VLDB 2026 Research / reviewers in the wild / expert
Letian Fu
dblp:289/7912
· DBLP profile ↗
10ranked-venue papers
3as first author
10since 2021 · last 2025
—ORCID · none
Domains — the database's venue-derived domains; a paper can count in several
Artificial intelligence and machine learning · 10 · 3 first-author · 10 since 2021Systems, architecture and hardware · 7 · 2 first-author · 7 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2025 | OTTER: A Vision-Language-Action Model with Text-Aware Visual Feature ExtractionabstractVision-Language-Action (VLA) models aim to predict robotic actions based on visual observations and language instructions. Existing approaches require fine-tuning pre-trained vision-language models (VLMs) as visual and language features are independently fed into downstream policies, degrading the pre-trained semantic alignments. We propose OTTER, a novel VLA architecture that leverages these existing alignments through explicit, text-aware visual feature extraction. Instead of processing all visual features, OTTER selectively extracts and passes only task-relevant visual features that are semantically aligned with the language instruction to the policy transformer. This allows OTTER to keep the pre-trained vision-language encoders frozen. Thereby, OTTER preserves and utilizes the rich semantic understanding learned from large-scale pre-training, enabling strong zero-shot generalization capabilities. In simulation and real-world experiments, OTTER significantly outperforms existing VLA models, demonstrating strong zero-shot generalization to novel objects and environments. Video, code, checkpoints, and dataset: https://ottervla.github.io/. Fangchen Liu, Letian Fu, Tingfan Wu, Mustafa Mukadam, Jitendra Malik, Kenneth Y. Goldberg, Pieter Abbeel |
ICML | 3 |
| 2025 | Robo-DM: Data Management for Large Robot DatasetsabstractRecent results suggest that very large datasets of teleoperated robot demonstrations can be used to train transformer-based models that have the potential to generalize to new scenes, robots, and tasks. However, curating, distributing, and loading large datasets of robot trajectories, which typically consist of video, textual, and numerical modalities - including streams from multiple cameras - remains challenging. We propose Robo-DM, an efficient open-source cloud-based data management toolkit for collecting, sharing, and learning with robot data. With Robo-DM, robot datasets are stored in a self-contained format with Extensible Binary Meta Language (EBML). Robo-DM can significantly reduce the size of robot trajectory data, transfer costs, and data load time during training. Compared to the RLDS format used in OXE datasets, Robo-DM's compression saves space by up to 70x (lossy) and 3.5x (lossless). Robo-DM also accelerates data retrieval by load-balancing video decoding with memory-mapped decoding caches. Compared to LeRobot, a framework that also uses lossy video compression, Robo-DM is up to 50x faster when decoding sequentially. We physically evaluate a model trained by Robo-DM with lossy compression, a pick-and-place task, and In-Context Robot Transformer. Robo-DM uses 75x compression of the original dataset and does not suffer reduction in downstream task accuracy. Code and evaluation scripts can be found on website https://github.com/BerkeleyAutomation/fog_x. Kaiyuan Chen 0001, Letian Fu, Yunliang Chen 0001, Kush Hari, Ashwin Balakrishna, Ted Xiao, Pannag R. Sanketi, John Kubiatowicz, Kenneth Y. Goldberg |
ICRA | 2 |
| 2025 | Blox-Net: Generative Design-for-Robot-Assembly Using VLM Supervision, Physics Simulation, and a Robot with ResetabstractGenerative AI systems have shown impressive capabilities in creating text, code, and images. Inspired by the importance of research in industrial Design for Assembly, we introduce a novel problem: Generative Design-for-RobotAssembly (GDfRA). The task is to generate an assembly based on a natural language prompt (e.g., “giraffe”) and an image of available physical components, such as 3D-printed blocks. The output is an assembly, a spatial arrangement of these components, accompanied by instructions for a robot to build it. The output geometry must 1) resemble the requested object and 2) be reliably assembled by a 6 DoF robot arm with a suction gripper. We then present Blox-Net, a GDfRA system that combines generative vision language models with well-established methods in computer vision, simulation, perturbation analysis, motion planning, and physical robot experimentation to solve a class of GDfRA problems without human supervision. Blox-Net achieved a Top-1 accuracy of$\mathbf{6 3. 5 \%}$in the semantic accuracy of its designed assemblies. Six designs, after Blox-Net's automated pertubation redesign, were reliably assembled by a robot, achieving near-perfect success across$\mathbf{1 0}$consecutive assembly iterations with human intervention only during reset prior to assembly. The entire pipeline from the textual word to reliable physical assembly is performed without human intervention. Project Page: https://bloxnet.org/ Andrew Goldberg 0001, Kavish Kondap, Tianshuang Qiu, Zehan Ma, Letian Fu, Justin Kerr, Kaiyuan Chen 0001, Kuan Fang, Kenneth Y. Goldberg |
