Dynamic switching of type-I/type-II structures in tracking servosystems

The subject of this note is an improved algorithm for the switching of Type-I and Type-II structures in tracking servosystems. Unlike the traditional control laws, the proposed algorithm takes into account not only the error, but its derivative(s) as well. The suggested control rule can be easily realized and is based upon concepts of the theory of variable structure systems (VSS). The advantages of the proposed algorithm (including robustness of the servosystem with respect to plant parameters, transport delays, and disturbances, as well as global asymptotical stability of the servosystem) are demonstrated analytically, and experimentally.