Improved Safe Tracking Error-Constrained Control for Unknown Interconnected Time-Delay Nonlinear Systems With Discontinuous References.

Abstract

In this article, we address the improved error-constrained control problem for unknown, strongly interconnected time-delay nonlinear systems with input saturation and conflicted output constraints. The further challenge we face is that the presence of discontinuous reference signals poses greater difficulties for control design. To tackle these issues, a mechanism for generating smooth, safe reference signals is first devised. Additionally, we propose a novel approach that utilizes improved prescribed performance functions to confine tracking errors within predetermined constant bounds in finite time, while avoiding potential singularity issues arising from abrupt changes in the reference signal. Furthermore, a decentralized adaptive learning error-constrained control strategy is proposed, employing neural networks to approximate complex uncertainties with an asymptotic dynamic surface control method. Stability analysis confirms that the proposed control scheme guarantees the asymptotic stability of the system and ensures safe tracking within conflicted irregular output constraints, even in the presence of input saturation. Finally, simulation results demonstrate the efficacy of the presented control strategy.