Air segment guidance and control for the Bi-Modal Unmanned Underwater/Air System

Air segment guidance and control for the Bi-Modal Unmanned Underwater/Air System. The Bi-modal unmanned Underwater/Air System (BUUAS) is a vehicle designed in the RMIT University and able to perform a particular Underwater/Airborne mission profile, with the purpose to carrying airborne surveillance mission with reduced exposure risk with respect to its submarine mothership. The vehicle assumes a dual aerodynamic configuration for the two different phases of the mission. In order to investigate the guidance and control characteristics of the vehicle, a simulator has been implemented. Particular attention has been given to the presence of the Y-tail configuration, featuring an anhedral angle, and to the water-to-air transition phase, where the wing is deployed by changing its sweep angle. The FDC simulator structure is employed and correlated to data of the BUUAS vehicle and with two different aerodynamic models. The first one uses data of preliminary wind tunnel tests, performed on a previous BUUAS version. Further investigation and wind tunnel tests are have been performed in order to obtain a second and more accurate aerodynamic model, where the influence of the tail on others volumes is taken into consideration. The simulator is tested for the two different aerodynamic models and for different trajectories. In order to investigate the dynamics of the wing deployment and to test the robustness of the control system during this phase, the simulation is run using six different intermediate aerodynamic models for the different weep angle ranges. autopilots, necessary for the unmanned flight, are implemented and integrated in the simulator.