On the theory and application of absolute coordinates-based multibody modelling of the rigid–flexible coupled dynamics of a deep-sea ROV-TMS (tether management system) integrated model

This paper presents a novel method to investigate the dynamics between the interconnected rigid and very flexible bodies of a deep-sea ROV-TMS with highly coupled dynamics. The aim is to develop an accurate yet effective system model, which is applicable to a wide range of deep-sea working-class ROV applications. The use of different sets of generalized coordinates in rigid–flexible multibody system usually leads to complex forms of constraints Jacobian and quadratic velocity vector when the interconnected rigid and flexible bodies share highly coupled dynamics. Thus, the compatibility of the formulations used in modelling is pivotal to a correct representation of the dynamics of an underwater multibody system with highly coupled dynamics. To this end, a mixed formulation, which is fully-based on absolute coordinates, is presented in modelling the dynamics of underwater tethered vehicle system. The development of system model of a basic ROV-TMS and theoretical implementations are presented in this paper. The applicability of the presented model is assessed through numerical simulations for the realistic scenarios during the deep-sea ROV operations. The numerical studies show that the proposed model is able to capture the nonlinear dynamics of cable and cable drum, and the nonlinear coupling dynamics between the tether cable and the ROV.