Leader-Following Control System Design for a Towed Vessel by Tugboat

Abstract

In this study, a motion control problem for the vessels towed by tugboats or towing ships on the sea is considered. The towed vessels, such as barge ships, are used for several purposes. Generally, these vessels have no power propulsion system and are towed using ropes and towing vessel (tugboats). The basic mathematical model of the towed vessel in which three active rudders are attached was introduced from a previous study. Owing to the dependency of the motions of the towed vessel to the towing ship, a method is suggested to cope with the undesirable disturbance and improve the tracking performance. For the simulation study, a model of the towed vessel with a towing ship is made, and necessary physical parameters are identified from the experiment. For the defined and linearized model, a control system is designed, and the control performance is also evaluated. A simulation study is conducted and the effectiveness of the proposed control strategy is verified

A Review of Autonomous Tugboat Operations for Efficient and Safe Ship Berthing

“…Main Features [18] A tugboat is assumed (modeled) as a single thruster (2006) [19] Adaptive control techniques to compensate for the fluidity of hydrodynamic coefficients and unknown contact points (2007) [2] Uses RPI (redistributed pseudoinverse) algorithm, an improved thrust allocation algorithm for improved controllability (2011) [24] Modeling considering environmental disturbances such as wind, tide, and waves applying the SMC (Sliding Model Control) technique, one of the robust control techniques that is resistant to environmental disturbances such as wind, tide, and waves (2011) [27] Modeling considering the dynamics of the tug line leader-following control that follows the route by considering the tug line between the tug and the ship to be towed (2019) [28] Modeling considering multibody dynamics considering ships, tugboats, and environmental disturbances using simplified dynamic equations (2020)…”

“…In the work by Quan [27], the vessel to be towed was modeled as a system with three active rudders, and tugboats were independently modeled. The modeling process considered both the dynamics of the towline and the ship characteristics, such as the length of the towline and relative position of the tugboat.…”

“…In 2019, there was a study [27] which controlled a ship using a towline between the tugboat and the ship being towed, as shown in Figure 16. When the tugboat tows the ship using a towline, the system is affected by environmental disturbances such as waves and currents.…”

“…If the tugboat and the vessel to be towed follow different paths due to waves and complex maneuvering environments, the risk of collision is high, making precise control of the path essential. To address this challenge, Quan [27] proposed a basic mathematical model of a tugboat equipped with three active rudders (see Figure 16). As tugboats are dependent on the towline to pull the vessel or deal with obstacles, Quan proposed a follow-up control for the leader to enhance the tracking performance of the towed vessel along the path of the tugboat.…”

“…Figure16. Schematic description of the system proposed by Quan[27]. Towline and tugboats are modeled as multibody dynamics.…”