Foundation models and large-scale human data provide rich sources of manipulation intent, but translating this intent into multi-fingered robot behavior remains difficult. Dexterous hands still lack a reusable low-level primitive that reliably establishes contact across tasks and embodiments. We propose GOTT, a reach-acquire-move framework built around a single cross-embodiment contact-acquisition primitive. Given a robot-agnostic object trajectory and a reach specification, GOTT first brings the hand near a task-relevant contact region. The shared closed-loop primitive then establishes stable contact from this approximate initialization, and a pose-conditioned controller tracks the desired object motion. Reach specifications may come from future-aware planning, external models, or human demonstrations, while the primitive and tracking backend remain unchanged. Simulation and real-world experiments show that GOTT is able to establish robust contact across diverse objects, arm-hand platforms, and seen and unseen hand morphologies. It also consistently improves end-to-end task success over open-loop grasp execution.
Figures & tables
Figure 1: Contact-acquisition training and cross-embodiment policy. (A) The RL policy starts from randomized initial configurations and learns to establish stable contact using local hand-object observations. (B) Padding and binary masks map different hands into a shared observation and action space, allowing one policy to operate across hand embodiments.
Figure 2: Future-aware planning. We roll out the hand motion induced by each candidate initial configuration over the full object trajectory and solve IK along this motion. Red segments indicate joint jumps from discontinuous IK solutions. We reject candidates that are initially reachable but become infeasible later and select the remaining candidate with the least cumulative joint motion.
Figure 3: Alternative sources of reach specifications. Given a desired object trajectory, GOTT can construct a reach specification through future-aware planning or use additional guidance from reference grasps or human approach trajectories. The shared contact-acquisition primitive refines the resulting approximate initializations into stable contact.
Figure 4: Real-world evaluation setup. (a) in-distribution (blue) and out-of-distribution (purple) test objects; (b) three robot embodiments used for evaluation.
Method
Setting
XHand
Sharpa
Allegro
Avg.
BODex [ 7 ]
-
45.4
27.2
43.6
38.7
DRO [ 53 ]
-
31.3
47.0
43.2
40.5
CrossDex [ 61 ]
Specialist
30.4 ± 10.9
74.9 ± 1.5
34.5 ± 3.3
46.6 ± 4.1
Unified
44.7 ± 2.9
52.8 ± 3.7
57.6 ± 1.0
51.7 ± 1.5
Ours
Specialist
64.3 ± 0.7
81.4 ± 1.2
80.4 ± 1.8
75.4 ± 1.0
Unified
74.1 ± 1.2
75.0 ± 1.1
87.1 ± 4.4
78.7 ± 1.1
Table 1: Simulation lifting success on three left hands (%). BODex and DRO are executed as open-loop grasp baselines. CrossDex and GOTT are evaluated as specialist policies trained separately for each hand and unified policies trained jointly across all three hands. Learned-policy results report mean ± standard deviation across three seeds. Best results per column are bolded.
Variant
4433
4333
4324
Avg.
Oracle (per-variant)
69.0 ± 6.8
71.6 ± 1.1
76.0 ± 4.0
72.2 ± 1.2
Allegro-only (zero-shot)
29.4 ± 19.7
12.9 ± 8.6
9.4 ± 8.1
17.2 ± 12.1
Three-hand (zero-shot)
74.4 ± 6.5
72.2 ± 4.8
69.6 ± 9.6
72.1 ± 6.9
Table 2: Zero-shot generalization to unseen Allegro variants. Lifting success rate (%), reported as mean ± standard deviation over three seeds. xyzw denotes per-finger link counts ( 4444 = original Allegro). Oracle trains one policy per variant; Allegro-only trains on the original Allegro; Three-hand is our unified policy over XHand+Sharpa+original Allegro, evaluated zero-shot.
Figure 5: Qualitative grasps on training and unseen embodiments. We compare the full GOTT (top) with the variant without rdist (bottom) on three training hands and three unseen Allegro variants.
Figure 6: Qualitative illustration of four real-world tasks.
