MEMS-based Reconfigurable Manifold Update
Presentation at MAPLD 2005
Warren Wilson‡, James Lyke‡
Joseph Iannotti* and Glenn Forman*‡Space Vehicle Directorate/Air Force Research
Laboratory
*General Electric Global Research
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Motivation for Reconfigurable Systems
• Maximizes utilization of space assets to allow:
– Recovering from faults (fault-tolerance)
– Reconfiguration after deployment
• Reconstituting / “refocusing” assets for current mission
• Reconfiguring / “refocusing” assets for new missions
• Single platform and distributed functionality
• Accelerates the possibility of “space-on-demand” by enabling plug-and-play spacecraft
– Adaptive interfaces to dramatically reduce the time for development, integration
– Space logistics / remote servicing
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Role of Adaptive Wiring in Reconfigurable Systems
AdaptiveManifold of
Reconfigurable Interconnections
componentsockets
Reconfigurabledigital
Reconfigurableanalog
A/D
D/A Reconfigurablemicrowave
A/D
D/A
connectors
Reconfigurablepower
discretecomponentpatchboard
MA
TR
IX O
F E
MB
ED
DE
D S
WIT
CH
ES
MA
TR
IX O
F E
MB
ED
DE
D S
WIT
CH
ES
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Reconfigurable analog
• Programmable analog architectures
– Configurable process chains
• Alter gain, offset, filtration characteristics
– Configurable analog blocks
• Permits flexible arrangement of some analog building blocks
• Limitations
– Frequency of operation
– Ranges of resistances, capacitances require supplemental, external, non-programmable discrete components
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Reconfigurable Power
• Permit alteration of input voltage, output voltage, and load conditions under software control
– maintain optimal electrical efficiency under variations
• Industry practice
– Some configurable power technologies permit modular power supplies by manual arrangement of discrete building blocks (e.g., Lambda)
– Smart-power approaches in microprocessors and FPGAs to permit different supply and I/O voltage levels
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Reconfigurable Microwave
• Emergent techniques
– Direct digital synthesis (generated modulated carrier directly in real-time)
– Reconfigurable antenna
• Electronically steerable antenna
• MEMS-based antenna reshaping
• Other techniques to modify dielectric / conductor configurations of antenna under software control
– Software radio
• Minimize non-digital content of RF systems, permit agile manipulation of radio protocols for transceivers
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C & DHProcessor
Interface Card
Interface Card
Interface Card
Interface Card
B
u s
COMM
GNC
GNC
GNC
PMAD
telemetry
Payload (s)
Conventional Spacecraft Avionics
8Wilson MAPLD 2005/P223Command & Data Handling
AdaptiveWiring
Manifold
MSP
Sp
aceWire
Sp
aceWire
Sp
aceWire
Sp
aceWire
Sp
aceWire
Optical Sensor
Optical Sensor
C&
DH
Inte
rfac
e
Inte
rfac
e
CO
MM
Compact PCI bus
comp. comp.
Legacy components
Software Radio
Software Radio
SensorSensor
SensorSensor
SensorSensor
SensorSensor
SensorSensor
SensorSensor
SensorSensor
SensorSensor
SensorSensorSensorSensor
SensorSensor
SensorSensor
SensorSensor
MSP
MSP
MSP
MSP
Space-wire
FP
FP
FP
FP
FPFPFP
FP
FP
FP
FPFP
MSP = Malleable Signal ProcessorFP = Fusion Processor
Plug-and-play network
Reconfigurable Spacecraft Avionics
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Adaptive Manifold
• Reconfigurable switch manifold used to program front end electronics and signal/processing paths of a satellite
– Enabling the ability to break or make conductive pathways at will
– Permit maximal use of a scarce satellite resource
– Effectively re-route the signal paths to optimize the extractable data
– Correct defects found during construction/integration/mission
• Applied as the interface of self-configuring systems, the idea would be equivalent to an advanced plug-and-play
– where choice of each pin location and its impedance characteristics could be re-definable at will
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Adaptive Manifold II
• Such a manifold would required
– Locally embedded relays: hundreds or thousands of switches distributed among a circuit's interconnections
– A configuration control system: which would set the “0s” and “1s” of each particular relay
• E.g., programmed by a bitstream generation process
– Currently used in certain digital field programmable gate array (FPGA) system
• A MEMS-based “smart substrate” can handle signals with extreme excursions in amplitude and frequency
– The complete separation of the switched circuit from the switching circuit is an advantage when cascading switches within the manifold
– The MEMS switches can operate under voltage constrains that would take a transistor switch out of saturation, or worse, cause device breakdown
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Conventional vs. Adaptive Wiring Manifold
