Design of a High-Temperature Utility Electromechanical Actuator 2012-01-2214
Electric actuation on aerospace platforms has significant advantages compared to its hydraulic counterparts, particularly in terms of enhanced reliability, reduced maintenance, advanced diagnostic/performance capabilities, and possibly reduced weight and cost. It is thus not surprising that military and commercial aerospace sectors are introducing more electrical actuation architectures. A logical continuation of this trend is the replacement of hydraulic utility actuators in applications with harsh environments such as wide-range ambient temperatures and high vibration, where hydraulic actuation is still dominating. Such environments provide new challenges to the design of electric actuators, particularly considering that performance, weight, volume, and cost should be competitive with the equivalent hydraulic systems. Some of these challenges are addressed in this paper, which describes the design of an electromagnetic utility actuator capable of operating in −40 to 200°C ambient temperature in a highly corrosive and vibrating environment. It focuses mainly on the design of the powertrain, leveraging the specific, low duty-cycle operating requirements to reduce geartrain and motor size, and the application of evolutionary multi-objective optimization techniques to design the motor. The design efforts yield an optimized combination of motor and geartrain in terms of mechanical performance including a motor design with a power density three times greater than comparable machines designed for continuous duty cycle. Further, the paper discusses several challenges associated with wide-temperature operation including component and material selections that operate in a desirable fashion across the entire temperature range. Such selections include bearings, lubrication, sealing materials, sensors, and electronic components capable of operating at 200°C.