Variable structure control of similar composite system with uncertainties of unknown bound

For a class of similar composite systems with uncertainties of unknown bound, a variable structure control (VSC) design method is proposed. The system under consideration is with uncertainties in every subsystem and the interconnections. The uncertainties may be nonlinear, time varying and bounded, but the bounds are unknown and the uncertainties meet the matching conditions. The uncertainties are estimated by using adaptive law. It is proved that the states of the subsystems converge to the switching surfaces. The given simulation example shows the rightness and effectiveness of the proposed scheme.