Trash Cleanup
Mustard Pouring
Whiteboard Erasing
Drill Use
Avg. (%)
Method
gSR
tSR
gSR
tSR
gSR
tSR
gSR
tSR
gSR
tSR
DRO
6/10
0/10
5/10
5/10
5/10
3/10
7/10
6/10
57.5
35.0
BODex
5/10
2/10
4/10
2/10
7/10
3/10
7/10
7/10
57.5
35.0
Ours
8/10
7/10
8/10
7/10
10/10
9/10
9/10
9/10
87.5
80.0
Table 3: Real-world task results. Per-task grasp success rate (gSR) and task success rate (tSR) across four manipulation tasks on Franka-Sharpa platform, 10 trials each. Best per column in bold.
Figure 7: Success rate versus table height offset z on the SimToolReal eraser object.
Figure 8: Visualization of three sources of object trajectories.
Figure 9: Execution of unseen DexYCB demonstrations. Transparent hands indicate motion over time. (a) Annotated human hand-object motion. (b) Open-loop kinematic replay fails to maintain contact in physics simulation. (c) Our reactive primitive acquires stable contact and executes the demonstrated object trajectory.
Variant
XHand
Sharpa
Allegro
Avg.
Full GOTT
74.1 ± 1.2
75.0 ± 1.1
87.1 ± 4.4
78.7 ± 1.1
w/o link position obs.
49.4 ± 6.4
57.9 ± 10.3
75.7 ± 10.6
61.0 ± 4.4
proprio history length =1
56.5 ± 5.1
65.0 ± 2.1
67.5 ± 3.0
63.0 ± 3.3
OHRA-style [ 54 ] obs.
24.9 ± 22.8
31.2 ± 25.2
20.9 ± 15.6
25.7 ± 18.3
w/o rcontact
0.0 ± 0.0
0.0 ± 0.0
0.0 ± 0.0
0.0 ± 0.0
w/o rlift
0.8 ± 0.1
2.7 ± 1.3
1.0 ± 1.2
1.5 ± 0.8
Table 4: Ablation results. Success rate (%) on three left hands.
Selection
Affordance
Future-aware
gSR (%)
tjSR (%)
func. (%)
tSR (%)
Random
✗
✗
100
80
35
20
IK-only
✗
✓
95
90
30
30
VLM (gpt-5.6-sol)
✓
✓
90
70
80
55
VLM (gemini-flash-latest)
✓
✓
70
50
65
50
VLM (claude-opus-4-7)
✓
✓
80
70
85
65
VLM (claude-opus-5)
✓
✓
95
75
85
60
Table 5: Affordance- and Future-aware selection on Drill Use (20 scenes). Random and IK-only use affordance-agnostic candidates and select by random sampling and trajectory feasibility, respectively. VLM variants first generate candidates from a task-relevant contact region and then apply future-aware IK selection.
Appendix figures & tables14 assets
Supplementary material from the paper’s appendix.
Appendix
Symbol
Term
Value
wd
distance
16.0
wc
contact
4.0
wop
object position stability
10.0 (init. 2.0 )
wor
object rotation stability
10.0 (init. 2.0 )
wl
lifting
1.0
Tcur
annealing steps
105
Appendix
Table 6: Reward weights.
Hand
DoF
Thumb (6)
Index (5)
Middle (5)
Ring (5)
Pinky (5)
Allegro
16
RAF[ ]F[ ]
R[ ]FFF
R[ ]FFF
R[ ]FFF
[ ][ ][ ][ ][ ]
Sharpa Wave
22
[ ]AFAFF
[ ]AFFF
[ ]AFFF
[ ]AFFF
FAFFF
XHand
12
[ ]AF[ ]F[ ]
[ ]AFF[ ]
[ ][ ]FF[ ]
[ ][ ]FF[ ]
[ ][ ]FF[ ]
Appendix
Table 7: Canonical 26-DoF joint layout and per-hand instantiation. Each finger is allocated a fixed number of slots in the canonical layout (6 for the thumb, 5 for each non-thumb finger); slots are filled by a hand’s native joint when present, and masked ( [] ) otherwise. F, A, and R denote flexion, abduction/adduction, and axial rotation respectively. Reading order within each finger is base → tip.
Component
Composition
Dim
Joint positions
26 canonical ×K frames
26K
Joint targets
26 canonical ×K frames
26K
Link positions
21 links ×3×K frames
63K
Hand-object vectors
21 links ×1 nearest pt ×3
63
Joint mask
active canonical joints
26
Link mask
active canonical links
21
Appendix
Table 8: Observation components. K=5 .
