An Ejecting System for Autonomous Takeoff of Flapping-Wing Robots

Autonomous takeoff of flapping-wing robots (FWRs) is crucial for accelerating response speed and reducing costs in executing tasks. Jumping-aided takeoff is an effective method adopted by birds. However, the limited power density of motors poses challenges in achieving this type of takeoff for FWRs. In this study, we introduce a ground-based FWR ejecting system that utilizes a symmetric slider-crank mechanism (S-SCM) to store energy in spring. This stored energy is then converted into the takeoff speed of the FWR. The dynamic model of each working stage is established, and the design parameters are optimized according to simulation results. The prototype of the FWR ejecting system is fabricated for experimental validations. The results indicate that the system can provide a takeoff speed of 4 m/s for the 270 g FWR. Notably, the system is deployable on rough terrains and only adds a 3.2 g payload to the robot. Our work advances the autonomous takeoff of FWRs, promoting the application of such robots.