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Nicholas Roy

60 accepted papers

2026

Autonomous Search for Sparsely Distributed Visual Phenomena through Environmental Context Modeling

ICRA 2026poster

Autonomous underwater vehicles (AUVs) are increasingly used to survey coral reefs, yet efficiently locating specific coral species of interest remains difficult: target species are often sparsely distributed across the reef, and an AUV with limited battery life cannot afford to search everywhere. Wh…

2026

Beyond Waypoints: Semantic-Centric Autonomy with Unreliable Maps through Learned Abstractions

ICRA 2026poster

Autonomous navigation that relies on precise metric maps is inherently fragile to environmental changes and mapping inaccuracies. These discrepancies often lead to failures in localization and path planning, as the robot's internal representation of the world no longer matches reality. We propose an…

Cited by 0Scholar
2026

Far-Field Image-Based Traversability Mapping for a Priori Unknown Natural Environments

ICRA 2026poster

While navigating unknown environments, robots rely primarily on proximate features for guidance in decision making, such as depth information from lidar or stereo to build a costmap, or local semantic information from images. The limited range over which these features can be used may result in poor…

Cited by 0SourceScholar
2026

Structured Interfaces for Automated Reasoning with 3D Scene Graphs

ICRA 2026poster

In order to provide a robot with the ability to understand and react to a user's natural language inputs, the natural language must be connected to the robot's underlying representations of the world. Recently, large language models (LLMs) and 3D scene graphs (3DSGs) have become a popular choice for…

2025

Anomalies-by-Synthesis: Anomaly Detection using Generative Diffusion Models for Off-Road Navigation

ICRA 2025

In order to navigate safely and reliably in off-road and unstructured environments, robots must detect anomalies that are out-of-distribution (OOD) with respect to the training data. We present an analysis-by-synthesis approach for pixel-wise anomaly detection without making any assumptions about th

Cited by 2SourceScholar
2025

FORGE: Force-Guided Exploration for Robust Contact-Rich Manipulation Under Uncertainty

RA-L 2025

We present FORGE, a method for sim-to-real transfer of force-aware manipulation policies in the presence of significant pose uncertainty. During simulation-based policy learning, FORGE combines a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">force

Cited by 31SourceScholar
2025

Far-Field Image-Based Traversability Mapping for a Priori Unknown Natural Environments

RA-L 2025

While navigating unknown environments, robots rely primarily on proximate features for guidance in decision making, such as depth information from lidar to build a costmap, or local semantic information from images. The limited range over which these features can be used may result in poor robot beh

Cited by 2SourcecodeScholar
2025

PIETRA: Physics-Informed Evidential Learning for Traversing Out-of-Distribution Terrain

RA-L 2025

Self-supervised learning is a powerful approach for developing traversability models for off-road navigation, but these models often struggle with inputs unseen during training. Existing methods utilize techniques like evidential deep learning to quantify model uncertainty, helping to identify and a

Cited by 25SourceScholar
2025

Streaming Flow Policy: Simplifying diffusion/flow-matching policies by treating action trajectories as flow trajectories

CoRL 2025oral

Recent advances in diffusion$/$flow-matching policies have enabled imitation learning of complex, multi-modal action trajectories. However, they are computationally expensive because they sample a *trajectory of trajectories*—a diffusion$/$flow trajectory of action trajectories. They discard interme…

Cited by 0SourceScholar
2024

Adaptive multi-altitude search and sampling of sparsely distributed natural phenomena

IROS 2024poster

In this paper, we propose a novel method for autonomously seeking out sparsely distributed targets in an unknown underwater environment. Our Sparse Adaptive Search and Sample (SASS) algorithm mixes low-altitude observations of discrete targets with high-altitude observations of the surrounding subst…

Cited by 0SourceScholar
2024

AutoTAMP: Autoregressive Task and Motion Planning with LLMs as Translators and Checkers

ICRA 2024poster

For effective human-robot interaction, robots need to understand, plan, and execute complex, long-horizon tasks described by natural language. Recent advances in large language models (LLMs) have shown promise for translating natural language into robot action sequences for complex tasks. However, e…

Cited by 142SourcecodeScholar
2024

Deep Evidential Uncertainty Estimation for Semantic Segmentation under Out-Of-Distribution Obstacles

ICRA 2024poster

In order to navigate safely and reliably in novel environments, robots must estimate perceptual uncertainty when confronted with out-of-distribution (OOD) obstacles not seen in training data. We present a method to accurately estimate pixel-wise uncertainty in semantic segmentation without requiring…

