Kybernetika 59 no. 3, 342-364, 2023

Fixed-time safe tracking control of uncertain high-order nonlinear pure-feedback systems via unified transformation functions

Chaoqun Guo, Jiangping Hu, Jiasheng Hao, Sergej Čelikovský and Xiaoming HuDOI: 10.14736/kyb-2023-3-0342


In this paper, a fixed-time safe control problem is investigated for an uncertain high-order nonlinear pure-feedback system with state constraints. A new nonlinear transformation function is firstly proposed to handle both the constrained and unconstrained cases in a unified way. Further, a radial basis function neural network is constructed to approximate the unknown dynamics in the system and a fixed-time dynamic surface control (FDSC) technique is developed to facilitate the fixed-time control design for the uncertain high-order pure-feedback system. Combined with the proposed unified transformation function and the FDSC technique, an adaptive fixed-time control strategy is proposed to guarantee the fixed-time tracking. The novel original results of the paper allow to design the independent unified flexible fixed-time control strategy taking into account the actual possible constraints, either present or missing. Numerical examples are presented to demonstrate the proposed fixed-time tracking control strategy.


dynamic surface control, fixed-time safe control, nonlinear pure-feedback systems, state constrains, unified transformation function


93D15, 70K20


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