Predefined-time control of nonlinear systems: A sigmoid function based sliding manifold design approach

This work addresses the predefined-time convergence problem for a class of second order nonlinear systems subjected to matched disturbances. A novel family of sigmoid function based ter-minal sliding surfaces is proposed for which robust fixed time convergence is guaranteed. The sta-bility properties are established through the Lyapunov framework. In the proposed technique, bound on the settling time is user-defined for arbitrary initial conditions. Furthermore, switching control law is designed to avoid singularity, thus sufficient condition for singularity free controller is determined. The utility of proposed control scheme is validated by simulating two numerical examples from recent relevant literature.(c) 2021 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/ 4.0/).