The Coupling Effect: Experimental Validation of the Fusion of Fossen and Featherstone to Simulate UVMS Dynamics in Julia

As Underwater Vehicle Manipulator Systems (UVMSs) have gotten smaller and lighter over the past years, it is becoming increasingly important to consider the coupling forces between the manipulator and the vehicle when planning and controlling the system. A number of different models have been proposed, each using different rigid body dynamics or hydrodynamics algorithms, or purporting to consider different dynamic effects on the system, but most go without experimental validation of the full model, and in particular, of the coupling effect between the two systems. In this work, we return to a model combining Featherstone's rigid body dynamics algorithms with Fossen's equations for underwater dynamics by using the Julia package RigidBodyDynamics.jl. We compare the simulation's output with experimental results from pool trials with a ten degree of freedom UVMS that integrates a Reach Alpha manipulator with a BlueROV2. We validate the model's usefulness and identify its strengths and weaknesses in studying the dynamic coupling effect.