Track-following Controller For An Acoustically Excited Double-paddle Scanner

This paper presents preliminary results on the experimental application of a track-following control to an acoustically actuated micro-scanning mirror. Scanning mirrors demand high degree of precision in keeping constant the scanner operational frequency and amplitude of oscillation. This can hardly be achieved by using only open-loop strategies, since these micro devices are very sensitive to environmental conditions, which could cause changes in their natural frequencies. In order to maintain constant the operating frequency and amplitude, a closed-loop control strategy is proposed. The outline of this strategy is that the angular velocity of the scanning mirror must follow a sinusoidal reference signal of predefined frequency and amplitude. This control design is based on the internal model principle. We require that the acoustically actuated micro-scanner must oscillate at 1164Hz with a peak velocity of 0.08 m/sec. The obtained experimental results show that it was possible to control this new kind of optical scanners to the specified frequency and amplitude with small tracking error. © 2006 IEEE.609614Ahmida, K.M., Ferreira, L.O., Provazzi, A., Arruda, J.R.F., A device for acoustical excitation of optical scanners (2005) Patent, Protocol No. PI/MU: PI0504353-0, , OctoberAhmida, K.M., Ferreira, L.O.S., Design and modeling of an acoustically excited double-paddle scanner (2004) J. Micromech. Microeng, 14, pp. 1337-1344Aksyuk, V., Barber, B., Giles, Ruel, R., Stulz, L., Bishop, D., Low insertion loss packaged and fibre connectorised MEMS reflective optical switch (1998) Electron. Lett, 34, pp. 1413-1414Anderson, B.D.O., Moore, J.B., (1990) Optimal Control -Linear Quadratic Methods, , Prentice-Hall, New JerseyBarbaroto, P.R., Ferreira, L.O.S., Doi, I., Si-liG process for inductive meso systems (2003) Appl. Surf. Sci, 1, pp. 406-410Chen, C.-T., (1984) Linear System Theory and Design, , Oxford University Press, New YorkFerreira, L.O., Moehlecke, S., A silicon microme-chanical galvanometric scanner (1999) Sensors and Actuators, 73 (3), pp. 252-260Ferreira, L.O.S., Induction microscanner. U.S. Patent No, US 6,285,485 B1, A, September 2001Ferreira, L.O.S., Pourlborz, F., Ashar, P., Malek, C.K., Torsional scanning mirrors actuated by electromagnetic induction and acoustic waves (1998) Proc. of the International Conference on Microelectronics and Packaging - ICMP98, pp. 155-162. , CuritibaFrancis, B.A., Wonham, W.M., Internal model principle of control theory (1976) Automatica, 12 (5), pp. 457-465Franklin, G.F., Powell, J.D., Workman, M.L., (1994) Digital Control of Dynamic Systems, , Addison-Wesley Publishing Company, New YorkLjung, L., (1999) System Identification: Theory for the User, , Prentice-Hall, New JerseyMarshall, G.F., (1985) Laser Beam Scanning: Opto-Mechanical Devices, Systems, and Data Storage Optics, , pubMarcel Dekker, Inc, New YorkMiyajima, H., Murakami, K., Katashiro, M., MEMS optical scanners for microscopes (2004) IEEE J. Sci. Top. Quantum Electron, 10, pp. 514-527Oliveira, L.C.M., Barbaroto, P.R., Ferreira, L.O.S., Doi, I., A novel si micromachined moving-coil induction actuated mm-sized resonant scanner (2006) J. Micromech. Microeng, 16 (1), pp. 165-172Reid, G.T., Marshall, S.J., Rixon, R.C., Stewart, H., A laser scanning camera for range data acquisition (1988) J. Phys. D: Appl. Phys, 21 (1), pp. S1-S3Urbach, J.C., Fisli, T.S., Starkweather, G.K., Laser scanning for electronic printing (1982) Proc. IEEE, 70, pp. 597-618Vangbo, M., Staffan, K., Backhand, Y., Low cost micromachined mirrors for display systems (1999) J. Micromech. Microeng, 9 (1), pp. 85-88Zeleny, R., Scanning the scene (2004) SPIE OEMag, pp. 30-3