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Learning Dexterity: Dactyl Robot Hand Manipulation via Sim-to-Real Transfer

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Credibility Rating

4/5
High(4)

High quality. Established institution or organization with editorial oversight and accountability.

Rating inherited from publication venue: OpenAI

A 2018 OpenAI capabilities milestone relevant to AI safety discussions around sim-to-real generalization, robustness, and the gap between simulated training environments and real-world deployment conditions.

Metadata

Importance: 52/100blog postprimary source

Summary

OpenAI presents Dactyl, a system that trains a Shadow Dexterous Hand robot entirely in simulation using reinforcement learning, then transfers the learned policy to a physical robot without fine-tuning. The system achieves unprecedented dexterous object manipulation by solving challenges including high-dimensional control, noisy observations, and sim-to-real transfer gaps. This demonstrates that physically-accurate world modeling is not required for real-world task performance.

Key Points

  • Dactyl trains entirely in simulation using the same RL algorithm as OpenAI Five, then deploys to a real robot hand with 24 degrees of freedom without fine-tuning.
  • Sim-to-real transfer is achieved through domain randomization, adapting to real-world physics without precise physical modeling of contact or friction.
  • The system handles noisy, partial observations from fingertip sensors and RGB cameras, inferring unobservable quantities like friction and slippage.
  • Generalizes across multiple object geometries (blocks, prisms), showing the approach is not limited to task-specific strategies.
  • Represents a milestone in dexterous robotic manipulation, an area where traditional robotics approaches had seen limited progress.

Cited by 1 page

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OpenAI

July 30, 2018

[Milestone](https://openai.com/research/index/milestone/)

# Learning dexterity

We’ve trained a human-like robot hand to manipulate physical objects with unprecedented dexterity.

[Read paper(opens in a new window)](https://arxiv.org/abs/1808.00177)

![Learning Dexterity](https://images.ctfassets.net/kftzwdyauwt9/296c85d3-a3a1-448a-083f6b2029b1/695e55d1e8c1f265c5e8d9b1e9fda631/learning-dexterity.jpg?w=3840&q=90&fm=webp)

Illustration: Ben Barry & Eric Haines

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Our system, called Dactyl, is trained entirely in simulation and transfers its knowledge to reality, adapting to real-world physics using techniques we’ve been working on for the [past⁠](https://openai.com/index/spam-detection-in-the-physical-world/) [year⁠](https://openai.com/index/generalizing-from-simulation/). Dactyl learns from scratch using the same general-purpose reinforcement learning algorithm and code as [OpenAI Five⁠](https://openai.com/index/openai-five/). Our [results⁠](https://openai.com/index/learning-dexterity/#results) show that it’s possible to train agents in simulation and have them solve real-world tasks, without physically-accurate modeling of the world.

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## The task

Dactyl is a system for manipulating objects using a [Shadow Dexterous Hand⁠(opens in a new window)](https://www.shadowrobot.com/products/dexterous-hand/). We place an object such as a block or a prism in the palm of the hand and ask Dactyl to reposition it into a different orientation; for example, rotating the block to put a new face on top. The network observes only the coordinates of the fingertips and the images from three regular RGB cameras.

![Robot hand with cube](https://images.ctfassets.net/kftzwdyauwt9/a7b8ffc6-71ea-43ef-2f7165b499d8/d5103aff11fd3f1d794e5f9b3adcf162/195A4726-21.jpg?w=3840&q=90&fm=webp)

Although the first humanoid hands were developed decades ago, using them to manipulate objects effectively has been a long-standing challenge in robotic control. Unlike other problems such as [locomotion⁠(opens in a new window)](https://www.bostondynamics.com/atlas), progress on dextrous manipulation using traditional robotics approaches has been slow, and [current techniques⁠(opens in a new window)](https://www.youtube.com/playlist?list=PLOXw6I10VTv_CcTXlvHmGbWH-_wUOoRoO) remain limited in their ability to manipulate objects in the real world.

Reorienting an object in the hand requires the following problems to be solved:

- **Working in the real world.** Reinforcement learning has shown many successes in simulations and video games, but has had comparatively limited results in the real world. We test Dactyl on a physical robot.
- **High-dimensional control.** The Shadow Dexterous Hand has 24 degrees of freedom compared to 7 for a typical robot arm.
- **Noisy and partial observations.** Dactyl works in the physical world and therefore must handle noisy and delayed sensor readings. When a fingertip sensor is occluded by other fingers or by th

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