Trajectory Tracking Control of Parking Automated Guided Vehicles Using Nonlinear Disturbance Observer-based Sliding Mode

• A nonlinear disturbance observer (NDO) is designed to estimate disturbing forces and torques from caster wheels in P-AGVs, enhancing robustness. • The proposed NDO-NTSM controller improves trajectory tracking stability by 42–68% compared to traditional NTSM, as validated experimentally. • Kinematic and dynamic models of P-AGVs with mecanum wheels are developed, explicitly considering disturbance influences. • Stability of the NDO and NDO-NTSM control systems is theoretically proven via Lyapunov functions, ensuring reliable performance.