Nonlinear Dynamics and Wear Characteristics of a High-Frequency Flapping-Wing Mechanism with Multiple Revolute-Joint Clearances

Micro flapping-wing air vehicles are increasingly used in low-altitude and aerospace applications, creating a growing need for accurate motion and stable dynamic performance. This trend motivates a detailed investigation of the dynamic behavior of their actuation mechanisms. Manufacturing and assembly tolerances inevitably introduce small clearances into the kinematic joints, which reduce the motion accuracy of the mechanism, induce high-frequency vibration, and accelerate interfacial wear. Most existing studies on the dynamic behavior of mechanisms with clearances focus primarily on conventional planar mechanisms or single-clearance scenarios. However, the nonlinear dynamics, wear behavior, and chaotic responses of high-frequency flapping-wing mechanisms with multiple clearance joints remain insufficiently understood. Consequently, this paper investigates the dynamic responses and kinematic joint wear characteristics of a high-frequency planar flapping-wing actuating mechanism featuring multiple revolute-joint clearances. First, a clearance model for multiple planar revolute joints is established. Second, the Lankarani–Nikravesh normal contact force model and a modified Coulomb friction model are integrated to characterize nonlinear impact and frictional behaviors at the clearances. Subsequently, we construct a dynamic wear model for the revolute-joint clearances based on Archard’s law. Finally, a multibody dynamic model of the high-frequency flapping-wing mechanism considering multiple revolute-joint clearances is developed. The nonlinear dynamic responses of the mechanism are analyzed, and the effects of clearance size and driving speed on the flapping trajectory, velocity fluctuations, and joint wear are quantified. The results provide a theoretical basis for tolerance design, dynamic optimization, and service-life prediction of high-frequency mechanisms such as those used in micro flapping-wing air vehicles.