Finite Time Thrust Vector Tracker based on a New Smooth Second Order Adaptive Sliding Mode Controller

This paper introduces a novel adaptive second-order sliding mode algorithm for finite-time control of uncertain nonlinear systems. Traditional first-order sliding modes are hindered by chattering and dependence on the upper bound of uncertainty. Although adaptive sliding modes with dynamic gains remove the need for this upper bound, they still suffer from chattering and lack finite-time stability. The proposed algorithm incorporates an additional term in the control law, ensuring a smooth control signal, eliminating chattering, and achieving finite-time stability of the closed-loop system. This method is applied to a thrust vector-based flying object for pitch angle tracking amidst aerodynamic coefficient uncertainties and environmental disturbances. The performance of the proposed thrust vector system is demonstrated through computer simulations, comparing it with two other adaptive first-order and an adaptive super-twisting sliding mode methods. Simulation results show significant improvements in control performance, including reduced chattering and enhanced stability, underscoring the practical effectiveness of the proposed method.

Keywords:

Thrust vector control , Second order sliding mode , Chattering , Finite time stability , Adaptive gains