.
1805 mm
60 mm
θ
Wall
Laser
Pointer
Figure 6.1: Measuring the gimbal’s step size
60
Chapter 6 — Measurements and Results 61
The angle, θ, which represents 100 steps is calculated as:
θ = arctan60
1805= 1.904o
Thus the measured size of one gimbal step = 0.01904o. From Section 3.3.2, the rotational
resolution of the gimbal is:
Motor step size
Total gear ratio=
15
786= 0.01908o
The measured gimbal step angle of 0.01904o is very close to the calculated value of
0.01908o.
6.1.2 Moment of Inertia Calculation
The aim of the first test on the air bearing table is to calculate the moment of inertia
of the cart and CMG system. This is done by using the CMG as a reaction wheel with
the spin-axis of the momentum wheel perpendicular to the ground level. The momentum
wheel is accelerated from zero and the angular acceleration of the cart is measured. The
moment of inertia of the ideal cart and CMG system Is is given from the conservation of
angular momentum as:
Is =Iwω
θ
with Iw = 0.0015 kgm2 the moment of inertia of the momentum wheel, ω the angular
acceleration of the momentum wheel and θ the angular acceleration of the cart. The
results of five consecutive tests are shown in Table 6.1. The measurements shown in the
table are the average for the first few seconds of each maneuver when the torque is still
at maximum.
ω/100 (o/s2) θ (o/s2) Is (kgm2)
9.9 2.85 0.521
9.8 2.85 0.5158
9.9 2.80 0.5304
10.5 2.96 0.5321
9.88 2.65 0.559
Table 6.1: Results from Moment of Inertia Tests
Chapter 6 — Measurements and Results 62
The average moment of inertia calculated from the measurements for the cart and CMG
system is Is = 0.535 kgm2. Figure 6.2 display the angular acceleration of the momentum
wheel and the cart, as well as the angular rotation and angular rate of the cart.
0 5 10 150
50
100
150
200
250
300
350Gyro Angular Rotation
Ang
le (
degr
ees)
0 5 10 150
5
10
15
20
25
30Gyro Rate
degr
ees/
s
time (s)
0 5 10 15
−2
0
2
4
6
8
10
12Gyro Acceleration & Wheelacc/100
degr
ees/
s2
time (s)
Gyro AccWheel Acc/100
Figure 6.2: Angular acceleration of Momentum Wheel and Cart (Gyro)
6.1.3 Glass Surface Test
Since the CMG setup consists of only one CMG, the resulting torque output of the CMG is
around two axes. The spin-axis of the momentum wheel is parallel to the ground plane and
the gimbal is rotated around an axis also parallel to the ground plane, but perpendicular
to the spin-axis as shown in Figure 6.3. For small gimbal angles, the output torque will
be large about an axis perpendicular to the ground plane. This will cause the cart to
rotate. The torque generated about the second axis will be very small and will have no
effect since the cart can only rotate around one axis.
The gimbal is rotated through a specific angle and then back to zero again. Repeating
this process will be referred to as ‘mirror’. The CMG is ‘mirrored’ from +15 degrees to
an inclination angle of -15 degrees with a gimbal rate of 500 steps/s (9.54 o/s). A wheel
speed of ω = 2000 rpm is used for the tests.
Chapter 6 — Measurements and Results 63
Spin-axis
Gimbal-axisGround plane
Figure 6.3: Diagram of the CMG setup
When a CMG is gimballed to a certain inclination angle and back to zero again, the
angular rate of the cart should reach a maximum at the maximum gimbal inclination angle
and return to zero when the gimbal is back at zero degrees, as described in Section 2.2.1.
In Figure 6.4 the gimbal inclination angle is plotted with the angular rate of the cart
(Gyro).
0 10 20 300
50
100
150
200
250
300Gyro Angular Rotation
Ang
le (
degr
ees)
0 10 20 30
−10
0
10
20
30Gyro Rate & Gimbal Angle
degr
ees/
s &
deg
rees
0 10 20 30−10
−5
0
5
10Gyro Acceleration
degr
ees/
s2
time (s)0 10 20 30
−10
−5
0
5
10Gimbal Rate
degr
ees/
s
time (s)
Gyro RateGimb Angl
Figure 6.4: Measured results of ’Mirror’ Test
As shown in the measured results, the angular rate of the cart does not always return
to zero when the gimbal angle is zero. This is as a result of the unevenness of the glass
Chapter 6 — Measurements and Results 64
surface and a little bit of friction. Since it is not possible to achieve a 100% even glass
surface by adjusting the legs of the table, all the measurements done on the air bearing
table will have a small error.
6.1.4 Constant Angular Rate Test
It is important to know the magnitudes of the disturbances due to the glass surface of
the air bearing table. Once it is determined, the accuracy of the results from the tests
on the air bearing table can more easily be explained. The disturbances are measured by
looking at the effect it has when the cart is rotating at a constant rate.
0 10 20 30 400
100
200
300
400
500
600Gyro Angular Rotation
degr
ees
0 10 20 30 400
5
10
15
20Gyro Rate
degr
ees/
s
time (s)
0 10 20 30 40−2
0
2
4
6
8Gyro Acceleration
degr
ees/
s2
time (s)
Figure 6.5: Measurements for constant angular rate input
The CMG is gimballed to an inclination angle of 30 degrees at a rate of 500 steps/s. In an
ideal case this would result in the cart moving at a constant angular rate. The measured
values are shown in Figure 6.5. Looking at the angular rate and acceleration of the cart,
one can clearly see the effect friction and an uneven glass surface has on the cart. The
change in angular rate can be divided into two parts. The one is a linear decrease in the
angular rate due to friction, and the other one is a periodic disturbance due to the uneven
surface.
Chapter 6 — Measurements and Results 65
The average deceleration of the cart due to friction is measured as θ = −0.586 o/s2. Using
Equation 2.3, the disturbance friction torque is calculated as:
Tavg = Isθ = 5.47 mNm
where the moment of inertia of the cart Is = 0.535 kgm2. The unevenness of the glass
surface causes a sinusoidal disturbance in the acceleration of the cart, with an amplitude
of between 0.5 and 1 o/s2 which results in a maximum torque of approximately 4.7 to 9.3
mNm.
6.2 CMG Tests
6.2.1 Rest-to-Rest Slew
The CMG is gimballed from +15 degrees to an inclination angle of -15 degrees, and back
to +15 degrees again, at a gimbal rate of 500 steps/s (9.54 o/s). This results in the cart
rotating almost 55 degrees with a maximum angular rate measured as 17.4 degrees/s.
The average angular acceleration of the cart is measured as 5.77 degrees/s2. The shape of
the results displayed in Figure 6.6 are very similar to the shape of the simulation results
from Section 2.3.
From Equation 2.6 the CMG torque is calculated as:
T = h× δ = 0.052315 Nm
with the angular momentum h = 209.42 × 0.0015 × cos δ Nms and the gimbal rate δ =
0.1665 rad/s. Since the gimbal angle δ is small, cos δ ≈ 1. Using this with Equation 2.3
gives:
θ =T
Is=
0.052315
0.535= 0.09779 rad/s2 (5.61 o/s2)
This calculated value of the angular acceleration (5.61 o/s2) is close to the average mea-
sured value of 5.77 o/s2. Using Equation 2.5, the rotation of the cart can be calculated.
