Abstract:

The global rejection problem for a class of nonlinear systems with unknown external disturbances was studied. The unknown external disturbances contain an unknown bounded disturbance and a class of nonharmonic periodic disturbance generated by a nonlinear exosystem. Based on the normalized parameter internal model, a new nonlinear internal model was designed by utilizing the state variable system and the external system structure. Based on the controller for the disturbancefree system, a state feedback controller was designed to ensure all the signals of the closedloop system were globally uniformly bounded. Simulation results showed the effectiveness of the proposed control algorithm.

Key words: non-harmonic periodic disturbances, global stability, Van der Pol oscillator,  disturbance rejection