Group
Parameter
Range
Type
Object
Scale
[0.96,1.04]
× nominal
Mass
[0.5,3.0]
× nominal (from ρ⋅V⋅scale3 )
Static/dynamic friction
[0.5,1.5]
absolute
Restitution
[0.0,0.1]
absolute
Robot links
Static/dynamic friction
[0.5,2.0]
absolute
Restitution
[0.1,0.5]
absolute
Appendix
Table 9: Domain randomization ranges. All distributions are uniform. Multiplicative ranges ( × ) scale the per-object or per-robot nominal value; absolute ranges directly set the parameter value.
Parameter
Value
Parallel environments
4096
Horizon (rollout) length
60
Minibatch size
8192
Mini-epochs per update
5
Discount γ
0.95
GAE λ ( tau )
0.90
Appendix
Table 10: PPO hyperparameters.
Figure 10: Simulation training assets.
Figure 11: Task-aware region selection for Drill Use . (a) Four rendered views provided to the VLM. (b) The VLM identifies functional parts and selects the pistol grip as the task-relevant holding region, with multiple grasp points spanning the grip. (c) Back-projected grasp points define the contact region (yellow), from which candidate initializations are sampled.
Embodiment
O1
O2
O3
O4
O5
O6
O7
O8
O9
O10
Total (%)
Franka-Sharpa
4
4
5
5
5
5
4
3
5
5
90
Franka-XHand
5
5
5
4
5
3
5
4
5
4
90
Tianji-XHand
5
5
4
4
5
5
5
5
5
5
96
Appendix
Table 11: Per-object grasp success across embodiments (out of 5 trials). Objects are abbreviated as O1-O10: O1 mustard-bottle , O2 bleach-cleanser , O3 drill-red , O4 tomato-soup , O5 meat-can , O6 red-bottle , O7 drill-green , O8 apple-tea , O9 eraser , O10 maize . Objects O1–O5 are seen during training; O6–O10 are unseen.
Figure 12: Qualitative comparison on real-world tasks. Subfigures (a)-(b) are from BODex, and (c)-(d) are from DRO.
Scale
@006
@008
@010
@012
avg.
Floating
69.79
73.79
72.09
67.26
70.73
Tabletop
53.29
60.90
60.05
54.28
57.13
Appendix
Table 12: Effect of generation-time table constraints on BODex grasp success rate (%). Allegro right hand, 4 object scales, evaluated under BODex’s original protocol. Only the generation phase differs between the two columns. Objects are taken from DexGraspNet [ 51 ] , normalised so that each object’s bounding-box diagonal measures 1 m, and then rescaled to four target diagonals ( @006 = 0.06 m, @008 = 0.08 m, @010 = 0.10 m, @012 = 0.12 m).
Figure 13: Evaluation protocol comparison. The same BODex grasps evaluated under BODex’s original protocol and our tabletop protocol.
DRO variant
Allegro
Sharpa
XHand
Av.
Released ckpt
43.2
47.0
31.3
40.5
Fine-tune 1 ep.
21.6
52.2
31.1
35.1
Fine-tune 5 ep.
20.0
37.9
32.0
30.0
Retrain 5 ep.
19.8
40.6
32.6
31.0
Retrain 40 ep.
18.6
35.5
31.3
28.5
Appendix
Table 13: DRO variants. Lifting success rate (%) under our tabletop protocol; best per column in bold.
Stage
Time
4-view rendering
0.11 ± 0.01 s
VLM-based affordance reasoning
14.9 ± 0.9 s
Candidate generation
0.76 ± 0.01 s
IK filtering
3.95 ± 0.06 s
cuRobo planning ( N=10 )
9.6 ± 0.5 s
FoundationPose
45 Hz
Appendix
Table 14: Per-stage runtime, averaged over 10 rollouts.
Figure 14: Contact-predictor accuracy under observation noise. Per-step accuracy of the debounced switch signal, averaged over the three hands, as the predictor input is perturbed along one axis at a time (solid: object position, 0–5 cm; dashed: joint angle, 0–0.5 rad). Our proprioceptive predictor is unaffected by object-pose noise and degrades least under joint noise.
