Adaptive Fuzzy Control of Strict-Feedback Nonlinear Time-Delay Systems with Full-State Constraints

Integral barrier Lyapunov function‐based adaptive fuzzy output feedback control for nonlinear delayed systems with time‐varying full‐state constraints

“…Meanwhile, the time‐varying state constraint problems and input saturation are simultaneously considered compared with the existing nonstrict‐feedback control results 11,12 . Especially the problem that the selection range of the initial value in References 32‐36 is small has been solved. In addition, we also address the issue of “explosion of complexity” existing in References 32‐36.…”

“…Especially the problem that the selection range of the initial value in References 32‐36 is small has been solved. In addition, we also address the issue of “explosion of complexity” existing in References 32‐36. Finally, the convergence speed of the variables in the system () can be accelerated by selecting appropriate design parameters.…”

“…Compared with the logarithmic 29,36 and tangent 35 constraint functions, which have stricter requirements on initial value selection, the integral barrier Lyapunov function (IBLF) can expand the selection of the initial value and directly constrain the state. We combine the IBLF with the DSC technique for the first time to study the nonstrict feedback time-delay systems with time-varying full-state constraints and input saturation, where the problem of explosion of complexity existing in the above results [29][30][31][32][33][34][35][36] can be avoided. 2.…”

“…The Lyapunov‐Krasovskii functions (LKF) and Lyapunov‐Razumikhin functions are the main tools used to compensate for delay functions 30‐33 . By combining LKF with FLS or NNs, some novel adaptive control strategies were proposed to address the stability problems for nonlinear delayed systems in References 34 and 35. But the above results do not consider the problem of constraints.…”

“…The main contributions of this article are as follows:Compared with the logarithmic 29,36 and tangent 35 constraint functions, which have stricter requirements on initial value selection, the integral barrier Lyapunov function (IBLF) can expand the selection of the initial value and directly constrain the state. We combine the IBLF with the DSC technique for the first time to study the nonstrict feedback time‐delay systems with time‐varying full‐state constraints and input saturation, where the problem of explosion of complexity existing in the above results 29‐36 can be avoided. Different from the state‐feedback‐based results in Reference 36, this article constructs a fuzzy observer to estimate the unmeasurable state and combines the observer with the LKF to compensate for the effect of the delay function. An auxiliary control signal is introduced to solve the problem of input saturation. Besides, a novel LKF is constructed to deal with the problem of time delay where inequality technique is utilized.…”