Robustness properties of discrete-variable structure controllers

Abstract

The present paper is concerned with linear discrete-time plants with uncertain constant or slowly time-varying plant parameters. In view of the successful use of continuous robust variable structure control in the field of parameter-disturbed plants (Franke 1982 a, c, Opitz 1984 a), the results obtained will be extended to discrete-variable structure control. Application of the hyperstability theory yields a whole class of discrete-variable structure control laws, which are robust against bounds on control variables and a certain set of parameter disturbances of the plant. Additionally, an important result of this paper is that, as in the continuous case, the robust discrete-variable structure controller needs only measurement-vector input.