Full control of a quadrotor using parameter-scheduled backstepping method: implementation and experimental tests

Abstract

This paper proposes a nonlinear controller for a quadrotor helicopter, under the control of which the system is globally asymptotically stabilized with good control quality. The proposed controller is synthesized by Command Filtered Backstepping method with a novel parameter scheduling scheme. By scheduling controller parameters within the system-stabilizing region, the convergence speeds of errors in each step are adaptively adjusted based on different flight conditions. Amplitudes of control signals are reduced during fast tracking progress to avoid actuator saturation, which is hardly modeled and may cause instability. The controller also allows more aggressive tuning that achieves better regulation accuracy. The technology to implement the proposed controller is illustrated in detail, and key parameters of quadrotor model and the actuator’s dynamics are identified by experiments. To validate the proposed method, experimental flight tests are conducted under three typical flight conditions. Results comparing to other methods such as PID, sliding mode control and dynamic surface control are demonstrated, showing that the proposed controller is practical to an actual quadrotor system and can achieve good control performance.