Automatic Microgravity Flight System and Flight Testing Using a Small Unmanned Aerial Vehicle

This paper presents the attempt to apply UAV (Unmanned Aerial Vehicle) technology to microgravity experiments. The 6-degree of freedom simulation model of an electric-motor-driven test-bed UAV of which span and weight are 2.4 m and 2.5 kg respectively is established, and the feasibility of microgravity flight is examined using the simulation model and two types of acceleration feedback systems, i.e., acceleration component feedback in body axes and wind axes. The simulation results show that less than 0.15 G environment can be reached for more than several seconds, and the quality of the G-level and the duration differs depending on the type of the feedback. The flight testing system has been also developed including the onboard control system, data communication system, and the ground station together with the test-bed vehicle. Flight tests using the acceleration component feedback in body axes are performed, and one the results shows that minimum G-level reached approximately 0.15 G as implied by the simulation though the adjustment of the control gains was not enough. This G-level may not be satisfactory for practical use at the moment, but the feasibility of the microgravity flight using UAVs is confirmed by the flight data.