Existence conditions and applications of shifting sliding mode control

By introducing shifting factors into sliding surfaces, shifting sliding-mode control (SSMC) is defined. Sufficient existence conditions for SSMC are proved. Based on SSMC, output tracking, in which perfect tracking is achieved in a finite time under matched and bounded unmatched uncertainties, and optimal LQ (linear quadratic) regulation under matched uncertainties are considered. SSMC makes it possible for the design of a control law (to induce sliding motion) and of system performances to be completed separately. This gives designers one more degree of freedom in improving system performances in the sliding-mode control setting