The multiswitching algorithm has demonstrated its ability in achieving the global tracking stability and preventing the control singularity for strict-feedback systems. However, its direct application to the nonstrict-feedback systems is prohibited due to the serious algebraic-loop problem. Via exploring the ability of the dynamic surface control for conquering such a difficulty, the direct-compensation approach ensured the semiglobally uniformly ultimately bounded stability for nonstrict-feedback systems with unity control coefficients so far. This article aims to integrate these two methods to tackle a more challenging task of controlling multiinput-multioutput nonstrict-feedback systems with unknown control-affine functions and time-varying delays. Comparing with the existing schemes in the literature, the proposed design exhibits the following distinct features: 1) the control-affine functions and the delayed functions can depend on the whole state vector; 2) the time delays can be incoherent among different states; and 3) the globally uniformly ultimately bounded stability is achieved without incurring the control singularity, explosion of complexity, and the algebraic-loop problems simultaneously.
關聯:
IEEE TRANSACTIONS ON FUZZY SYSTEMS 卷冊: 28 期: 10 頁數: 2592-2604
