Low-Contact Grasping of Soft Tissue with Complex Geometry using a Vortex Gripper

TL;DR

This paper introduces a vortex gripper for low-contact soft tissue manipulation in surgery, analyzing its force characteristics across various shapes and conducting in vivo tests to evaluate its potential and limitations.

Contribution

It presents the design and comprehensive force analysis of a vortex gripper for soft tissue manipulation, including in vivo experiments, advancing minimally invasive surgical tools.

Findings

Vortex gripper can levitate and manipulate soft tissues with minimal contact force.

The force characteristics depend on nozzle parameters and surface geometry.

Limitations identified for medical applications suggest directions for future improvements.

Abstract

Soft tissue manipulation is an integral aspect of most surgical procedures; however, the vast majority of surgical graspers used today are made of hard materials, such as metals or hard plastics. Furthermore, these graspers predominately function by pinching tissue between two hard objects as a method for tissue manipulation. As such, the potential to apply too much force during contact, and thus damage tissue, is inherently high. As an alternative approach, gaspers developed using a pneumatic vortex could potentially levitate soft tissue, enabling manipulation with low or even no contact force. In this paper, we present the design and well as a full factorial study of the force characteristics of the vortex gripper grasping soft surfaces with four common shapes, with convex and concave curvature, and ranging over 10 different radii of curvature, for a total of 40 unique surfaces. By changing the parameters of the nozzle elements in the design of the gripper, it was possible to investigate the influence of the mass flow parameters of the vortex gripper on the lifting force for all of these different soft surfaces. An $\pmb{ex}$ $\pmb{vivo}$ experiment was conducted on grasping biological tissues and soft balls of various shapes to show the advantages and disadvantages of the proposed technology. The obtained results allowed us to find limitations in the use of vortex technology and the following stages of its improvement for medical use.