arXiv subjects

Iok Tong Lei

Publications and source records attributed to Iok Tong Lei.

4 recordsLinked to original sources

arXiv2026

ACE: Agentic Control for Embodied Manipulation via Zero-shot Workflow Reasoning

General-purpose manipulation requires both semantic reasoning over task constraints and reliable execution of contact-rich actions. We present ACE, an agentic manipulation harness that composes a high-level language agent with a reusable mask-conditioned visuomotor policy. Given an open-ended instruction, the agent solves semantic constraints, binds objects to destination roles, and decomposes the task into executable transfers represented by tracked pick-and-place masks. Execution feedback supports outcome assessment, re-grounding, and retry, while persistent object and task context preserves earlier associations when manipulation changes visible cues. We evaluate ACE on two physical multi-step tabletop tasks, Semantic Formula Assembly and Constraint Retrieval. The visuomotor policy is trained only on generic pick-and-place demonstrations and reused without complete demonstrations of either evaluation task, enabling task-level zero-shot composition. Across 20 randomized trials per task, ACE achieves 70% and 80% success, respectively, compared with 55% and 70% without persistent context. These results suggest that an agentic harness can extend a primitive-trained manipulation policy to semantically distinct tasks through explicit object-destination interfaces and closed-loop execution feedback.

cs.RO↗

arXiv2026

XS-VLA: Teaching Tiny Vision-Language-Action Models with Spatial Supervision and Demonstration Conditioning

How can richer training supervision improve robot control while keeping the deployed policy compact? We present XS-VLA, a staged training framework using teacher-derived spatial labels and demonstration-conditioned action learning. Coarse-Grained Spatial Distillation (CSD) initializes the backbone through an auxiliary region-label task. Latent Flow Matching (LFM) then conditions an action-space velocity field on a demonstration latent, using KL regularization while jointly optimizing the backbone and action modules. The deployed policy contains 243.99M parameters and operates without the teacher or posterior encoder. XS-VLA achieves 90.25% average LIBERO success in each of two training seeds, compared with 86.00% for a SmolVLA-256M base trained under our settings. Ablations examine both training stages through matched image pretraining and Huber/MSE controls. On three Mobile ALOHA tasks, average strict success increases from 21.7% to 65.0%. These results demonstrate the control utility of auxiliary representation initialization and regularized demonstration-conditioned flow learning for compact VLA~policies.

cs.RO↗

arXiv2026

OpenSPM: An Environment-Transferable Robotic Key Spatial Pose Memory and Closed-Loop High-Frequency Flow-Matching Action Generation Model

Open-environment tabletop robotic manipulation requires systems to possess semantic understanding, precise geometric pose estimation, and high-frequency action generation. While end-to-end vision-language-action (VLA) models excel at semantic generalization, they often lack explicit geometric constraints for fine-grained tasks and require costly training. To bridge the gap between high-level semantics and low-level physical execution, we propose OpenSPM, an open environment spatial persistent memory framework consisting of spatial pose memory and flow-matching action generation model. OpenSPM first leverages semantically conditioned 3D perception and Kalman filtering to track continuous 6D poses. It then extracts key spatial poses from human demonstrations, keeping them as transferable, object-centric spatial persistent memory entries. During inference, OpenSPM retrieves relevant memory entries in terms of natural language instructions, transfers the spatial poses to new scenes using SE(3) transformations, and generates high-frequency action chunks via a lightweight conditional flow-matching model. Combined with real-time proprioceptive state feedback and terminal residual correction, the system effectively suppresses trajectory error accumulation. Evaluated on ten LIBERO-GOAL tasks, OpenSPM achieves an 85.6% success rate and an equivalent control frequency of 1033.3 Hz, while requiring minimal inference AI computing power. Extensive ablations illustrate that structured spatial persistent memory and closed-loop residual correction play a crucial role in reliable, high-frequency robotic manipulation.

cs.RO↗

arXiv2025

Hint of Pseudo Code (HoPC): Zero-Shot Step by Step Pseudo Code Reasoning Prompting

Prompting a language model (LM) is an increasingly important research topic for better utilization of large language models (LLMs). While simple prompting is effective for single-step questions, it fails to activate the correct knowledge path for multi-step reasoning tasks consistently. The few-shot Chain of Thought (CoT), serves as an advanced prompting strategy that explains and demonstrates the reasoning process to the LLM, outperforming simple prompting in challenging reasoning tasks such as arithmetic and common-sense reasoning. The Program of Thought (PoT) aims to generate text and programming language solutions for multi-step reasoning problems. In zero-shot CoT, the prompt is simply ``Let's think step by step'', which is overly simplistic and does not adequately demonstrate a robust reasoning process for complex reasoning challenges. Additionally, PoT requires an extra interpreter to execute the answer and struggles with semantic reasoning problems like StrategyQA. This paper introduces a novel Hint of Pseudo Code (HoPC) prompting technique that does not require extra interpreter as in PoT and incorporates a more powerful zero-shot problem decomposition and semantic code reasoning capabilities than zero-shot CoT. It consists of three components: problem decomposition, semantic code reasoning, and answer extraction. We prompt these components as hints in a sequential, step by step manner, making it easy to tailor and explain for various tasks.

cs.AI↗