Flight Control System for Gust Resistant Micro Air Vehicle

Abstract

This paper discusses the preliminary development of flight control system for a gust resistant Micro Air Vehicle (MAV). Maintaining the state of autonomous hover for a MAV in presence of any disturbance is a challenging task which depends on the robustness of the control system as wll as rotor control power for a rotor based vehicle. This paper compares two different approaches for achieving autonomous hover. In the first part, a PID controller is implemented for attitude stabilization of the vehicle using the states measured with an Inertial Measurement Unit (IMU). In the second part, PID controller is refined to incorporate velocity feedback by using an optic flow sensor for autonomous hovering of a micro coaxial. This is achieved in various steps. First, the PI controller for yaw stabilization is tuned by performing an open loop excitation on a yaw test stand. Next, with the yaw gains set, an open loop flight is carried out to identify the extent of control input needed for hovering flight. Next, two PID controllers are implemented with the optic flow sensor as velocity feedback to resist motion in the presence of disturbance and hover in the absence of disturbance. Finally, the resulting controller is successfully tested in a closed environment and the performance of the vehicle with and without the controller is compared. The controller is ovserved to be able to satisfactorily maintain the hover of the MAV.