Robust Inverse Dynamics Control of the Remotely Operated Underwater Vehicle Manipulator

Abstract

Underwater robots are used to discover, develop and exploit underwater resources. In recent years, with the increase of military, commercial and scientific applications of automatic submarines, the use of these vessels has been thoroughly investigated by researchers. In this research, analysis, and control of the structure of a manipulator with 6-DOF (degree of freedom) which is a Remotely Operated Underwater Vehicle (ROV) robot is studied. Different control methods including proportional-integral-derivative control (PID), inverse dynamics control (IDC), and robust inverse dynamics control (RIDC) are applied to the robot and a sensitivity analysis due to parametric uncertainties has been performed. The results show that despite the high cost incurred by increasing the controller gains, there is a relatively large tracking error which indicates that the PID is not appropriate for this control application and it is not able to compensate for the manipulator's gravity terms. Furthermore, the performance of the two controllers IDC and RIDC are very similar to each other but the RIDC controller has a longer settling time, but less sensitive to parameter variations.