To address the impact of modeling errors and unknown external disturbances on the trajectory tracking accuracy of robotic arm systems in practical applications

an adaptive non-singular fast terminal sliding mode control strategy based on a nonlinear disturbance observer (ANFTSMC-DO) is designed. First

a nonlinear disturbance observer is devised to estimate disturbance information online. By selecting an appropriate nonlinear gain function

the estimation error converges rapidly in an exponential manner. Next

an adaptive non-singular fast terminal sliding mode controller is employed to handle parameter variations and unmodeled dynamics

preventing system performance degradation over time. Meanwhile

under the premise of ensuring robust stability and control accuracy

the proposed method effectively suppresses chattering

thereby enhancing resistance to external disturbances. Finally

simulations verify the effectiveness of the proposed method.