Pseudo-airspeed estimation and control for solar-powered unmanned aerial vehicles (UAVs) without Pitot airspeed sensor

Solar-powered UAVs have large scales, low airspeed, and narrow envelopes, the low flight speed cannot be accurately measured by the Pitot sensor, combined with wind interference, can lead to energy over- or under-abundance during the landing, which in turn induces control instability. However, high-precision airspeed sensors and data fusion algorithms add weight and cost burdens. This paper reproduces the measurement deficiencies of Pitot sensor for low airspeed through wind tunnel and on-board experiments, and demonstrates the feasibility of airspeed estimation without Pitot sensor through accurate aerodynamic and thrust modeling. Then, a pseudo-airspeed estimation method based on aerodynamic and thrust modeling, as well as an incremental nonlinear dynamic inversion (INDI) throttle switching and pseudo-airspeed feedback control architecture are proposed, and the stable flight of a solar-powered UAV without Pitot sensor is verified by model parameter high-low bias test, pseudo-speed estimation experiment, and control simulation. This provides a viable scheme for failure identification and signal substitution of Pitot sensor, which can increase the robustness of landing control for low-speed, lightweight aircraft, and is necessary for the control of multiple solar-powered UAVs articulated into a mega-scale platform.