Improved digital model of parafoil-unmanned aerial vehicle accurate recycling system

Abstract

Using parachute to recycle the air-mid load is widely adopted by medium-sized unmanned air vehicles to landing, however the uncontrolled landing location results in lower recovery efficiency. By using Parafoil-UAV recovery system, UAV can land at a smaller scope around the target location accurately. The theoretical research foundation of control block and digital validation platform of Parafoil-UAV system are based on the digital model of the system. This paper presents an improved method to build the digital model: the method to calculating the apparent mass and rotational inertial of the parafoil; Based on the CFD method, aerodynamic coefficients of specified parafoil can be obtained by aerodynamic performance tests; Using infinitesimal method to calculate the aerodynamic forces and moment of the canopy accurately. For Parafoil-UAV system, forces analysis is conducted to the overall system first and then to the single block, and according to kinematic equations, the 9-DOF digital model is established in Matlab/Simulink platform. Through the digital model, the major forms of motions such as gliding, turning and flared landing can be simulated successfully, and the trajectory of the system under the control inputs can also be obtained.