Sponsor: Milli-Sensor Systems and Actuators
Personnel: Charles Chung and Mark G. Allen
The merger of inertial sensors with micromachining technology presents the possibility of a wide range of new applications previously unattainable due to performance and/or cost constraints. Such applications may include active suspension in automobiles, position sensing in robots, and portable, "intelligent" maps. Miniaturized, batch-fabricated, navigational grade sensors offers the possibility of fabricating high accuracy sensors at a fraction of today's costs. The photomicrograph shows a completed prototype.
Sponsor: Army Research Office
Personnel: Jennifer English and Mark G. Allen
My current research focuses on the design, fabrication and implementation of wireless micromachined ceramic sensors for high temperature environments. These sensors include pressure, temperature, position, and acceleration sensors. The sensors are fabricated from ceramic tapes, pastes and slurries using processing techniques from the microelectronics packaging industry. A proof-of -concept device, a capacitive pressure sensor has been fabricated and tested. A picture of this device is given.
Sponsor: DARPA and AFOSR
Personnel: Sung-Pil Chang, Jeong-Bong Lee, and Mark G. Allen
This work is a part of the work to develop and demonstrate robust MEMS-based sensors and actuators and to apply these actuators to realistic aerodynamic flow applications such as UAV (unmanned airborne vehicles) or microUAV platforms. In an initial stage of the work, robust substrates, such as stainless steel, are studied as substrates for micromachined devices. The use of robust substrates may allow for the co-fabrication of micromachined sensors and sensor packages. Lamination combined with traditional micromachining processes has been investigated as a suitable technology for these investiations. To illistrate this technology, a capacitive pressure sensor array has been designed, fabricated, and characterized using a stainless steel substrate, Kapton film as a diapragm, and an electroplated nickel fixed back electrode. The net capacitance change over the applied pressure range (O to 34 kPa) was appoximately 0.14 pF. Multivibrator circuitry has been integrated with pressure sensors in a hybrid fashion and used for frequency-modulated output measurements. An important attribute of this design is that only the steel substrate and the pressure sensor inlet is exposed to the flow; i.e., the sensor is self-packaged.
Sponsor: U. S. Army through MSSA
Personnel: Todd Kaiser and Mark G. Allen
A conventional spinning wheel gyroscope was designed by MSSA, but instead of ball bearings to support the wheel, an air bearing was incorporated into the design. The housing was machined with an end mill, then polished to a mirror-like finish. A thin material was then deposited on the housing, patterned and etched to produce the micron sized grooves that would support the wheel when spinning.
Capacitance plate pickoffs were also used in the design. Two opposing patterns were placed on insulating material. They were formed by depostion of adhesion and seed layers, photoresist patterning and electroplating of copper to form the capacitance pickoffs.
Sponsor: U. S. Navy through MSSA
Personnel: Todd Kaiser, Chuck Chung, and Mark G. Allen
A novel design for an accelerometer using gyroscopic torque to null a pendulous proof mass is being micromachined. The design includes a three gimballed system, with sensors and actuators. The three axis are perpendicular with sensors for motion on all three axes, and electrostatic drives for two of the members.