Contact Trajectory Prompting: In-Context Transfer of Contact-Rich Behaviors from a Single Demonstration
Authors: Xian Nie, Yujie Zang, Yuhang Zheng, Yupeng Zheng, Songen Gu, Wendi Chen, Chuan Wen, Cewu Lu, +3 more
Organizations: Shanghai Jiao Tong University · TARS Robotics · National University of Singapore · Institute of Automation, Chinese Academy of Sciences · Fudan University
In-context robot learning enables robots to acquire new behaviors from demonstrations without test-time parameter updates. However, visual and kinematic specifications alone may not distinguish contact-rich behaviors that share similar motions but require different interaction intensities or patterns. We propose Contact Trajectory Prompting (CTP), a framework for one-shot transfer of contact-rich manipulation behaviors. CTP encodes motion and contact information from a single demonstration into an ordered contact trajectory prompt that captures their temporal evolution and specifies the desired physical interaction behavior. During execution, the policy uses online sensory feedback to retrieve interaction-relevant information from the prompt, conditioning closed-loop action generation on the demonstrated contact behavior. Across real-world wiping, rotation, and insertion tasks on objects excluded from training, CTP achieves 78.7% overall success, outperforming the strongest evaluated baseline by 13.0 percentage points. Changing only the reference demonstration enables CTP to follow contact specifications for both intensity and direction, including an intermediate wiping force level and clockwise or counterclockwise cap rotation. These results demonstrate that contact trajectories serve as effective behavioral specifications, extending in-context robot learning beyond motion imitation to physical interaction transfer. Project website: https://ctp-robotics.github.io/project_page.
Figures & tables
Fig. 2: Overview of CTP. (a) Prompt pretraining: The prompt encoder maps motion and force signals into ordered tokens and is pretrained through reconstruction. (b) Prompt-conditioned policy training: Online observations attend to a reference prompt from a different demonstration of the same behavior, conditioning action generation with auxiliary force supervision. (c) One-shot execution: A single demonstration enables in-context adaptation of contact-rich behaviors with a frozen policy.
Fig. 3: Benchmark tasks and one-shot transfer evaluation. Training demonstrations (left) specify wiping, rotation, and insertion behaviors. The policy is evaluated on unseen objects (right) with similar physical interaction patterns. A–C denote the unseen instances used for each task family.
Fig. 4: Real-world experimental setup for one-shot behavior transfer. Objects on the left are used for training. Objects on the right are unseen during training and used for one-shot evaluation.
Method
Wiping
Rotation
Insertion
Overall
A
B
C
A
B
C
A
B
C
DP-FT
16.7%
33.3%
41.7%
100.0%
66.7%
0.0%
75.0%
0.0%
33.3%
40.7%
π0.5 -FT
58.3%
33.3%
8.3%
100.0%
8.3%
8.3%
66.7%
50.0%
0.0%
37.0%
BPP*
83.3%
41.7%
50.0%
100.0%
91.7%
58.3%
66.7%
58.3%
41.7%
65.7%
CTP
83.3%
83.3%
66.7%
100.0%
100.0%
91.7%
83.3%
66.7%
33.3%
78.7%
TABLE I: One-shot transfer to unseen objects. For each task family, A–C match the instances in Fig. 3 .
Fig. 5: Behavior specification with contact prompts. (a) Behavior-conditioned score when changing only the reference demonstration to specify wiping intensity or cap rotation direction. (b) PCA of contact prompt embeddings, colored by task and behavior.
Fig. 6: Contact prompts specify graded wiping intensity. Solid curves show mean fingertip force over normalized time; shaded regions indicate ± 1 standard deviation. Force is the fingertip force magnitude after subtracting the grasping baseline. (a) Contact phase of wiping. (b) Light, medium, and heavy reference trajectories. (c) Executed force profiles with a position-only prompt (CTP-P). (d) Executed force profiles with CTP.
Fig. 7: Online contact grounds execution under height perturbations. Task success rates of CTP and a variant without online contact observations at nominal height and under vertical shifts.
