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Micro Robots Sumit Tripathi Saket Kansara

Micro Robots

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Page 1: Micro Robots

Micro Robots

Sumit TripathiSaket Kansara

Page 2: Micro Robots

Outline

Introduction

Challenges Fabrication Sensors Actuators

MEMS Micro robot

Applications

Future scope

Page 3: Micro Robots

Introduction

Programmable assembly of nm-scale (~ 1-100 nm){μm-scale (~ 100 nm-100 μm)} components either by manipulation with larger devices, or by directed self-assembly.

Design and fabrication of robots with overall dimensions at or below the μm range and made of nm-scale {μm-scale} components.

Programming and coordination of large numbers (swarms) of such nanorobots.

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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 tube’s axis Extremely strong

Biological proteins, bacteria etc.

Image: Berkeley University

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Actuator-Rotary Nanomachine.

The central part of a rotary nanomachine.(Figure courtesy of Prof. B. L. Feringa’s 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 conformationSubject to continuous rotation

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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.

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Motor run by Mycoplasma 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

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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

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Cantilever Sensors

Department of Physics and Physical Oceanography, Memorial University, St. John’s, Newfoundland,Canada

θ=Angle of incidence

Φ=Azimuthal angle

Nc is the surface normal to cantilever

ξ =Angle of inclination of PSD

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Cantilever Sensors

Detection Mechanismso Detect the deflection of a cantilever caused by surface stresseso 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:

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Micro-Electro-Mechanical-System

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

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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

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Configuration Space

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

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Steering Arm subsystem

• Dimple dimension .75 μm

• Disk radius 18 μm

• Cantilever beam 133 μm long

Controls direction by raising and lowering 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

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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

Page 16: Micro Robots

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

Page 17: Micro Robots

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 7.5 μm higher 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

Page 18: Micro Robots

Electrical Grids

Consist of an array of metal electrodes on a silicon substrate.

Electrodes are insulated from the substrate by a 3 μm thicklayer 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 of gold-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

Page 19: Micro Robots

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-μm), intense electric fields can be established with fairly low voltages.

High torque to speed ratios.

μ 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. BrooksMIT Artificial Intelligence Laboratory

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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 research and education

Micro robot interacting with blood cells

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Future Scope

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Future Scope

Realization of ‘Microfactories’ Self assembling robots Use in hazardous locations for planning resolution

strategies Search in unstructured environments, surveillance Search and rescue operations Space application such as the ‘Mars mission’ Self configuring robotics (change shape) Micro-machining

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Acknowledgements

1) B. L. Feringa, “In control of motion: from molecular switches to molecular motors,” Acc. Chem. Res., vol. 34, no. 6, pp. 504–513, June 2001.

2) H. C. Berg, Random Walks in Biology. Princeton, NJ: Princeton Univ. Press, 1993.3) http://www.physorg.com/news79873873.html4) K.R. Udayakumar, S.F. Bart, A.M. Flynn, J.Chen, L.S. Tavrow, L.E. Cross, R.A. Brooks and

D.J.Ehrlich, “Ferroelectric Thin Film Ultrasonic Micromotors”Fourth IEEE Workshop on Micro Electro Mechanical Systems, Nara, Japan, Jan. 30 - Feb. 2, 1991.

5) JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 15, NO. 1, FEBRUARY 2006 1An Untethered, Electrostatic, Globally Controllable MEMS Micro-Robot Bruce R. Donald, Member, IEEE, Christopher G. Levey, Member, IEEE, Craig D. McGray, Member, IEEE,Igor Paprotny, and Daniela Rus

6) K.W. Markus, D. A.Koester, A. Cowen, R. Mahadevan,V. R. Dhuler,D.Roberson, and L. Smith, “MEMS infrastructure: The multi-user MEMSprocesses (MUMPS),” in Proc. SPIE—The Int. Soc. Opt. Eng., Micromach.,Microfabr. Process Technol., vol. 2639, 1995, pp. 54–63.

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