ICRA | 5 |
| 2025 | Safe and Efficient Navigation for Differential-Drive Robots in Dynamic Pedestrian EnvironmentsabstractDifferential-drive robots are widely used in dynamic pedestrian environments, such as hospitals, for time-sensitive tasks like medication delivery, which require high navigation efficiency to ensure timely arrivals. However, existing methods tend to overemphasize safety, resulting in overly conservative behaviors and prolonged navigation times, which in turn lead to reduced efficiency. To address this issue, this paper proposes a novel navigation framework that integrates a pedestrian risk map, modeled using asymmetric Gaussian distributions, into B-spline trajectory optimization. Rather than strictly avoiding high-risk regions, the method balances collision risk and trajectory length minimization, leading to more effective navigation. Additionally, multiple planning modes enhance adaptability in complex environments, ensuring both safety and efficiency. Furthermore, kinematic constraints specific to differential-drive robots are incorporated to ensure the feasibility of the generated trajectories. Simulations and real-world experiments validate the proposed method’s effectiveness in achieving safe and efficient navigation in dynamic pedestrian environments. The video is available at https://youtu.be/S9qJmXyPEzw. Letian Fu, Wanlei Li, Yunjiang Lou |
IROS | 2 |
| 2024 | A Touch, Vision, and Language Dataset for Multimodal AlignmentabstractTouch is an important sensing modality for humans, but it has not yet been incorporated into a multimodal generative language model. This is partially due to the difficulty of obtaining natural language labels for tactile data and the complexity of aligning tactile readings with both visual observations and language descriptions. As a step towards bridging that gap, this work introduces a new dataset of 44K in-the-wild visiontouch pairs, with English language labels annotated by humans (10%) and textual pseudo-labels from GPT-4V (90%). We use this dataset to train a vision-language-aligned tactile encoder for open-vocabulary classification and a touch-visionlanguage (TVL) model for text generation using the trained encoder. Results suggest that by incorporating touch, the TVL model improves (+29% classification accuracy) tactile-vision-language alignment over existing models trained on any pair of those modalities. Although only a small fraction of the dataset is human labeled, the TVL model demonstrates improved visual-tactile understanding over GPT-4V (+12%) and open-source vision-language models (+32%) on a new touch-vision understanding benchmark. Code, checkpoints and data are available on https: //tactile-vlm.github.io. Letian Fu, Gaurav Datta, Will Panitch, Jaimyn Drake, Joseph Ortiz, Mustafa Mukadam, Mike Lambeta, Roberto Calandra, Kenneth Y. Goldberg |
ICML | 1 |
| 2024 | Lifelong LERF: Local 3D Semantic Inventory Monitoring Using FogROS2abstractInventory monitoring in homes, factories, and retail stores relies on maintaining data despite objects being swapped, added, removed, or moved. We introduce Lifelong LERF, a method that allows a mobile robot with minimal compute to jointly optimize a dense language and geometric representation of its surroundings. Lifelong LERF maintains this representation over time by detecting semantic changes and selectively updating these regions of the environment, avoiding the need to exhaustively remap. Human users can query inventory by providing natural language queries and receiving a 3D heatmap of potential object locations. To manage the computational load, we use Fog-ROS2, a cloud robotics platform, to offload resource-intensive tasks. Lifelong LERF obtains poses from a monocular RGBD SLAM backend, and uses these poses to progressively optimize a Language Embedded Radiance Field (LERF) for semantic monitoring. Experiments with 3-5 objects arranged on a tabletop and a Turtlebot with a RealSense camera suggest that Lifelong LERF can persistently adapt to changes in objects with up to 91% accuracy. Adam Rashid, Chung Min Kim, Justin Kerr, Letian Fu, Kush Hari, Ayah Ahmad, Kaiyuan Chen 0001, Marcus Gualtieri, Christian Juette, Nan Tian, Liu Ren 0001, Kenneth Y. Goldberg |
