Conceptual design of optimal thrust system for efficient cable burying of ROV threncher

ROV trencher is a kind of heavy-duty work class ROV with high pressure water jetting tools cutting the sea floor and burying the cable. This ROV is mostly used for PLIB (post lay inspection and burial) operation. For a ROV trencher, usually there is a pair of jetting legs mounted at the bottom and stowed in a horizontal position in its rest mode. While burying cable in the sea floor, they are folded out by hydraulic cylinders, and cut the sea floor by jetting high pressure water and simultaneously bury the post laid cable. In this working process, there are various external forces acting on the vehicle. From control point of view, obviously there are some of optimal issues that of how we should construct the thrust system so that can minimize or maximize kinds of optimal criteria such as minimizing power consumption, or maximizing some of burial performances (burial depth, progress rate etc.). All of these conceptual design considerations for effective thrust system will be considered in this paper.