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ID Date Author Type Categoryup Subject Text Attachments
  643   Sun Jun 23 14:39:28 2013 Giorgos MamakoukasDailyProgressSUSFinished 6 PCB BoardsOn Friday, we tried to get zero offset
for the voltage output of the strain gauge,
by replacing our fixed-value R2
  645   Mon Jun 24 23:32:04 2013 Giorgos MamakoukasDailyProgressSUSPower PCB boards and design of the boxWe wanted to wire up different PCB boards
aiming to power our PCB boards that are connected
to the strain gauge and amplify the signal.
  648   Tue Jun 25 22:26:03 2013 GiorgosDailyProgressSUSRare Panel Design and Mechanical Set-upToday, we started designing the box that
will hold all of our circuits.
Particularly, we used a software
  650   Wed Jun 26 22:58:44 2013 GiorgosDailyProgressSUSHall-effect sensors and transfer functions Today, I wired up the power PCB boards
for the DC motors and then talked and read
about Hall-effect sensors. The box that will
  652   Fri Jun 28 00:30:46 2013 GiorgosDailyProgressSUSHall-effect sensors circuitsToday, we analyzed the transfer function
of our circuit:
  656   Fri Jun 28 16:54:02 2013 GiorgosDailyProgressSUSLow-pass filtering, Current booster, and Design of the Box PanelsToday, we determined our low-pas filter
circuits and its components. To achieve our
cut-off filtering, we need to change the
  660   Wed Jul 3 00:01:51 2013 GiorgosDailyProgressSUSDAC and ADC controllersOn Monday and Tuesday, we talked about
the ADC & DAC controller and the time
signal input from the function generator.
  661   Wed Jul 3 22:56:53 2013 GiorgosDailyProgressSUSADC/DAC controllers, Power BoardsToday, we completed the power boards and
tested to make sure they work. We had a problem
with the LM2991 negative voltage regulator;
  662   Tue Jul 9 01:24:56 2013 GiorgosSummarySUSHE sensors test, arrangement, and offset & Strain Gauge arrangementToday, we first talked about the connection
of the HE conditioning boards to the HE sensors
and the arrangement of the wires on the connector.
  663   Tue Jul 9 18:13:29 2013 GiorgosSummarySUSStrain Gauge Voltage Offset Strain Gauge Boards
Our conditioning boards did not have
a low-pass filter. That is a problem, since
  665   Thu Jul 11 01:01:30 2013 GiorgosSummarySUSLED connections, Power Boards, and DC magnetic field boardsLED connections
We use LEDs to indicate whether our
power boards work. For one power board, we
  669   Tue Jul 16 00:15:08 2013 GiorgosDailyProgressSUSDigital Voltage Meters, Labeling and RestDigital Voltage Meters
We need 5V to operate our digital
voltage meters that indicate the offset from
  671   Tue Jul 16 22:37:22 2013 GiorgosDailyProgressSUSHE & Coils Boxes: Labeling and Power Lines for Fit-through BoardsProgress on HE & Coil Boxes
I used the labeling device to print
labels for the HE sensors and coils' boxes.
  672   Fri Jul 19 16:14:06 2013 Edward Taylor & Nic SmithDailyProgressSUSSolid works ModelThe solid works model for the experimental
apparatus has been set up and the parts have
been ordered. Today, I cleaned the cryostat
  673   Mon Jul 22 18:26:30 2013 BenDailyProgressSUSWiring Shadow Sensor Emitter Today I figured out the proper orientation
for the SME2470 Emitter and the SMD2420
Detector which we will be using for the shadow
  676   Wed Jul 24 01:00:36 2013 GiorgosDailyProgressSUSFinished 1st Stage - Installation of MatLabToday, the front panels for the HE and
Coils Board arrived. I spent the day preparing
the last power lines for the DC coil boards,
  680   Wed Jul 24 22:10:08 2013 GiorgosDailyProgressSUSAdjusting DC motors resistors, Bode Plots in Matlab and Test ComponentsDC motors - Tuning Adjustable Resistors
I first tuned the resistors of our
DC motors circuits, such that the voltage
  682   Thu Jul 25 22:51:39 2013 GiorgosDailyProgressSUSComputer Feedback (Integrator & Damping), Motors' Speed and ADC bits/voltage conversionComputer Feedback Filter
I installed Linux on my office computer
today, because Windows was sometimes crashing.
  684   Mon Jul 29 14:22:04 2013 GiorgosDailyProgressSUSADC & DAC bits/volts conversion, HE output and saturation of Transfer FunctionsADC & DAC
The bits/volts conversion factor
is different for our ADC and DAC. Specifically,
  685   Tue Jul 30 09:20:18 2013 GiorgosDailyProgressSUSHE output & DAC output/voltage followerHE output
We tested the HE output and found
that all the outputs were fine, except for
  686   Tue Jul 30 11:14:16 2013 KojiDailyProgressSUSHE output & DAC output/voltage followerHow much was the input impedance of the
DAC conditioning board before putting the
high-impedance voltage follower?
