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Technion – Israel Institute of Technology Department of Electrical Engineering High Speed Digital Systems Lab. DIFFERENTIAL POLARIZATION DELAY LINE Controller FINAL REPORT. D0215 Supervisor : Mony Orbach Performed by: Maria Terushkin Guy Ovadia. Project Goals. - PowerPoint PPT Presentation
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DIFFERENTIAL POLARIZATION DELAY LINE Controller
FINAL REPORT
D0215D0215
Supervisor :Supervisor :Mony OrbachMony Orbach
Performed by:Performed by:Maria TerushkinMaria Terushkin
Guy OvadiaGuy Ovadia
Technion – Israel Institute of TechnologyDepartment of Electrical EngineeringHigh Speed Digital Systems Lab
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Project GoalsProject Goals
The ultimate goal of the project isThe ultimate goal of the project is
providing digital control for providing digital control for the DDLthe DDL
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DDL overviewDDL overview splits light within a splits light within a
fiber into orthogonal fiber into orthogonal polarizationspolarizations
actively varies the actively varies the time that one time that one polarization travels polarization travels compared to the other compared to the other polarizationpolarization
combines the two combines the two polarizations together polarizations together againagain
•Delay range ±50psec
•Delay Resolution 0.0017 pSec
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Project DescriptionProject Description Previous usage of the DDLPrevious usage of the DDL Current usage of the DDLCurrent usage of the DDL
PC
controller
Tunable laser source
optical spectrum analyzer
DDL
Function generator
Manual control
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The world as we see itThe world as we see it DDL contains:DDL contains:
DC brush motorDC brush motor EncoderEncoder Limit switchesLimit switches
-50 0 +50
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Controller IOsController IOs Inputs:Inputs:
Encoder signals A,BEncoder signals A,B Limit indicatorsLimit indicators Commands from PC (via USB)Commands from PC (via USB)
controller DDL
Output:Output: PWM varying duty-cyclePWM varying duty-cycle Reports to PC (via USB)Reports to PC (via USB)
PCUSB
PWM
Encoder feedback + limits
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System requirements System requirements
1.1. Maximal travel beyond the home/end Maximal travel beyond the home/end indications – 2mmindications – 2mm
2.2. Steady state error – not greater than a single Steady state error – not greater than a single encoder countencoder count
3.3. No cumulative positional error No cumulative positional error
4.4. Up to 3 sec convergence to the required set Up to 3 sec convergence to the required set point after reaching itpoint after reaching it
5.5. No closed loop control after reaching desired No closed loop control after reaching desired positionposition
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Theoretical backgroundTheoretical background Digital PID Digital PID
Continuous time domainContinuous time domain
Discrete time domainDiscrete time domain
WhereWhere
0
0
)()()()( u
dt
tdeTKdtte
T
KteKtu dc
t
i
cc
00
))1()(()()()( u
T
teteTKie
T
TKteKtu
s
dct
ii
scc
tconstimealdifferentiegralTT
timesamplingT
gainK
positioncurrentpositiondesirederrorte
conditioninitialu
signalcontroltu
di
s
c
tan/int,
)(
)(
0
P Plant
I
D
++
-
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ImplementationImplementation
HardwareHardware MMC (PCB) + Driver (wire-wrap board) MMC (PCB) + Driver (wire-wrap board)
FPGA LogicFPGA Logic PID algorithmPID algorithm Communication with PC via DLPCommunication with PC via DLP
SoftwareSoftware GUIGUI Command line interfaceCommand line interface
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Hardware overviewHardware overview
MMC wire-wrap
Altera
Cyclone
tran
scei
ver
tran
scei
ver
tran
scei
ver
H
bridge
HIP4020
Power
management
Power
management
DLP
USB245M
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FPGA logic overviewFPGA logic overview
Synchronization
Debouncing
Filtering
Of signals
Position
DecodingPID
PWM
Duty-cycle
homing
Limit
protection
Communication
Main Controller
mux
Control lines
to all blocks
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Application SoftwareApplication Software
Two versions:Two versions: GUI version for interactive useGUI version for interactive use Command line version for automationCommand line version for automation
Both versions save the last known Both versions save the last known delay, and load it on controller delay, and load it on controller power-up.power-up.
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GUI Application GUI Application commandscommands
User commandsUser commands Set delaySet delay Redefine current delayRedefine current delay Immediate stopImmediate stop
Service commandsService commands Manual PWM override + direction Manual PWM override + direction
controlcontrol PID constants calibrationPID constants calibration Initiate Homing procedureInitiate Homing procedure Record internal dataRecord internal data
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Command line Command line applicationapplication
Contains a subset of commands Contains a subset of commands useful for automationuseful for automation Set delay (in pSec or encoder counts)Set delay (in pSec or encoder counts) Load windup constant (controls speed)Load windup constant (controls speed)
Compatible with VEE Pro and MatlabCompatible with VEE Pro and Matlab
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Discussion and conclusionsDiscussion and conclusions
Meeting system requirementsMeeting system requirements
Position vs. Position vs. TimeTime
go to 10 pSecgo to 10 pSec
12121 encoder12121 encoder
countscounts
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Discussion and conclusions cont.Discussion and conclusions cont.
Use of a model:Use of a model: Differences between the model and the Differences between the model and the
DDL and their consequencesDDL and their consequences Use of work previously done in the Use of work previously done in the
lab – pros and cons.lab – pros and cons. Power upPower up Chip safetyChip safety
Implementation alternativesImplementation alternatives MicrocontrollerMicrocontroller
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What’s next ?What’s next ? Algorithm improvement / additional featuresAlgorithm improvement / additional features
Trajectory planningTrajectory planning Dual loop (velocity control)Dual loop (velocity control) Notch filter (mechanical resonance)Notch filter (mechanical resonance) Backlash compensation algorithmBacklash compensation algorithm User defined software limitsUser defined software limits
Hardware improvementHardware improvement Custom PCB, no wire-wrapCustom PCB, no wire-wrap
Tighter integration with the equipment at the EO labTighter integration with the equipment at the EO lab Automatic zero detection / calibrationAutomatic zero detection / calibration
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Demonstration – EO lab.Demonstration – EO lab. Short demonstration:Short demonstration:
Homing procedureHoming procedure ““go to” 20 pSec delay positiongo to” 20 pSec delay position Return to 10 pSecReturn to 10 pSec Find zero manually and set it thereFind zero manually and set it there Power off the controllerPower off the controller Turn back on – last known position is retrievedTurn back on – last known position is retrieved
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The enDThe enD
Just follow the yellow optical fiber !Just follow the yellow optical fiber !(to the land of OZ optics)(to the land of OZ optics)