Multibody dynamic modeling and analysis of parafoil systems considering suspension configurations
Abstract
The suspension structure between the canopy and the payload directly affects the payload attitude stability and landing safety of parafoil systems. To quantitatively evaluate the influence of different suspension structures, this paper develops a twelve-degree-of-freedom (12-DOF) multibody dynamic model by extending the conventional six-degree-of-freedom (6-DOF) parafoil model to include the translational and rotational motion of the payload, with the suspension lines modeled as spring-damper units. Based on practical engineering configurations, four typical suspension structures are designed. Numerical simulations are conducted under constant crosswind conditions during three flight phases: radial flight, energy management, and flare landing. The effects of suspension structures on payload stability and landing safety are analyzed by comparing payload attitude histories, oscillation amplitudes during loitering, pitch-forward angles during flare landing, and touchdown velocities. The results show that suspension structures significantly affect payload attitude stability. The pyramid structure effectively reduces attitude oscillations and pitch-forward motion, whereas the cross-line suspension provides a lower vertical touchdown velocity. The vertical touchdown velocity is mainly governed by the aerodynamic characteristics of the parafoil and is insensitive to variations in suspension structure. The results provide a reference for the selection and parameter optimization of suspension structures for parafoil systems.