DUO Policy: Learning Fine-Grained Manipulation
from Human Videos via Dual-Actor Policy

Mingxi Jia1 Patton Yin1 Haojie Huang2 Ivy Xiao He1 Xuanru Liu1 Gefei Liu1 Dian Wang3 Stefanie Tellex1
1Brown University  2Northeastern University  3Stanford University
Under review
DUO Policy switches between a hand policy for the coarse phase and a robot policy for the fine-grained phase of coffee pod insertion.
DUO Policy switches between a hand policy trained on low-cost but imprecise human hand data and a robot policy trained on sparse but precise robot data.
+17%over the best baseline across 4 simulation tasks
+52%over the best baseline across 3 real-world tasks
3×better wall-clock data-collection efficiency

Abstract

Behavioral cloning is an effective way to learn visuomotor policies, but it depends on slow and expensive robot data collection. Prior work has shown that human videos can be a useful alternative data source for manipulation. However, embodiment and precision gaps limit the resulting cross-embodiment policies to coarse behaviors, so they cannot learn precise tasks such as insertion. We propose DUO Policy (Dual-Actor Policy), a visuomotor policy learning approach that reduces how much robot data is needed to train a robust policy. It does this by splitting the learned skill into a human hand policy and a robot policy. DUO Policy uses a dual-actor architecture with an adaptive gate. The gate combines a hand policy pretrained on low-cost human videos, which handles coarse manipulation, with a robot policy trained on sparse robot data, which handles fine-grained manipulation. We evaluate the approach on complex manipulation tasks, including coffee pod insertion, laptop closing, and grasping in cluttered scenes. DUO Policy outperforms the best baseline by an average of 17% on four simulation tasks and 52% on three challenging real-world tasks, and it is 3× more efficient in wall-clock data-collection time.

Real-World Tasks

We evaluate on three real-world tasks that each need fine-grained control. The videos show DUO Policy rollouts (playback speed is marked in the corner).

Desk Cleanup

Close the laptop and the book, then place the mouse precisely aligned with the laptop.

Candy Sorting

Sort eight cluttered candy bags into two boxes by color, starting from widely varying poses.

K-Cup Coffee Making

Place the mug, open the machine, insert the pod, close the lid, and press brew. This task is long-horizon and needs tight tolerances.

Supplementary Video

Not loading? Watch on Google Drive.

Why Is Fine-Grained Manipulation Hard?

A fine-grained task naturally splits into a coarse, free-space phase and a precise, contact-rich phase. Robot data is precise but sparse, so a robot-only policy easily drifts out of distribution in free space. Human hand data covers the workspace densely but is imprecise because of the embodiment gap, so a hand-only policy fails at narrow "chokepoints" such as inserting a pod. DUO Policy uses each data source where it is strongest.

Dataset coverage and policy behaviors of hand-only, robot-only and DUO policies.
(a) Dataset coverage. Human data is dense but noisy; robot data is precise but sparse. (b) Policy behaviors. πhand collides at the insertion, πrobot fails out of distribution, and πDUO hands control to the robot policy exactly at the chokepoint.

Method

DUO Policy architecture: a frozen hand policy, a robot policy, and a policy gate.

DUO Policy has two branches. The hand policy πhand is pretrained on human videos and frozen. The robot policy πrobot is trained on a small amount of robot data. A state-dependent binary policy gate g decides which branch acts at each step:

π(o) = g(o) πrobot(o) + (1 − g(o)) πhand(o)

3D hand-policy pretraining

The hand policy is a point-cloud diffusion policy trained on retargeted human hand poses from multi-view RGB-D video. 3D input lets it learn stable behaviors without in-hand cameras. A 2D policy drops 49.1% in our ablation.

Gate supervision at no extra cost

Robot data is collected human-in-the-loop (HG-DAgger) while the hand policy runs. The binary intervention signal marks where the hand policy falls short and directly supervises the gate, so no extra labels are needed.

Local perception, separate action spaces

The gate and the robot policy see only the in-hand view, which makes precise control invariant to the global layout. Each branch uses its own action space and normalization statistics, so the much smaller robot corrections are not squashed.

From human video to robot-ready point clouds

Data preprocessing pipeline from multi-view human video to point clouds with a rendered gripper.
Hand poses are detected with WiLoR and retargeted to end-effector actions. The human hand is removed from the point cloud and replaced with a rendered gripper, so pretraining and deployment observations match.

Real-World Results

Success rates on the three real-world tasks shown in the task videos above.

Success rates

MethodDesk CleanupCandy SortingK-Cup Coffee
DUO (ours)17/2072/8014/20
DP3 (+ in-hand images)9/2028/802/20

Data-collection efficiency

Success rate versus wall-clock data collection time on candy sorting.

On Candy Sorting, 10 minutes of human hand video (216 demonstrations) plus 30 minutes of human-in-the-loop correction brings DUO Policy to 90% success. With the same 40-minute budget of SpaceMouse teleoperation, DP3 reaches only 35%, and it needs about 70 more minutes of robot data to become competitive.

Simulation Results

On MimicGen tasks, every method is pretrained on noisy Panda demonstrations without in-hand views, to mimic human video. Each is then finetuned with 20, 30 or 40 UR5 demonstrations. Numbers are success rates (%), and parentheses show the difference from the best baseline.

MethodObs Stack D1Stack Three D1 HammerCleanup D1Coffee D2
203040203040 203040203040
DUO (ours)PCD 88 (-7)9595 35 (+15)50 (+20)50 (+15) 55 (+45)60 (+47)65 (+52) 90 (+52)93 (+57)90 (+30)
DP3PCD95959520202310813484560
Diffusion PolicyRGB83888810303581310183033
UMIRGB5365953132310813202840
Phantom (zero-shot)RGB50300
Phantom-SFTRGB6073785101355351015
MasqueradeRGB133863385353184853

Spatial generalization

Spatial generalization map for coffee pod insertion.
Noisy pretraining data covers the whole workspace, but robot data covers only a small region. DUO Policy inserts the pod across most of the workspace, while the baseline succeeds only near the robot demonstrations.

Convergence and robustness to noisy human data

Convergence of training strategies.
Convergence: DUO improves faster and converges higher than SFT, co-training and training from scratch.
Success rate under increasing pretraining noise.
Robustness: DUO degrades the least as noise in the pretraining trajectories grows.

Ablations (Coffee D2, 3 seeds)

PurposeVariationSuccess (%)
Finetune strategyDual actors → SFT86.7 (↓4.9)
Dual actors → Co-training71.7 (↓19.9)
Data recipew/o robot data0 (↓91.6)
w/o cross-embodiment pretraining28.3 (↓63.3)
w/o inpainting63.3 (↓28.3)
Perception3D pretrain → 2D pretrain42.5 (↓49.1)
Multi-view → single-view76.7 (↓14.9)
DUO (ours)91.6

BibTeX

@article{duopolicy2026,
  title   = {Learning Fine-Grained Manipulation from Human Videos via Dual-Actor Policy},
  author  = {Jia, Mingxi and Yin, Patton and Huang, Haojie and He, Ivy Xiao and Liu, Xuanru and Liu, Gefei and Wang, Dian and Tellex, Stefanie},
  journal = {arXiv preprint},
  year    = {2026}
}