Box
Box
Box
Box
Box Box
Box
Box
Box
Box
open closed
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Programmable Connections
• AWM combines wiring, switches, and control to make arbitrary terminal-to-terminal connectivity possible in a wiring system
• Program switches using routing heuristics
ABCD
EFGH
IJKL
MNOP
QRST
UVWX
switchboxswitch
ABCD
EFGH
IJKL
MNOP
QRST
UVWX
switchboxswitch
ABCD
EFGH
IJ
MNOP
QRST
UVWX
ABCD
EFGH
IJ
MNOP
QRST
UVWX
ABCD
EFGH
IJKL
MNOP
QRST
UVWX
ABCD
EFGH
IJKL
MNOP
QRST
UVWX
Program A-P connection
Program A-P,C-K, F-Q-S connections
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Adaptive Manifolds
• Approaches to embed large numbers of micro-relays into packages, boards, and wiring harness
• Strategies for reconfiguration
• Algorithms for altering system configurations
– Satellite itself becomes a large “field programmable device”
• Concepts for repair-ability and extensibility
• Disciplines for design and application of reconfigurable systems
28VDC
5VDC
-15VDC
ProgramVDC
Analog_2
Diagnostic
COMM_1
COMM_2
+15VDC
Analog_1
Smart-wiring based avionics system
Dockable-assemblies Satellite-as-a-device
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Payload Attachment Pointsand Switch Resource Distribution
• Mounting sites contain terminals connected to one of six types of wiring resources
– Four wiring types (volatile and non-volatile, MEMS, non-MEMS)
– Fixed (common connections)
– Configuration (future)
• Wiring resources contained in switchboxes
Digital (FPID) – 75%
MEMS – 10%
Solid state power – 10%
Latching
Macro EM – 5%
Example population strategy
switchbox
switchbox
switchbox
switchbox
switchbox
switchbox
switchbox
switchbox
switchbox
Mou
ntin
g si
teM
ount
ing
site
fixed
fixed
switchbox
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Summary of switch requirements for an adaptive manifold
• Bistable / multistable
• Electrical performance
– Low resistance
– High bandwidth
– High-isolation (low crosstalk)
• Hot-switching
– High melting contacts
Mechanical performance• 50 micron gap
•Sets maximum switching voltage
• 2 micron thick gold alloy contracts•Sets lifetime under hot switching
• 0.2 m/s contact velocity•Related to hot switching lifetime
• 70 mΩ constriction resistance•Sets maximum cold current
• 50/200 μs lag open/close time•Sets maximum relay duty cycle
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Latching Relay Requirements
Design Goals Logic Switch Manifold Configuration Switch Manifold
Power Bus Switch Manifold
Constriction resistance < 1 Ω < 50 mΩ < 8 mΩ
Configuration SPST, switchyard SPDT, SPMT, switchyard SPST
Switch density (#/mm2) > 100 > 10 > 1
Energy to switch
0 ↔ 1
< 0.1 mJ < 1 mJ < 1 mJ
Hot switching capabilities TTL levels 15V @ 100 mA 10 V @ 1 A
Current handling capabilities
TTL levels 1 A 10 A
Lifetime (cycles) > 107 > 106 > 104
Time to switch
0 ↔ 1
< 100 μs < 1 ms < 10 ms
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Fixed contact
pad
Moving contact
(teeter-totter)
Coil contracts
Torsion suspensions
Moving contact
pad
Magfusion’s RF Latching Relay
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Design of Avionics Manifold
• Design is to arbitrarily connect among 3 payloads and 4 ports
– The ports connect to additional panels
– Each payload allows 12 connections: 10 RF, 2 power
• Construct a macro-relay version of a simple manifold
– 260 latching MEMS RF metal-to-metal relays in a “mesh” configuration
– 10 latching macro DC metal-to-metal relays to supply high current power
– Circuit board on printed wiring board (10 layers)
• Expected benefits
– Development of control circuitry
– Establish software algorithms and user-interface
– Examine scaling issues
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Circuit design for demo AWM
• Circles represent connections
– Open: selectable connections
– Filled: fixed connections
• Each line represents a set of individually switched circuits elements
– 2 power, 10 RF, and logic
– Compromise configuration
• Limitation on number of MEMS RF switches available
– N(N-1)/2 = >2,000 switches
• N = (3+4)*10
– Demo configuration used only 260 MEMS RF latching switches
North
Payload 1
East
Payload 2
South
Payload 3
West
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Implementation of AWM demo
• Manifold is a panel based on flexible circuitry
• “Payload sites” serve as points to mount subsystems or complex components
• Switchboxes are small circuit boards containing
– MEMS switches
– Control ASIC
• Microcontroller (CPU) used to manage switchbox configurations (e.g. JTAG interface or Robust USB)
• Multiple panels can communicate partial configurations to form composite adaptive wiring assemblies
Switchbox
Panel
CPUCPU
PAYLOADSITE
PAYLOADSITE
PAYLOADSITE
SwitchboxASIC
(ATK/MRCunder AFRL
Support)
Magfusion Switch
Other MEMSSwitches
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Video Capture over SPA-S, Video-PC_TV over SPA-U, Space-Cube and GPS Demonstration on One
Panel: Meets Transfer Rates!
