Micro Robots

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Transcript of Micro Robots

  • 1. Micro Robots Sumit Tripathi Saket Kansara

2. Outline

  • Introduction
  • Challenges
    • Fabrication
    • Sensors
    • Actuators
  • MEMS Micro robot
  • Applications
  • Future scope

3. Introduction

  • Programmable assembly of nm-scale (~ 1-100 nm){m-scale (~ 100 nm-100 m)} components either by manipulation with larger devices, or by directed self-assembly.
  • Design and fabrication of robots with overall dimensions at or below the m range and made of nm-scale {m-scale} components.
  • Programming and coordination of large numbers (swarms) of such nanorobots.

4. FABRICATION

  • Materials:
    • Polymer actuators( Polypyrrole (PPy) actuators):
          • Can be actuated in wet conditions or even in aqueous solution.
          • Have reasonable energy consumption.
          • Easily deposited by electrochemical methods
    • Titanium-Platinum alloy
          • Used to manufacture electrodes
          • Corrosion resistant
          • Titanium adhesive alloy, high fracture energy(4500 J/m2 or more)
    • Silicon substrate: capability of bonding between two surfaces of same or different material
    • Carbon nanotubes:
          • Assembly of aligned high density magnetic nanocores
          • Flexible characteristics along the normal to the tubes axis
          • Extremely strong
    • Biological proteins, bacteria etc.

Image: Berkeley University 5. Actuator-Rotary Nanomachine. The central part of a rotary nanomachine.(Figure courtesy of Prof. B. L. Feringas group (Univ of Groningen.)

  • Power is supplied to these machines electrically, optically, or chemically by feeding them with some given compound.
  • Rotation due to orientation in favorable conformation
  • Subject to continuous rotation

6. Drawbacks of molecular machines of This Kind

  • Moving back and forth or rotating continuously
  • Molecules used in these machines are not rigid
  • Wavelength of light is much larger than an individual machine .
  • Electrical control typically requires wire connections .
  • The force/torque and energy characteristics have not been investigated in detail.

Rotary Nanomachine. 7. Motor run byMycoplasma mobile Image credit: Yuichi Hiratsuka, et al.

  • Bacterium moves in search of protein rich regions.
  • The bacteria bind to and pull the rotor.
  • Move at speeds of up to 5 micrometers per second.
  • Tracks are designed to coax the bacteria into moving in a uniform direction around the circular tracks.

Protrusions 8. Motion of a Mycoplasma mobile -driven rotor . Image credit: Yuichi Hiratsuka, et al.

  • Some Other Types:
  • Chlamyodomonas :Swim toward light (phototaxis)
  • Dictyostelium amoeba crawl toward a specific chemical substance (chemotaxis).

Each rotor is 20 micrometers in diameter 9. Cantilever Sensors Department of Physics and Physical Oceanography, Memorial University, St. Johns, Newfoundland,Canada =Angle of incidence=Azimuthal angle Ncis the surface normal to cantilever = Angle of inclination of PSD 10. Cantilever Sensors

  • DetectionMechanisms
  • Detect the deflection of a cantilever caused by surface stresses
  • Measure the shift in the resonance frequency of a vibrating cantilever
  • Drawbacks
  • Inherent elastic instabilities at microscopic level
  • Difficult to fabricate nanoscale cantilevers

Image:L. Nicu, M. Guirardel, Y. Tauran, and C. Bergaud (a) cantilevers(b) bridges. Optical microscope images of SiNx: 11. Micro-Electro-Mechanical-System

  • 60 m by 250 m by 10 m
  • Turning radius 160 m
  • Speed over 200 m/s
  • Average step size 12 nm
  • Ability to navigate complex paths

12. The state transition diagram of USDA Bruce R. Donald , Member, IEEE , Christopher G. Levey , Member, IEEE , Craig D. McGray , Member, IEEE , Igor Paprotny, and Daniela Rus 13. Configuration Space Bruce R. Donald , Member, IEEE , Christopher G. Levey , Member, IEEE , Craig D. McGray , Member, IEEE , Igor Paprotny, and Daniela Rus 14. Steering Arm subsystem

  • Dimple dimension .75 m
  • Disk radius 18 m
  • Cantilever beam 133 m long
  • Controls direction by raising andlowering the arm
  • Simultaneous operation with scratch drive
  • Control in the form of oscillating voltages

Bruce R. Donald , Member, IEEE , Christopher G. Levey , Member, IEEE , Craig D. McGray , Member, IEEE , Igor Paprotny, and Daniela Rus 15. Control Waveforms

  • Drive waveform actuates the robot
  • Forward waveform lowers the device voltage
  • Turning waveform increases the device voltage

Bruce R. Donald , Member, IEEE , Christopher G. Levey , Member, IEEE , Craig D. McGray , Member, IEEE , Igor Paprotny, and Daniela Rus 16. Power delivery mechanism

  • Uses insulated electrodes on the silicon substrate
  • Forms a capacitive circuit with scratch drive
  • Actuator can receive consistent power in any direction and position
  • No need of position restricting wires

Bruce R. Donald , Member, IEEE , Christopher G. Levey , Member, IEEE , Craig D. McGray , Member, IEEE , Igor Paprotny, and Daniela Rus 17. Device Fabrication

  • Surface micromachining process:
      • Consists of three layers of polycrystalline silicon, separated by two layers of phosphosilicate glass.
      • The base of the steering arm is curled so that the tip of the arm is approximately 7.5mhigher than the scratch drive plate
      • Layer of tensile chromium is deposited to create curvature

Bruce R. Donald , Member, IEEE , Christopher G. Levey , Member, IEEE , Craig D. McGray , Member, IEEE , Igor Paprotny, and Daniela Rus 18. Electrical Grids

  • Consist of an array of metal electrodes on a silicon substrate.
  • Electrodes are insulated from the substrate by a 3mthicklayer of thermal silica
  • Coated with 0.5 of zirconium dioxide
    • High-impedance dielectric coupling
  • Silicon wafers: oxidized for 20 h at 1100C in oxygen
  • Wafers are patterned with the Metal pattern
  • Three metal layers are evaporated onto the patterned substrates
    • Middle layer consists ofgold-Conductive
    • Two layers of chromium-adhesion layers between the gold, the oxidized substrate, and the zirconium dioxide

Bruce R. Donald , Member, IEEE , Christopher G. Levey , Member, IEEE , Craig D. McGray , Member, IEEE , Igor Paprotny, and Daniela Rus 19. Some Other Kinds

  • Piezoelectric motors for mm Robots
      • Not required to support an air gap
      • Mechanical forces are generated by applying a voltage directly across the piezoelectric film.
      • Ferroelectric thin films (typically 0.3-m), intense electric fields can be established with fairly low voltages.
      • High torque to speed ratios.
  • Robots Driven by external Magnetic fields Include a permanent magnet
      • Can be remotely driven by external magnetic fields
      • Suitable for a mobile micro robot working in a closed space.
      • Pipe line inspection and treatment inside human body.

Anita M. Flynn, Lee S. Tavrow, Stephen F. Bart and Rodney A. Brooks MIT Artificial Intelligence Laboratory 20. Applications

  • See and monitor things never seen before
  • Medical applications such as cleaning of blood vessels with micro-robots
  • Military application in spying
  • Surface defect detection
  • Building intelligent surfaces with controllable (programmable) structures
  • Tool for re