Optimization-Based Automatic Docking and Berthing of ASVs Using Exteroceptive Sensors: Theory and Experiments

MPC-based Reinforcement Learning for a Simplified Freight Mission of Autonomous Surface Vehicles

“…Docking refers to stopping the vessel exactly at the endpoint B as well as avoiding collisions between any part of the vessel and the quay [4]. The "accurate stop" requires not only an accurate docking position but also zero-valued velocities and thruster forces at the final time, i.e., we ought to minimize…”

“…Autonomous Surface Vehicles (ASVs) are widely applied for many fields, such as freight transportation, military, search and rescue [1], and therefore attract broad attention for scientific and industrial researches. Various methods have been proposed to solve the problem of operating and automating the ASV, including path following, collision avoidance, and autonomous docking [2], [3], [4]. However, designing a control strategy that could realize both collision-free path following and docking in a freight mission with time-varying disturbances is still a topic worth exploring.…”

Warm-started Semionline Trajectory Planner for Ship's Automatic Docking (Berthing)

“…The underactuation and the restricted harbor area greatly limit the existence of the feasible solutions, which is reasonable. This suggests that the presence of a feedback controller is necessary, so that practically when the trajectory planner fails, the previously obtained trajectory can still be used as the set point for the feedback controller (Martinsen et al, 2020).…”

“…Research on trajectory planner for docking operation sees various efforts to balance three things: low computational cost (Bitar et al, 2020;Martinsen et al, 2020), applicability to underactuated conventional vessel (Maki et al, 2021(Maki et al, , 2020Mizuno et al, 2015), and feasibility with respect to the surrounding dynamic (Han et al, 2021;Mizuno et al, 2015) and geometric information (Bitar et al, 2020;Liao et al, 2019;Martinsen et al, 2019;Miyauchi et al, 2021b). This is relevant, because in practice a shipmaster will try to replan a new trajectory for docking operation if it is considered not feasible anymore.…”

“…The one introduced in Mizuno et al (2015) is relatively fast and also applicable to conventional vessel, but there are no spatial constraints that can guarantee safe trajectory. On the other hand, Martinsen et al (2020) showed a fast planner that guarantee a safe trajectory, but applicable for a fully/overly actuated vessel.…”