Adaptive Second-order Sliding Mode Observer for Quadrotor Attitude Estimation

The problem studied in this paper is that of quadrotor attitude estimation using an adaptive second-order sliding mode (SM) observer. The gains are dynamically adapted to the sliding motion to ensure the convergence of observer error to the sliding manifold in the finite time. Position measurements of quadrotor are used in this adaptive SM observer to provide the pitch and roll angle estimates that are robust to the accelerometer and/or gyroscope faults. In addition, the observer is extended for the case where position measurements are corrupted by bias and noise. Simulation results illustrate the benefits of the proposed techniques compared to kalman and complementary filter.