Eagle-scale flapping-wing flying robots (FWFRs) hold significant application value in fields such as resource exploration and counter-terrorism operations. However, when performing low-altitude detection tasks in confined spaces, such as reconnaissance in urban areas, there exists a significant risk of collision with surrounding buildings or other objects. Especially for eagle-scale large FWFRs, safe flight in confined spaces poses greater challenges due to their large size and mass, lack of hovering and omnidirectional flight, and the need for relatively high flight speed threshold to sustain sufficient lift. To address these challenges, a collision-free autonomous tracking control method based on periodic motion equivalence is proposed. Firstly, a kinematic and dynamic equations considering the periodic motion equivalent of a flapping-wing aircraft are derived, and the cyclic fluctuations of aircraft fuselage are analyzed. Then the obstacle-free flight constraints of the FWFR are established. Secondly, an obstacle-avoidance control strategy is designed based on dynamics window trajectory planning and periodic equivalent flight control. The complex flight path of FWFR is decomposed into several basic sub-paths to avoid obstacles and approach the desired path, hence the whole tracking task can be realized by utilizing several simple tracking strategies for basic sub-paths. The attitude and longitudinal motion are then controlled by combining PID control laws with periodic average equivalent flight dynamics. Finally typical flight experiments are conducted to verify the proposed method. The experimental results show that the developed eagle-scale flapping wing flying robots can fly safely between buildings along the desired trajectory.
Wei et al. (Sun,) studied this question.