Singularity‐Free Prescribed Performance Control of Uncertain Nonlinear Systems With Input Saturation: An Innovative Performance Compensation Approach

ABSTRACT Most existing results on PPC subject to input constraints focus on to design a dynamic system with input saturation errors to coordinate the performance boundaries. However, these methods have the following limitations. First, although the error does not exceed the performance boundaries under input saturation, the dynamic system still generates correction signals; second, the compensation of the performance boundary fails to establish a relationship with the tracking error; third, tedious offline tuning the parameters of the dynamic system is inevitable for achieving superior compensation. Moreover, the initial value problem limits the flexibility of performance function selection. To address these issues, this article is devoted to develop a novel approach towards performance compensation and the key characteristics include: (1) A decision mechanism (DM) is devised, which provides a reference basis for whether or not to compensate for performance boundaries; (2) To establish a link between the compensation term and the tracking error while avoiding offline tuning parameters of the dynamic system, an innovative compensation mechanism (CM) with a simple structure is established; (3) Based on the designed DM and CM, an initial value compensation mechanism (IVCM) is designed, which permits the initial value problem to be solved while guaranteeing the transient and tracking performance of the tracking error; (4) A low‐complexity controller without approximate structure is developed, which simplifies the control design of the system and reduces computational complexity. Finally, the effectiveness of the presented control scheme is verified through comparative simulations.