Robust trajectory tracking of an underactuated ROV under compound flow disturbances using ADRC-GISMC

Abstract Trajectory tracking of remotely operated vehicles (ROVs) remains difficult when hydrodynamic coupling, plant uncertainty, actuator constraints, and spatially varying flow disturbances act simultaneously. This study presents a simulation-based evaluation of an ADRC-GISMC strategy for an underactuated ROV under an engineering-oriented compound disturbance model combining background-current and local outfall-plume components. SMC, ADRC, ADRC-SMC, and ADRC-GISMC are compared using the same full six-degree-of-freedom rigid-body plant, rank-deficient thruster-allocation layer, reference trajectory, and actuator settings. Under the tested balanced and strong conditions, ADRC-GISMC does not minimize every tracking metric; instead, it provides a metric-dependent trade-off among position tracking, attitude response, executed moment-energy demand, and allocation feasibility. This trade-off is further examined through a paired Monte Carlo analysis with 100 plant-parameter samples, actuator-constraint and measurement/sampling tests, a local one-factor-at-a-time disturbance-sensitivity analysis, a local point-of-action sensitivity study, and geometric path-following and tolerance-band diagnostics. The results support ESO-based disturbance compensation combined with global integral sliding mode as an application-level control integration for the numerical evaluation of underactuated ROV trajectory tracking under the specified conditions. Accordingly, the conclusions are restricted to the specified numerical scenarios, parameter ranges, actuator settings, and evaluation metrics.