RockSat-C 2012
ISTR
Individual Subsystem Testing Report
Zero TiltFrostburg State University
Kaetie Combs, Francisco Diaz , Sean Hughes, Jared Hughes, Andrew Huntley, Subhasis Ghosh, Mayowa Ogundipe, Derek Val-Addo, Michael Stevenson, Shaun O’Donnell, Ian
Cuddahee, Michael Young, David Wall
February 13 2012
1
RockSat-C 2012
ISTR
Mission Overview
• Mission Statement: Zero Tilt’s goal is to provide, for the first time, a stable environment throughout the flight of a Sounding Rocket via two concurrent objectives:
– Tilt correction system– Despun platform system
2
whs.mil
RockSat-C 2012
ISTR
Mission Objectives
• We plan to:
– Counteract the platform spin– Orient the platform parallel to the earth’s surface at all
times
• We expect to prove that it is possible to correct spin, tilt, and determine the altitude based upon a level reference.
• This could benefit any scientific experiment that requires stabilization
3
RockSat-C 2012
ISTR
Mission Objectives: Theory and Concepts
• The underlying theory and concepts:
– negative feedback control systems– concepts of torque and centripetal
force – Micro electromechanical systems
(MEMS)– Real-Time Systems Theory (for multi-
tasking
4
RockSat-C 2012
ISTR
Mission Overview: Mission Requirements
• Mission Objectives:– Counter the spin of the rocket during flight.– Keep a level surface to earth using our
conceptual design.– Prove successful by using the stored gyroscope
output and the feedback from various motors.• Minimum success criteria
– Our main goals as the Zero Tilt team is to receive results indicating that we achieved zero tilt for the flight of a sounding rocket.
5
RockSat-C 2012
ISTR
Functional Block Diagrams
6
shoponline2011.com
Zero Tilt System
Tilt System
Despun System
Power System
RockSat-C 2012
ISTR
Power Subsystem (Despun)
7
Power Supply: 9 volt Lithiums24 Volt Total
De-spin Motor
Voltage Regulator
5 to 3 volts
Flash Memory
Atmega 32 Processor
Voltage Regulator
24 to 5 Volts
High G Accelerometer High G
Accelerometer
RockSat-C 2012
ISTR
Power Subsystem (Tilt)
8
Power Supply: 9 volt Lithiums24 Volt Total
Spin Motor
Voltage Regulator
24 to 6 volts
Flash Memory
Atmega 32 Processor
Gyroscope
Low GAccelerometer
Voltage Regulator
24 to 3 volts
Tilt Motor
Voltage Regulator
24 to 5 volts
RockSat-C 2012
ISTR
Despun System
9
Flash Memory
Atmega 32 Processor
High G Accelerometer
High G Accelerometer
Motorcontroller/Driver
Despun Motor
RockSat-C 2012
ISTR
Tilt System
10
Flash Memory
Atmega 32 Processor
Low-G Accelerometer
Spin Motor
Tilt Motor
Gyroscope
RockSat-C 2012
ISTR
Changes from CDR
• Decided to consider a new servo motor that has lower power requirements, a faster response time, and more torque.
• We are running power wires from slip ring directly onto board due to our decision to limit our turn radius on the tilt platform.
• Due to Servo Considerations some minor design changes are being made for placement on Tilt platform.
11
RockSat-C 2012
ISTR
Program Management and Team Updates
12
Pictured from left to right: Mayowa Ogundipe, Subhasis Ghosh, Jared Hughes, Ian Cuddahee, Sean HughesDerek Val-Addo, Andrew Huntley, Kaetie Combs, Michael Stevenson, Francisco Diaz, Michael Young, Dr. Mohammed Eltayeb, Shaun O’Donnell, David Wall
RockSat-C 2012
ISTR
Schedule Update
• We are on schedule electrically and are waiting on the fabrication of mechanical parts to finish testing.
• We have shifted the completion of the mechanical tests later because of machining time.
• We are focusing our efforts on completing the electrical elements so that we know they will be reliable on the mechanical layout.
