An Online Inertia Identification Based Disturbance Observer for Attitude Loop of Quadrotor System

The online inertia identification based anti-disturbance control method is concerned for the attitude loop of quadrotor system in this paper. The inertia matrix is important in the attitude-loop stabilization, state estimation and failure diagnosis for quadrotor or spacecraft generally, however, it is challenge to measure directly or calculate from the model due to the geometry complexity. An online identification method is proposed for the inertia matrix without specific command signals, which can converge to the real one with small storage and incremental computation. Compared with the existing algorithm, the proposed approach works well in the scenario where the inertia is time-variant, such as variable payload. Besides, an extended state observer is designed with identified inertia to compensate for the external disturbance existing inherently in the attitude loop of quadrotor system. The results of simulation and experiment are presented to show the validity of proposed approach, including inertia identification and disturbance observation.