Cited by 14SourceScholar
2024

Generating Sparse Probabilistic Graphs for Efficient Planning in Uncertain Environments

ICRA 2024poster

Environments with regions of uncertain traversability can be modeled as roadmaps with probabilistic edges for efficient planning under uncertainty. We would like to generate roadmaps that enable planners to efficiently find paths with expected low costs through uncertain environments. The roadmap mu…

Cited by 2SourceScholar
2024

How to Train Your Neural Control Barrier Function: Learning Safety Filters for Complex Input-Constrained Systems

ICRA 2024poster

Control barrier functions (CBFs) have become popular as a safety filter to guarantee the safety of nonlinear dynamical systems for arbitrary inputs. However, it is difficult to construct functions that satisfy the CBF constraints for high relative degree systems with input constraints. To address th…

Cited by 34SourceScholar
2024

PRompt Optimization in Multi-Step Tasks (PROMST): Integrating Human Feedback and Heuristic-based Sampling

EMNLP 2024main

Prompt optimization aims to find the best prompt to a large language model (LLM) for a given task. LLMs have been successfully used to help find and improve prompt candidates for single-step tasks. However, realistic tasks for agents are multi-step and introduce new challenges: (1) Prompt content is…

2024

Scalable Multi-Robot Collaboration with Large Language Models: Centralized or Decentralized Systems?

ICRA 2024poster

A flurry of recent work has demonstrated that pre-trained large language models (LLMs) can be effective task planners for a variety of single-robot tasks. The planning performance of LLMs is significantly improved via prompting techniques, such as in-context learning or re-prompting with state feedb…

Cited by 97SourcecodeScholar
2023

A Sampling-Based Approach for Heterogeneous Coalition Scheduling with Temporal Uncertainty

RSS 2023poster

Scheduling algorithms for real-world heterogeneous multi-robot teams must be able to reason about temporal uncertainty in the world model in order to create plans that are tolerant to the risk of unexpected delays. To this end, we present a novel sampling-based risk-aware approach for solving Hetero…

Cited by 4SourcePDFScholar
2023

Autonomous Navigation, Mapping and Exploration with Gaussian Processes

RSS 2023poster

Navigating and exploring an unknown environment is a challenging task for autonomous robots, especially in complex and unstructured environments. We propose a new framework that can simultaneously accomplish multiple objectives that are essential to robot autonomy including identifying free space fo…

Cited by 13SourcePDFScholar
2023

Scenario Diffusion: Controllable Driving Scenario Generation With Diffusion

NeurIPS 2023poster

Automated creation of synthetic traffic scenarios is a key part of scaling the safety validation of autonomous vehicles (AVs). In this paper, we propose Scenario Diffusion, a novel diffusion-based architecture for generating traffic scenarios that enables controllable scenario generation. We combine…

Cited by 35SourcePDFScholar
2022

A Hierarchical Deliberative-Reactive System Architecture for Task and Motion Planning in Partially Known Environments

ICRA 2022poster

We describe a task and motion planning architecture for highly dynamic systems that combines a domain-independent sampling-based deliberative planning algorithm with a global reactive planner. We leverage the recent development of a reactive, vector field planner that provides guarantees of reachabi…

Cited by 3SourceScholar
2022

Convex Iteration for Distance-Geometric Inverse Kinematics

RA-L 2022

Inverse kinematics (IK) is the problem of finding robot joint configurations that satisfy constraints on the position or pose of one or more end-effectors. For robots with redundant degrees of freedom, there is often an infinite, nonconvex set of solutions. The IK problem is further complicated when

Cited by 31SourcecodeScholar
2022

Hierarchical Planning for Heterogeneous Multi-Robot Routing Problems via Learned Subteam Performance

RA-L 2022

This letter considersa particular class of multi-robot task allocation problems, where tasks correspond to heterogeneous multi-robot routing problems defined on different areas of a given environment. We present a hierarchical planner that breaks down the complexity of this problem into two subprobl

Cited by 26SourceScholar
2022

Tell me why! Explanations support learning relational and causal structure

ICML 2022spotlight

Inferring the abstract relational and causal structure of the world is a major challenge for reinforcement-learning (RL) agents. For humans, language{—}particularly in the form of explanations{—}plays a considerable role in overcoming this challenge. Here, we show that language can play a similar ro…

2021

Learning and Planning for Temporally Extended Tasks in Unknown Environments

ICRA 2021poster

We propose a novel planning technique for satisfying tasks specified in temporal logic in partially revealed environments. We define high-level actions derived from the environment and the given task itself, and estimate how each action contributes to progress towards completing the task. As the map…

