A novel ship-mounted rope-based cleaning mechanism: Dynamic modeling and sliding mode controller design

Abstract

The cleaning of cargo holds on ships typically requires extensive manual labor, resulting in inefficient operations and elevated risk factors. To address these challenges, this study proposes the utilization of rope-driven parallel mechanisms (RDPMs) as an innovative solution for automated cleaning. Additionally, a novel rope-based cleaning mechanism (R-BCM) is introduced, and its kinematic model is derived using robotics principles. Recognizing the challenges associated with accurately gauging ship attitude in marine environments, a dynamic model of separated disturbance is established. To improve tracking accuracy, shorten response time, and reduce power consumption, an adaptive sliding mode control with an improved exponential reaching law (IER-SMC) is proposed. The stability of this system is rigorously analyzed. Numerical simulations are conducted to evaluate the control performance of the system, particularly under conditions of ship movement and external disturbances. The simulation results show that, compared to the sliding mode control with a traditional exponential reaching law (TER-SMC), IER-SMC improves convergence speed by 51.0%, reduces steady-state error by 64.7%, and decreases energy consumption by 1.05%. Furthermore, the R-BCM prototype is developed, and cleaning simulation experiments are conducted. The experimental results show that, compared to TER-SMC, IER-SMC improves convergence speed by 44.4%, reduces steady-state error by 22.3%, and decreases energy consumption by 10.8%. Moreover, after a single cleaning operation, the applied mud and sand mixture is almost completely removed. These findings underscore the effectiveness of the IER-SMC in achieving rapid convergence, low power consumption, and precise tracking, making it a promising approach for enhancing the efficiency and safety of cargo hold cleaning operations on ships.