Since the cart accelerates for the first half of the slew, and decelerates for the second
half, the rotation of the cart is calculated for the first half and then multiplied by two to
obtain the total slew rotation angle. The time, thalf , for half of the slew is obtained from
Figure 6.6 as thalf = 3.15 seconds. The rotation angle is then calculated as:
θT = 2 × θhalf =T
Ist2half = 0.9703 rad (55.6 o)
Chapter 6 — Measurements and Results 66
0 2 4 60
10
20
30
40
50
60Gyro Angular Rotation
Ang
le (
degr
ees)
0 2 4 6−20
−10
0
10
20
30Gyro Rate & Gimbal Angle
degr
ees/
s &
deg
rees
0 2 4 6−8
−6
−4
−2
0
2
4
6Gyro Acceleration
degr
ees/
s2
time (s)0 2 4 6
−10
−5
0
5
10Gimbal Rate
degr
ees/
s
time (s)
Gyro RateGimb Angl
Figure 6.6: Measured results of the Rest-to-Rest Slew
The calculated value of the rotation angle (55.6 o) is very similar to the measured value
(≈ 55 o) from the test. The calculated values of the angular acceleration and rotation
angle proof the validity of the measurements.
6.2.2 Moving Demand Test
The Moving Demand simulation done in Section 5 is used to obtain an array of gimbal
angle rotations which will cause the cart to do a slew maneuver similar to the pitch
rotation of the satellite in the moving demand simulation of Section 5.4. The moment
of inertia of the CMG system as measured in Section 6.1.2 is used with the following
parameters:
• tMID = 25 seconds after the start of slew 1.
• qMID = [0 0 0 1]T (0o pitch, 0o roll, 0o yaw).
• ωoIMG = [0 − 6 0]T degrees/s.
• ρS2,TOT = 80o.
Chapter 6 — Measurements and Results 67
The angular rotation and rate obtained from a mathematical simulation are displayed
together with the measured results in Figure 6.7.
0 10 20 30 40−40
−20
0
20
40
60Angular Rotation
degr
ees
0 10 20 30 40−5
0
5
10
15Angular Rate
degr
ees/
s
0 10 20 30 40−60
−40
−20
0
20
40
60Gyro Angular Rotation
degr
ees
time (s)0 10 20 30 40
−10
−5
0
5
10
15Gyro Rate
degr
ees/
s
time (s)
Figure 6.7: Measured results of the Moving Demand
From the Measured Angular Rate figure, the effect of friction and the uneven glass surface
is clearly visible, especially when the cart is suppose to move at a constant angular
rate. The friction causes a constant deceleration of the cart. Keeping the effects of the
disturbances in mind, the measured results are quite similar to the simulations and clearly
illustrates the pitch rotation of the Moving Demand.
Chapter 7
Conclusions
This thesis showed the design of a Single Gimbal Control Moment Gyro actuator which
can be used in small satellite applications. The CMG was tested on an air bearing table
to evaluate the working of the controller and the CMG. A mathematical model of a small
satellite with an actuator configuration containing six CMG’s and an attitude controller
were derived to simulate the rotation of the satellite when using CMG’s. These simulations
were compared to practical tests done with a single CMG prototype on the air bearing
table to verify the performance of the CMG.
7.1 Results Obtained
The following results were obtained in this thesis:
• The BLDC motor was successfully controlled with inner analogue current and outer
discrete speed control loops to within 0.6 rpm of the commanded wheel speed.
• The gimbal has a rotational resolution of 0.0191 degrees.
• A mathematical model of a satellite was developed according to the parameters
given in Section 1.1 and was used to simulate the behaviour of the satellite with
CMG’s. It was shown in the simulations of Section 2.3 that a 30 degree rotational
maneuver is possible within 10 seconds.
• A three-axis quaternion feedback control law under slew rate constraint was de-
rived for the satellite’s attitude control. This was successfully implemented in the
mathematical model of the satellite to demonstrate a 30 degree rotation within the
permitted 10 seconds with less than 0.2% overshoot.
68
Chapter 7 — Conclusions 69
• A control mode known as the Moving Demand approach, used during imaging, was
also introduced into the mathematical model. This approach successfully imple-
mented consecutive slew maneuvers via a time varying attitude and rate demand to
ensure better tracking of the attitude command. Tracking errors were kept below
0.005 degrees during simulations.
• A single CMG prototype was designed and built according to the specifications of
Section 1.1 and tested on an air bearing table. The results of the tests correspond
to the mathematical simulations and the theory of Chapter 2, 4 and 5.
7.2 Additional Work
The following is a list of additional work that can still be done:
• The steering logic of the CMG’s can be extended to a pseudoinverse steering logic.
This would mean only four CMG’s are required to gimbal at different gimbal rates,
giving the controller full 3-axis freedom, but also making it more vulnerable to
singularities.
• The prototype CMG can be used as a VSCMG and a control law for an integrated
power and attitude control system can be developed.
• All the electronics used for controlling the CMG can be combined on one pcb.
This would dramatically downsize the area needed and thus a more compact CMG
‘package’ can be designed.
• A complete CMG product with all the electronics included can be developed, de-
signed to specific specifications. This product has to be as compact and light as
possible so it can be used on a small satellite.
• The surface of the air bearing table needs to be leveled more accurately to conduct
tests with reduced disturbances. From the tests done in Chapter 6, one can see the
unevenness of the glass surface has a noticable influence on the measurements. Re-
search in developing a smooth surface which is 100% level, would thus tremendously
increase the quality of the measurements.
Bibliography
[1] AGILENT TECHNOLOGIES, INC. HEDS-9100 - Two Channel Optical
Incremental Encoder Modules, August 2001.
[2] AHMED, J., COPPOLA, V., and BERNSTEIN, D., “Adaptive Asymptotic
Tracking of Spacecraft Attitude Motion with Inertia Matrix Identification.” Journal
of Guidance, Control, and Dynamics, 1998, Vol. 21, No. 5, No. 5, pp. 684–691.
[3] ARSAPE. Low voltage driver for 2 phase stepper motors, May 2000.
[4] CYGNAL INTEGRATED PRODUTS, INC. C8051F040/1/2/3 Mixed-Sygnal ISP
FLASH MCU Family , August 2002.
[5] DE LA MORINAIS, G. C., SALENC, C., and PRIVAT, M., “Mini CMG
Development for Future European Agile Satellite.” 5th International ESA
Conference on Spacecraft Guidance Navigation and Control Systems, Frascati
(Rome), October 2002.
[6] DEFENDINI, A., FAUCHEUX, P., GUAY, P., MORAND, J., and HEIMEL, H.,
“A Compact CMG Product for Agile Satellites.” 5th International ESA Conference
on Spacecraft Guidance Navigation and Control Systems, Frascati (Rome),
October 2002.
[7] DUNGATE, D. G. et al., “Topsat Imaging Mode ADCS Design.” 5th International
ESA Conference on Spacecraft Guidance Navigation and Control Systems, Frascati
(Rome), October 2002.
