StRETcH: a Soft to Resistive Elastic Tactile Hand

TL;DR

This paper introduces StRETcH, a soft tactile hand with variable stiffness that uses an elastic membrane and a depth sensor to accurately measure contact geometry and object compliance for robotic manipulation.

Contribution

It presents a novel, easily manufactured soft tactile end-effector capable of controllably varying stiffness and accurately estimating contact features for manipulation tasks.

Findings

Achieves sub-millimeter contact geometry estimation.

Successfully manipulates deformable objects like dough.

Estimates stiffness of balloons with different fillings.

Abstract

Soft optical tactile sensors enable robots to manipulate deformable objects by capturing important features such as high-resolution contact geometry and estimations of object compliance. This work presents a variable stiffness soft tactile end-effector called StRETcH, a Soft to Resistive Elastic Tactile Hand, that is easily manufactured and integrated with a robotic arm. An elastic membrane is suspended between two robotic fingers, and a depth sensor capturing the deformations of the elastic membrane enables sub-millimeter accurate estimates of contact geometries. The parallel-jaw gripper varies the stiffness of the membrane by uni-axially stretching it, which controllably modulates StRETcH's effective modulus from approximately 4kPa to 9kPa. This work uses StRETcH to reconstruct the contact geometry of rigid and deformable objects, estimate the stiffness of four balloons filled with different substances, and manipulate dough into a desired shape.