Hierarchical Motion Planning and Tracking for Autonomous Vehicles Using Global Heuristic Based Potential Field and Reinforcement Learning Based Predictive Control

The autonomous vehicle is widely applied in various ground operations, in which motion planning and tracking control are becoming the key technologies to achieve autonomous driving. In order to further improve the performance of motion planning and tracking control, an efficient hierarchical framework containing motion planning and tracking...

Speed and heading control-based collision avoidance for a ship towing system

Collision avoidance is a priority task for ensuring the safety of a maritime transportation system. However, for a ship towing system, which is characterized by multiple vessels and physical connections, the research works about collision avoidance is limited. Thus, this paper proposes a speed and heading control-based conflict resolution of...

Distributed Dynamic Coordination Control for Offshore Platform Transportation Under Ocean Environmental Disturbances

Transportation of a large offshore platform from inland waters to the open sea is a hazardous and challenging mission. With the development of the autonomous surface vessel (ASV), the problem of large floating object transportation has a chance to be solved by applying multiple physical-connected autonomous tugboats. This article proposes a...

A Single-Stage Regulating Voltage-Doubling Rectifier for Wireless Power Transfer

In this letter, a 6.78-MHz single-stage regulating voltage-doubling rectifier is presented for biomedical wireless power transfer (WPT) applications. Derived from a full-wave voltage doubler, a theoretical voltage conversion ratio (VCR) of 2 can be achieved, which benefits the end-to-end voltage gain of a biomedical WPT system with varying...

Collision prevention of ship towing operation under environmental disturbance

Towing operations are highly reliant on the experience of the towing operators. Safety concerns arise when towing operations are subjected to environmental disturbances and dynamic traffic conditions. However, a systematic framework and approaches to enhance the safety and automation of towing operations remain lacking. This work proposes a...

Multi-Objective Cooperative Control for a Ship-Towing System in Congested Water Traffic Environments

This paper proposes a multi-objective cooperative control method for a ship-towing system in congested water traffic environments. The control objectives are to coordinate multiple autonomous tugboats for transporting a ship to: (i) follow the waypoints, (ii) adjust the heading, (iii) track the speed profile, and (iv) resolve collisions. The...

COLREGS-Compliant collision avoidance for physically coupled multi-vessel systems with distributed MPC

This paper proposes a distributed control scheme for autonomous tugboats to tow a ship in a restricted water traffic environment ensuring collision avoidance while being compliant with maritime regulation called COLREGS. The complex problem is cooperatively solved by addressing three sub-optimization problems. The first is to optimize the...

Multi-vessel cooperative speed regulation for ship manipulation in towing scenarios

This paper proposes a multi-agent control scheme for multiple physically interconnected tugboats performing a ship towing process. These tugs are coordinated by two control layers. In the higher layer, the supervisory controller outputs the desired towing forces and reference trajectories for the tugs. This information is used by a tug's...

Cooperative multi-agent control for autonomous ship towing under environmental disturbances

Among the promising application of autonomous surface vessels (ASVs) is the utilization of multiple autonomous tugs for manipulating a floating object such as an oil platform, a broken ship, or a ship in port areas. Considering the real conditions and operations of maritime practice, this paper proposes a multi-agent control algorithm to...

Cooperative control of autonomous tugs for ship towing

Autonomous surface vehicles (ASVs) are seeing a significant development over the last decade. In recent years, their commercial applications are attracting the attention of many companies. One of the promising subjects is to develop autonomous tugs for ship berthing. This paper focuses on the cooperative control of autonomous tugs for ship...