[8] FORD, K. A. and HALL, C. D., “Singular Direction Avoidance Steering for
Control Moment Gyros.” Journal of Guidance, Control, and Dynamics, 2000,
Vol. 23, No. 4, No. 4, pp. 648–656.
[9] HEIBERG, C., BAILEY, D., and WIE, B., “Precision Spacecraft Pointing Using
Single-Gimbal Control Moment Gyroscopes with Disturbance.” Journal of
Guidance, Control, and Dynamics, 2000, Vol. 23, No. 1, No. 1, pp. 77–85.
70
BIBLIOGRAPHY 71
[10] LAPPAS, V. J., STEYN, W. H., and UNDERWOOD, C., “Attitude Control for
Small Satellites using Control Moment Gyros.” Acta Astronautica, 2002, Vol. 51,
No. 1-9, No. 1-9, pp. 101–111.
[11] LITEF GMBH. uFORS User Manual , May 2001.
[12] ONERA. Satellite attitude control using CMG , May 1999. [Online] Available:
http://www.onera.fr/dcsd-en/gyrodynes.
[13] RADIOMETRIX LTD. TX2 & RX2 Data Sheet , February 2002.
[14] SCHAUB, H. and JUNKINS, J. L., “Singularity Avoidance Using Null Motion and
Variable-Speed Control Moment Gyros.” Journal of Guidance, Control, and
Dynamics, January-February 2000, Vol. 23, No. 1, pp. 11–15.
[15] SHAMMA, M. and MICHAELIS, T., “Double Gimballed Momentum Wheel Design
for Small Satellites.” Proc. 1st International Conf. on Spacecraft Guidance,
Navigation and Control Systems, Noordwijk, The Netherlands, June 1991,
pp. 369–391.
[16] STEYN, W. H., “Reaction Wheel Electronics Design.” Private communication,
January 2004.
[17] TSIOTRAS, P. and SHEN, H., “Satellite Attitude Control and Power Tracking
with Energy/Momentum Wheels.” Journal of Guidance, Control, and Dynamics,
January-February 2001, Vol. 24, No. 1, pp. 23–33.
[18] UNITRODE CORPORATION. UC2625 - Brushless DC Motor Controller ,
November 1999.
[19] WERTZ, J. R. (Ed.), Spacecraft Attitude Determination and Control . Kluwer
Academic Publishers, 1990.
[20] WERTZ, J. R. and LARSON, W. J. (Eds), Space Mission Analysis and Design.
Microcosm Press and Kluwer Academic Publishers, 1999.
[21] WIE, B., BAILEY, D., and HEIBERG, C., “Rapid Multi-Target Acquisition and
Pointing Control of Agile Spacecraft.” AIAA Guidance, Navigation, and Control
Conference, Denver, August 2000.
[22] WIE, B. and LU, J., “Feedback Control Logic for Spacecraft Eigenaxis Rotations
Under Slew Rate and Control Constraints.” Journal of Guidance, Control, and
Dynamics, November 1995, Vol. 18, No. 6, pp. 1372–1377.
BIBLIOGRAPHY 72
[23] WIE, B., Space Vehicle Dynamics and Control . AIAA Education Series, AIAA,
Washington, DC, 1998.
[24] YOON, H. and TSIOTRAS, P., “Spacecraft Adaptive Attitude and Power Tracking
with Variable Speed Control Moment Gyroscopes.” Journal of Guidance, Control,
and Dynamics, November-December 2002, Vol. 25, No. 6, pp. 1081–1090.
Appendix A
CMG Machine Drawing
73
APPENDIX A - CMG MACHINE DRAWING 74
Figure A.1: Drawing of CMG stand with Gimbal
Appendix B
Schematics of Brushless DC Motor
Electronics
75
APPENDIX B - SCHEMATICS OF BRUSHLESS DC MOTOR ELECTRONICS 76
12
34
ABCD
43
21
D C B A
SH
TO
F6
1V
ER
SIO
N:
0.0
A
DW
G.N
O.:
ES
L0
3-1
04
02
0-2
13
-01
-0.0
A
TIT
LE
:
Bru
sh
less D
C M
oto
r E
lectr
on
ics
CO
PY
RIG
HT
RE
SE
RV
ED
FIL
E:
BLD
Cdri
ver0
.Sch
RE
VIS
ION
DE
TA
ILS
VE
RS
ION
C/N
OT
ED
RW
NC
HK
AP
PR
S.E
NG
DA
TEESL
HA
LL
1H
AL
L2
HA
LL
3
ISE
NS
E1
ISE
NS
E2
E/A
_O
UT
E/A
_O
UT
2.5
V R
EF
I_M
ON
SP
EE
D_D
IR
ISE
T
ISE
T_M
ON
2.5
V R
EF
I_M
ON
SP
EE
D_O
UT
SP
EE
D_D
IRS
PE
ED
_P
PR
SP
EE
D_O
UT
INH
IBIT
ST
EP
_D
IR
DE
BU
G
TE
ST
TP
2T
ES
TT
P1
DE
BU
G
ISE
T_M
ON
ISE
T
XC
FS
econ
d D
raft
12-1
1-20
03
4-O
ct-2
004
Prin
t
+12V
PG
ND
AG
ND
+5V
AG
ND
+5V
PG
ND
+12V
+5V
GN
D
GN
D
PW
M_Q
UA
DS
EL
PW
M_C
OA
ST
PW
M_D
IR
ISE
NS
E2
ISE
NS
E1
ISE
TE
/A_O
UT
2.5
V R
EF
+5V
RE
F
ISE
T_M
ON
I_M
ON
+5V
AG
ND
BL
DC
curr
ents
ense
BL
DC
curr
ents
ense
.Sch
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
AO
UT
1A
OU
T0
AIN
0
AV
RE
F
VB
US
+5V
GN
D
+3.3
V
A+
3.3
VA
GN
D
SD
AS
CL
VB
US
_G
ND
AIN
1A
IN2
P1.0
P1.1
TX
D1
RX
D1
AIN
3
CA
NH
_B
CA
NL_B
AD
CS
_S
YN
C_S
HIE
LD
CA
N_S
HIE
LD
_B
AD
CS
_S
YN
C_L
CA
NL_B
AD
CS
_S
YN
C_H
CA
NH
_B
CA
NH
_A
CA
NL_A
CA
N_S
HIE
LD
_A
CA
NL_A
CA
NH
_A
UN
RE
G_P
WR
_S
UP
PLY
UN
RE
G_P
WR
_S
UP
PLY
UN
RE
G_P
WR
_R
ET
UR
NU
NR
EG
_P
WR
_R
ET
UR
N
RE
G5_P
WR
_R
ET
UR
NR
EG
5_P
WR
_R
ET
UR
N
RE
G5_P
WR
_S
UP
PLY
RE
G5_P
WR
_S
UP
PLY
TM
ST
DI
TC
K
TD
O
TX
D0
RX
D0
P0.6
P0.7
gen
eric
gen
eric
.node.
sch
PD
AP
DB
PD
C
PU
AP
UB
PU
C
ISE
NS
E1
ISE
NS
E2
HA
LL3
HA
LL2
HA
LL1
+12V
PG
ND
+5V
GN
D
HA
LLA
+5V
HA
LLB
PH
AS
E A
HA
LLC
PH
AS
E B
GN
D
PH
AS
E C
BL
CD
mosf
ets
BL
CD
mosf
ets.
