Sensing from control: Airframe deformation for simultaneous actuation and state estimation

This work is inspired by the hawkmoth Manduca sexta, which has been shown to actively use its abdomen for deforming-airframe-based flight control through inertial actuation. The active role of the abdomen induces Coriolis forces in flight, which may allow the moth to detect the body yaw rate. We explore the simultaneous sensing and control mechanisms of the abdomen through the use of an engineered flexible abdomen. The flexible abdomen dynamics are derived using a Lagrangian approach. Nonlinear observability analysis shows that abdomen pitch actuation is required for yaw rate observability, thus supporting the hypothesis that the abdomen serves a simultaneous sensing and actuation role. We successfully demonstrate that a range of yaw rate estimates can be extracted from Coriolis-induced strain measurements on the flexible abdomen using only a pair of strain sensors. Two different estimation schemes are utilized in this demonstration: a model-based unscented Kalman filter and a data-driven approach.