Page 73 - The Mechatronics Handbook

degree of freedom Stewart platforms have been proposed [56], including one that allows strut lengths
to be moved in 0.10 nm increments across a 100 nm work envelope. A number of other nanodevices
including box-spring accelerometers, displacement accelerometers, pivoted gyroscopic accelerometers,
and gimbaled nanogyroscopes have been proposed and designed [56].
Currently, much thought is being devoted to molecular assembly and self-replicating devices (self-
replicating nanorobots). Self-assembly is arguably the only way for nanotechnology to advance in an
engineering or technological sense. Assembling a billion or trillion atom device—one atom at a time—
would be a great accomplishment. It would take a huge investment in equipment, labor, and time. Freitas
[56] describes the infrastructure needed to construct a simple medical nanorobot: a 1-µm spherical
respirocyte consisting of about 18 billion atoms. He estimates that a factory production line deploying
a coordinated system of 100 macroscale scanning probe microscope (SPM) assemblers, where each
assembler is capable of depositing one atom per second on a convergently-assembled workpiece, would
result in a manufacturing throughput of two nanorobots per decade. If one conjectures about enormous
increases in assembler manufacturing rates even to the extent of an output of one nanorobot per minute,
it would take two million years to build the first cubic centimeter therapeutic dosage of nanorobots.
Thus, it is clear that the future of medical nanotechnology and nanoengineering lies in the direction of
self-assembly and self-replication.

References
1. Bridgman, P. W., Dimensional Analysis, 2nd Ed., Yale University Press, 1931.
2. Buckingham, E., “On physically similar systems: illustrations of the use of dimensional equations,”
Physical Review, 4(4):345–376, 1914.
3. Huntley, H. E., Dimensional Analysis, Dover Publications, 1967.
4. Langhaar, H. L., Dimensional Analysis and Theory of Models, John Wiley and Sons, 1951.
5. Taylor, E. S., Dimensional Analysis for Engineers, Oxford University Press, 1974.
6. Israelachvili, J. N., Intermolecular and Surface Forces, Academic Press, 1985, pp. 9–10.
7. Fearing, R. S., “Microactuators for microrobots: electric and magnetic,” Workshop on Micromecha-
tronics, IEEE International Conference on Robotics and Automation, 1997.
8. Bobbio, S. M., Keelam, M. D., Dudley, B. W., Goodwin-Hohansson, S., Jones, S. K., Jacobson, J. D.,
Tranjan, F. M., Dubois, T. D., “Integrated force arrays,” Proceedings of the IEEE Micro Electro
Mechanical Systems, 149–154, 1993.
9. Jacobson, J. D., Goodwin-Johansson, S. H., Bobbio, S. M., Bartlett, C. A., Yadon, L. N., “Integrated
force arrays: theory and modeling of static operation,” Journal of Microelectromechanical Systems,
4(3):139–150, 1995.
10. Yamaguchi, M., Kawamura, S., Minami, K., Esashi, M., “Distributed electrostatic micro actuators,”
Proceedings of the IEEE Micro Electro Mechanical Systems, 18–23, 1993.
11. Kim, C. J., Pisano, A. P., Muller, R. S., “Silicon-processed overhanging microgripper,” Journal of
Microelectromechanical Systems, 1(1):31–36, 1992.
12. Matsubara, T., Yamaguchi, M., Minami, K., Esashi, M., “Stepping electrostatic microactuator,”
International Conference on Solid-State Sensor and Actuators, 50–53, 1991.
13. Niino, T., Egawa, S., Kimura, H., Higuchi, T., “Electrostatic artificial muscle: compact, high-power
linear actuators with multiple-layer structures,” Proceedings of the IEEE Conference on Micro Electro
Mechanical Systems, 130–135, 1994.
14. Huang, J. B., Mao, P. S., Tong, Q. Y., Zhang, R. Q., “Study on silicon electrostatic and electroqua-
sistatic micromotors,” Sensors and Actuators, 35:171–174, 1993.
15. Mehragany, M., Bart, S. F., Tavrow, L. S., Lang, J. H., Senturia, S. D., Schlecht, M. F., “A study of
three microfabricated variable-capacitance motors,” Sensors and Actuators, 173–179, 1990.
16. Trimmer, W., Gabriel, K., “Design considerations for a practical electrostatic micromotor,” Sensors
and Actuators, 11:189–206, 1987.

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