Sch
+5V
GN
D
+5V
GN
D
+12V
PG
ND
HA
LL
1H
AL
L2
HA
LL
3
ISE
NS
E1
ISE
NS
E2
TC
KT
MS
TD
IT
DO
RX
D0
TX
D0
PH
AS
E A
PH
AS
E B
PH
AS
E C
+5V
GN
D
HA
LL
AH
AL
LB
HA
LL
C
TC
KT
MS
TD
IT
DO
RX
D0
TX
D0
PH
AS
E A
PH
AS
E B
PH
AS
E C
HA
LL
AH
AL
LB
HA
LL
C
+3.3
V
GN
D
+3.3
V
PD
AP
DB
PD
C
PU
AP
UB
PU
C
HA
LL3
HA
LL2
HA
LL1
ISE
NS
E1
ISE
NS
E2
SP
EE
D_P
PR
PW
M_D
IR
E/A
_O
UT
+5V
RE
F
SP
EE
D_O
UT
SP
EE
D_D
IR
+12V
PG
ND
+5V
GN
D
PW
M_Q
UA
DS
EL
PW
M_C
OA
ST
CH
AN
NE
L_A
CH
AN
NE
L_B
BL
DC
dri
ver
contr
oll
erB
LD
Cdri
ver
contr
oll
er.S
ch
CH
AN
NE
L_A
CH
AN
NE
L_B
HA
LLA
+5V
HA
LLB
PH
AS
E A
HA
LLC
PH
AS
E B
GN
D
PH
AS
E C
CA
NH
_B
CA
NL_B
AD
CS
_S
YN
C_S
HIE
LD
CA
N_S
HIE
LD
_B
AD
CS
_S
YN
C_L
CA
NL_B
AD
CS
_S
YN
C_H
CA
NH
_B
CA
NH
_A
CA
NL_A
CA
N_S
HIE
LD
_A
CA
NL_A
CA
NH
_A
UN
RE
G_S
UP
PLY
UN
RE
G_S
UP
PLY
UN
RE
G_R
ET
UR
NU
NR
EG
_R
ET
UR
N
RE
G5_R
ET
UR
NR
EG
5_R
ET
UR
N
RE
G5_S
UP
PLY
RE
G5_S
UP
PLY
TM
ST
DI
TC
K
TD
O
TX
D0
RX
D0
+3.3
V
GN
D
CH
AN
NE
L_A
+5V
CH
AN
NE
L_B
RX
D1
TX
D1
BL
CD
dri
ver
Intr
fsB
LC
Ddri
ver
Intr
fs.S
ch
+5V
CH
AN
NE
L_A
CH
AN
NE
L_B
RX
D1
TX
D1
P0.6
CL
K_P
UL
SE
RF
EN
AB
LE
P1.0
SP
EE
D_P
PR
APPENDIX B - SCHEMATICS OF BRUSHLESS DC MOTOR ELECTRONICS 77
12
34
56
78
ABCD
87
65
43
21
D C B A
SH
TO
F6
2V
ER
SIO
N:
0.0
A
DW
G.N
O.:
ES
L03-1
04020-2
13-0
2-0
.0A
TIT
LE
:
Bru
sh
less D
C M
oto
r E
lectr
on
ics
CO
PY
RIG
HT
RE
SE
RV
ED
FIL
E:
generic.n
ode.s
ch
RE
VIS
ION
DE
TA
ILS
VE
RS
ION
C/N
OT
ED
RW
NC
HK
AP
PR
S.E
NG
DA
TEESL
P3
.0P
3.1
P3
.2P
3.3
P3
.4P
3.5
P3
.6P
3.7
P2
.0P
2.1
P2
.2P
2.3
P2
.4P
2.5
P2
.6P
2.7
P1
.2P
1.3
P1
.4P
1.5
P1
.6P
1.7
AO
UT
1A
OU
T0
AIN
0
AV
RE
FA
VR
EF
VB
US
+5
V
GN
D
+3
.3V
A+
3.3
V
+5
V
+3
.3V
A+
3.3
V
AG
ND
Sta
ndard
Bus Inte
rface (
SB
I)
TX
D1
GN
D2
VC
C3
RX
D4
Vre
f5
CA
NL
6C
AN
H7
RS
8
U3
PC
A82C
250?
TX
D1
GN
D2
VC
C3
RX
D4
Vre
f5
CA
NL
6C
AN
H7
RS
8
U4
PC
A82C
250?
+5
V
+5
V
CA
NS
EL
CA
NH
_A
CA
NL
_A
CA
NH
_B
CA
NL
_B
nC
AN
SE
L
CA
NR
X
CA
NT
X
CA
NR
X_A
CA
NR
X_B
CA
N tra
nceiv
ers
and m
ultip
lexer
R3
120
R2
120
Note
: O
nly
the
last
node
should
hav
e a
term
inat
ion r
esis
tor.
