藤原 大悟

<p>Flight control system with position compensation applicable to trajectory tracking of agile maneuvers that require an attitude rotation and a reverse of main rotor thrust of single-rotor helicopters is proposed. The outer loop position compensator calculates the desired attitude and rotor thrust which reduce position tracking error by utilizing a kinematics equation established near the reference trajectory. The desired attitude is set using the magnitude of the rotor thrust in the reference trajectory, which enables continuous position feedback compensation based on the fact that the relationship between rotational and translational motion becomes independent as the rotor thrust decrease. To achieve high-bandwidth control of lateral-longitudinal angular rates in the inner loop, two-degree-of-freedom servo system is designed using a linear model with blade flapping motion dynamics. The control system is applied to autonomous control of flip maneuvers which include transition between upright and inverted hovering. The reference trajectory of a flip maneuver is generated as a parameterized simple equation which can be adjusted to the helicopter ability. Simulation and outdoor flight tests of the autonomous flip maneuvers demonstrated the capability of position feedback compensation that reduces position tracking error during out-of-trimmed flight state. This control technique can be extended to various agile flights for quick execution of flight tasks or recovery maneuvers from dangerous state.</p>

<p>Aiming at the realization of agile autonomous flight for the extension of the flying range of single-rotor helicopters in the limited flight time, the flight control system design and the control performance verification for the high-speed turn flight are conducted. To achieve the reference following control for large attitude angles and the rotor thrust, the control system is composed of the main-rotor thrust and body torque centralized controller based on the MIMO (Multiple-Input, Multiple-Output) helicopter model including the blade motion dynamics, rotor speed proportional-integral controller, the attitude controller designed via the backstepping method based on the quaternion attitude model, and the guidance controller based on translational motion model. Simulation results show that the hovering and 10-m/s straight cruise flight followed by over 45-degree bank turn is feasible by using the proposed control system. In addition, flight tests have been conducted using the experimental small unmanned electric helicopter equipped with the flight control computer, and the high speed turn agile autonomous flight was successful in the real environment.</p>