Adapt as You Say: Online Interactive Bimanual Skill Adaptation via Human Language Feedback
Authors: Zhuo Li, Dianxi Li, Tao Teng, Quentin Rouxel, Zhipeng Dong, Dennis Hong, Darwin Caldwell, Fei Chen
Organizations: Collaborative and Versatile Robots (CLOVER) Laboratory, T-Stone Robotics Institute, The Chinese University of Hong Kong, Hong Kong · Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, USA · Department of Advanced Robotics, Istituto Italiano di Tecnologia, Genoa, Italy
Developing general-purpose robots capable of autonomously operating in human living environments requires the ability to adapt to continuously evolving task conditions. However, adapting high-dimensional coordinated bimanual skills to novel task variations at deployment remains a fundamental challenge. In this work, we present BiSAIL (Bimanual Skill Adaptation via Interactive Language), a novel framework that enables zero-shot online adaptation of offline-learned bimanual skills through interactive language feedback. The key idea of BiSAIL is to adopt a hierarchical reason-then-modulate paradigm, which first infers generalized adaptation objectives from multimodal task variations, and then adapts bimanual motions via diffusion modulation to achieve the inferred objectives. Extensive real-robot experiments across six bimanual tasks and two dual-arm platforms demonstrate that BiSAIL significantly outperforms existing methods in human-in-the-loop adaptability, task generalization and cross-embodiment scalability. This work enables the development of adaptive bimanual assistants that can be flexibly customized by non-expert users via intuitive verbal corrections. Experimental videos and code are available at https://rip4kobe.github.io/BiSAIL/.
Figures & tables
Fig. 1: Illustration of Online Interactive Bimanual Skill Adaptation. (a) Offline-learned bimanual skills often encounter diverse task variations when deployed in human-centric environments. (b) BiSAIL enables online interactive adaptation of learned bimanual skills through human language feedback, facilitating zero-shot generalization to unseen task variations.
Fig. 2: An Overview of BiSAIL. (1) High-level Adaptation Objective Reasoning: ESA-CoT infers a structured bimanual adaptation objective from multimodal task variations; (2) Mid-level Bimanual Motion Modulation: Initial motion proposals sampled from BMP are first iteratively optimized toward the adaptation objective, and then modulated through compositional sampling to enforce dual-arm coordination and task compatibility; (3) Low-level Skill Adaptation Refinement: A closed-loop reflection mechanism evaluates post-adaptation outcomes to refine both the adaptation objective and the resulting bimanual motion.
Fig. 3: Problem Formulation. We formulate the online interactive bimanual skill adaptation as a constrained probabilistic optimization problem.
Fig. 4: Bimanual Skill Adaptation Objective Reasoning. ESA-CoT enables the objective reasoning through a structured chain-of-thought, augmented with robot embodied information and bimanual domain knowledge.
Fig. 5: Bimanual Motion Prior Learning. BMP is implemented as an unconditional diffusion model with Transformer encoder-only architecture.
Fig. 6: BMP Dataset Generation. Self-supervised bimanual motion data generation pipeline for training BMP.
q(τ)=∑i=1Mexp(ζR(τi;l,o))exp(ζR(τ;l,o))
Algorithm 1 Online Bimanual Motion Modulation
Fig. 7: Bimanual Motion Modulation via Compositional Sampling. We employ MCMC sampling to optimize the joint motion distribution over adaptation objective, task-specific policy and coordination constraint.
Fig. 8: Experimental Setup. (a) Overview of the dual-arm robot platform. (b) Evaluation tasks comprising six bimanual scenarios.
Fig. 9: Qualitative Results of Adaptation Objective Reasoning. ESA-CoT infers feasible rewards and coordination across diverse task variations.
Method
RA (%) ↑
ER (%) ↑
ROUGE-L ↑
Few-shot Prompting
25.3 ± 1.2
17.6 ± 1.5
N/A
Vanilla CoT
44.5 ± 0.6
38.7 ± 0.4
0.55 ± 0.08
ESA-COT (w/o UIU)
85.7 ± 0.6
79.4 ± 0.7
0.88 ± 0.05
ESA-COT (w/o TCA)
80.1 ± 0.7
75.7 ± 0.2
0.77 ± 0.03
ESA-COT (w/o EA)
58.7 ± 0.5
49.6 ± 1.1
0.68 ± 0.06
ESA-COT (w/o AOR)
75.4 ± 0.7
69.7 ± 0.9
0.67 ± 0.07
TABLE I: Quantitative results of adaptation objective reasoning
Method
FID ↓
Diversity ↑
Smoothness ↓
Time (s)
U-Net
20.61 ± 0.07
0.58
0.04 ± 0.01
0.10
Transformer (Dec-only)
13.54 ± 0.13
0.73
0.12 ± 0.03
0.27
Transformer (Enc-Dec)
3.21 ± 0.05
0.94
0.03 ± 0.04
0.51
BMP (w/o auxiliary)
3.73 ± 0.02
0.91
0.09 ± 0.03
0.16
BMP (Ours)
2.48 ± 0.02
0.93
0.02 ± 0.06
0.16
TABLE II: Quantitative results of BMP evaluation
Fig. 10: Qualitative Results of Online Bimanual Motion Modulation. Left: Task variation and original bimanual motion distribution. Right: Comparison of modulated motions from various baselines. Our method (h) achieves the best balance of intent alignment, task compatibility, and dual-arm coordination.
Fig. 11: Qualitative Results of BMP Evaluation. (a)–(c): Motions sampled from task-specific DP under different settings. (d)–(e): Motions sampled from BMP architectural variants. (f): Our BMP generates motion proposals that balance spatial diversity, temporal smoothness, and sampling efficiency.