RE
2R
O1
DE
3A
6
B7
DI
4
VC
C8
GN
D5
U1
LT
C1480
AD
CS
_S
YN
C_H
AD
CS
_S
YN
C_L
+3
.3V
AD
CS
_S
YN
C
RS
485 d
river
for
AD
CS
_S
YN
C
L1
EX
XC
3216
A+
3.3
V+
3.3
V
Analo
gue G
round P
lane
Dig
ital G
round P
lane T
P4
AG
ND
TP
5G
ND
R13
1M
C22
1nFC
hassis
Gro
und P
lane
Dig
ital G
round P
lane
C18
1uF
C6
0.1
uF
R10
0E
+5
V
TP
6+
5V
C24
10uF
, 25V
C2
4.7
uF
, 20V
C7
0.1
uF
+5
V
TP
7+
3.3
V
R14
0.2
7R
, 1%
X2
DC
FIL
TE
R
R12
0E
RE
G5_P
WR
_S
UP
PL
Y
RE
G5_P
WR
_R
ET
UR
N
TM
ST
CK
TD
IT
DO
+3
.3V
A+
3.3
V+
3.3
V
VDD24
VDD41
VDD57
AV+3
DGND25
DGND40
DGND56
AV+6
AGND4
AGND5
TM
S5
8
TC
K5
9
TD
I6
0
TD
O6
1
/RS
T6
2
XT
AL
11
7
XT
AL
21
8
MO
NE
N1
9
VR
EF
7
VR
EF
A8
AIN
0.0
9
AIN
0.1
10
AIN
0.2
11
AIN
0.3
12
HV
CA
P1
3
HV
RE
F1
4
HV
AIN
+1
5
HV
AIN
-1
6
CA
NT
X2
CA
NR
X1
DA
C0
64
DA
C1
63
P0
.05
5
P0
.15
4
P0
.25
3
P0
.35
2
P0
.45
1
P0
.55
0
P0
.64
9
P0
.74
8
P1
.02
9
P1
.12
8
P1
.22
7
P1
.32
6
P1
.42
3
P1
.52
2
P1
.62
1
P1
.72
0
P2
.03
7
P2
.13
6
P2
.23
5
P2
.33
4
P2
.43
3
P2
.53
2
P2
.63
1
P2
.73
0
P3
.04
7
P3
.14
6
P3
.24
5
P3
.34
4
P3
.44
3
P3
.54
2
P3
.63
9
P3
.73
8
U5
C8051F
041
R4
100k
TX
D0
RX
D0
SD
AS
CL
CE
X0
T2
TP
3A
DC
S_S
YN
C
XT
AL
1X
TA
L2
C5
0.1
uF
DA
C B
yp
ass C
ap
s
C17
<tb
d>
Y1
16M
Hz
C3
22pF
C4
22pF
R9
10k
SD
A
R8
10k
SC
L
SD
AS
CL
+3
.3V
CA
NT
XC
AN
RX
+5V
_se
nse
+5V
_se
nse
+5V
AV
RE
F
R1
120
Pow
er
filter
and c
urr
ent m
easure
ment re
sis
tor
Initia
l desig
nF
.G.R
A??/0
3/2
003
Pow
er
Regula
tor
Decouplin
g c
apacitors
C9
0.1
uF
C12
0.1
uF
C13
0.1
uF
C15
0.1
uF
C16
0.1
uF
+5
V
A+
3.3
V
C11
0.1
uF
C10
0.1
uF
+3
.3V
OU
T1
SE
NS
E2
GN
D3
BY
P4
SH
DN
5
GN
D6
GN
D7
IN8
U6
LT
1763-3
.3
C25
0.0
1uF
+5
V
+5
V
X1
DC
FIL
TE
R
R11
0E
UN
RE
G_P
WR
_S
UP
PL
Y
UN
RE
G_P
WR
_R
ET
UR
NV
BU
S_
GN
D
Pow
er
filter
AIN
1A
IN2
TX
D1
RX
D1
P1
.0P
1.1
TX
D1
RX
D1
AIN
3
C21
1nF
C14
0.1
uF
C1
4.7
uF
, 20V
XC
FS
econ
d D
raft
(Add
apte
d fo
r R
W d
esig
n)12
-11-
2003
4-O
ct-2
004
Prin
t
ES
L04-1
00000-2
13-0
1-0
.0A
Ori
gin
ally
the
Gen
eric
Node:
AD
CS
_S
EL
+3
.3V
C54
0.1
uF
123
U2A
SN
74H
C00N
GN
D7
VC
C1
4
U2E
SN
74H
C00N
89 1
0
U2C
SN
74H
C00N
11
12
13
U2D
SN
74H
C00N
4 56
U2B
SN
74H
C00N
Pow
er
Addit
ional
100nF
outp
ut
cap. at
gro
undin
g c
ircu
it.
Gen
eric
CA
N N
od
e.
CA
NL
_A
CA
NH
_A
CA
N_S
HIE
LD
_A
AD
CS
_S
YN
C_H
AD
CS
_S
YN
C_L
CA
N_S
HIE
LD
_B
J3J2
J1
AD
CS
_S
YN
C_S
HIE
LD
CA
NL
_A
CA
NH
_A
CA
NH
_B
CA
NL
_B
CA
NH
_B
CA
NL
_B
CA
N
CA
NH
_B
CA
NL
_B
AD
CS
_S
YN
C_
SH
IEL
D
CA
N_
SH
IEL
D_
BA
DC
S_
SY
NC
_L
CA
NL
_B
AD
CS
_S
YN
C_
H
CA
NH
_B
CA
NH
_A
CA
NL
_A
CA
N_
SH
IEL
D_
A
CA
NL
_A
CA
NH
_A
UN
RE
G_P
WR
_S
UP
PL
Y
UN
RE
G_P
WR
_R
ET
UR
NR
EG
5_P
WR
_S
UP
PL
Y
RE
G5_P
WR
_R
ET
UR
NU
NR
EG
_P
WR
_S
UP
PL
Y
UN
RE
G_P
WR
_R
ET
UR
N
RE
G5_P
WR
_S
UP
PL
Y
RE
G5_P
WR
_R
ET
UR
N
UN
RE
G_
PW
R_
SU
PP
LY
UN
RE
G_
PW
R_
SU
PP
LY
UN
RE
G_
PW
R_
RE
TU
RN
UN
RE
G_
PW
R_
RE
TU
RN
RE
G5
_P
WR
_R
ET
UR
N
RE
G5
_P
WR
_R
ET
UR
N
RE
G5
_P
WR
_S
UP
PL
Y
RE
G5
_P
WR
_S
UP
PL
Y
R6
10k
R5
10k
R7
10k
+3
.3V
TM
S
TD
IT
CK
TD
O
TX
D0
RX
D0
APPENDIX B - SCHEMATICS OF BRUSHLESS DC MOTOR ELECTRONICS 78
12
34
ABCD
43
21
D C B A
SH
TO
F6
3V
ER
SIO
N:
0.0
A
DW
G.N
O.:
ES
L0
3-1
04
02
0-2
13
-03
-0.0
A
TIT
LE
:
Bru
sh
less D
C M
oto
r E
lectr
on
ics
CO
PY
RIG
HT
RE
SE
RV
ED
FIL
E:
BLD
Cdri
verc
ontr
olle
r.S
ch
RE
VIS
ION
DE
TA
ILS
VE
RS
ION
C/N
OT
ED
RW
NC
HK
AP
PR
S.E
NG
DA
TEESL
ISE
NS
E2
5
E/A
IN
(+
)1
VR
EF
2
ISE
NS
E3
ISE
NS
E1
4
DIR
6
SP
EE
D-I
N7
H1
8
H2
9
H3
10
RC
-BR
AK
E21
QU
AD
SE
L22
0V
-CO
AS
T23
SS
TA
RT
24
RC
-OS
C25
PW
M IN
26
E/A
OU
T27
E/A
IN
(-)
28
PD
C12
PD
B13
PD
A14
GND15
PU
C16
PU
B17
PU
A18
VCC19 T
AC
H-O
UT
20
PWR VCC11
U8
UC
2625
+C
42
4.7
uF
, 35V
C35
100nF
VD
D6
INA
2
INB
4
GN
D3
OU
TA
7
OU
TB
5
U9
MA
X4427E
SA
VD
D6
INA
2
INB
4
GN
D3
OU
TA
7
OU
TB
5
U10
MA
X4427E
SA
+12V
+12V
+12V
C43
4n7
C34
100nF
C23
1nF
CO
AS
TD
IRC
MD
QU
AD
SE
L
+5V
C44
10nF
+12V
TP
16
TP
17
TP
20
TP
14
TP
15
TP
19
TP
29
PD
AT
P30
PD
BT
P31
PD
C
TP
13
TP
18
PD
AP
DB
PD
C
PD
AP
DB
PD
C
PU
A
PU
BP
UC
+12V
+12V
+12V
HA
LL3
HA
LL2
HA
LL1
R37
150k
+5V
ISE
NS
E1
ISE
NS
E2
DIR
CM
DP
WM
_D
IR
4 56
U11B
HC
86
TP
32
SP
EE
D_P
PR
TP
35
DIR
CM
D
1 23
14 7V+
V-
U11A
HC
86
+5V
UC
2625
MA
X4427E
SA
's
SP
EE
D_P
PR
PW
M_D
IR
E/A
_O
UT
R32
68k, 1%
R30
10k
R31
20k
+5V
RE
F
SP
EE
D_O
UT
SP
EE
D_P
PR
R36
0E
PG
ND
Ref
er a
lso t
o g
ener
ic_node.
