Optimal Control of Free-floating Autonomous Underwater Vehicles for Manipulation Tasks in Shallow Sea Culture Collection

Abstract. There is an urgent demand for collection operations in the shallow sea cultivation. However, there have been very few investigations on underwater robots for this purpose. The overall objective of this paper is to investigate approaches for combined free-floating AUV and manipulation arm systems to autonomously collect shallow sea culture under complicated underwater conditions. For this purpose, following targets will be gained: 1）Development of new approaches for fast and precise identification and positioning of shallow sea culture (e.g. sea cucumber, dead fish) under complicated underwater conditions (e.g. convoluted terrain, weak light, fluctuating stream);2）Development of a detailed dynamic model for the combined AUV and manipulator system (UVMS) which can be applied for stable and reliable control to autonomously collect sea culture under complicated underwater conditions;3）Development of an optimal control strategy to realize operations for the combined AUV and manipulation arm to autonomously collect shallow sea culture subject to multiple operating constraints. The above objectives can be fulfilled by answering the following questions. A system design to to reliably identify the target object, which need imaging data processing, segmentation and classification, to estimate its position relative to the object, which calls for a position estimator that fuses imaging data (e.g., sonar, vision) with IMU measurements, to control its position relative to the object for station-keeping and the tool at the end of the arm system need to be set in the right position and orientation. The dynamics of both the AUV and the arm system (MS), their interactions with the environment need to be modeled, and to minimize the time, minimum energy, minimum error and smoothness to a target position.