Large Envelope Flight Control of Helicopter via Model Following Control Integrated with Gain Scheduling

As a unique configuration of aircraft, helicopters are widely used in military and civil fields, and the flight control system is the basis for helicopters to execute upper-level tasks. But due to the structural characteristics, compared with fixed-wing and multi-rotor unmanned aerial vehicles, channel coupling is a major difficulty in helicopter flight control design. The explicit model following control has good channel decoupling ability among many control methods, but it's currently applied in single flight node only. In this paper, the explicit model following control is integrated with gain scheduling to adaptively adjust parameters according to the flight mode, extending the explicit model following control to large envelope flight. First, the controller under 16 forward-flying nodes is designed separately based on the explicit model following control theory. Then, the explicit model following control is combined with gain scheduling, and three gain scheduling strategies based on control parameters switching, control parameters interpolation, and model parameters interpolation are proposed respectively. Finally, the forward flight velocity controller is designed to control the flight mode indirectly, and the three scheduling strategies are tested by sinusoidal command tracking while the flight mode is dynamically changing. Furthermore, a position controller is designed to test the performance of the scheduling strategy based on control parameters switching in specific tasks by tracking circular and square routes.