Sch
C46
220pF
+5V
C45
220pF
TP
37
CH
AN
NE
L_A
TP
36
CH
AN
NE
L_B
+5V
TP
38
SP
EE
D_D
IR
VC
C14
GN
D7
D2
CLK
3
nS4
nR1
Q5
nQ
6
U12A
74H
CT
74
SP
EE
D_D
IRS
PE
ED
_D
IR
CH
AN
NE
L_A
CH
AN
NE
L_B
VC
C14
GN
D7
D12
CLK
11
nS10
nR13
Q9
nQ
8
U12B
74H
CT
74
+5V
C47
100nF
+5V
74H
C74
CH
AN
NE
L_A
CH
AN
NE
L_B
C32
100nF
+C
40
4.7
uF
, 35V
+12V
C33
100nF
+C
41
4.7
uF
, 35V
+12V
C36
100nF
+5V
74H
C86
XC
FS
econ
d D
raft
12-1
1-20
03
4-O
ct-2
004
Prin
t
CH
AN
NE
L_A
CH
AN
NE
L_B
R33A
10k
R33B
10k
R33C
10k
R34A
10k
R34B
10k
R34C
10k
+12V
PG
ND
+12V
PG
ND
+5V
+5V
GN
DG
ND
EN
CO
DE
R
QU
AD
SE
LP
WM
_Q
UA
DS
EL
TP
33
QU
AD
SE
L
9
10
8U
11C
HC
86
PW
M_Q
UA
DS
EL
CO
AS
TP
WM
_C
OA
ST
TP
34
CO
AS
T
12
13
11
U11D
HC
86
PW
M_C
OA
ST
CH
AN
NE
L_A
CH
AN
NE
L_B
APPENDIX B - SCHEMATICS OF BRUSHLESS DC MOTOR ELECTRONICS 79
12
34
ABCD
43
21
D C B A
SH
TO
F6
4V
ER
SIO
N:
0.0
A
DW
G.N
O.:
ES
L0
3-1
04
02
0-2
13
-04
-0.0
A
TIT
LE
:
Bru
sh
less D
C M
oto
r E
lectr
on
ics
CO
PY
RIG
HT
RE
SE
RV
ED
FIL
E:
BLC
Dm
osfe
ts.S
ch
RE
VIS
ION
DE
TA
ILS
VE
RS
ION
C/N
OT
ED
RW
NC
HK
AP
PR
S.E
NG
DA
TEESL
+12V
C38
100nF
+C
53
22uF
, 25V
PG
ND
C37
100nF
PG
ND
ISE
NS
E1
ISE
NS
E2
PH
AS
E C
PH
AS
E B
PH
AS
E A
PG
ND
PG
ND
PG
ND
TP
24
TP
25
TP
26
TP
28
TP
27
TP
40
+12V
TP
39
PG
ND
R44
240
R45
240
R42
0.2
7R
43
0.2
7
PD
A
PD
B
PD
C
PU
A
PU
B
PU
C
+12V
ISE
NS
E1
ISE
NS
E2
PH
AS
E A
PH
AS
E B
PH
AS
E C
HA
LL
A
HA
LL
B
HA
LL
C
+5V
GN
D
C52
2n2
C51
2n2
C50
2n2
TP
23
TP
22
TP
21
HA
LL3
HA
LL2
HA
LL1
HA
LL
1H
AL
L2
HA
LL
3
G
SD
2
7,8
1
Q3A
IRF
7319
GS D
4
5,6
3Q
2B
IRF
7319
GS D
4
5,6
3Q
3B
IRF
7319
G
SD
2
7,8
1
Q2A
IRF
7319
GS D
4
5,6
3Q
1B
IRF
7319
G
SD
2
7,8
1
Q1A
IRF
7319
XC
FS
econ
d D
raft
12-1
1-20
03
4-O
ct-2
004
Prin
t
R35A
10k
R35B
10k
R35C
10k
C49A
10nF
C49B
10nF
C49C
10nF
C48A
10nF
C48B
10nF
C48C
10nF
R40A
100k
R40B
100k
R40C
100k
R38C
10
R38B
10
R38A
10
R39A
10
R39B
10
R39C
10
R41D
1k
R41C
1k
R41B
1k
+12V
PG
ND
+12V
PG
ND
+5V
+5V
GN
D
D8
30B
Q100
D9
30B
Q100
D10
30B
Q100
D3
30B
Q100
D5
30B
Q100
D7
30B
Q100D
230B
Q100
D6
30B
Q100
D4
30B
Q100
HA
LLA
+5V
HA
LLB
PH
AS
E A
HA
LLC
PH
AS
E B
GN
DP
HA
SE
C
APPENDIX B - SCHEMATICS OF BRUSHLESS DC MOTOR ELECTRONICS 80
12
34
ABCD
43
21
D C B A
SH
TO
F6
5V
ER
SIO
N:
0.0
A
DW
G.N
O.:
ES
L0
3-1
04
02
0-2
13
-05
-0.0
A
TIT
LE
:
Bru
sh
less D
C M
oto
r E
lectr
on
ics
CO
PY
RIG
HT
RE
SE
RV
ED
FIL
E:
BLD
Ccurr
ents
ense.S
ch
RE
VIS
ION
DE
TA
ILS
VE
RS
ION
C/N
OT
ED
RW
NC
HK
AP
PR
S.E
NG
DA
TEESL
567
48
U7B
LM
358A
48
2 31
U7A
LM
358A
R26
12k, 1%
R24
39k
R23 0
R21 0
R28
2M
2C
19
1uF
R25
39k
R27
12k, 1%
R29
2M
2 C20
1uF
E/A
_O
UT
R18
100k, 1%
R16
10k
R17
10k
R19
100k, 1%
R20
10k
C31
100nF
C26
100nF
C29
100nF
ISE
T
TP
8IS
EN
SE
1T
P9
ISE
NS
E2
TP
10
I_M
ON
TP
11
ISE
T
TP
12
E/A
_O
UT
I_M
ON
ISE
NS
E2
ISE
NS
E1
+5V
+5V
ISE
T
ISE
T_M
ON
E/A
_O
UT
LM
358A
C27
100nF
+5V
RE
F
2.5
V R
EF
+5V
RE
F
ISE
T_M
ON
I_M
ON
XC
FS
econ
d D
raft
12-1
1-20
03
17-N
ov-2
004
Prin
t
+5V
+5V
AG
ND
AG
ND
NC
1
IN2
NC
3
GN
D4
NC
5O
UT
6N
C7
NC
8D
1
MA
X6166
C39
100nF
TP
41
2.5
V R
EF
APPENDIX B - SCHEMATICS OF BRUSHLESS DC MOTOR ELECTRONICS 81
12
34
ABCD
43
21
D C B A
SH
TO
F6
6V
ER
SIO
N:
0.0
A
DW
G.N
O.:
ES
L0
3-1
04
02
0-2
13
-06
-0.0
A
TIT
LE
:
Bru
sh
less D
C M
oto
r E
lectr
on
ics
CO
PY
RIG
HT
RE
SE
RV
ED
FIL
E:
BLC
Ddri
verI
ntr
fs.S
ch
RE
VIS
ION
DE
TA
ILS
VE
RS
ION
C/N
OT
ED
RW
NC
HK
AP
PR
S.E
NG
DA
TEESL
XC
FS
econ
d D
raft
12-1
1-20
03
4-O
ct-2
004
Prin
t
WP
24 W
P28
WP
25 W
P29
WP
26 W
P30
WP
27 W
P31
BL
DC
MO
TO
R
HA
LLA
+5V
HA
LLB
PH
AS
E A
HA
LLC
PH
AS
E B
GN
DP
HA
SE
C
Pow
er
CA
N
WP
1W
P9
WP
2W
P10
WP
3W
P11
WP
4W
P12
WP
5W
P13
WP
6W
P14
WP
7W
P15
WP
8
CA
NH
_B
CA
NL_B
AD
CS
_S
YN
C_S
HIE
LD
CA
N_S
HIE
LD
_B
AD
CS
_S
YN
C_L
CA
NL_B
AD
CS
_S
YN
C_H
CA
NH
_B
CA
NH
_A
CA
NL_A
CA
N_S
HIE
LD
_A
CA
NL_A
CA
NH
_A
WP
23
WP
19W
P22
WP
18W
P21
WP
17W
P20
WP
16
UN
RE
G_P
WR
_S
UP
PLY
UN
RE
G_P
WR
_S
UP
PLY
UN
RE
G_P
WR
_R
ET
UR
N
UN
RE
G_P
WR
_R
ET
UR
N
RE
G5_P
WR
_R
ET
UR
N
RE
G5_P
WR
_R
ET
UR
N
RE
G5_P
WR
_S
UP
PLY
RE
G5_P
WR
_S
UP
PLY
12
34
56
78
910
P2
JTA
G
+3.3
V
TM
ST
DI
TC
KT
DO
JT
AG
TM
ST
DI
TC
KT
DO
TX
D0
RX
D0
1 2 3
P4
UA
RT
0
TX
D0
Ser
ial
Inte
rface
RX
D0
+3.3
V+
3.3
VG
ND
GN
D
CH
AN
NE
L_A
CH
AN
NE
L_B
WP
32
WP
34 W
P33
WP
35
CH
AN
NE
L_A
+5V
CH
AN
NE
L_B
+5V
+5V
Op
tica
l In
crem
enta
l E
nco
der
TX
D0
RX
D0
1 2 3
P8
UA
RT
1
TX
D1
RX
D1
Appendix C
CMG Setup for Practical Tests
The practical tests of the CMG were done on an air bearing table, which consists of a table
