Flapping trajectory characteristics and attitude control approach of a flapping-wing robot with 2-DOF parallel mechanism

This article investigates the flapping trajectory characteristics and attitude control methods of a flapping robot with the 2-degree-of-freedom (2-DOF) flapping mechanism. Inspired by the flying insects in nature, a 2-DOF parallel mechanism is utilized to realize the complex wingtip trajectories such as the elliptical and figure-of-eight shapes. Firstly, the kinematics of the mechanism are analyzed, and on this basis, the flapping trajectory characteristics of the end-effector of the parallel mechanism used for flapping-wing motion are analyzed, focusing on revealing the influence law of the parameters of the sweeping motion in the stroke on the flapping trajectory characteristics. The high-speed camera is utilized to further develop the kinematics experiment, and results show that the experiment data is in good agreement with that of the analysis. Finally, these characteristics are used to guide the attitude control of the flapping wing robot with the 2-DOF parallel mechanism, which theoretically forms a set of decoupled attitude control approaches for pitch, roll, and yaw. The results of this study are to provide a way of multi-degree-of-freedom motion of the insect-scale flapping-wing robot on the one hand and to expand the current attitude control method of the insect-scale flapping-wing robot on the other hand.