High-Temperature Opto-Fluidic Actuator

Sponsored by: Allied Signal Aerospace Equipment Systems

Fluid control and actuator systems are common components on modern jet aircraft. These devices operate many critical engine components from speed controllers to air bleed valves. The no moving parts nature of fluidic systems makes them highly reliable and mechanically robust, attributes that are necessary for equipment in commercial airline use. Typically, however, the fluid controller or actuator must be coupled with an electromechanical device to interface it with the rest of the engine or aircraft control system. In this way, the true benefit of the fluidic technology is not realized due to the integration of less reliable, more costly, and often bulky heavy electro-mechanical components.

AITHER personnel conducted a research program for Allied Signal Aerospace Equipment Systems (now Honeywell Aerospace) to develop and test a high-temperature opto-fluidic actuator for the last engine compressor stage air bleed valve for the Boeing 777. The actuator concept would mate a fluidic low-pressure control circuit and high-pressure rotational drive circuit with an optical command link. The benefit of this concept would be the elimination of the electronic control circuit and electric torque motor, which added considerable weight to the bleed valve assembly.

AITHER personnel were responsible for developing the optical command link and low-pressure control circuit based on a fluidic amplifier design and acousto-fluidic interface developed under the DARPA Small Low Cost Interceptor Device (SLID) Program. A preliminary control circuit was built and tested by AITHER using the existing SLID technology and demonstrated to work at low to moderated temperatures. The circuit did not operate successfully at the elevated temperatures (600 ºF) experienced in the high-pressure compressor of a turbine engine.