Equivalent Vertical Dynamics of Flapping-Wing Flying Robot in Regulation Control: Displacement Transmissibility Ratio

This paper presents an equivalent dynamic model for vertical regulation control of a flapping-wing flying robot. The model is presented based on the data of a series of flight experiments for an available platform. The system shows oscillations in motion in all experiments with an approximate frequency between [3. 5, 4. 5](Hz), changing within a limited range. The behavior of the equivalent model represents a system with base excitation. The displacement transmissibility ratio (TR) is found for the model to investigate the oscillatory behavior in the system during the flight. Reduction of the oscillations through the transmissibility ratio will decrease the uncertainty in flight and consequently, that could increase the success rate of perching on a branch (now it has a 10 - 15(cm) uncertain periodic motion); perching needs precision on the last meter approaching phase. An analytical expression for TR is presented which is used for parameter selection, tuning, and selection of the flapping frequency, as the base excitation source. The study shows that the robot works in a proper zone of the frequency ratio, and also, the sensitivity of the TR is high concerning the changes in the stiffness constant.