Cross-embodiment dexterous grasping aims to synthesize stable grasps across heterogeneous multi-fingered hands with little or no embodiment-specific tuning. Existing interaction-centric methods achieve promising results, but their object representations often underrepresent local surface geometry, while their robot descriptors do not explicitly encode both robot morphology and kinematics. We propose MANGO-Grasp, an anisotropic interaction framework that represents objects as geometry-oriented 3D Gaussian primitives and robot hands as surface keypoints encoded into morpho-kinematic descriptors. The object primitives are adaptively allocated by geometric complexity and shaped as surface-aligned plates with outward normals, encoding local geometry. Mahalanobis fields over keypoint--primitive pairs serve as interaction prediction targets during training and as optimization guidance for grasp realization at inference. These fields rise sharply for displacement along the surface normal but only gently within the tangent plane, matching the directional structure of contact. Grasps are realized with one shared optimization formulation and hyperparameter setting across all embodiments. On the CMAP and MultiGripperGrasp benchmarks, MANGO-Grasp outperforms the strongest seen-hand baseline by up to 8.24 percentage points in simulation. It also transfers zero-shot to the unseen SharpaWave hand, improving over the strongest zero-shot baseline by up to 16.57 percentage points, and achieves 86% success in real-world experiments. The code and additional materials will be made available upon publication at https://connor-zh.github.io/MANGO-Grasp/.
Heng Zhang, Kevin Yuchen Ma, Mike Zheng Shou +2
Robotics & Autonomous Systems Division, Institute for Infocomm Research, Agency for Science, Technology and Research (A*STAR-I2R), Singapore · College of Computing and Data Science, Nanyang Technological University, Singapore · Show Lab, National University of Singapore, Singapore
Human demonstrations offer a scalable way to collect manipulation data, but their contacts may be unstable or infeasible when transferred to a robot hand. Collecting demonstrations directly on the target robot avoids this mismatch but substantially increases the cost of data collection. To address this trade-off, we present Touch2Robot, a framework that lets humans collect demonstrations while seeing how the target robot hand would contact the object. We capture human hand motion, tactile-glove measurements, and object motion during human manipulation. These recordings guide object-specific RL policies to reproduce the demonstrated object motion while favoring contacts consistent with the recorded human touch. We distill the learned behaviors into a unified real-time retargeter that maps incoming human observations and object geometry to robot hand configurations. During collection, the predicted robot configuration is synchronized with the tracked object pose in simulation to reconstruct robot-object contacts, which are visualized to help the demonstrator adapt subsequent interactions to the target hand. Across four real-world tasks, Touch2Robot improves average real-robot replay completion from 37.9% to 72.1% over visual-only feedback, while reducing the collection time per replay-successful demonstration from 58.6s to 18.2s. Reconstructed target-hand contacts achieve 44.2% F1 against real-robot tactile measurements, and policies trained on Touch2Robot demonstrations improve downstream Diffusion Policy performance by 29.1 percentage points over visual-only feedback. These results show that bringing robot touch into the human demonstration loop improves both the quality and efficiency of scalable dexterous data collection. Project webpage: https://Touch2Robot.github.io/.
Shengcheng Luo, Xiaoyang Cheng, Hong Ying +6
ShanghaiTech University · Beijing Institute for General Artificial Intelligence (BIGAI) · Shanghai Jiao Tong University +1
Reinforcement learning explores effectively in domains such as Atari games, navigation, and locomotion, where novelty over states or dynamics is a sufficient signal. In contrast, dexterous manipulation requires rich physical hand--object interactions, but existing methods often suffer from unstable contact-based novelty signals, inefficient distance novelty signals, or reliance on task-specific priors. We propose ContactExplorer, a general exploration method for dexterous manipulation tasks. ContactExplorer represents contact as the intersection between object surface points and hand keypoints, encouraging dexterous hands to discover diverse and novel contact patterns, namely which fingers contact which object regions. It maintains a contact counter conditioned on discretized object states obtained via learned hash codes. This counter is leveraged in two complementary ways: (1) a count-based contact coverage reward that promotes exploration of novel contact patterns, and (2) an energy-based reaching reward that guides the agent toward under-explored contact regions. We evaluate ContactExplorer on seven contact-rich manipulation tasks and five dexterous hand embodiments. Experimental results show that ContactExplorer substantially improves sample efficiency and success rates over existing exploration methods, that it reduces the need for task-specific priors, and that it remains effective across hand embodiments and transfers to the real world. Project page is https://contact-explorer.github.io.
Zixuan Liu, Ruoyi Qiao, Chenrui Tie +5
School of Computing, National University of Singapore · RoboScience