On the Development of a Six-Degree-of-Freedom Model of a Low-Aspect-Ratio Parafoil Delivery System

Abstract

Numerous papers in the area of parafoil system design have been published over the past 50 years. They cover the following major topics: The future of the Army's air delivery mission includes the use of precision-guided autonomous airdrop methods to resupply troops in the field. High-glide systems, ram-air parafoil-based, allow for a safe standoff delivery as well as wind penetration. This paper addresses the development of a six-degree-offreedom model of a low-aspect ratio controllable parafoil-based delivery system. The model is equally suitable for modeling and simulation and for the design of guidance, navigation and control (GNC) algorithms. This gliding parafoil model was developed in the MATLAB/Simulink ® environment. Apparent mass and inertia effects are included in the model. Initial test cases have been run to check model fidelity.Advanced computational methods for the 3D flow simulation around the parafoil canopy; [1][2][3] Wind-tunnel experiments; [4][5][6][7] Real drop experiments. [8][9][10][11][12][13][14][15][16][17][18]

Development of Control Algorithm for the Autonomous Gliding Delivery System

“…35. This model matches flight test data and is characterized by the following integral parameters: the average descent rate is 3.7-3.9m/s, glide ratio is about 3.0, the turn rate of ~6°/s corresponds to the full deflection of one flap.…”

“…The trajectory tracking control system discussed in Section V has been tested in simulation using a nonlinear 6DOF model of the Pegasus parafoil that also includes the available actuator model. 35 Fig.14 shows a comparison between flight test data collected during Pegasus drop at the YPG and model's response to the wind collected during the same drop. Clearly, the 6DOF model provides a reasonable approximation of the parafoil dynamics.…”

Multicriteria Parametrical Identification of the Parafoil-Load Delivery System

“…The present paper does not intend to discuss various numerical techniques of parameter identification, but addresses the physical issues (multicriteria essence) behind the identification process and is organized as follows. Section 2 introduces the cargo parafoil model developed during a structural identification 5 and names several groups of parameters to be identified. Because of the different nature of these groups of parameters several adequacy criteria are suggested to be used.…”

“…While the structural identification for parachute-and parafoil-based payload delivery systems is considered to be more or less settled, [1][2][3][4][5] the parametrical identification (defining aerodynamic and control coefficients, apparentmass-tensor elements, etc. ), especially for those high-degree-of-freedom models developed in the past decade 1,3,5 still needs to be addressed and it is being addressed by different group of researches for different aerodynamic deceleration systems.…”

“…), especially for those high-degree-of-freedom models developed in the past decade 1,3,5 still needs to be addressed and it is being addressed by different group of researches for different aerodynamic deceleration systems.…”