USING ARTICULATED BODY ALGORITHM WITHIN SLIDING-MODE CONTROL TO COMPENSATE DYNAMIC COUPLING IN UNDERWATER-MANIPULATOR SYSTEMS

Abstract

A control scheme is presented for compensating dynamic coupling between an underwater robotic vehicle (URV) and a manipulator. During task execution the torques commanded at the manipulator joints lead to reactions at the junction point of the manipulator and vehicle. These reactions disturb the vehicle position and orientation and are the source of the vehicle-manipulator coupling. In many underwater robotic vehicle-manipulator (URVM) applications, the URV serves as a base while the manipulator performs a required task. Therefore, it is necessary to hold the URV as stationary as possible. In the current work, Slotine’s sliding mode control approach is used to compensate the dynamic effect of the underwater manipulator on the URV. The articulated body (AB) algorithm is used both for the time-domain simulation of the system and for the dynamic equations within the model-based sliding-mode controller. The AB algorithm is preferred for the time-domain system simulation, as it provides a computationally efficient simulation scheme. Finally, a three DOF manipulator mounted on a URV is considered, and results of time-domain numerical simulations of the proposed control scheme are presented.