In this paper, we consider the practical prescribed-time performance guaranteed tracking control problem for a class of uncertain strict-feedback systems subject to unknown control direction. Due to the existence of unknown nonlinearities and uncertainties, it is challenging to design a controller that can ensure the stability of closed-loop system within a predetermined finite time while maintaining the specified transient performance. The underlying problem becomes further complex as the control directions are unknown. To deal with the above problems, a special translation function as well as Nussbaum type function are introduced in the prescribed performance control (PPC) framework. Finally, a PPC as well as preset finite time tracking control scheme is designed, and its effectiveness is confirmed by both theoretical analysis and numerical simulation.

This paper addresses the lane-keeping control problem for autonomous ground vehicles subject to input saturation and uncertain system parameters. An enhanced adaptive terminal sliding mode based prescribed performance control scheme is proposed, which enables the lateral position error of the vehicle to be kept within the prescribed performance boundaries all the time. This is achieved by firstly introducing an improved performance function into the controller design such that the stringent initial condition requirements can be relaxed, which further allows the global prescribed performance control result, and then, developing a multivariable adaptive terminal sliding mode based controller such that both input saturation and parameter uncertainties are handled effectively, which further ensures the robust lane-keeping control. Finally, the proposed control strategy is validated through numerical simulations, demonstrating its effectiveness.