Composite Robust Controller Design for Robotic Arm Trajectory Tracking under Parametric Uncertainties

Robotic arms are critical for industrial automation. However, it requires a fast and accurate trajectory-tracking response despite the presence of system parametric uncertainties and time-dependent external disturbances. This paper addresses the robotic arm trajectory-tracking problem using a second- order sliding mode observer (SOSMO)-based integral sliding mode control (ISMC) scheme. Initially, we propose a SOSMO design to estimate total system perturbations. The observer estimation errors converge to a small tunable region around zero in finite time. Later, exploiting the SOSMO estimates, a robust ISMC is designed to improve the trajectory tracing performance of the system. We employ the Lyapunove stability theory to prove the convergence of observer estimation and closed-loop system state error to zero in finite time. Finally, comparative numerical simulation results validate the effectiveness and robust performance of the proposed composite control algorithm.