A flow disturbance estimation and rejection strategy of multirotors with round trip trajectories

This paper presents a round trip strategy of multirotors with unknown flow disturbances. The method is designed to decrease flight time for return trips, while the safety is ensured. The disturbance force and torque estimation model is derived from the onboard inertial measurement unit (IMU) sensor data. The estimation made during the previous time step is used as feedforward thrust and torque during the inbound trip, and the disturbances are recorded for the feedforward inputs of the return trip. As a demonstration of the capabilities for this approach, static point and repetitive trajectory experiments are shown along with a comparison against a conventional PD controller. The benefits of this round trip strategy is further verified by multiple experiments. Faster return trip velocity is obtained with small position errors. We also confirm drastically reduced position errors along the flow direction.