Locomotion performance of a crawler-based polymetallic nodule sampling vehicle: MPS-MBD coupled simulation and sea trials

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• Integrated sediment, vehicle dynamics, fluid environment via MPS–MBD coupling. • Measured sediment geomechanics to clarify the interaction model and sea-trial site. • Verified simulation by 5 km sea trials in subsidence, pitch, and turning radius. • Revealed slope and entry-angle effects on PNSV locomotion and stability. • Proposed optimal track-speed ratios to mitigate slip and maintain trajectory. Deep-sea polymetallic nodule mining necessitates comprehensive exploration activities, placing stringent demands on the locomotion stability of sampling vehicles due to the complex seabed environment. This study unifies the multibody dynamics of a crawler-based polymetallic nodule sampling vehicle (PNSV), its interactions with deep-sea sediments, and a Moving Particle Semi-implicit (MPS) fluid domain within a computational framework. By embedding a sediment constitutive ground model, sediment geotechnical parameters obtained via in-situ penetration and vane-shear tests are integrated into the MBD model of PNSV, thereby capturing the interactions between the crawler tracks and the seabed sediment. A multi-resolution MPS particle domain is utilized to simulate the fluid environment. Sea trials of the PNSV at a depth of 5 km in the Eastern Pacific Ocean demonstrate strong agreement between simulation results and experimental observations across key performance metrics, including subsidence depth, pitch angle, and turning radius, validating both the PNSV’s design and the simulation methodology. Building upon this validated simulation model, a comprehensive investigation is performed into the influence of varying slope angles and entry angles on the uphill and downhill trajectories and overall reliability of the PNSV. Moreover, a velocity-adjustment control strategy is proposed for trajectory correction, effectively mitigating lateral slippage and maintaining stable straight-line locomotion. The presented approach provides valuable insights for enhancing the locomotion performance of deep-sea crawler-based vehicles.