Semi-global finite-time stabilization of feedforward nonlinear systems by output feedback

Abstract

Semi-global finite-time stabilization via output feedback is investigated for a class of uncertain feedforward (upper-triangular) systems with high-order growth in unmeasured states and nonconstant growth rate. Compared with the existing results, we further relax the restrictive conditions imposed on nonlinearities to achieve semi-global stabilization rather than global stabilization. First, the linear part of nonlinear system with unknown control coefficient is studied to obtain a global finite-time stabilizer. Second, by introducing a new scaling change, we succeed to address the problem of semi-global output feedback stabilization for a class of feedforward systems, which have not been solved due to the contradiction between the small scaling gain employed for feedforward system in [8] and the large scaling gain used for semi-global stabilization in [11, 15]. Finally, we give an example to illustrate the usefulness of our results.