ABSTRACT This paper introduces an exact filter based on a modified version of the Super‐Twisting Algorithm with time‐varying gains. Exploiting the superior features of the proposed filter compared to a standard low‐pass filter, an adaptive Generalized Super‐Twisting Algorithm (GSTA) based on a modified version of the Dual‐Layer scheme is also proposed. A key contribution of this work is the development of a self‐tuning exact filter for estimating the equivalent control. The proposed scheme effectively handles unknown bounded disturbances and their bounded time derivatives, as well as linearly bounded disturbances dependent on the sliding variable, while providing non‐conservative gains for the GSTA. Unlike previous dual‐layer schemes, which require implicit knowledge to design the low‐pass filter time constant, the proposed approach does not rely on any prior knowledge of upper bounds for the disturbance and its time derivative.
Nunes et al. (Wed,) studied this question.