Regulation-Triggered Batch Least-Squares Identifier based Adaptive Control with Unknown Control Coefficients

This paper focuses on regulation-triggered batch least-squares identifier based adaptive control for nonlinear systems with unknown control coefficients. Batch least-squares identifiers (BaLSI) are designed to estimate the unknown parameters, while a regulation-triggered condition is proposed to activate the BaLSI. Previous appeared excitation are stored and utilized for parameter updates at the triggering moments, based on which the persistently exciting (PE) conditions are no longer needed. Effects of unknown parameters can be eliminated after finite times of parameter updates. Compared with the existing results, the unknown control coefficients are considered, which may lead to singular control input. It implies that as the estimate of control coefficient approaches zero, the control input tends towards infinity. To address the aforementioned issue, two distinct control schemes have been proposed, which pertain to the parameter update law and the control law respectively.