Surveillance Sensors

Current biological and chemical sensors are bulky and heavy and require experienced technicians to operate them. Several MEMS-based biological and chemical warfare sensors under development that could be packaged in a container the size of a shoe box could automate the detection process.

Infrared cameras are widely used for surveillance, but liquid gas coolers, which are required for conventional cameras, impose a significant operational burden. A MEMS-based infrared camera would not require a low-temperature operating environment and would greatly expand the surveillance capabilities of UAVs.

Actuators

UAVs could use MEMS-based actuators for steering fiber optics and for signal switching of onboard electronics. Systems to control flow separation will require actuators with displacements on the order of millimeters and actuation forces on the order of milli-Newtons. Three types of force are available for actuation: electrostatic, electromagnetic, and thermal-pneumatic forces. EMAs can provide the forces required for UAVs. Electrostatic forces usually are an order of magnitude too low. Thermal-pneumatic actuators offer the highest force level, but packaging is more involved, and the frequency response is low.

A much greater force will be necessary for structural control. Possible candidates for these actuators include thin piezoelectric actuators, magnetostrictive alloys, and shape-memory alloys. The typical displacement of current actuators using these technologies (typically in the micron range) is too low for use in UAVs. In addition, thin-film processing technology requires further development to make thin piezoelectric actuators a practical alternative. Versatile thin-film, smart material-processing technologies compatible with microtransducer fabrication techniques would significantly reduce packaging costs. Research is needed to overcome the limitations of current technology and satisfy the demand for miniature actuators.

Recommendation. The U.S. Air Force should monitor developments in microelectromechanical system (MEMS) and undertake research to develop and apply a new generation of MEMS sensors and actuators.



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