AWM Components
R-USB configuration network
ASIM (Appliqué Sensor Interface Module)Payload Interface (USB, xTEDS)
Front/back sides of Switchcard
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AWM Panel Configuration with Payload Cards
Input for configuration and spacecraft power
One of 13 Switch Module Cards(using 10 latching Magfusion relays, 2 latching macro power switchesrelays mounted on underside of card)
AWM USB Configuration Interface (bottom side)
Payload Interface Card
SpaceWirePort
USBPort
Panel to panel Connector
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Back View AWM Panel Configuration
Switch Module Card(10 Magfusion Switches)(Total of 4 installed on bottom)
AWM USB1.1 Configuration Interface
USB1.1 Hub card for on and off panel enumeration/control
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AWM Demo
NI Frame Grabber
1st Space Wire BoardSPACEBALL 3DM-GX1
DVD player
3DM-GX1Inclinometer &
Orientation Sensor
Display:SPACEBALL rotating cube
2nd PC running Display2
2nd Space Wire Board
Display:DVD movie
PC running AWM CONFIG. SW (not needed once system configured)
Display:AWM CONFIGURATION GUI
OPC NORTH
TEDS
Panel 1
OPC SOUTH
OP
C E
AS
T
OP
C W
ES
T
PA
Y 2
PAY 3
PAY 1
OPC NORTH
TEDS
Panel 2
OPC SOUTH
OP
C E
AS
T
OP
C W
ES
T
PAY 1
Optional TEDS Port
1 Distinct SpaceWire interconnect routed via AWM for payload to payload interconnect2 Distinct USB routes:TEDS – USB 1.1 TEDS interface used for enumeration and controlUSB – USB 1.1 (2.0 capable) interface routed via AWM for payload to payload interconnect
All panels, switch cards and hub cards are identicalPayload cards are similar but haveunique ID for function identification
(host)
(slave)
PA
Y 2
PAY 3
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RF Characteristics of AWM
2.7 GHz Diff Eye thru Switchcard and 15 inch of PCB
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RF Characteristics of AWM
2.7 GHz Diff Eye Cables Alone
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Take Away Items from AWM Demo
• All passive (Relay) AWM will have length limitations that impact desired high speed SpaceWire performance
• Latching switches are desirable but have seen issues with available array density
• “Electronic” (FPIDS, FPGA’s, etc...) can provide configurable I/O’s and signal regeneration while providing adaptive routing features
• System architecture may include optical interconnect for “Long Hauls”; thru an entire panel, acts as repeater as well
• All passive backplane gives flexibility and producibility
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• Physical location/orientation of panels provide challenge in AWM routing
• USB1.1 is convenient but has issues in this application with respect to upstream-downstream
• At high speeds, un-terminated stubs due to unused routes are not tolerated
• Higher density switching hardware minimizes stub length and as such minimizes number of switches needed
• SpaceWire standard needs more work in the area of:
– Tx and Rx mask spec
– Acceptable Interconnect Degradation spec
– Interoperability spec
Take Away Items from AWM Demo
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Summary
• Hopefully, AWM may do for spacecraft what FPGAs do for digital microelectronics
• AWM is a ready consumer of MEMS relays
– Excellent vehicle to study large-scale reliability
• AWM will provide a meaningful set of ground and space experiments
– Not limited to RF
– Expected to have many non-space applications
• The AWM concept is to be included and further developed in the responsive technology test cell located in the Responsive Space Testbed at the AFRL Space Vehicle Directorate, Kirtland AFB, NM
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Concept: A software-definable wiring system•Pre-built (into structures), rapidly-programmable•Can be modified in orbit
Benefits:
•Rapid integration on ground
•Debug support (temporary probe wires)
•On-orbit rewiring (fault, defect rectification)
•Reliability and utility of MEMS switches
Objective is to Demonstrate:•Rapid payload integration •Space system reconfiguration •Systems on-orbit protection •Self-organizing sensor network •Adaptive MEMS-based wiring manifold•Reconfigurable RF system•Self-aware cognitive software
RE-CONFIGURABLE/ADAPTIVE MANIFOLD
Phase 1 – Construct exerciser panel; establish specs for switchboxes compatible with testable switches
Phase 2 – Create space MEMS switch reliability experiment with diagnostics; require several hundred switches; 12-month spaceflight / Tacsat 4 (2007 launch)
Phase 3 – Create non-toy space experiment based on adaptive wiring manifold; include at least four payload attachment sites; 12-month spaceflight / Tacsat 5 (2008 launch)
Spacecraft busSubsystems
28VDC
5VDC
-15VDC
ProgramVDC
Analog_2
Diagnostic
COMM_1
COMM_2
+15VDC
Analog_1
payloadattachmentpoint
Switch boxes
high densityinterconnectbetweenswitchboxes
CMP
configurationmanagement processor
Generic Adaptive Wiring Manifold Architecture