Organizations: Zhejiang University · Beijing Zhongguancun Academy · Institute of Automation, Chinese Academy of Sciences · University of Science and Technology of China · Eastern Institute of Technology
Action-conditioned world models offer a promising foundation for generalist robotic intelligence by predicting the consequences of actions. However, existing robotic datasets provide limited coverage of the diverse interaction dynamics required for generalizable world modeling. Large-scale egocentric human videos offer complementary interaction experience, yet the embodiment gap between human hands and robotic manipulators hinders effective cross-embodiment learning. Meanwhile, the predominance of successful demonstrations leaves failure dynamics substantially underrepresented, limiting the ability of world models to anticipate unsuccessful executions. To address these limitations, we introduce HF-WM, an action-conditioned world model that combines Human interaction learning with Failure-aware post-training. To bridge the embodiment gap, we develop a dual-branch framework that couples video generation with auxiliary pointflow prediction, using stabilized pointflow as a unified motion representation across human and robot interactions while suppressing egocentric camera motion. To improve failure modeling, we further perform Group Relative Policy Optimization (GRPO) post-training on perturbed actions derived from successful demonstrations, guided by action alignment and physical plausibility rewards, enabling the model to learn plausible failure dynamics without paired ground-truth videos. Extensive experiments demonstrate that HF-WM achieves state-of-the-art performance in action-conditioned video generation and exhibits strong utility for policy evaluation in downstream robotic tasks.
Figures & tables
Figure 1: Overview of HF-WM architecture. HF-WM extends learning beyond successful robot demonstrations in two stages. Stage 1 uses a dual-branch architecture with stabilized pointflow supervision to learn interaction dynamics from egocentric human interactions (Sec. 3.2 ). Stage 2 applies GRPO to counterfactual action perturbations, guided by action alignment and physical plausibility rewards, to model failure dynamics without paired failure-video supervision (Sec. 3.3 ).
Figure 2: Dual-branch architecture of HF-WM with stabilized pointflow. The auxiliary pointflow branch predicts interaction motion from intermediate video representations, while pointflow stabilization suppresses egocentric camera motion so that supervision is better focused on interaction-induced dynamics. The pointflow branch is used only during training and introduces no additional inference overhead.
Figure 3: Qualitative comparison of action-conditioned video generation. Evaluated on both successful and failed execution samples, our method is compared against six models and achieves much better visual quality with precise action following.
Method
PSNR ↑
SSIM ↑
LPIPS ↓
FVD ↓
FID ↓
L2latent↓
IDM ↓
Cosmos-Predict2.5 ( Ali et al., 2025 )
18.874
0.746
0.266
60.119
54.108
0.486
1.268
TesserAct ( Zhen et al., 2025 )
17.383
0.757
0.263
60.563
59.889
0.523
1.663
Ctrl-World ( Guo et al., 2025 )
21.683
0.770
0.305
36.916
64.665
0.418
0.949
Cosmos 3 ( Agarwal et al., 2026 )
20.233
0.766
0.178
42.987
36.780
0.365
1.108
OSCAR ( Wu and Gao, 2026 )
23.357
0.840
0.142
31.815
28.241
0.292
0.579
Kinema4D ( Xu et al., 2026 )
20.015
0.804
0.157
30.511
30.890
0.326
0.914
Table 1: Quantitative comparison with baselines. Best / second-best results are bolded / underlined.
Figure 4: Qualitative ablation of the key components in HF-WM. Large-scale human interaction data broadens the diversity of object interactions, while unified pointflow supervision provides a shared motion representation that facilitates cross-embodiment transfer. Building on this foundation, GRPO post-training improves the modeling of failure dynamics across diverse execution outcomes.
Variant
PSNR ↑
SSIM ↑
LPIPS ↓
FVD ↓
FID ↓
L2latent↓
IDM ↓
baseline(Cosmos3)
20.233
0.766
0.178
42.987
36.780
0.365
1.108
embodied data only
21.448
0.833
0.120
23.650
20.574
0.332
0.424
+ human
24.997
0.876
0.093
15.229
16.980
0.303
0.391
Δ gain ↑
3.549
0.043
0.027
8.421
3.594
0.029
0.033
embodied data + pointflow
21.573
0.835
0.117
22.993
20.011
0.329
0.406
+ human + pointflow
25.294
0.880
0.090
15.327
16.972
0.227
0.376
Table 2: Ablation study on the effectiveness of human interaction data and pointflow constraints.
Variant
PSNR ↑
SSIM ↑
LPIPS ↓
FVD ↓
FID ↓
L2latent↓
IDM ↓
w/o GRPO
25.828
0.887
0.086
14.993
15.991
0.198
0.355
failure-aware GRPO + action alignment
25.826
0.887
0.086
14.957
15.957
0.198
0.348
failure-aware GRPO + physical plausibility
25.574
0.862
0.098
15.307
15.454
0.209
0.381
failure-aware GRPO + full rewards
26.077
0.889
0.082
14.449
14.291
0.193
0.332
Table 3: Quantitative ablation of GRPO for learning from failure cases.
Figure 5: Real-world and HF-WM estimated success rates across six generalist robot policies.
Appendix figures & tables14 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 6: HF-WM architecture and attention visibility. Left: attention mask. Right: accessible keys/values and masking constraints for AR, DM, and PF queries.
