Dual-Phase Rope-Spun Electret Rotary Generator for Morphing Wing Energy Harvesting and Deformation Monitoring

One of the critical challenges of morphing unmanned aerial vehicle (UAVs) is the high-precision and real-time monitoring of wing deformation, restricting their flight safety and range. Here, we present a conformal curved surface measurement method of the morphing wing by dual-phase rope-spun electret rotary generator (d-ERG). The rope-spun structure consists of a coil spring with a thread, an electret layer with a rotating axis, and a stator with dual-phase electrode. The thread can be tightly attached to the curved surface for conformal measurement. The dual-phase electrode design is introduced to detect the direction of deformation with a phase difference. The displacement of the morphing wing is characterized by the response frequencies of the output voltage by Fast Fourier Transform instead of the output voltage amplitudes, exhibiting an ultra-high displacement sensitivity of 100μm and a good linearity R² (coefficient of determination) of 99%. The proposed d-ERG has potential applications in high-precision and self-powered sensing of irregular motions.