Fixed-time integral sliding mode control design for a class of uncertain nonlinear systems based on a novel fixed-time stability condition

This paper develops a different approach to fixed-time controller design by introducing a totally novel fixed-time stability condition formulated according to the Lyapunov function technique. Based on this condition, a fixed-time sliding mode control law is derived for a class of uncertain nonlinear systems. This controller assures complete robustness of the closed-loop system against matched uncertainties and exogenous disturbances from the beginning owing to the elimination of the reaching phase by benefiting from a novel integral terminal sliding surface. This surface constructed in accordance with the proposed condition determines whole dynamics of the closed-loop system and guarantees its fixed-time stability. Numerical simulations are reported to validate the effectiveness of the theoretical results.