Lumped mass model of underwater tethered ROV

Hello, I am modelling the dynamics of underwater vehicle (ROV) which incorporates tether dynamics as well. However, I modelled the dynamics of vehicle, and trying to model the tether dynamics in Simulink, but I am struggling to model it. I have equations for lumped mass model but I am confused from where to start. Can anyone help me with this?

Answer 1

[Sam Chak]

Hi @Dhruvit

Without providing the governing physical laws, it is relatively difficult to show you how to model it in Simulink.

However, I have found an example that is an unanswered question asked by @Bart Savalle two years ago. In the thread, he posted dynamics (ODE) with Drag Force acting on the submerged tethered system, written in the MATLAB function.

https://www.mathworks.com/matlabcentral/answers/817745-simple-simulation-of-a-tethered-floater-going-up-and-down

[Dhruvit]

This is the equations for tether dynamics from the paper "An Open-Source Benchmark Simulator: Control of a BlueROV2 Underwater Robot".

[Sam Chak]

Hi @Dhruvit

The tether dynamics are given by Eq. (26). It appears to be a flexible tether due to the presence of multiple nodes along its length. Mathematically, I believe the modeling approach is similar to how you modeled the dynamics of the ROV. Could you please show what you designed for the ROV model? This will allow for a comparison with Eq. (26).