Figure 7: Visualization of pointflow stabilization on egocentric interactions. Camera-motion compensation suppresses coherent background drift while preserving hand-object interaction motion.
Event class
Gripper event pattern
Target share
None
Gripper perturbation
Geometric total
close_hold
Open → Closed (hold)
18.75%
50%
reopen: 35%
15%
close_reopen
Open → Closed → Open
18.75%
50%
force_closed: 35%
15%
open_hold
Closed → Open (hold)
18.75%
50%
reclose: 8.75% suppress: 26.25%
15%
open_close
Closed → Open → Closed
18.75%
50%
force_open: 35%
15%
remain_open
Open (hold)
12%
50%
Not applied
50%
partial_hold
Indeterminate
8%
50%
Not applied
50%
Appendix
Table 4: Gripper event patterns, target sampling shares, and perturbation routing probabilities. Target shares are relative to all training samples; routing probabilities are conditional on the event class and sum to 100% per row.
Figure 8: Qualitative examples for the action alignment reward. Each row compares video-action pairs with higher (left) and lower (right) alignment. Action-skeleton overlays in full-frame views and end-effector crops highlight differences in consistency between the specified actions and observed robot motion.
Figure 9: Prompt template for GT Describer and Future-Event Contract Generator.
Method (Success/Failure)
PSNR ↑
SSIM ↑
LPIPS ↓
FVD ↓
FID ↓
L2latent↓
IDM ↓
Cosmos-Predict2.5 ( Ali et al., 2025 )
19.869/17.878
0.755/0.736
0.268/0.263
42.001/78.237
47.525/60.691
0.449/0.523
1.191/1.344
TesserAct ( Zhen et al., 2025 )
18.192/16.574
0.762/0.751
0.245/0.280
59.452/61.673
59.053/60.724
0.517/0.528
1.522/1.804
Ctrl-World ( Guo et al., 2025 )
21.746/21.620
0.788/0.752
0.301/0.309
32.247/41.585
61.721/67.608
0.406/0.429
0.887/1.011
Cosmos 3 ( Agarwal et al., 2026 )
21.172/19.293
0.815/0.716
0.142/0.213
38.512/47.461
34.205/39.354
0.349/0.381
1.101/1.114
OSCAR ( Wu and Gao, 2026 )
23.674/23.040
0.860/0.820
0.118/ 0.165
29.638/33.992
21.297/35.185
0.243/0.340
0.445/0.712
Kinema4D ( Xu et al., 2026 )
20.630/19.400
0.834/0.773
0.117 /0.197
27.155/33.866
23.495/38.285
0.270/0.381
0.904/0.923
Appendix
Table 5: Quantitative comparison with baselines on successful and failed executions. Each entry reports Success / Failure. Bold / underline denote the best / second-best results.
Variant
PSNR ↑
SSIM ↑
LPIPS ↓
FVD ↓
FID ↓
L2latent↓
IDM ↓
mid [12,14,16,18]
25.756
0.886
0.087
15.163
16.031
0.201
0.377
back [20,22,24,26]
25.689
0.885
0.087
15.326
16.361
0.202
0.393
uniform [8,14,20,26]
25.761
0.886
0.086
15.047
16.211
0.201
0.357
front [4,6,8,10]
25.828
0.887
0.086
14.993
15.991
0.198
0.355
Appendix
Table 6: Ablation study on the feature extraction layers of the pointflow branch.(SFT)
Figure 10: Intermediate rollout examples during GRPO training with individual reward components. Each panel shows corresponding frames from a ground-truth video and four candidate rollouts. Top: With only the action alignment reward, some candidates exhibit physically implausible interaction dynamics and degraded background quality. Bottom: With only the physical plausibility reward, the generated motion appears physically plausible but deviates from the conditioning actions. ( Note. Variation across candidates arises from stochastic exploration during GRPO training. Their relatively lower visual fidelity is a consequence of the reduced denoising steps adopted for training efficiency.)
Figure 11: Qualitative case of GRPO post-training under action perturbations. Starting from the original action skeleton, we introduce two counterfactual perturbations, Up and Reopen . Before GRPO, the model fails to faithfully reflect the perturbed actions and produces physically implausible outcomes, such as the cup remaining unnaturally suspended instead of falling after release. After GRPO, the generated candidates better follow the perturbed actions and exhibit more physically plausible object dynamics.
Pearson r↑
Spearman ρ↑
Kendall τb↑
SISRΔ↓ (pp)
MMRV ↓
0.9826
0.9559
0.9286
2.41
0.002
Appendix
Table 8: HF-WM policy evaluation on 90 matched sessions.
Figure 14: Additional qualitative results for HF-WM.
Figure 16: Uncover the wooden block. Each strip shows the world-model rollout (top) and the real-robot video (bottom) at six time steps. The real column is the RoboArena human success label; the WM column is the world-model verdict (Sec. 4.4 ). A red cell marks disagreement. On this task 1 of 6 policies succeeds on the real robot.
Figure 17: Put the food on the plate. Each strip shows the world-model rollout (top) and the real-robot video (bottom) at six time steps. The real column is the RoboArena human success label; the WM column is the world-model verdict (Sec. 4.4 ). A red cell marks disagreement. On this task 5 of 6 policies succeed on the real robot.