Event-based uniform prescribed-time output feedback control for irregular output-constrained nonlinear systems

Abstract

This paper proposes an event-based uniform prescribed-time output feedback control (PTOFC) approach for irregular output-constrained nonlinear systems (OCNSs). Unlike the most existing methods of OCNSs, they mainly focus on OCNSs with infinite-time/deferred output constraints (i.e., the output constraints existing for all $t\ge 0$ or $t\ge t_0$), while many actual systems often suffer from irregular output constraints (including infinite-time constraints, deferred constraints, unconstrained, constrained and unconstrained alternations, etc.), leading to new challenges in control design. By devising a stretch model-based nonlinear mapping function, and combining with event trigger control (ETC) technique, an event-based unified output feedback control algorithm is proposed, and the significant advantage is its suitability for infinite-time/deferred/alternant OCNSs, as well as unconstrained systems, without necessitating modifications to the control structure, and the communication burden is also effectively reduced. Furthermore, with the aid of the scaling transformation function (STF)-based prescribed-time stability (PTS) criteria, a novel prescribed-time state observer (PTSO)-based PTOFC algorithm is designed, under which the settling time can be pre-set arbitrarily regardless of the initial system states and control parameters. Meanwhile, the problems of singularity and large initial control input in conventional prescribed-time control schemes are eliminated. The presented approach is verified by means of simulation examples.