ICRA | 4 |
| 2023 | Safe Self-Supervised Learning in Real of Visuo-Tactile Feedback Policies for Industrial InsertionabstractIndustrial insertion tasks are often performed repetitively with parts that are subject to tight tolerances and prone to breakage. Learning an industrial insertion policy in real is challenging as the collision between the parts and the environment can cause slippage or breakage of the part. In this paper, we present a safe self-supervised method to learn a visuo-tactile insertion policy that is robust to grasp pose variations. The method reduces human input and collisions between the part and the receptacle. The method divides the insertion task into two phases. In the first align phase, a tactile-based grasp pose estimation model is learned to align the insertion part with the receptacle. In the second insert phase, a vision-based policy is learned to guide the part into the receptacle. The robot uses force-torque sensing to achieve a safe self-supervised data collection pipeline. Physical experiments on the USB insertion task from the NIST Assembly Taskboard suggest that the resulting policies can achieve 45/45 insertion successes on 45 different initial grasp poses, improving on two baselines: (1) a behavior cloning agent trained on 50 human insertion demonstrations (1/45) and (2) an online RL policy (TD3) trained in real (0/45). Letian Fu, Lars Berscheid, Kenneth Y. Goldberg, Sachin Chitta |
ICRA | 1 |
| 2022 | LEGS: Learning Efficient Grasp Sets for Exploratory GraspingabstractWhile deep learning has enabled significant progress in designing general purpose robot grasping systems, there remain objects which still pose challenges for these systems. Recent work on Exploratory Grasping has formalized the problem of systematically exploring grasps on these adversarial objects and explored a multi-armed bandit model for identifying high-quality grasps on each object stable pose. However, these systems are still limited to exploring a small number or grasps on each object. We present Learned Efficient Grasp Sets (LEGS), an algorithm that efficiently explores thousands of possible grasps by maintaining small active sets of promising grasps and determining when it can stop exploring the object with high confidence. Experiments suggest that LEGS can identify a high-quality grasp more efficiently than prior algorithms which do not use active sets. In simulation experiments, we measure the gap between the success probability of the best grasp identified by LEGS, baselines, and the most-robust grasp (verified ground truth). After 3000 exploration steps, LEGS outperforms baseline algorithms on 10/14 and 25/39 objects on the Dex-Net Adversarial and EGAD! datasets respectively. We then evaluate LEGS in physical experiments; trials on 3 challenging objects suggest that LEGS converges to high-performing grasps significantly faster than baselines. See https://sites.google.com/view/LEGS-exp-grasping for supplemental material and videos. Letian Fu, Michael Danielczuk, Ashwin Balakrishna, Daniel S. Brown, Jeffrey Ichnowski, Eugen Solowjow, Kenneth Y. Goldberg |
ICRA | 1 |
| 2022 | Mechanical Search on Shelves using a Novel "Bluction" ToolabstractShelves are common in homes, warehouses, and commercial settings due to their storage efficiency. However, this efficiency comes at the cost of reduced visibility and accessibility. When looking from a side (lateral) view of a shelf, most objects will be fully occluded, resulting in a constrained lateral-access mechanical search problem. To address this problem, we introduce: (1) a novel bluction tool, which combines a thin pushing blade and a suction cup gripper, (2) a simulation pipeline and perception model that combine ray-casting with 2D Minkowski sums to efficiently generate target occupancy distributions, and (3) a novel search policy, which optimally reduces target object distribution support area using the bluction tool. Experimental data from 2000 simulated shelf trials and 18 trials with a physical Fetch robot suggest that a bluction tool can improve the average success rate by 26% in simulation and 67% in physical experiments over the highest-performing push-only policy. Michael Danielczuk, Chung Min Kim, Letian Fu, Zachary Tam, Jeffrey Ichnowski, Anelia Angelova, Brian Ichter, Kenneth Y. Goldberg |
ICRA | 4 |
| 2022 | Mechanical Search on Shelves with Efficient Stacking and Destacking of Objects
Letian Fu, Michael Danielczuk, Chung Min Kim, Zachary Tam, Jeffrey Ichnowski, Anelia Angelova, Brian Ichter, Kenneth Y. Goldberg |
ISRR | 2 |