with a glass surface. The CMG with electronics are placed on an aluminium frame which
has three carbon nozzles and a small gas canister. The canister is filled with nitrogen to
a pressure of about 15 MPa. This is slowly released through the carbon nozzles, which
then lifts the frame from the glass surface, leaving it almost frictionless and very sensitive
to any disturbance. For this reason the glass surface has to be as level as possible and
dustfree. The aluminium frame with gas canister is shown in Figure C.1.
Figure C.1: Picture of aluminium frame with gas canister and nozzles
82
APPENDIX C - CMG SETUP FOR PRACTICAL TESTS 83
The air bearing table has a metal frame with 15 legs of which the height are seperately
adjustable. The legs can be extended or shortened by adjusting a nut. A cable is attached
to the frame next to each leg. This is used to pull the frame down and keep it in place
once the height of the table has been adjusted. A 35mm thick Superwood surface is placed
on top of the metal frame. This is covered by a layer of felt to protect the glass surface.
The glass surface is then placed on top of the felt. A picture of the table is shown in
Figure C.2.
Figure C.2: Picture of the table with glass surface
A miniature fibre optic rate sensor [11] was used in the CMG setup to measure the
angular rotation of the CMG system. The sensor transmits an angle increment to the
microcontroller each time it receives a trigger pulse. One angle increment has a resolution
of 0.00024414 degrees. The angle increment is transmitted as RS422 by the sensor and has
to be converted to RS232 before the microcontroller can receive the data. The measured
data is then transmitted from the microcontroller to a PC via an RF link to minimize the
external disturbances.
A 12V battery was used to provide power to the BLDC motor and RF link. An LM317
adjustable regulator was used to adjust the 12V supply to 5V for the rate sensor, stepper
motor and all the electronics. A diagram of the setup is shown in Figure C.3 and a picture
in Figure C.4.
APPENDIX C - CMG SETUP FOR PRACTICAL TESTS 84
Stepper
MotorRate
Gyro
RF Link
BLDC
Motor
12V
Power
Supply
CMG
Electronics
PC
RF Link
Figure C.3: Diagram of the CMG setup
Figure C.4: Picture of the CMG setup
Appendix D
CMG Interface Program
The program, CMGprobe, is used as interface between the user and the Control Moment
Gyro. The CMG is fully controllable from this program and has functions such as load
and save. A picture of the control panel is shown in Figure D.1. The control panel consists
mainly of the following four parts: stepper motor control, BLDCM control, data sampling
and data display.
D.1 Stepper Motor Control
The stepper motor control panel is used to control the gimbal maneuvers. The rotation
angle of the gimbal is controlled by the Gimble Rotation window. A maximum angle
increment of 90 degrees is allowed to protect the gimbal. The gimbal rate can be modified
in the Steps/Sec window. A minimum of 10 steps/sec and a maximum of 500 steps/sec is
allowed. The direction of the gimbal rotation is set by the Clockwise bit. The Mirror bit
is used when the gimbal needs to rotate by an angle increment and back. This process
repeats until it is stopped. When the gimbal needs to rotate by a certain amount of
stepper motor steps, the Steps window is used. The total angle deviation of the gimbal
is displayed in the Gimbal Angle window.
The definition of the buttons are as follows:
• Start - When the Start button is pressed, the gimbal will rotate by the angle specified
in the Gimbal Rotation window at a rate of Steps/Sec and in the direction selected
by the Clockwise bit.
• Stop - The Stop button will immediately stop the gimbal.
• Step - Pressing the Step button will cause the gimbal to step the amount of steps
85
APPENDIX D - CMG INTERFACE PROGRAM 86
specified in the Steps window at a rate of Steps/Sec in the selected direction.
• Go to Zero - This button cause the gimbal to rotate back to the zero degree gimbal
angle position.
• Zero Angle - This button resets the Gimbal Angle to zero.
• Start Sending - When this button is pressed, gimbal excursion angles are read in
from the file specified in the window. This is used to implement a ’Moving Demand’.
Each 100 ms the new excursion angle will be sent to the microcontroller and the
needed gimbal rate is calculated from the difference between two following angles
excursions.
