the assignment is attached to the zip file but here is some of it so u have an i

the assignment is attached to the zip file but here is some of it so u have an ideaSV Basic Properties:
– SV has same 3 reaction wheels (RWs) as & MOI as HW4
– Body-mount radiator normal: -?2 (point away from sun and Earth for max efficiency)
– Solar panel normal: ― ?3 (point towards sun whenever possible)
– Payload boresight: ?3 (point this axis towards targets when asked to)
– Sun direction: ― ?2
– Control Law: ? = ?? ??(1:3) + ??? + ?? ∑? ― 4
? ??(1:3)∆??
o Control law units: rad
?2
o Gains: ?? = 70 ?? = 1200 ?? = 30
SV Thruster Properties:
– 8x 1 N thrusters (See
properties sheet on
CANVAS)
– Nominal thrust is 0.9 N
at beginning of life (BOL)
– Tank filled with 5.5 kg
of propellant (LMP-103S)
– Assume each pulse
consumes 6.93E-05
kg/pulse where each
pulse is 100 ms in
duration (same as
controller frequency)
CASE 1 (1 pt) – Thruster Detumble to Sun Safe Mode
Goal: Detumble SV only using thrusters and point solar panels
directly at sun (see fig.)
Requirements:
Use thrusters in model as shown above (turn RWs off)
Initial quaternion: ?(0) = [ ―0.3062 0.1768 0.362 0.839]?
Final quaternion: see image on right
SV initial angular rates: ??(0) = ?
180[2 2 2]? rad/s
SV final angular rates: ?? = ?
180[0 0 0 ]? rad/s
Initial & final RW spin rates: ?(0) = 2?
60[1,000 1,000 1,000]? [rad
s ]
Analysis time period: 0 – 1,000 s
Deliverables:
a. Explain which thruster pairs need to be fired for control about each SV axis, both
+ and – torque needed to attain 3-DOF control. For example, “thrusters 5 & 1 fire
together for torque about the ― ?2 axis”
b. Explain how much torque is applied when thrusters are firing in the pairs as
described in part a. of this problems – both positive and negative torques?
c. Provide graphical screenshots showing the initial and final SV orientations
d. Write 2-3 sentences explaining “bang-bang” control and show evidence in the
plots where you see this type of control in effect
e. How much propellant did the thrusters consume (kg & percentage of total)?
CASE 2 (1 pt) – Thruster & RW Detumble to Sun Safe
Goal: Detumble SV using thrusters and RWs and point solar panels
at sun
Requirements:
Use thrusters and RWs, but never at the same time
Initial quaternion: ?(0) = [ ―0.3062 0.1768 0.362 0.839]?
Final quaternion: see image on right
SV initial angular rates: ??(0) = ?
180[2 2 2]? rad/s
SV final angular rates: ?? = ?
180[0 0 0 ]? rad/s
Initial RW spin rates: ?(0) = 2?
60[1,000 1,000 1,000]? [rad
s ]
Analysis time period: 0 – 1,000 s
Commanded Attitude with
constraints applied
Commanded Attitude with
constraints applied
Deliverables:
a. Provide graphical screenshots (main screen w/values showing) showing the initial
and final SV orientation
b. Write 2-3 sentences explaining when thrusters are used and when RWs are used
– show they are not used at the same time
c. How much propellant did the thrusters consume to detumble and compare to
Case 1? Was it less?
CASE 3 (1 pt) – Disturbance Torque
Goal: Use RWs and thrusters to fight a gravity gradient disturbance torque
Requirements:
Initial quaternion: ?(0) = [0 0 0 1]?
Final attitude: ?3 axis pointed at ? = 1
3[1 1 1]
Final attitude: ― ?2 axis pointed from sun ( ― ?2) as well as
you can
SV initial and final angular rate: ??(0) = ?
180[0 0 0]? rad/s
Initial RW spin rates: ?(0) = 2?
60[0 0 0]? [rad
s ]
Dist. Torque: M_b_ext = [ 0.001 0.001 0.001 ]? [Nm]
Analysis time period: 0 – 2,600 s (may be greater to see RW saturation)
Deliverables:
a. Provide graphical screenshots (main screen with values) showing starting and
final SV orientations and values
b. Plot the total SV angular momentum ?? in the inertial frame and RW speeds –
explain in 2 sentences what is occurring (1 sentence per topic)
c. Did RW rates change or saturate? Provide a plot and 2 sentences of explanation
BONUS QUESTIONS:
a. (1 POINT) Your boss said Case 2 uses too much propellant. Figure out how to
reduce propellant by half. Your boss said to turn in evidence to prove it and 2
sentences explaining how you did it.
b. (1 POINT) Your boss told you to add a thruster control law to unload the
RWs when they get above 3,500 rpm for Case 3. Your boss also said the
thrusters shall fire long enough to unload the RW below 1,000 rpm and
the RWs must be on when the thrusters are firing. Your boss also said
that you will likely have to extend the final time period to > 5-7,000 s to
see when the RWs get saturated. Your boss said to turn in evidence to
prove it and 2 sentences explaining how you did it.
Commanded Attitude with