Design and dynamic analysis of an underwater manipulator

Abstract

Underwater Vehicle/Manipulator System (UVMS) is an important equipment for the exploitation of marine resources. The paper introduces a five function manipulator, which is the main operating tool of UVMS and has four DOFs and a claw. All joints are driven by hydraulic cylinders for a better impermeability to seawater. A novel wrist mechanism utilizing groove cam is presented for achieving a rotation motion output. In addition, the dynamics of the manipulator interacting with the UVMS system is analyzed based on Kane’s method. The effects from the fluid environment are also taken into consideration, which include added mass, drag force, and buoyancy. Finally, dynamic simulations of UVMS are performed to reveal the effect of the volume ratio between the manipulator and vehicle on the stability of UVMS and a critical ratio is found.