Variant
Nominal
Height perturbed
Prompt representation
Raw concat
77.8%
52.8%
Encoder, from scratch
88.9%
61.1%
Pretrained encoder
97.2%
94.4%
Prompt injection
Mean pooling
80.6%
38.9%
TABLE II: Ablation of prompt representation and injection.
Generalizable contact-rich manipulation requires robots to preserve intended task behavior while adapting its physical realization to changing contact conditions. However, interaction forces can vary substantially with small changes in surface geometry, orientation, and friction, making policies trained directly on raw force measurements difficult to transfer beyond demonstrated conditions. We introduce FACE, a contact-factorized imitation learning framework that separates intended task behavior from environment-dependent contact factors. Our representation expresses interaction forces in normalized, contact-relative coordinates, while a learned contact-normal estimator and an online friction estimator infer the local contact normal and effective friction scale. Together, these estimators enable force observations to be encoded and policy outputs to be decoded into physical motion and force commands during execution. In this way, FACE adapts execution to current contact conditions while preserving the intended task behavior, without updating the policy parameters. We evaluate FACE on real-robot contact-rich manipulation under unseen variations in surface properties and geometry, demonstrating robust generalization across contact conditions through controlled comparisons with variants that adapt prior approaches to our setting. Videos and additional materials can be found on the project page: https://rcilab.khu.ac.kr/face.
Jiho Hong, Daeun Song, Sanghyun Kim +1
Kyung Hee University · Ewha Womans University · University of Central Florida
Keypoint tracking alone is insufficient for object interaction tasks such as sitting on a chair, wiping a board, or pushing furniture, where the robot can reach the correct pose without making meaningful physical contact with the object. We present CONTACTMIMIC, a learning framework that tracks explicit partlevel binary contact commands alongside keypoint trajectories. CONTACTMIMIC is made possible through the use of contact-following rewards and a trajectory augmentation scheme aimed at breaking the correlations between keypoint trajectories and contact labels. The resulting policy successfully decouples contact behavior from keypoint geometry, and achieves precise physical contact as well as contact-controllability (produce or suppress contact during deployment as desired). Simulation experiments across 10 diverse human-object interaction motions confirm that CONTACTMIMIC exhibits contact controllability that enables it to complete manipulation tasks without task-specific rewards, while also outperforming keypoint-only trackers on contact-relevant tasks. Ablations confirm the necessity of the proposed trajectory augmentation scheme and sim2real deployment validates contact controllability in the real world across 5 different motions. Video results are available on https://lixinyao11.github.io/contactmimic-page/.
Learning contact-rich dexterous manipulation from human demonstrations provides a scalable source of interaction data, yet transferring such skills to robots remains challenging due to unreliable human--robot correspondence. Existing human-to-robot transfer methods typically rely on visual appearance or motion similarity, which may associate similar motions with different contact states and force patterns. Tactile dynamics provide interaction-aware cues to distinguish manipulation processes with similar motions but different contact states. We introduce tactile-guided optimal transport (TacOT), a framework for human-to-robot contact-rich manipulation. TacOT leverages action--tactile dynamic time warping to identify human--robot demonstration correspondences with consistent interaction dynamics and uses these correspondences to guide soft optimal transport alignment in a shared policy representation space. This enables human demonstrations to provide contact-rich supervision for robot policy learning without requiring predefined frame-level human--robot pairing. Across four real-world dexterous manipulation tasks, TacOT improves closed-loop success rates over action-guided OT by up to 17 points on in-distribution tasks and 20 points under targeted human-to-robot out-of-distribution transfer. Further analyses show that tactile-guided correspondence selects demonstration pairs with more consistent contact dynamics and produces latent representations that better reflect interaction-state evolution. These results demonstrate that tactile dynamics provide an effective semantic signal for establishing reliable human-to-robot correspondence in contact-rich dexterous manipulation.
Xingting Li, Yifan Han, Zijian Lin +4
Shenzhen Ubiquitous Data Enabling Key Lab, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China. · School of Artificial Intelligence, Shanghai Jiao Tong University, Shanghai 200030, China. · Xspark AI, Shenzhen, China. +1