Estimation of the practical stability region of a class of robust controllers with input constraint

In this paper, new practical stability results are obtained from a class of proposed constrained robust controllers. Unlike the previous relevant work, the stability investigation is now extended to the actual control modification region. For the class of uncertain systems with an unstable nominal part, our results give a closer estimation of regions of attraction and of ultimate boundedness. The closed loop stability is shown to be maintained in a region where the modified control and its original are distinct.