Actuator Load Estimation From Distributed Optical Sensing of Airframe Deformation

Real-time health monitoring of flight control actuators usually involves the comparison of measured signals either with numerical models or with statistical data. As the external loads experienced by the system influence the operation of most actuators, such loads are a useful quantity to compare with the actuator output and perform onboard fault detection. In common flight controls, the actuator load is not directly available as a measured signal, due to the reliability and complexity penalties often associated to the installation of dedicated sensors and transducers. In this work, we discuss the use of distributed sensing of the airframe strain to infer the aerodynamic loads acting on the flight control actuator. We address a specific sensing technology based on Fiber Bragg Gratings (FBGs) as it combines a good accuracy with minimal invasivity and low complexity. Specifically, we combined a structural and an aerodynamic model to collect a database to train data-driven surrogates intended to map from strain measures to actuator load. Figure 1 displays the information flow of the proposed process.