Function-Based Analysis and Redesign of a Flyable Electromechanical Actuator Test Stand

Critical faults prevent electromechanical actuators (EMAs) from controlling primary flight surfaces aboard commercial and military human air/spacecraft. However, the efficiency and simplicity of the EMAs makes them appealing for use. For successful implementation, diagnostic and prognostic techniques identifying these critical faults must be optimized. This paper builds the foundation for the design of a second-generation test stand whose aim is to inject known EMA faults and record the data output while onboard an aircraft. First, an overview of faults is presented. Next, functional modeling is introduced as an effective system level representation to implement early design changes. Specifically, functional modeling is proposed to isolate functions of the test stand that can affect faulted and nominal actuator data collection through violations of post-processing statistical assumptions. The data collected from the EMA test stand will be used for actuator prognostic purposes and therefore must closely represent a full-scale actuator installation. This methodology will increase experiment validity, verifiable conclusions made regarding actuator remaining useful life, and overall system reliability.