Adaptive sliding mode strategy: A cross-coupled synchronization control method for improving the dynamic accuracy of dual-drive gantry systems under spatial perturbations

Abstract

Dual-drive feed systems are widely applied in high-end manufacturing. However, their synchronization accuracy is severely limited by nonlinearities, including weak mechanical coupling, nonlinear friction, and time-varying inertia induced by center-of-gravity (CoG) shifts. To address these issues, this paper proposes a finite-time cross-coupled synchronization control method using a linear extended state observer (LESO) and adaptive nonsingular terminal sliding mode control (ANTSMC). A nonlinear model incorporating CoG-dependent inertia asymmetry, elastic coupling, and nonlinear friction is established, and a cross-coupled control (CCC) architecture is introduced to formulate the generalized coupling error. Next, a LESO is designed to estimate and feedforward-compensate for total disturbances—including CoG shifts and external loads—in real time. Combined with the ANTSMC scheme, the generalized coupling error, together with the tracking and synchronization errors, is driven into a prescribed neighborhood within a finite time. Furthermore, an adaptive switching gain law with a dead-zone constraint is developed. This mechanism dynamically adjusts the switching gain to handle asymmetric impacts while reducing unnecessary steady-state switching activity and control-input chattering. Finally, simulations and experiments on a dual-drive gantry system validate the proposed strategy. The results demonstrate that the LESO-ANTSMC scheme significantly suppresses complex time-varying disturbances, substantially improving dynamic synchronization and tracking precision.