Disturbance Observer-Based High-Order Fully Actuated Robust Control of Uncertain Robotic Systems

Model uncertainties and external disturbances significantly impact the performance of trajectory tracking control in robotic systems. This paper proposes a novel control strategy based on high-order fully actuated (HOFA) system theoretical methods. The robotic system with nonlinear properties is transformed into a closed-loop linear system by pseudo-linear parameter design. The tracking controller is designed for the linearized system by combining robust control methods. Recognizing the system’s susceptibility to disturbances during operation, a nonlinear disturbance observer (NDO) is designed to estimate and compensate for the lumped disturbances, and the stability of the system is demonstrated. Finally, comparative simulations based on the UR5 robot validate the effectiveness of the proposed control strategy.