• Our main concern is completing our mechanical fabrication so we can finish testing.
13
RockSat-C 2012
ISTR
Subsystem Overview
• Subsystems
– Electrical
• Discussion by Mayowa Ogundipe, and Derek Val-Addo
– Power
• Discussion by Andrew Huntley, Jared Hughes, and Sean Hughes
– Mechanical
• Discussion by Shaun O’Donnell, and David Wall
14
nisd.net
RockSat-C 2012
ISTR
Electrical Subsystem Update
• Status– What is complete/what has been tested?– What has not yet been checked out?
15
RockSat-C 2012
ISTR
Electrical Subsystem Update (Continued)
16
RockSat-C 2012
ISTR
Electrical Subsystem Update
• What were the results?
– We were able to collect gyroscope and accelerometer data. (dps for gyroscope, and voltage for the accelerometer)
– We were able to convert dps to degrees for the Gyroscope and voltage to g’s for the accelerometer.
– We were able to program the servo motor to react to changes in degree measure read from the gyroscope, either positive or negative.
17lochnessproject.org
RockSat-C 2012
ISTR
Power Subsystem Update
• Status– What is complete/what has been tested?– What has not yet been checked out?
18
RockSat-C 2012
ISTR
Power Subsystem Update
19
Power Requirements
Device
maximum Current drawn(mA) Operating Voltage(V)
Max Operating Voltage number
Total Current drawn(mA/H)
Maximum power dissapation(W)
Atmega 32 1.1 2.7-5.5 5.5 2 2.2 0.0121
High-G Accelerometer ADXL278 2.9 5(+-5%) 5 2 5.8 0.029
Low-G Accelerometer ADXL203 1.1 5 5 1 1.1 0.0055
Motor Controller TB6585FG 14 4.7 4.7 1 14 0.0658
Voltage Regulator MAX3379 0.3 1.2-5.5 5.5 7 2.1 0.01155
Gyroscope L3G3200D 6.1 2.4-3.6 3.6 1 6.1 0.02196
Flash memory AT26DF161A 5 2.7-3.6 3.6 2 10 0.036
Motor 2 HS145CR 150 4.8-6 6 1 150 0.9
Motor 0 3268...BX4 SC 2000 24 24 1 2000 48
Motor 1 HS-5245MG 230 4.8-6 6 1 230 1.38
Total 2421.3 50.46191
Current provided Weight Voltage Total Batteries
Lithuim Batteries 2700-3400mA/hr 15 1.5 16
Alkaline 1800-2600mA/hr 23 1.5 16
ENERGIZER LA522
1000 mA Continous
Current 33.9 grams 9 6
RockSat-C 2012
ISTR
Mechanical Subsystem Update
• Status– What is complete/what has been tested?– What has not yet been checked out?
20
RockSat-C 2012
ISTR
Mechanical Subsystem Update
21
• Discussion of current mechanical objectives including machining schedule, tilt platform construction, and slip ring mounting
RockSat-C 2012
ISTR
Plan for Subsystem Integration
22
RockSat-C 2012
ISTR
Lessons Learned
• Subsystem testing requires rigid time restraints and an understanding of the time required to complete tasks. Taking into account setbacks and off-ramps. Designing a system would benefit also from an understand as to how it will be constructed. Engineering tasks are best approached by assigning specific tasks and deadlines to groups so that any dependencies can be accounted for.
• If we started this project over we would ensure more carefully that the pieces selected could perform their designated tasks. We would also assign more ambitious deadlines and complete dependent items in a more time efficient manner.
• So far, by designating tasks we have been able to work ahead in certain areas and share discoveries with the entire team. We have class discussions and demonstrations that function as learning tools for all of us.
23http://sparetimeuniversity.com/?page_id=153
RockSat-C 2012
ISTR
Conclusions
In conclusion we hope to get up to speed with our mechanical subsystem. We intend to continue work with the electrical system and iron out Flash memory requirements and PCB board layouts so they will be ready for the Systems Integration Testing. We need to more extensively test power and ensure that our new selected batteries can supply the current and voltage needed.
24
