Sliding mode control based on extended observer for underactuated quadrotor UAV

This paper introduces an anti-interference robust control strategy for underactuated quadrotor UAV. The strategy consists of an extended state observer and a sliding mode controller. A high gain extended observer was designed to solve the problem of the low measurement accuracy of derivative of the state in real quadrotor UAV system. The oberver can estimate derivative of a given signal with a high accuracy, so it can reduce the hardware requirements in real system, the observer is also used to evaluate the outside disturbance. A sliding mode controller was designed for the underactuated quadrotor UAV, and then set the estimation of disturbance as a part of the control signal, in this way the outside disturbance can be suppressed. Thus the anti-interference ability of the system was improved. Simulation results verify the effectiveness of the proposed algorithm.