Document Type


Publication Title

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports


The project originally proposed for this fellowship focused on developing a framework for multimodal control of an unmanned surface vehicle (USV) – transitioning it from an underactuated system to an overactuated one. This would assist in two main functions USVs are typically tasked with: transiting and station-keeping. This project has since expanded to encompass novel territory in control theory, robotics, and computer science. The author is hopeful that the work reported here will assist in the transition of USVs from an academic pursuit into a valuable, pervasive tool for the oceanic sciences and the ocean industry. For the continued expansion USVs play in day-to-day maritime operations, they will need to exhibit a variety of behaviors that manned vessels exhibit in the same environment (e.g., transiting, berthing, docking, etc.), which most likely will be determined by different controllers with varying system models [1]. So far, the literature has been mostly focused on developing controllers suitable for a particular task with certain performance requirements, dictating the type of controller, gains, and parameters used. However, this approach does not translate well to the breadth of operations USVs will need to exhibit in the near future. Although some research has been conducted on incorporating different behaviors through motion planning [2], this leads to difficulties in computationally expensive control space searches and forces the system to go through a replanning cycle when perturbed under the presence of unmodeled disturbances (e.g. environmental disturbances). There lies an advantage in redistributing this behavior “switch” (and thus, controller “switch”) to the low-level control system, , as in [3], rather than a high-level motion planner.


Karl Dietrich von Ellenrieder

Publication Date



Year received Link Fellowship: 2014-2015



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