Terminal Sliding Mode Control of Coordinated Motion of Free-Floating Space Robot with Dual-Arms

The control problem of coordinated motion of free-floating dual-arm space robot with external disturbance is discussed. Combined the linear momentum conversation and the Lagrangian approach, the full-controlled dynamic equations of free-floating space robot with dual-arms is established and then inverted to the state equation for control design. Based on the terminal sliding mode control (SMC) technique, a mathematical expression of the terminal sliding surface is proposed, and the terminal SMC scheme of coordinated motion between the base's attitude and the arms' joints of free-floating dual-arm space robot with external disturbance is developed. This proposed control scheme not only guarantees that the sliding phase of the closed-loop system exists, but also ensures that the output tracking error converges to zero in finite time. In addition, the control scheme eliminates the reaching phase of SMC and guarantees the global robustness and stability of the closed-loop system, because the initial state of system is always at the terminal sliding surface. A planar free-floating space robot with dual-arms is simulated to verify the feasibility of the proposed control scheme.