Saturation-Tolerant Finite-Time Prescribed Performance Control of Interconnected Nonlinear Systems via Setting Time Adjustment

This article proposes a finite-time prescribed performance control (FTPPC) method for interconnected nonlinear systems with input saturation. By adding nonnegative auxiliary signals to the setting time of finite-time prescribed performance functions (FTPPFs), we present saturation-tolerant FTPPFs, which are easy to observe the convergence time. Compared with traditional FTPPFs, saturation-tolerant FTPPFs are able to expand from or restore to the expect constraint boundaries based on the input saturation error as well as whether the system enters the collision avoidance regions. Thus, the potential conflicts between input saturation and FTPPFs are resolved. Combined with saturation-tolerant FTPPFs, a low-complexity control algorithm is proposed, which omits the need for a function to estimate the unknown terms and reduces the computation. With the designed control scheme, the boundedness of all closed-loop signals is strictly proved when the feasibility condition is satisfied. Ultimately, simulations are presented to show the capability of the designed controller.