Cited by 26SourceScholar
2021

MultiViewStereoNet: Fast Multi-View Stereo Depth Estimation using Incremental Viewpoint-Compensated Feature Extraction

ICRA 2021poster

We propose a novel learning-based method for multi-view stereo (MVS) depth estimation capable of recovering depth from images taken from known, but unconstrained, views. Existing MVS methods extract features from each image independently before projecting them onto a set of planes at candidate depth…

Cited by 4SourceScholar
2021

Online High-Level Model Estimation for Efficient Hierarchical Robot Navigation

IROS 2021poster

We would like to enable a robot to navigate efficiently and robustly in known, structured environments that are large enough to cause traditional planning approaches to incur considerable computational cost. Hierarchical planners are a promising way to increase planning efficiency in such environmen…

Cited by 2SourceScholar
2021

Reactive Task and Motion Planning under Temporal Logic Specifications

ICRA 2021poster

We present a task-and-motion planning (TAMP) algorithm robust against a human operator's cooperative or adversarial interventions. Interventions often invalidate the current plan and require replanning on the fly. Replanning can be computationally expensive and often interrupts seamless task executi…

Cited by 54SourceScholar
2021

Toward Robust and Efficient Online Adaptation for Deep Stereo Depth Estimation

ICRA 2021poster

Although deep neural networks have achieved state-of-the-art performance for stereo depth estimation, they can suffer from a significant drop in accuracy when tested on images from novel domains. Recent work has shown that self-supervised online adaptation is a promising approach for closing this pe…

Cited by 6SourceScholar
2021

VoluMon: Weakly-Supervised Volumetric Monocular Estimation with Ellipsoid Representations

IROS 2021poster

Deep learning approaches to estimating 3D object pose and geometry present an attractive alternative to online estimation techniques, which can suffer from significant estimation latency. However, a practical hurdle to training state-of-the-art deep 3D bounding box estimators is collecting a suffici…

Cited by 2SourceScholar
2020

A Smooth Representation of Belief over SO(3) for Deep Rotation Learning with Uncertainty

RSS 2020poster

Accurate rotation estimation is at the heart of robot perception tasks such as visual odometry and object pose estimation. Deep neural networks have provided a new way to perform these tasks, and the choice of rotation representation is an important part of network design. In this work, we present a…

2020

Enabling Topological Planning with Monocular Vision

ICRA 2020poster

Topological strategies for navigation meaningfully reduce the space of possible actions available to a robot, allowing use of heuristic priors or learning to enable computationally efficient, intelligent planning. The challenges in estimating structure with monocular SLAM in low texture or highly cl…

Cited by 9SourceScholar
2020

Learned Sampling Distributions for Efficient Planning in Hybrid Geometric and Object-Level Representations

ICRA 2020poster

We would like to enable a robotic agent to quickly and intelligently find promising trajectories through structured, unknown environments. Many approaches to navigation in unknown environments are limited to considering geometric information only, which leads to myopic behavior. In this work, we sho…

Cited by 19SourceScholar
2020

Visual Prediction of Priors for Articulated Object Interaction

ICRA 2020poster

Exploration in novel settings can be challenging without prior experience in similar domains. However, humans are able to build on prior experience quickly and efficiently. Children exhibit this behavior when playing with toys. For example, given a toy with a yellow and blue door, a child will explo…

Cited by 6SourceScholar
2019

Inferring Task Goals and Constraints using Bayesian Nonparametric Inverse Reinforcement Learning

CoRL 2019

Recovering an unknown reward function for complex manipulation tasks is the fundamental problem of Inverse Reinforcement Learning (IRL). Often, the recovered reward function fails to explicitly capture implicit constraints (e.g., axis alignment, force, or relative alignment) between the manipulator,

Cited by 0SourcePDFScholar
2019

Information-Guided Robotic Maximum Seek-and-Sample in Partially Observable Continuous Environments

RA-L 2019

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Cited by 52SourceScholar
2019

Robust Object-based SLAM for High-speed Autonomous Navigation

ICRA 2019poster

We present Robust Object-based SLAM for High-speed Autonomous Navigation (ROSHAN), a novel approach to object-level mapping suitable for autonomous navigation. In ROSHAN, we represent objects as ellipsoids and infer their parameters using three sources of information - bounding box detections, image…

