Prescribed-time control for nonlinear systems with asymmetric output constraints

YANG Hang; HUANG Ying-bo; LI Guang; NA Jing

doi:10.7641/CTA.2025.50070

Abstract：This paper proposes a prescribed-time controller for a class of nonlinear systems with asymmetric output constraints and time-varying parameters.Compared with the traditional constraint control in which the designer cannot preset the convergence time and the assumption that the initial value satisfies the constraints,the proposed controller can not only regulate the system state to zero within a prescribed-time while satisfying the constraints,but also prevent the potential singularity issue of controller when the system initial value violates the constraints.Firstly,the construction of virtual constraint boundaries eliminates the requirement for initial states to satisfy constraint conditions,while guarantee-ing that states violating constraints can recover to constraint satisfaction within a prescribed-time.Secondly,an equivalent transformation method is designed to achieve synchronous convergence of system states and transformation function under asymmetric constraints.Unlike existing prescribed-time control approaches that require uncertain nonlinearities to meet linear growth conditions or unknown constant parameters,the studied nonlinear system in this paper incorporates uncer-tain time-varying parameters.By employing backstepping techniques based on the congelation of variables method and prescribed-time regulation function,a prescribed-time controller capable of handling the asymmetric output constraints and time-varying parameters is designed.Finally,the effectiveness of the proposed method is demonstrated through two numerical simulations.