Force control experiment of a 3-link dual-arm underwater robot with model error compensator

The underwater environment is an extreme condition for humans, making direct underwater operations hazardous. Consequently, the development of underwater robots equipped with manipulators (UVMS: Underwater Vehicle-Manipulator System) to perform tasks in place of humans has been pursued. We have proposed Resolved Acceleration Control (RAC) methods for UVMS as position control methods. Additionally, as a force control method for UVMS end-effectors, we have proposed position-based impedance control methods using the RAC methods for UVMS. However, accurately modeling the fluid forces acting on the robot underwater is challenging, resulting in modeling errors. To compensate for such errors, the Model Error Compensator (MEC) has been proposed. The MEC incorporates the model of the controlled system and compensates for the modeling errors by feeding back the difference between the model output and the controlled system output. In this paper, we construct a control system for a 3-link dual-arm underwater robot by adding MEC to a position-based impedance control method using the RAC method for UVMS, and verify the usefulness of the constructed control system through force control experiments.