More Detailed Disturbance Measurement and Active Disturbance Rejection Altitude Control for a Flapping Wing Robot Under Internal and External Disturbances

Abstract With the goal of designing a biologically inspired robot that can hold a stable hover under internal and external disturbances. We designed a tailless Flapping-wing Micro Aerial Vehicle (FMAV) with onboard 3D velocity perception. In this way, the wind disturbance caused by the relative motion of the FMAV can be quantified in real time based on the established altitudinal dynamics model. For the rest of the total disturbance, an active disturbance rejection controller is proposed to estimate and suppress those disturbances. In comparison with the traditional PID controller, this proposed approach has been validated. The results show that, in the hovering flight with the internal unmodeled dynamics, the root-mean-square of height controlled is only 2.53 cm. Even with the different weights of loads mounting on the FMAV, the ascending trajectory of flights remains impressively consistent. In the forward flight with the external disturbance, the root-mean-square error of height controlled is 2.78 cm. When the FMAV flies over a ladder introducing an abrupt external disturbance, the maximum overshoot is only half of that controlled by the PID controller. To our best knowledge, this is the first demonstration of FMAVs with the capability of sensing motion-generated wind disturbance onboard and handling the internal and external disturbances in hover flight.