Onboard Flow Sensing For Downwash Detection and Avoidance On Small Quadrotor Helicopters.

摘要

Small rotary-wing UAVs are susceptible to gusts and other environmental disturbances that a ect inow at their rotors. Inow variations cause unexpected aerodynamic forces through changes in thrust conditions and unmodeled blade apping dynamics. This pa- per introduces an onboard, pressure-based ow measurement system developed for a small quadrotor helicopter. The probe-based instrumentation package provides spatially dis- tributed airspeed measurements along each of the aircraft- xed axes. Lateral and vertical windspeed estimates enable the development of disturbance-tolerant ight control strate- gies. The focus of this paper is vertical ow disturbances such as those caused by the downwash of a second vehicle. Real-time velocity measurements are incorporated into a recursive Bayesian estimator to localize a nearby rotorcraft using its downwash. A path planner developed for proximity ight is demonstrated through indoor ight testing with multiple vehicles to safely guide an instrumented quadrotor around the downwash of nearby rotorcraft.