ESO-based Trajectory Tracking Control of a 7-DOF Manipulator: A High-Order Fully Actuated System Approach

The 7-DOF manipulator system is a complex dynamic system characterized by high nonlinearity and strong coupling. To tackle these challenges, this study focuses on developing a trajectory-tracking controller based on the high-order fully actuated (HOFA) system approach. The dynamic model is derived using the Lagrange dynamic equation. Subsequently, the system model is converted into a HOFA model, and the trajectory tracking controller is formulated through direct parameterization within the HOFA system model framework. Internal and external uncertainties, including variations in internal model parameters and external frictional forces, can impact the tracking precision of the actual manipulator system in operational conditions. To address these uncertainties affecting tracking accuracy and overall performance, a nonlinear extended state observer (ESO) is devised to counteract the aggregated system disturbances. The simulation outcomes illustrate the effectiveness of the HOFA method and ESO in enhancing manipulator trajectory tracking accuracy and ensuring strong resilience.