In this paper, an adaptive fixed-time prescribed performance sliding mode control is proposed for an energy harvesting system. The tracking problem is developed for this harvesting system to extract permanent and desired energy. At first, the sliding surface is limited to a small neighborhood around zero with fixed-time prescribed performance bounds, which leads to reduction of the settling time and elimination of the chattering phenomenon. Then, an adaptive fixed-time sliding mode structure with only one adaptation law is presented to estimate and compensate the uncertainties without knowing the information of the upper bound of the disturbances, uncertainties, and their derivatives. Because the sliding surface is a function of the tracking error, the tracking error also remains in a predefined range around zero within a fixed time, and the settling time is independent of the initial conditions of the system. The Lyapunov stability theory is utilized to show the fixed-time stability of the closed-loop system. The efficiency and superiority of the proposed control scheme are verified through simulations of an energy harvesting system.
Ovaysi et al. (Mon,) studied this question.