Dynamics Modeling and Parameter Identification of a Double-Layer 6-DOF Stewart Platform for Simulating Marine Exploration Processes

Effective stability control is essential for marine resource exploration platforms, but conducting experiments on actual platforms is costly and risky. To address these challenges, this article proposes a simulation system based on a double-layer 6-degree-of-freedom (DOF) Stewart platform, enabling realistic simulations of marine exploration processes and various control experiments. The lower platform simulates environmental disturbances (e.g., waves, wind, and currents), while the upper platform replicates the exploration platform’s movements. This double-layer structure effectively models the interactions between the platform’s movements and the environmental forces, providing a more accurate representation of real-world conditions. A comprehensive dynamics model is established using the Lagrangian method and the virtual work principle to account for both kinematic and dynamics interactions. A nonlinear gray system estimation (NGSE) method with a trust-region reflective algorithm is used for parameter identification, and model order reduction improves accuracy and feasibility. Comparisons with real marine platform models validate the system, confirming that it accurately simulates marine resource exploration dynamics. The experimental results show that the parameter estimation error of the proposed model remains below 8.08%. The active-compensation strategy reduces the root-mean-square (rms) horizontal displacement from 0.122 to 0.023 m, representing an 81% decrease, and lowers the rms attitude error from 0.139 to 0.012 rad, corresponding to a 91% reduction. These results confirm the reliability of the dynamics model and highlight the experimental system’s value for stability control research on marine exploration platforms.