Backstepping Based Adaptive Control for a Mini Rotorcraft with Four Rotors

In this paper, an adaptive control strategy applying on a mini four-rotor rotorcraft is proposed. The controller is designed using the backstepping method and function estimation. In the control architecture for this rotorcraft, a two-layer structure is adopted consisting of an inner-loop controller and an outer-loop controller. The inner-loop controller is responsible for the angular rotations control, and the outer-loop controller is responsible for the position control. In the outer-loop controller design, a mass estimator and a disturbances estimator are designed when the mass of the aircraft is varying and the external disturbances exist. The control laws are established which ensures that the system is Lyapunov stable and that the aircraft behaves adaptively. The inner-loop controller is designed based PI control. The simulation results illustrate that, the mini four rotors rotorcraft with the controller can well adapt to the sudden change of its mass and the external disturbances, which shows the great robustness of the mini four-rotor rotorcraft.