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 research and education

Micro robot interacting with blood cells 21. Future Scope 22. 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

23. Acknowledgements

B. L. Feringa, In control of motion: from molecular switches to molecular motors, Acc. Chem. Res., vol. 34, no. 6, pp. 504513, June 2001.

H. C. Berg, Random Walks in Biology. Princeton, NJ: Princeton Univ. Press, 1993.

http://www.physorg.com/news79873873.html

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 MicromotorsFourth IEEE Workshop on Micro Electro Mechanical Systems, Nara, Japan, Jan. 30 - Feb. 2, 1991.

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

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. SPIEThe Int. Soc. Opt. Eng., Micromach.,Microfabr. Process Technol., vol. 2639, 1995, pp. 5463.

24. THANK YOU