Trim and Stability Analysis of Parafoil/Payload System Using Bifurcation Methods

Abstract

Ever since its invention by Jalbert, parafoils have been used for cargo and military delivery, recreation, surveillance, agriculture, advertising, etc. Recently, autonomous parafoil /payload (p/p) systems for payload delivery have been subject to several investigations. Unlike airplane 6-DOF model, p/p system requires 9-DOF model since it is a two-body system with payload suspended below the parafoil canopy through a number of lines. Presence of large vertical distance between center of gravity of the system and centers of canopy drag (mostly inlet drag), line drag and payload drag results in nonlinear trim and stability characteristics. Rigging angle and magnitude of brake deflection are important design parameters which aect the trim and stability characteristic of p/p system. Bifurcation methods are convenient for numerical computation of trim and stability including nonlinear eects. Thus, present work focuses on the use of bifurcation analysis to determine the eect of various design parameters on the longitudinal trim and stability characteristics of the p/p system using 4-DOF longitudinal flight dynamic model.