Visual Pressure Estimation and Control for Soft Robotic Grippers

TL;DR

This paper introduces VPEC, a visual method for estimating and controlling pressure in soft robotic grippers using external RGB images, enabling precise manipulation tasks.

Contribution

The paper presents a novel visual pressure estimation and control method for soft robotic grippers, allowing for closed-loop pressure regulation using external camera images.

Findings

VPEC accurately infers pressure from RGB images during contact.

Enables closed-loop pressure control for precise manipulation.

Successfully grasps small objects with controlled pressure.

Abstract

Soft robotic grippers facilitate contact-rich manipulation, including robust grasping of varied objects. Yet the beneficial compliance of a soft gripper also results in significant deformation that can make precision manipulation challenging. We present visual pressure estimation & control (VPEC), a method that infers pressure applied by a soft gripper using an RGB image from an external camera. We provide results for visual pressure inference when a pneumatic gripper and a tendon-actuated gripper make contact with a flat surface. We also show that VPEC enables precision manipulation via closed-loop control of inferred pressure images. In our evaluation, a mobile manipulator (Stretch RE1 from Hello Robot) uses visual servoing to make contact at a desired pressure; follow a spatial pressure trajectory; and grasp small low-profile objects, including a microSD card, a penny, and a pill. Overall, our results show that visual estimates of applied pressure can enable a soft gripper to perform precision manipulation.