Fig. 12: Comparison of MCMC and CG sampling. Bimanual motions are projected to 2D using PCA and visualized via KDE [ 36 ] . (a) Original component distributions. (b) CG sampling produces OOD motions. (c) Our MCMC sampling yields motions near the intersection of all components, avoiding distribution shift.
Fig. 13: Real Robot Experiment Results. BiSAIL demonstrates flexible and generalizable online interactive bimanual skill adaptation across diverse task variations, manipulation scenarios and coordination categories.
Fig. 14: Comparison with End-to-End Adaptation Baseline. (a) In ID settings, BiSAIL and YAY show comparable IA error. (b) In OOD settings, YAY shows a marked increase in IA error, while BiSAIL maintains low error.
Method
IA (%) ↑
TA (%) ↑
CS (%) ↑
Post-hoc Ranking
53.2 ± 1.1
40.5 ± 1.4
38.9 ± 2.2
BMM (w/ MPPI)
65.4 ± 1.7
68.2 ± 1.5
63.6 ± 2.8
BMM (w/ CEM)
71.6 ± 1.3
72.4 ± 2.1
70.2 ± 1.2
BMM (w/o MCMC)
76.5 ± 2.4
55.7 ± 2.6
58.3 ± 2.2
BMM (w/ CG, g=300)
78.9 ± 1.5
75.8 ± 1.3
72.1 ± 1.4
BMM (w/ CG, g=500)
64.7 ± 1.6
62.3 ± 2.7
64.5 ± 1.2
TABLE III: Quantitative results for online bimanual motion modulation
Generalizable bimanual robotic manipulation requires a reusable task prior that can persist across increasingly diverse tasks, objects, scenes, embodiments, and execution conditions, thus avoiding the prohibitive cost of large-scale teleoperated demonstrations and policy retraining. In this work, we present VLBiMan++, an extended framework that expands the generalization boundary of vision-language anchored one-shot bimanual manipulation. Starting from a single human demonstration, VLBiMan++ performs task-aware decomposition to identify reusable and adaptable skill components, and employs vision-language grounded geometric adaptation to transfer these skills to novel configurations without retraining. Building on this foundation, we systematically extend generalization along five dimensions: task generalization through diverse and long-horizon skill compositions; object generalization across unseen categories, varying geometries, and more complex articulated or deformable objects; scene generalization under clutter, occlusion, and dynamic interference; embodiment generalization across heterogeneous dual-arm robotic platforms; and deployment generalization through prolonged closed-loop execution under repeated external perturbations. To support this broader scope, we further introduce object-state-aware adaptation and lightweight trajectory optimization mechanisms that accommodate changes beyond simple rigid 6-DoF pose variations while preserving reliable bimanual coordination. Extensive real-world experiments demonstrate that VLBiMan++ maintains strong task success and adaptation capability across these increasingly challenging settings. Overall, VLBiMan++ advances one-shot bimanual manipulation from demonstrating isolated transferability toward a more systematic and scalable framework for generalization across tasks, objects, scenes, embodiments, and long-term deployment conditions.
Huayi Zhou, Wei Gao, Yiyang Han +2
Guangdong Provincial Key Laboratory of Visual Media and Multidimensional Intelligence, College of Computer Science and Software Engineering, Shenzhen University
Robust manipulation under uncertain object dynamics and geometry remains a core challenge in real-world robotics. Policies trained under fixed assumptions often degrade when object mass, friction, scale, or shape vary. Embedding-based adaptation methods such as Rapid Motor Adaptation (RMA) address this by conditioning actions on latent representations of environment dynamics inferred from interaction history. We investigate whether this paradigm scales from single arm settings to coordinated bimanual manipulation, where higher dimensional control, coupled contacts, and shared object forces introduce additional complexity. We evaluate bimanual RMA on three contact-rich ManiSkill tasks with randomized YCB object properties. Bimanual RMA, using observation-action history and dual wrist depth images, retains privileged policy performance on bimanual picking and lifting, while an otherwise matched stationary PPO policy without latent conditioning achieves low success; all methods remain limited on long-horizon stacking. We further demonstrate direct sim-to-real transfer on a dual Franka lifting task without real-world finetuning. Together, these results suggest that latent conditioning provides useful structure for scaling robust control to coordinated bimanual systems, while longer horizon tasks require additional temporal structure.
Seung-Bin Joo, Alessandro Albini, Luca Wiehe +3
Visual Geometry Group, University of Oxford, Oxford, United Kingdom · Soft Robotics Lab, Oxford Robotics Institute, University of Oxford, Oxford, United Kingdom · Technical University of Munich, Munich, Germany +1
Large Language Models (LLMs) have emerged as powerful reasoning engines for embodied control. In particular, In-Context Learning (ICL) enables off-the-shelf, text-only LLMs to predict robot actions without any task-specific training while preserving their generalization capabilities. Applying ICL to bimanual manipulation remains challenging as the high-dimensional joint action space and tight inter-arm coordination constraints rapidly overwhelm standard context windows. To address this, we introduce BiCICLe (Bimanual Coordinated In-Context Learning), the first framework that enables standard LLMs to perform few-shot bimanual manipulation without fine-tuning. BiCICLe frames bimanual control as a multi-agent leader-follower problem, decoupling the action space into sequential, conditioned single-arm predictions. Evaluated on 13 tasks from the TWIN benchmark, BiCICLe achieves 70.5% average success rate, outperforming the best training-free baseline by 6.1 percentage points and surpassing most supervised methods. We also demonstrate superior real-world performance on 3 tasks without hardware-specific retraining. The project page is available at https://alesspalma.github.io/bicicle
Alessio Palma, Indro Spinelli, Vignesh Prasad +4
Sapienza University of Rome, Italy · TU Darmstadt, Germany · Hessian.AI, Germany