Wind Uncertainty Modeling and Robust Trajectory Planning for Autonomous Parafoils

Abstract

A key challenge facing modern airborne delivery systems, such as parafoils, is the ability to accurately and consistently deliver supplies into dicult, complex terrain. Robustness is a primary concern, given that environmental wind disturbances are often highly uncertain and time-varying. This paper presents a new on-line trajectory planning algorithm that enables a large, autonomous parafoil with under-actuated dynamics to robustly execute collision avoidance and precision landing on mapped terrain, even with signicant wind uncertainties. This algorithm is designed to handle arbitrary initial altitudes, approach geometries, and terrain surfaces, and is robust to wind disturbances that may be highly dynamic throughout terminal approach. Real-time wind modeling and classication is used to anticipate future disturbances, while a novel uncertainty-sampling technique ensures that robustness to future variation is eciently maintained. The designed cost-to-go function enables selection of partial paths which intelligently trade o between current and reachable future states, while encouraging upwind landings. Simulation results demonstrate that this algorithm reduces the worst-case impact of wind disturbances relative to state-of-the-art approaches.

6-DOF Modeling and 3D Trajectory Tracking Control of a Powered Parafoil System

“…The trajectory of the multiphase homing is a combination of circular arcs and straight lines. The multiphase homing trajectory must meet the accuracy requirements of the landing point, and the course is against the wind at the end of the homing process [28], [29]. In addition to the two constraints of the multiphase homing, the optimal control homing must satisfy the minimum energy consumption of the control.…”

Autonomous parafoil precision landing using convex real-time optimized guidance and control

“…The idea exposed on [5] incorporates the actuator limitation in the optimization problem which allows both a refresh frequency of 1 Hz and a guarantee of non-saturation of actuators. The parafoil model used in [15] takes into account that the horizontal and vertical velocities are influenced by the altitude through the air density, leading to more representative results. The paper brings a method to take into account non-convex and difficult terrain, while it ignores the winch dynamics.…”

Accurate calculation of aerodynamic coefficients of parafoil airdrop system based on computational fluid dynamic

“…1 The Aviation Industry Corporation of China developed a kind of PADS,with the the thrust-to-weight ratio reaching 1:3, whereas the thrust-to-weight ratio of the other types of UAV was just 1:1. Moreover, the PADS can fly at low speed and low altitude, 2 the flight speed of the parafoil is 30-70 km/h, and the flight height ranges from several meters to several thousand meters. In addition, the PADS is easy to be carried by aircraft and missile and can be delivered remotely.…”