FEEDBACK CONTROL OF A

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FEEDBACK CONTROL OF A MICRO MANIPULATOR
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Z
knob
x
y
On 3 stages Total displacement 25mm (coarse
/ micrometer) 300?m (fine /
PZT) Resolution 100nm (Joystick)
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PZT flexure
Pipette (8?m diameter)
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Application of the micro-manipulator
Micro-injection (ICSI )
Micro-dissection
Zona
Capturing the X chromosome
Zona penetration
Dissecting
Taking out the dissected membrane
Taking the dissected part out
Zona Penetration
Storing the dissected chromosome
Sperm injection
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• MOTIVATION
• Motion Control of the tip
• 100nm is not enough for many sub-micron
  biological applications
• Dynamic Modeling
• The uncertainties are causing very low success
  rates in biological applications

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CURRENT SETUP
PiezzoDrill control
Manipulator control
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• Present work
• Analyical model of the manipulator (excluding
  the pipette).
• Experimental set-up and tests on the same .
• Comparison of the experimental and analytical
  results.
• Experiments (including the pipette) with Hg in
  the pipette and without.

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Dynamic model
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X3 displacement comparison (the experiments vs.
dynamic model)
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FFT comparison (the experiments vs. dynamic model)
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Nano level displacement measurement setup
Tip
Photonic probe
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Working principle of photonic probe
Resolution 2.5nm
Light source
Output (V)
Probe to target distance
Distance (?m)
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Experimental procedure
Photonic sensor
Gap
Read out (V)
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Joystick control
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Setup for ICSI experiment without Mercury
Read out (V)
Pipette dia. lt 8 ?
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Setup for ICSI experiment with Mercury
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X3 displacement comparison
with mercury
without mercury
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FFT comparison
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• Observations
• The key is at the micro-dynamics of the pipette
  tip.
• The pipette holder does not feel the presence
  of Hg.
• Robust control is possible at 10nm of
  resolution

• Obstacles
• Extreme flexibility at the tip (glass acts
  like fiber).
• Displacement sensing (in 2-D) at the pipette
  tip
• Complex visco-elastic interface between the Hg
  and the pipette.