Disturbance Observer-based Predefined-Time Tracking Control for Uncertain Space Robots

This paper investigates the problem of space robots tracking control in base attitude controlled mode. Recognizing the nonlinear and strongly coupled dynamics of the space robot, its dynamics model is constructed, which considers model uncertainties and satisfies the conservation of linear momentum. To achieve fast convergence and high-precision tracking performance, a novel control scheme is proposed to achieve the predefined-time stability. The upper bound on the convergence time of system is only related to the tuning parameters of the predefined-time controller. Considering the robotic system is susceptible to external disturbances during operation, a predefined-time observer is designed to compensate for lumped disturbances within a predefined time. Numerical simulations are presented to validate the effectiveness of the proposed method.