System identification of a square parachute and payload for the LAICAnSat

This work is a part of the LAICAnSat project of the University of Brasilia aimed at developing near-space experimental BalloonSats for scientific missions and remote sensing applications. The project is divided in two main parts: Low Altitude Part (LAP) and High Altitude Part (HAP). For the HAP, two successful launches were made with a 1200 g latex balloon using helium and carrying a payload with embedded sensors in order to collect local information. Regarding the LAP, which is the focus of this work, the team is currently working on the identification of the aerodynamic model parameters of a square parachute to be used in future launches. The final goal is the implementation of a suitable control system to land the payload in a predefined area. The main motivation to develop such a system is to make the payload rescue easier, avoiding areas of difficult access such as dense forests. Therefore, it is important to develop a system that is capable navigating the payload, and the first step for that is the aerodynamic model identification. To reach this objective, the team is using a remote controlled parachute to collect data for the identification process and test the proposed model. Trajectory and speed are acquired by the BeeLine GPS 2-meter in a trimmed flight and used to identify steady-state coefficients (C_L0 and C_D0). The derivatives parameters, such as C_Lα, C_Dα, and others, will be estimated using biologically inspired computing and parachutes wind-tunnel data from the literature.