Design, Kinematics, and Deployment of a Continuum Underwater Vehicle-Manipulator System

TL;DR

This work addresses the challenge of dexterous underwater intervention by integrating a continuum manipulator with a free-floating vehicle to form a continuum-UVMS. It derives a kinematic model with a total Jacobian that couples a six-DoF vehicle pose to a four-DoF continuum arm, and implements redundancy resolution via a weighted least norm (WLN) framework along with a gradient projection method (GPM) for multi-subtask optimization, all within a ROS-based control loop. The authors validate the approach through kinematic simulations and experimental demonstrations on a BlueROV2 platform, showing teleoperation and autonomous trajectory execution with improved end-effector accuracy and controllability. The study contributes an open-source waterproof continuum manipulator design, a formally derived UVMS kinematics, and a practical, low-cost solution for undersea manipulation, highlighting the potential for scalable, compliant underwater interventions. The results underscore the viability of combining WLN and GPM to manage redundancy and secondary objectives in a hydro environment, while identifying hardware and modeling limitations to guide future enhancements.

Abstract

Underwater vehicle-manipulator systems (UVMSs) are underwater robots equipped with one or more manipulators to perform intervention missions. This paper provides the mechanical, electrical, and software design of a novel UVMS equipped with a continuum manipulator, referred to as a continuum-UVMS. A kinematic model for the continuum-UVMS is derived in order to build an algorithm to resolve the robot's redundancy and generate joint space commands. Different methods to optimize the trajectory for specific tasks are proposed using both the weighted least norm solution and the gradient projection method. Kinematic simulation results are analyzed to assess the performance of the proposed algorithm. Finally, the continuum-UVMS is deployed in an experimental demonstration in which both teleoperation and autonomous control are tested for a given reference trajectory.

Figures (11)

• Figure 1: Continuum-UVMS integration schematic.
• Figure 2: Two segment continuum manipulator schematic.
• Figure 3: Underactuated gripper schematic.
• Figure 4: Continuum-UVMS coordinate frames used to define the kinematic model. {GCS} - global coordinate system; {A} - vehicle frame; {B} - base frame of $1^\text{st}$ continuum segment; {C} - base frame of $2^\text{nd}$ continuum segment; {D} - end-effector frame; {G} - goal frame.
• Figure 5: Time-lapse of the optimized simulation trajectory, visualized using RViz. The UVMS and goal pose coordinate frames can be seen in each frame. The starting configuration is shown in (i), and the coordinated motion of both the vehicle and manipulator can be seen between each frame until the end effector reaches the goal pose in (iv).