  688   Thu Aug 1 11:43:15 2013 GiorgosDailyProgressSUSSensing Matrix and CalibrationSensing Matrix
I calculated the entries of our sensing
matrix S x = y, where S is the 6x6 sensing
  689   Thu Aug 1 11:50:02 2013 KojiDailyProgressSUSHE output & DAC output/voltage follower


  692   Sat Aug 3 14:50:51 2013 GiorgosDailyProgressSUSCoupling from coil's signalCoupling from coils' signal
On Thursday, I measured the HE sensors
sensitivity to the magnetic field provided
  693   Sun Aug 4 22:44:36 2013 GiorgosSummarySUSVolts to N conversion factors & Correction of Transfer FunctionAs I mentioned in my previous post, the
signal from the plate's displacement is strongly
coupled with the coil's signal, so that our
  697   Tue Aug 6 09:27:43 2013 GiorgosDailyProgressSUSNegation of Cross Coupling with FeedbackNegation of Cross Coupling with Feedback
In my previous post, I commented
on how it is possible to negate the coupling
  702   Thu Aug 8 11:32:00 2013 GiorgosSummarySUSCompensation for Cross-Coupling and Vector FittingCross-Coupling Measurements
  703   Fri Aug 9 08:43:37 2013 GiorgosSummarySUSSimulink Model (1 DOF) - Step ResponseAfter minimizing
the coupling effects, I created a 1 DOF Simulink
Model to test whether the setup is stable
  705   Mon Aug 12 07:59:58 2013 GiorgosSummarySUSDAC and ADC saturation issuesInstability due to Saturation
  709   Tue Aug 13 21:09:44 2013 GiorgosSummarySUSOvercoming Saturation: Feedback through DC Coils and Mu-metalIn my previous post, I explained the saturation
issues of the ADC and DAC we faced. To prevent
saturation of the DAC, we will implement
  710   Tue Aug 13 22:49:45 2013 GiorgosDailyProgressSUSModel of 3 DoFDCs/ACs Matrices  StepResponse_DC1in3d0fSimulinkmodel.bmpBodePlot_ADC1only_3DoF_Simulink_13Aug13.bmpADCinput_forDC1only_in3DOF_13Aug13.bmp 
  711   Wed Aug 14 00:05:00 2013 GiorgosDailyProgressSUS3DoF Stability in SimulinkToday, I achieved stability in Simulink
for 3DoF, including noise to the hall-effect
sensors and the coil's conditioning. We had
  713   Thu Aug 15 23:19:36 2013 haixingNoise HuntingSUSpower spectrum and coherence of three hall effect sensorsThe hall effect sensor is quite noisy,
and I am trying to find where the noise comes
from. The first I tried today is to measure
  714   Fri Aug 16 18:37:56 2013 GiorgosDailyProgressSUSBringing Sensors closer to Plate, Correcting Offset and GainYesterday, we tried levitating for one
degree of freedom; we failed. The plate would
move back and forth the equilibrium, but
  715   Sat Aug 17 18:51:39 2013 GiorgosDailyProgressSUSNoise Reduction when sensors are closerNEW HE OFFSET  Noise.png 
  724   Fri Sep 6 15:47:40 2013 haixingSummarySUSachieving stable levitation of the plateWe levitate the plate by controlling three
vertical degrees of freedom---one translational,
and two tilts. Right now even without applying
  725   Fri Sep 6 17:07:39 2013 haixingSummarySUSissues to be investigated Since the plate is levitating, we are now
in the position for real work. Here are the
two major issues to investigate in the plan.
  727   Sun Sep 8 21:51:14 2013 haixingMiscSUSissue of matlab function "margin()" with an unstable plantI used the matlab function margin()
to plot the phase and gain margins for
the open-loop transfer function for maglev.
  153   Thu Jul 8 16:41:29 2010 JanMiscSeismometryRanger PicsThis Ranger
is now lying in pieces in West Bridge:
  154   Sat Jul 17 13:41:45 2010 JanMiscSeismometryRanger Just wanted to mention that the Ranger
is reassembled. It was straight-forward except
for the fact that the Ranger did not work
  157   Tue Jul 27 00:22:04 2010 JanMiscSeismometryRangerThe Ranger is in West Bridge again. This
time we will keep it as long as it takes
to add capacitive sensors to it.
  158   Mon Aug 23 22:07:39 2010 JenneThings to BuySeismometryBoxes for Seismometer Breakout BoxesIn an effort to (1)
train Jan and Sanjit to use the elog
  163   Tue Dec 21 06:58:09 2010 ranaThings to BuySeismometryTrillium Noise PlotNanometrics
has a couple of seismometers which are cheaper
than the T240 which may be of interest to
  169   Wed Jan 19 17:13:11 2011 JanComputingSeismometryFirst steps towards full NN Wiener-filter simulatorI was putting some things together today
to program the first lines of a 2D-NN-Wiener-filter
simulation. 2D is ok since it is for aLIGO
  170   Thu Jan 20 16:05:14 2011 JanComputingSeismometryWiener v. seismometer 0So I was curious about comparing the performance
of the array-based NN Wiener filter versus
the single seismometer filter (the seismometer
  171   Fri Jan 21 12:43:17 2011 JanComputingSeismometrycleaned up code and new resultsIt turns out that I had to do some clean-up
of my NN code:
1) The SNRs were wrong. The problem
  172   Sat Jan 22 20:19:51 2011 JanComputingSeismometrySpatial spectraAll right. The next problem I wanted to
look at was if the ability of the seismic
array to produce spatial spectra is somehow
  173   Sun Jan 23 09:03:43 2011 JanComputingSeismometryphase offset NN<->xiI just want to catch up on my conclusion
that a single seismometer cannot be used
to do the filtering of horizontal NN at the
  174   Sun Jan 23 10:27:07 2011 JanComputingSeismometryspiral v. randomA spiral shape is a very good
choice for array configurations to measure
spatial spectra. It produces small aliasing.
  175   Sun Jan 23 12:59:18 2011 JanComputingSeismometryLess seismometers, less subtraction?Considering equal areas covered by seismic
arrays, the number of seismometers relates
to the density of seismometers and therefore
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