Two-Finger Soft Gripper Force Modulation via Kinesthetic Feedback

TL;DR

This paper presents a method for modulating contact forces in a two-finger soft gripper using kinesthetic feedback without tactile sensors, enabling force control based on finger bending measurements.

Contribution

It introduces a novel force modulation approach using finger bending differences, validated on a physical device, advancing soft robotic grasping control.

Findings

Force modulation correlates with desired bending difference

Contact and pull-out forces are characterized successfully

Method works on real physical soft gripper

Abstract

We investigate a method to modulate contact forces between the soft fingers of a two-finger gripper and an object, without relying on tactile sensors. This work is a follow-up to our previous results on contact detection. Here, our hypothesis is that once the contact between a finger and an object is detected, a controller that keeps a desired difference between the finger bending measurement and its bending at the moment of contact is sufficient to maintain and modulate the contact force. This approach can be simultaneously applied to both fingers while getting in contact with a single object. We successfully tested the hypothesis, and characterized the contact and peak pull-out force magnitude vs. the desired difference expressed by a multiplicative factor. All of the results are performed on a real physical device.