Robust end-effector trajectory control of rigid robotic manipulators subjected to base vibrations

The end-effector tracking accuracy of rigid manipulators can be degraded by base-induced vibrations. This paper presents a robust control framework that explicitly accounts for model uncertainties, unmodeled dynamics, and external disturbances, including base vibrations. The framework first applies partial feedback linearization to simplify the base–manipulator model, resulting in a lumped disturbance term that captures these combined effects. A nonlinear disturbance observer is then employed to estimate this disturbance, and its effect on the output is compensated through outputfeedback linearization. Stability analysis ensures the uniform ultimate boundedness of the closed-loop system. The proposed method was validated through physics-based simulations. Results show enhanced robustness in tracking performance, with higher observer gains enabling the system to recover performance closer to the disturbance-free case. This demonstrates the<br/>potential of the proposed method for manipulators operating<br/>on moving or vibration-prone bases.