Gain Self-Adjustment Observation and Guaranteed Performance for Faulty Industrial Process System: A Performance Self-Recovery Approach

This article formulates a gain self-adjustment state observer-based performance self-recovery control (GASO-based PSrC) strategy for the industrial process system subject to actuator faults, and the main contributions of the GASO-based PSrC strategy can be summarized as its adaptability to external environmental variations, its capability to suppress faulty performance, and its plasticity in the postfault operation scenario, manifested in adjustable convergence rate and regulation precision for damaged process performance. Therein, a novel gain self-adjustment state observer (GASO) is constructed for estimating the disturbance and process states, thereby completing GASO gain update and maintenance as well as the accommodation of environment variation. To constrain sustained performance decay and steady-state evolution performance, a two-stage performance function with transient response and steady-state convergence is developed. An activation instruction based on the correntropy criterion is designed to detect faults and enable the guaranteed performance control scheme in the postfault operation scenario. Then, the proposed GASO-based PSrC framework is established to realize the scheduled process regulation level. Extensive experiment validations are accomplished on a micro-wastewater treatment process, and the regulation results on the dissolved oxygen (DO) concentration illustrate that the proposed control strategy can guarantee the user-defined performance requirement while mitigating the detriment of faults and disturbance.