In this paper, the design and control of a thermal stabilizing system for an optomechanical uncooled infrared (IR) imaging camera is presented, which uses an array of MEMS bimaterial cantilever beams to sense an IR image source. A one-dimensional lumped parameter model of the thermal stabilization system was derived and experimentally validated. A model-based discrete time linear quadratic gaussian regulator (LQGR) control scheme, with a stochastic ambient noise model, was implemented. The control system incorporates a reference model, which generates desired reference temperature trajectory, and integral action to respectively diminish overshoots and achieve zero steady state error in closed loop. Simulation results show that the designed LQGR is able to enhance ambient temperature low frequency disturbance attenuation by more than 50 dB. The control system is able to regulate the focal-plane array (FPA) temperature with a standard deviation of about 100 μK, in spite of the fact that the temperature measurement noise has a standard deviation of 1 mK. Noise analysis results for the present stage of the optomechanical IR imaging system are summarized. The noise equivalent temperature difference (NETD) of the current stage of the IR camera system can achieve about 200 mK.
Bibliographical noteFunding Information:
This project is supported by the DARPA IR program under grant N66001-00-C-8080.
Arunava Majumdar received the BTech degree in mechanical engineering from the Indian Institute of Technology, Bombay, India, in 1985 and the PhD degree in mechanical engineering from University of California, Berkeley, in 1989. He is currently a professor in the Department of Mechanical Engineering, University of California, Berkeley. Previously, he was with the Arizona State University, Temp, from 1989 to 1992 and the University of California, Santa Barbara (from 1992 to 1996) as a faculty member in mechanical engineering. His research interests in his group range from MEMS, micro/nanoscale thermophysics to nanobiomolecular engineering and nanoscale imaging. He is currently serving as an associate editor for the ASME Journal of Heat Transfer and the International Journal of Heat and Mass Transfer, and is co-editor-in-chief of Microscale Thermophysical Engineering. Dr. Majumdar is a recipient of the NSF Young Investigator Award, the ASME Melville Medal, and the ASME Best Paper Award from the Heat Transfer Division. He also serves as a member of the Council on Energy Engineering Research for the Department of Energy and the ASME Steering Committee on Nanotechnology.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering