A simple approach to estimate unmatched disturbances for nonlinear nonautonomous systems

In this work, an unmatched disturbance estimator using the time receding optimization principle is proposed for a class of multi‐input multi‐output nonlinear nonautonomous systems with unmatched disturbance in both continuous‐time and discrete‐time domains. Numerical simulations and comparison with existing method are performed to support the proposed method. The simulation results show that all the estimated disturbances converge to the unknown unmatched disturbances with a given estimation error.