D.2 BLDCM Control
The speed of the BLDC motor is controlled with the BLDCM Control panel. The current
loop of the BLDCM control can be accessed directly from this panel for current control.
A definition of the buttons are given below:
• Output Current Dem - The current loop command is directly controllable with this
button. The input range is from -4095 to 4095 where a negative value means rotation
in the anti-clockwise direction.
• Switch RW On/Off - Power to the momentum wheel is switched on and off, de-
pending on the RW On bit.
• Send Wheel Speed - A new speed command for the momentum wheel is sent when
the Send Wheel Speed button is pressed. The speed range for the momentum wheel
is -5000 to 5000 rpm with an accuracy of 0.6 rpm.
• Send Controller Gains - The controller gains of the speed loop can be changed by
sending new gain values. The default values are: K1 = 91 and K2 = 74.
D.3 Data Sampling
The telemetry received from the microcontroller can be sampled and stored in a file. This
is done by entering the path in the Files Directory window and a name for the file in the
File Name window. When the Start Sampling button is pressed, the telemetry received
will be written to the specified file. Sampling will stop when the Stop Sampling button
is pressed.
APPENDIX D - CMG INTERFACE PROGRAM 87
D.4 Data Display
The received telemetry is displayed in the Data Received window. It includes the mo-
mentum wheel speed, gimbal angle excursion, package number and the gyro angle. The
correct comport for the serial link can also be set on this panel.
APPENDIX D - CMG INTERFACE PROGRAM 88
Figure D.1: Picture of the CMGprobe control panel
Appendix E
Matlab Simulation Design and
S-function Code
89
APPENDIX E - MATLAB SIMULATION DESIGN AND S-FUNTION CODE 90
Uc
Pitch
Roll
Yaw
wheel speed
gim
b a
ngle
Torq
ue c
om
m
CM
G H
_H
do
t
Eu
ler
An
gle
s
Qu
ate
rnio
ns
W_
Sa
t
Sate
llite
Contr
olD
erivation
S-F
unction
Co
mm
an
d T
orq
ue
W_
Sa
t
CM
G d
ata
Gim
b r
ate
s
Req g
imb r
ate
s
Req G
imb r
ate
-K-
R2D
8
-K-
R2D
2
-K-
R2D
1Q
uate
rnio
ns
Quate
rnio
n d
em
and
Pa
ram
ete
rs
Input P
ara
mete
rs
In1
gim
b
wh
ee
l sp
ee
d
Gim
b a
ngle
s
Eule
r A
ngle
s
em
Qu
ate
rnio
ns
Qu
ate
rn c
om
m
W_
sa
t
Co
mm
an
d T
orq
ue
Contr
ol B
lock
Body R
ate
dem
and
3se
t G
imb
ra
tes
H_
Hd
ot
To
tal
da
ta
3 S
ets
of V
SC
MG
s
Figure E.1: Picture of Matlab Simulation
APPENDIX E - MATLAB SIMULATION DESIGN AND S-FUNTION CODE 91
function [sys,x0,str,ts] = ControlDerivation(t,x,u,flag)
switch flag, case 0, [sys,x0,str,ts]=mdlInitializeSizes; case 3, sys=mdlOutputs(t,x,u); case 1, 2, 4, 9, % Unused flags sys=[]; otherwise error(['Unhandled flag = ',num2str(flag)]);end% end sfuntmpl
%=========================================================================% mdlInitializeSizes% Return sizes, initial conditions, and sample times for the S-function.%=========================================================================%function [sys,x0,str,ts]=mdlInitializeSizessizes = simsizes;sizes.NumContStates = 0;sizes.NumDiscStates = 0;sizes.NumOutputs = 7;sizes.NumInputs = 9;sizes.DirFeedthrough = 1;sizes.NumSampleTimes = 1; % at least one sample time is needed
Spur GearheadsFor combination with:Stepper motor: AM 1524
Housing material metalGeartrain material all steelRecommended max. input speed for:– continuous operationBacklash, (preloaded) 1)
Bearings on output shaft preloaded ball bearingsShaft load, max.:– radial (6,5 mm from mounting face)– axialShaft press fit force, max.Shaft play (on bearing output):– radial– axialOperating temperature range
reduction ratio(nominal)
weightwithoutmotor
withoutmotor
length output torqueefficiencydirection
of rotation(reversible)
continuousoperation
intermittentoperation
Specifications
Zero Backlash
Orientation with respect to motorterminal circuit board is not defined
deep
deep
1) These gearheads are available preloaded tozero backlash only with motors mounted.
2) Limited by the preloaded ball bearings.A higher axial load negates the preload.
withmotor
APPENDIX G - DATASHEETS 103
AD VL M
53,5
22*76,3
1
4
1
12
5214,2 14,2*
4x M2 x 5,3
ARSAPESwitzerland
10,1
5*
ACC
DEC
RUN
STOP
FMA
XFM
IN
48
12 (M1)
*(M2, M3)
0
500
1000
1 2 30
1500
4
2000
3 3 3 V DC14 14 14 V DC
14 16 16 mA400 400 400 mA
0 ... 0,6 0 ... 0,6 0 ... 0,6 V DC1,6 ... 14 1,6 ... 14 1,6 ... 14 V DC
– 10 10– 2 000 2 000
0 ... +70 0 ... +70 0 ... +70 °C22 30 34 g
VL M1 VL M2 VL M3Series
Drive ElectronicsLow Voltage For combination with:
Stepper motor: AM 0820, AM 1020, AM 1524
Motor connector
Commandconnector
GND
Power supply (V+)
Switch
+5V CC GND
DIRF/H
• AD VL M1 basic drive is composed of a translator (full step and half step mode)and a power stage which is in this case in voltage mode.
• AD VL M2 contains the basic drive AD VL M1 and a pulse generator delivering variableclock frequency.
• AD VL M3 contains the basic drive AD VL M1 and a pulse generator with generation of ramps.This circuit can provide a velocity profile to start and stop the stepper motorwith acceleration and deceleration ramps.
The drivers type AD VL M are designed todrive the two phase stepper motors type AM ...3 types of drivers are available:
Velocity profile example
* only valid for the AD VL M2 and AD VL M3
Power supply voltage:- min.- max.
Power supply currentOutput current, max. (for each phase)
Logic input level:- low- high
Direction of rotation CW / CCW CW / CCW CW / CCWStep mode full step / half step full step / half step full step / half step
Step frequency:- min. full step/s- max. full step/s
Operating temperature rangeWeight
General description / Features / Command connector functions
Scale reduced
OPO
Speed(rpm)
Time (s)
4x2,7 (only for M1)
1 I OPO > full step mode, one phase ON (wave)2 I F/H > half step mode; default or low logic level = full step mode, 2 phases ON3 I DIR > ccw ; default or low logic level = cw4 I CLK > external clock input, active on the positive edge of the clock pulse5 I RUN > starts the clock generator *6 I STOP > stops the clock generator *7 I Inhibit > disables the current in both coils of the motor8 O Busy > low level as long as the clock is active *9 – GND > ground potentional: 0 Volt
10 O VCC > +5V output11 – GND > ground potentional: 0 Volt12 I VCO > external voltage input (Voltage Controlled Oscillator) *