A Theoretic Analysis of a Control System Structure of Towed Underwater Vehicles

In this paper, we present a control system analysis of towed underwater vehicles (TUVs) whose dynamics is extremely complex due to the flexible-cable dynamics and hydrodynamic forces. An explicit state-space representation of the dynamical model is given and, based on it, the fundamental properties such as controllability, observability, and stability are assessed in some details considering a degree of approximation of the cable dynamics, with a numerical and geometric approach. Additionally, we develop some machinery to assess output controllability. The analysis results clarify the significant features of a TUV as a control system and provide useful information for control-system design of TUVs.