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 pinch grasp


Beyond Anthropomorphism: Enhancing Grasping and Eliminating a Degree of Freedom by Fusing the Abduction of Digits Four and Five

Fritsch, Simon, Achenbach, Liam, Bianco, Riccardo, Irmiger, Nicola, Marti, Gawain, Visca, Samuel, Yang, Chenyu, Liconti, Davide, Cangan, Barnabas Gavin, Malate, Robert Jomar, Hinchet, Ronan J., Katzschmann, Robert K.

arXiv.org Artificial Intelligence

Abstract-- This paper presents the SABD hand, a 16-degree-of-freedom (DoF) robotic hand that departs from purely anthropomorphic designs to achieve an expanded grasp envelope, enable manipulation poses beyond human capability, and reduce the required number of actuators. This is achieved by combining the adduction/abduction (Add/Abd) joint of digits four and five into a single joint with a large range of motion. The combined joint increases the workspace of the digits by 400% and reduces the required DoFs while retaining dexterity. Experimental results demonstrate that the combined Add/Abd joint enables the hand to grasp objects with a side distance of up to 200 mm. Reinforcement learning-based investigations show that the design enables grasping policies that are effective not only for handling larger objects but also for achieving enhanced grasp stability. In teleoperated trials, the hand successfully performed 86% of attempted grasps on suitable YCB objects, including challenging non-anthropomorphic configurations. These findings validate the design's ability to enhance grasp stability, flexibility, and dexterous manipulation without added complexity, making it well-suited for a wide range of applications. A. Motivation Robust grasping for robotic manipulation is one of the key issues preventing the usage of robots in many applications [1]. The difficulty herein can be attributed to both software [2] and hardware challenges [3]. No robotic manipulator has been able to fully match the dexterity, power-to-weight ratio, and exteroception of the human hand [4]. Commercially available solutions, such as robotic grippers [5], the Shadow Robotic Hand [6], the Allegro Hand [7] and the Leap Hand [8], tend to be expensive or overly limited in their capabilities.


MISCGrasp: Leveraging Multiple Integrated Scales and Contrastive Learning for Enhanced Volumetric Grasping

Fan, Qingyu, Cai, Yinghao, Li, Chao, Jiao, Chunting, Zheng, Xudong, Lu, Tao, Liang, Bin, Wang, Shuo

arXiv.org Artificial Intelligence

Robotic grasping faces challenges in adapting to objects with varying shapes and sizes. In this paper, we introduce MISCGrasp, a volumetric grasping method that integrates multi-scale feature extraction with contrastive feature enhancement for self-adaptive grasping. We propose a query-based interaction between high-level and low-level features through the Insight Transformer, while the Empower Transformer selectively attends to the highest-level features, which synergistically strikes a balance between focusing on fine geometric details and overall geometric structures. Furthermore, MISCGrasp utilizes multi-scale contrastive learning to exploit similarities among positive grasp samples, ensuring consistency across multi-scale features. Extensive experiments in both simulated and real-world environments demonstrate that MISCGrasp outperforms baseline and variant methods in tabletop decluttering tasks. More details are available at https://miscgrasp.github.io/.


Finger-shaped sensor enables more dexterous robots

Robohub

MIT researchers have developed a camera-based touch sensor that is long, curved, and shaped like a human finger. Their device, which provides high-resolution tactile sensing over a large area, could enable a robotic hand to perform multiple types of grasps. Imagine grasping a heavy object, like a pipe wrench, with one hand. You would likely grab the wrench using your entire fingers, not just your fingertips. Sensory receptors in your skin, which run along the entire length of each finger, would send information to your brain about the tool you are grasping.


Dynamic Flex-and-Flip Manipulation of Deformable Linear Objects

Jiang, Chunli, Nazir, Abdullah, Abbasnejad, Ghasem, Seo, Jungwon

arXiv.org Artificial Intelligence

This paper presents the technique of flex-and-flip manipulation. It is suitable for grasping thin, flexible linear objects lying on a flat surface. During the manipulation process, the object is first flexed by a robotic gripper whose fingers are placed on top of it, and later the increased internal energy of the object helps the gripper obtain a stable pinch grasp while the object flips into the space between the fingers. The dynamic interaction between the flexible object and the gripper is elaborated by analyzing how energy is exchanged. We also discuss the condition on friction to prevent loss of contact. Our flex-and-flip manipulation technique can be implemented with open-loop control and lends itself to underactuated, compliant finger mechanism. A set of experiments in robotic page turning performed with our customized hardware and software system demonstrates the effectiveness and robustness of the manipulation technique.