CDIO EMFF Test Bed
Design Concept
CDIO Space Systems Product Development
Databasing Team
21 February 2002
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Mission Objective
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Demonstrate the feasibility of electromagnetic
control for formation-flying satellites.
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2-D Flat floor test bed
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3 independent devices
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3 DOF per device
Æ Simplifies
problem
while achieving
objective
Æ Proves feasibility of
planar control
Æ Simplifies dynamics
Planar control vs. linear control… it takes 3 points to make a plane. Plus, if we can
prove controllability for 3 devices, adding more should be… trivial…
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Requirements Flowdown
Mission objective
Power
Simulated Solar Cells
ACDS
Actuation
EM Shielding
Structure
Communication
Avionics
Carriage
Ground Comm
Power Amp
Frictionless mount
Inter-device Comm
On-board Computer
Reaction
De-spin
Inertial Metrology
Omnidirectional
Software
Signal Conditioning
Operations
Controller Interface
Ground computer
Human
Flat floor facility
20' x 30'
Relative Metrology
Separation distance
Separation distance: O(10cm)-O(1m)
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Design Trades
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Mass
Cost ($)
Time
Control accuracy
Control precision
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Electrical power
(current, voltage,
resistivity)
Feasibility
B-field
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Design Concept: Part I
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External power source
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Air bearing
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Bumpers
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Simplifies problem while
achieving objective
Not configuration used in
space
Provides near-frictionless
test environment
Effective representation of
dynamics
Cost
Requires air supply
Safety consideration
Low cost
Power: Also, can take more data at various power levels.
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Design Concept: Part II
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One electromagnet, reaction
wheel assembly per device
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All circuitry oriented to
move with EM package
(aligned with field)
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Shielding using highpermeability materials
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Permits full range of motion
Simplified dynamics
Less mass
Need more for control of
more DOF
Reduces magnetic
interference with circuits
Reduces need for shielding
Prevents magnetic
interference
È Mass vs. cost tradeoff
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Design Concept:
Inter-device Positioning
Relative Metrology
Infrared Sensors
Sonar
pseudo-GPS
Highly directional
Directional
Omnidirectional
Computer capacity
Not functional in space
Computer capacity
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Design Concept
Cylindrical
Housing
Avionics and
Communication
Rate Gyro
Torque Wheel
Electromagnet
Air Bearing
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Operations Concept
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Human interface via laptop
computer
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Ground/device
communication via RF
wireless modem
Disturbance rejection
autonomous; no input
required
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Familiar to users
Portable
Supports adequate software
packages
Not used in actual space
mission
Applicable to actual
operational situation
Fast
Simulates actual operational
situation
More complicated avionics
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Questions?
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