Nonsingular Terminal Sliding Mode Control for Flexible Spacecraft Attitude Control

Abstract

In this paper, a nonsingular terminal sliding mode control method is applied to design an attitude control law for flexible spacecraft. First, the Lagrange method is applied to establish the dynamic equation of the flexible spacecraft and the vibration equation of the flexible appendages. Then, by designing a nonlinear terminal sliding surface function, the spacecraft terminal sliding mode control law is designed. In order to solve the singular problem, a nonsingular terminal sliding mode control law is further designed. At the same time, the saturation function is introduced to replace the sign function to suppress chattering problem of flexible appendages. The Lyapunov method is used to prove that the involved nonsingular terminal sliding mode control law can realize the precise attitude control of the flexible spacecraft. Finally, a numerical simulation example verifies the effectiveness of the control law designed in this paper.