High Power-Density Linear Motor Actuator for Flight Control Systems Applications

A number of technical studies have concluded that the replacement of an aircraft's hydraulic systems with electrical actuation would result in substantial cost savings and increased reliability. Unfortunately, conventional electrical motors used in actuators have inherently low load capacity. Therefore, mechanical force amplifiers such as gear trains or ball/roller screws are coupled to the motor. These components add weight, compliance, and backlash; and increase maintenance and reduce reliability. Improvement in electric motor power density through the use of rare-earth magnets or amorphous materials are only incremental. This project is for the development of a Linear Motor Actuator (LMA) which is based upon redundant piezoelectric actuation. The proposed LMA promises power densities beyond that possible with magnetic motors, rapid response, fail-safety, ease of scaling, and no energy consumption to maintain load and position. The prototype scaled-down LMA to be fabricated and tested in Phase I of this project is based upon Bonneville Scientific's five years of experience in R&D on piezoelectric actuation for robotics. Phase I test results will be used in the design of the complete, full-size LMA and its associated computerized control system to be fabricated in Phase II of this project.