Humanoid manipulation requires reusable arm skills, yet demonstrating every possible skill combination is impractical. We present Humanoid Semantic Mixture-of-Experts Diffusion Policy (HS-MoDP), which composes separately demonstrated arm skills through independent semantic routing over a shared expert pool. This design preserves arm-specific skill control while sharing action-generation parameters across arms. A semantic scheduler integrates the learned policy with an existing locomotion controller through alternating manipulation and repositioning stages, extending the effective workspace and enabling skill reuse across location changes. To acquire demonstrations of whole-body contact manipulation, we develop G1Exo, an isomorphic exoskeleton that provides direct joint-level control of arm configurations. Experiments on a Unitree G1 show stronger skill composition than the baselines. G1Exo enables more reliable contact teleoperation than end-effector VR-IK, and its demonstrations improve contact-skill learning across four policy architectures. For HS-MoDP, switching from VR-IK to G1Exo demonstrations raises full cabinet workflow success from 35% to 65%. All project hardware designs and source code will be released as open source after the review process.
Figures & tables
Fig. 1 : G1Exo hardware and joint mapping: (a) wearable exoskeleton; (b) corresponding joints on the Unitree G1; (c) exploded view of a modular rotary joint. Labels 1–7 denote shoulder pitch/roll/yaw, elbow, and wrist roll/pitch/yaw, respectively. G denotes gripper control via the handle trigger.
Fig. 2 : Photographs of whole-body contact manipulation teleoperated with G1Exo. The upper row shows the operator wearing G1Exo, and the lower row shows the corresponding G1 robot configurations: (a) hugging a basket against the chest and (b) holding a basket under the arm.
Fig. 3 : Overview of HS-MoDP. A frozen VLM-based semantic scheduler selects base and arm skills for locomotion and manipulation. Arm-specific skill representations condition the MoE diffusion policy, which generates separate action streams for the two arms. Solid and dashed arrows denote action flow and conditioning, respectively.
Fig. 4 : Autonomous HS-MoDP execution: (a) box pushing with toy placement; (b) four left–right combinations; (c) bimanual basket lifting. Panels (a,c) show chronological sequences; (b) shows separate runs.
Task
Success (%)
π0.5
GR00T
MoDE
Ours
Single-arm skill primitives
R: toy
80
65
60
75
R: block
90
100
75
95
L: box
100
100
100
100
L: pumpkin
85
90
80
95
TABLE I : Skill combination. Single-arm skill primitives and dual-arm combinations were evaluated separately.
Fig. 5 : Autonomous HS-MoDP execution: (a) forearm bottle gathering; (b) right-arm–torso basket cradling; (c) cabinet bottle retrieval with concurrent wrist-assisted door closing. Frames in each row proceed chronologically from left to right.
Fig. 6 : Teleoperation on whole-body contact tasks. (a) Success rates. (b) Successful-trial completion times. Small points show participant means; bars and large points show their mean, and error bars indicate the sample standard deviation across participants.
Task
π0.5
GR00T
MoDE
Ours
G
V
G
V
G
V
G
V
Individual skills
Bottle gathering
100
45
100
55
100
50
100
65
Handleless-basket cradle
80
15
70
10
65
10
85
15
L: retrieval
80
85
65
70
80
75
80
75
R: retrieval
75
80
70
75
75
70
80
70
TABLE II : Autonomous whole-body and mobile manipulation success rates (%) by demonstration source.
Fig. 7 : Ablation on box pushing and toy pick-and-place. Box and Toy denote separately evaluated unimanual skill primitives; Combined denotes their concurrent execution.
Diffusion-based policies have established a new standard for precise robotic manipulation but face a critical scalability bottleneck: high-performance models are computationally expensive, while lightweight alternatives often fail to generalize across diverse multi-task environments. Mixture-of-Experts (MoE) architectures offer a promising path to efficiency by activating only a subset of parameters. However, existing MoE routing mechanisms typically rely on low-level noise or latent statistics, ignoring the compositional nature of manipulation tasks. This can fragment reusable behaviors across experts, limiting interpretability and transferability. We introduce Semantically Structured Mixture-of-Experts Diffusion Policy (SMoDP) for compositional robotic manipulation, a framework that grounds expert specialization in semantic task structure. SMoDP leverages a lightweight, inference-time skill predictor, supervised by offline annotations from Vision-Language Models (VLMs), to route action chunks to experts specialized for specific behavioral phases. To ensure robust assignment, we propose a dual contrastive alignment strategy that grounds multi-modal observations in language-defined skill semantics (Inter-modal) while enforcing routing consistency across visually distinct but functionally related behaviors (Intra-modal). Our approach outperforms representative diffusion and MoE-based baselines on multi-task benchmarks with significantly improved parameter efficiency and demonstrates effective compositional transfer to novel tasks through parameter-efficient fine-tuning. Project website: https://deng-cy20.github.io/SMoDP/
Chengyu Deng, Guanqi Chen, Yizhou Chen +4
The University of Hong Kong · Southern University of Science and Technology
Achieving human-level dexterity in complex, unstructured environments requires the seamless integration of whole-body scene interaction and dexterous object manipulation skills. While existing physics-based controllers generate physically plausible behaviors in each domain, they largely address these two capabilities independently. In this paper, we present Co2Skill that integrates scene interaction and dexterous manipulation through a unified policy formulation. Built on a pretrained motion prior, the policy uses task and phase dependent observation masks to select information relevant to the current interaction goals. We introduce a goal-conditioned loco-manipulation curriculum that combines partial reference guidance for precision with exploration from varied initial states while allowing goal-directed execution beyond the demonstrated trajectories. We further introduce a cross-task curriculum that jointly trains individual skills and selected task sequences, preserving physical states across task boundaries and maintaining grasps during subsequent scene interactions. Together, these support sequential task execution and simultaneous scene interaction with object manipulation. We evaluate sitting, standing, climbing, stair traversal, and goal-directed manipulation, together with sequential execution and with random different conditions. Additionally, we demonstrate skill compositions in indoor environments, illustrating their integration within the same control formulation.
Jeonghwan Kim, Hyeonwoo Kim, Hanbyul Joo
Department of Computer Science, Seoul National University
Embodied visuomotor models, including Diffusion Policy (DP) and Vision-Language-Action (VLA) models, have demonstrated promising performance on robotic manipulation benchmarks. However, their potential remains fundamentally constrained by the scarcity of large-scale embodied trajectory datasets, leading to insufficient compositional generalization in out-of-distribution (OOD) scenarios with limited capability to capture reusable skill structures. To address this limitation, we propose Skill-Based Memory (SkillMemo) framework that implicitly decomposes long-horizon demonstrations into latent atomic skills and integrates skill-level features into a dynamic episodic memory bank for solving compositional tasks. Specifically, we first introduce an expert-guided trajectory segmentation module built upon a Mixture-of-Experts (MoE) architecture, which implicitly partitions trajectories into distinct skill primitives represented by learned gating coefficients. We further design a skill-level episodic memory architecture that stores compact skill representations as retrievable key-value pairs. During inference, the memory bank retrieves the most relevant skill primitives which are subsequently fused with the model's current gating distribution, providing a robust contextual prior to refine action predictions. Extensive experiments on the simulation benchmark and real-world manipulation tasks demonstrate that SkillMemo consistently enhances both DP and VLA backbones, achieving state-of-the-art performance and outperforming π0.5, while exhibiting strong compositional generalization to unseen task configurations.
Changyuan Wang, Chubin Zhang, Zhenyu Wu +8
Shenzhen International Graduate School, Tsinghua University · Department of Automation, Tsinghua University · Nanyang Technological University +1