DexWrist: A Robotic Wrist for Constrained and Dynamic Manipulation

Fuente: arXiv
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Main Authors: Peticco, Martin, Ulloa, Gabriella, Marangola, John, Dashora, Nitish, Agrawal, Pulkit
Format: Preprint
Published: 2025
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author Peticco, Martin
Ulloa, Gabriella
Marangola, John
Dashora, Nitish
Agrawal, Pulkit
author_facet Peticco, Martin
Ulloa, Gabriella
Marangola, John
Dashora, Nitish
Agrawal, Pulkit
contents Development of dexterous manipulation hardware has primarily focused on hands and grippers. However, these end-effectors are often paired with bulky and highly stiff wrists that limit performance in human environments. More designs have adopted backdrivable actuation, but are still difficult to model and control due to coupled kinematics or high mechanical inertia from heavy links. We present DexWrist, a robotic wrist that advances manipulation in highly constrained environments and enables dynamic, contact-rich tasks. We achieve this by combining quasi-direct drive actuation with a decoupled parallel kinematic mechanism in a compact design. It delivers 3.75 +/- 0.05 Nm rated torque, 0.33 +/- 0.06 Nm backdrive torque, 10.15 +/- 1.34 Hz torque bandwidth, +/- 40 degrees ROM in both DOFs, and a one-to-one motor-to-DOF mapping in a 0.97 kg package. In practice, these properties increase workspace in cluttered environments and stabilize contact without the need for finely tuned admittance control. We evaluate DexWrist as a drop-in wrist upgrade in simulation and on two robot arms performing representative constrained and contact-rich tasks. In learned policy evaluations, DexWrist achieved 50-76% relative improvements in success rate, and reduced autonomous task completion times by 3-5x. More details about DexWrist can be found at https://dexwrist.csail.mit.edu.
format Preprint
id arxiv_https___arxiv_org_abs_2507_01008
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle DexWrist: A Robotic Wrist for Constrained and Dynamic Manipulation
Peticco, Martin
Ulloa, Gabriella
Marangola, John
Dashora, Nitish
Agrawal, Pulkit
Robotics
Development of dexterous manipulation hardware has primarily focused on hands and grippers. However, these end-effectors are often paired with bulky and highly stiff wrists that limit performance in human environments. More designs have adopted backdrivable actuation, but are still difficult to model and control due to coupled kinematics or high mechanical inertia from heavy links. We present DexWrist, a robotic wrist that advances manipulation in highly constrained environments and enables dynamic, contact-rich tasks. We achieve this by combining quasi-direct drive actuation with a decoupled parallel kinematic mechanism in a compact design. It delivers 3.75 +/- 0.05 Nm rated torque, 0.33 +/- 0.06 Nm backdrive torque, 10.15 +/- 1.34 Hz torque bandwidth, +/- 40 degrees ROM in both DOFs, and a one-to-one motor-to-DOF mapping in a 0.97 kg package. In practice, these properties increase workspace in cluttered environments and stabilize contact without the need for finely tuned admittance control. We evaluate DexWrist as a drop-in wrist upgrade in simulation and on two robot arms performing representative constrained and contact-rich tasks. In learned policy evaluations, DexWrist achieved 50-76% relative improvements in success rate, and reduced autonomous task completion times by 3-5x. More details about DexWrist can be found at https://dexwrist.csail.mit.edu.
title DexWrist: A Robotic Wrist for Constrained and Dynamic Manipulation
topic Robotics
url https://arxiv.org/abs/2507.01008