SOFT VARIABLE STRUCTURE CONTROL IN TIME-DELAY SYSTEMS WITH SATURATING INPUT

摘要

In order to achieve a short regulation cycle, time-optimal control has been considered in the past. However, the sensitivity to errors and uncertainties, and implementation difficulties in the practical systems, have incited other research directions to meet this objective. In this paper, soft Variable Structure Control (VSC) is analyzed from the perspective of linear time-delay systems with input constraint. The desired fast convergence under a smoothly varying control signal is obtained. The stability issues originating from the non-negligible delay are addressed explicitly by incorporating a dead-time compensator, applicable to both structurally stable and unstable plants. The properties of the obtained dynamic soft VSC system are demonstrated analytically and compared with the linear and saturating control structures.