Small-Gain Method-Based Adaptive Fuzzy Output Feedback Control for Nonlinear Systems With Irregular Constraints

An adaptive irregular constraint control problem is investigated in this study based on an output feedback control strategy. Nonlinear systems with irregular constraints are widely used in engineering fields such as the robot flexible operation. We consider such constraints referring to ones that may not only be asymmetric, but may also emerge in stages, or even be positive and negative at times. Ancillary constraint boundaries, which extend the originally imposed constraints to the full period of the system operation, are designed to accommodate the irregular constraints. Furthermore, the state observer is used to calculate the unmeasured states. Meanwhile, to get past the constraint that the nonlinearities in the system rely exclusively on the measured output, we employ the small-gain approach. Through the utilization of the input-state-practically stability (ISpS) theory, it is demonstrated that when the recommended adaptive control technique is applied, the system is semiglobal stable. Also, the output of the system follows the relevant trajectory. The validation of the findings from the simulation further highlights the advantages of the advised control program.