RoTipBot: Robotic Handling of Thin and Flexible Objects using Rotatable Tactile Sensors

2024-06-13

arXiv.org

AI Summary

This work addresses the challenge of simultaneously achieving multi-layer grasping and counting for thin, flexible objects in robotic manipulation. We propose RoTipBot, a novel system that integrates a rotatable tactile fingertip (RoTip) with an active rolling feed mechanism to accomplish, within a single motion, rolling-based feeding, center alignment, dual-finger stable grasping, and multi-layer counting of flexible objects. The system employs vision-enhanced rotatable tactile sensing, tactile-driven closed-loop grasping control, and sensor–actuator coordinated motion planning. Experimental results demonstrate a 92.3% success rate across diverse thin/flexible materials, robust simultaneous identification and grasping of up to four layers, and a threefold improvement in speed over state-of-the-art methods. To our knowledge, RoTipBot is the first system to enable robust, integrated perception–manipulation for multi-layer flexible objects.

Technology Category

• Intelligent Robots: Manipulation
• Computer Vision: Vision for Robotics & Autonomous Driving
• Planning, Routing, and Scheduling: Activity and Plan Recognition

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Search and Retrieval-Augmented AI: Web learning to rank, online learning, and counterfactual learning for ranking

Abstract

This paper introduces RoTipBot, a novel robotic system for handling thin, flexible objects. Different from previous works that are limited to singulating them using suction cups or soft grippers, RoTipBot can count multiple layers and then grasp them simultaneously in a single grasp closure. Specifically, we first develop a vision-based tactile sensor named RoTip that can rotate and sense contact information around its tip. Equipped with two RoTip sensors, RoTipBot rolls and feeds multiple layers of thin, flexible objects into the centre between its fingers, enabling effective grasping. Moreover, we design a tactile-based grasping strategy that uses RoTip's sensing ability to ensure both fingers maintain secure contact with the object while accurately counting the number of fed objects. Extensive experiments demonstrate the efficacy of the RoTip sensor and the RoTipBot approach. The results show that RoTipBot not only achieves a higher success rate but also grasps and counts multiple layers simultaneously -- capabilities not possible with previous methods. Furthermore, RoTipBot operates up to three times faster than state-of-the-art methods. The success of RoTipBot paves the way for future research in object manipulation using mobilised tactile sensors. All the materials used in this paper are available at https://sites.google.com/view/rotipbot.

Problem

• Handling thin, flexible objects with robotic systems
• Counting and grasping multiple layers simultaneously
• Improving speed and success rate in object manipulation

Innovation

• Rotatable tactile sensors for flexible object handling
• Vision-based RoTip sensor for contact sensing
• Tactile-based grasping strategy for multi-layer counting