Dual-Regulation Prescribed Performance Output Feedback Control for Nonlinear Systems with Abrupt Load Variations

This article proposes an innovative prescribed performance control (PPC) scheme for nonlinear systems with abrupt load variations, featuring a dual-regulation mechanism with passive and active modes. In passive mode, the controller evaluates both the tracking error and its distance to the prescribed boundaries, enabling adaptive relaxation when necessary. In active mode, the controller allows proactive boundary adjustment by relaxing or tightening the boundaries based on predefined tasks or predictable conditions, delivering greater flexibility in performance management. To accommodate arbitrary initial errors, the initial performance boundary is set to infinity, and a new transformation function is introduced to overcome the issue of initial control failure. Unmeasured states are estimated via an observer, while unknown nonlinearities are approximated using fuzzy logic systems (FLSs). Simulation results demonstrate the proposed method’s effectiveness and superiority.