The effect of tail configuration and parameters on the aerodynamic performance of flapping-wing flying robots: design and experiment

Abstract This study systematically addresses the design and aerodynamic optimization of tail configurations for bio-inspired flapping-wing robot. Based on a flapping-wing robot prototype, a theoretical model linking tail-size parameters to the pitch static stability margin was established. Six types of tail configurations — arc-shaped tail, triangular-shaped tail, swallow-shaped tail, webbed tail, T-shaped tail, and V-shaped tail — comprising 17 parametrically varied specimens were designed and fabricated. Through a high-precision decoupled wind-tunnel test platform (free stream velocity: 10 m/s, flapping frequency: 2.5 Hz), the three-axis aerodynamic moments (pitch, yaw, roll) under various actuation states were quantitatively measured. The influence of key geometric parameters such as characteristic width, opening angle, and control-surface area on handling and stability was thoroughly investigated. Experimental results show that the T-shaped tail (#53) performs best in pitch control moment and lateral-directional stability margin, with a peak pitch moment of 0.185 N·m — approximately 42 % higher than the baseline configuration — demonstrating the most outstanding overall performance. The V-shaped tail (#62) exhibits excellent lateral-directional control capability under differential actuation, achieving a roll moment of up to 0.106 N·m, albeit with pronounced control coupling effects. This research provides reliable experimental evidence and a theoretical reference for the configuration selection and parameter optimization of tails in flapping-wing robot, offering significant engineering guidance for enhancing flight quality and control effectiveness. In addition, this paper establishes a theoretical framework for preliminary tail size design based on pitch static stability and proposes a parametric design method for multi-configuration tails for flapping-wing robot. The research results not only provide a theoretical basis for tail parameter selection but also offer experimental references for tail configuration optimization and subsequent control-oriented system design.