Maximising Wrenches for Kinematically Redundant Systems with Experiments on UVMS

TL;DR

This paper develops and experimentally validates optimization methods to maximize contact wrenches in underwater robotic manipulators, enhancing their force and torque capabilities for various tasks.

Contribution

It introduces a bi-level optimization framework for wrench maximization in UVMS, including multiple contact and dynamic motion scenarios, with extensive experimental validation.

Findings

Significant increase in wrench capability over existing methods.

Effective optimization of configuration and actuator forces for various tasks.

Validated results on an underwater robotic platform.

Abstract

This paper presents methods for finding optimal configurations and actuator forces/torques to maximise contact wrenches in a desired direction for Underwater Vehicles Manipulator Systems (UVMS). The wrench maximisation problem is formulated as a linear programming problem, and the optimal configuration is solved as a bi-level optimisation in the parameterised redundancy space. We additionally consider the cases of one or more manipulators with multiple contact forces, maximising wrench capability while tracking a trajectory, and generating large wrench impulses using dynamic motions. We look at the specific cases of maximising force to lift a heavy load, and maximising torque during a valve turning operation. Extensive experimental results are presented using an underwater robotic platform equipped with a 4DOF manipulator, and show significant increases in wrench capability compared to existing methods for UVMS.