Adaptive state disturbance observer design for nonlinear system with unknown Lipschitz constant

This paper addresses the problem of state and disturbance estimation for Lipschitz nonlinear system with disturbance. The disturbance is generated by an exogenous system with additional unmodeled disturbance. Adaptive state observer and disturbance observer, including a H∞ performance level and a regional pole constraint, are designed, simultaneously. Compared with the existing results, Lipschitz constant does not appear in the observers, which means that our method can deal with the case that the Lipschitz constant is big or unknown. At the end of the paper, the simulation shows the effectiveness of the proposed method.