Cited by 94SourceScholar
2019

Task-Conditioned Variational Autoencoders for Learning Movement Primitives

CoRL 2019

Consider a task such as pouring liquid from a cup into a container. Some parameters, such as the location of the pour, are crucial to task success, while others, such as the length of the pour, can exhibit larger variation. In this work, we propose a method that differentiates between specified task

Cited by 0SourcePDFScholar
2018

Approximate Distributed Spatiotemporal Topic Models for Multi-Robot Terrain Characterization

IROS 2018poster

Unsupervised learning techniques, such as Bayesian topic models, are capable of discovering latent structure directly from raw data. These unsupervised models can endow robots with the ability to learn from their observations without human supervision, and then use the learned models for tasks such…

Cited by 10SourceScholar
2018

Deep Inference for Covariance Estimation: Learning Gaussian Noise Models for State Estimation

ICRA 2018poster

We present a novel method of measurement covariance estimation that models measurement uncertainty as a function of the measurement itself. Existing work in predictive sensor modeling outperforms conventional fixed models, but requires domain knowledge of the sensors that heavily influences the accu…

Cited by 78SourceScholar
2018

Efficient Planning for Near-Optimal Compliant Manipulation Leveraging Environmental Contact

ICRA 2018poster

Path planning classically focuses on avoiding environmental contact. However, some assembly tasks permit contact through compliance, and such contact may allow for more efficient and reliable solutions under action uncertainty. But, optimal manipulation plans that leverage environmental contact are…

Cited by 24SourceScholar
2018

Grounding Robot Plans from Natural Language Instructions with Incomplete World Knowledge

CoRL 2018

Our goal is to enable robots to interpret and execute high-level tasks conveyed using natural language instructions. For example, consider tasking a household robot to, “prepare my breakfast”, “clear the boxes on the table” or “make me a fruit milkshake”. Interpreting such underspecified instruction

Cited by 0SourcePDFScholar
2018

Learning over Subgoals for Efficient Navigation of Structured, Unknown Environments

CoRL 2018

We propose a novel technique for efficiently navigating unknown environments over long horizons by learning to predict properties of unknown space. We generate a dynamic action set defined by the current map, factor the Bellman Equation in terms of these actions, and estimate terms, such as the prob

Cited by 0SourcePDFScholar
2018

Near-optimal Irrevocable Sample Selection for Periodic Data Streams with Applications to Marine Robotics

ICRA 2018poster

We consider the task of monitoring spatiotemporal phenomena in real-time by deploying limited sampling resources at locations of interest irrevocably and without knowledge of future observations. This task can be modeled as an instance of the classical secretary problem. Although this problem has be…

Cited by 11SourceScholar
2018

Sensor-Based Reactive Execution of Symbolic Rearrangement Plans by a Legged Mobile Manipulator

IROS 2018poster

We demonstrate the physical rearrangement of wheeled stools in a moderately cluttered indoor environment by a quadrupedal robot that autonomously achieves a user's desired configuration. The robot's behaviors are planned and executed by a three layer hierarchical architecture consisting of: an offli…

Cited by 28SourceScholar
2018

Sensor-Based Reactive Symbolic Planning in Partially Known Environments

ICRA 2018poster

This paper considers the problem of completing assemblies of passive objects in nonconvex environments, cluttered with convex obstacles of unknown position, shape and size that satisfy a specific separation assumption. A differential drive robot equipped with a gripper and a LIDAR sensor, capable of…

Cited by 38SourceScholar
2017

Feature discovery and visualization of robot mission data using convolutional autoencoders and Bayesian nonparametric topic models

IROS 2017poster

The gap between our ability to collect interesting data and our ability to analyze these data is growing at an unprecedented rate. Recent algorithmic attempts to fill this gap have employed unsupervised tools to discover structure in data. Some of the most successful approaches have used probabilist…

Cited by 12SourceScholar
2016

Efficient Grounding of Abstract Spatial Concepts for Natural Language Interaction with Robot Manipulators

RSS 2016poster

Our goal is to develop models that allow a robot to understand natural language instructions in the context of its world representation. Contemporary models learn possible correspondences between parsed instructions and candidate groundings that include objects, regions and motion constraints. Howev…

Cited by 127SourcePDFScholar
2016

PROBE-GK: Predictive robust estimation using generalized kernels

ICRA 2016

Many algorithms in computer vision and robotics make strong assumptions about uncertainty, and rely on the validity of these assumptions to produce accurate and consistent state estimates. In practice, dynamic environments may degrade sensor performance in predictable ways that cannot be captured wi

Cited by 19SourceScholar
2015

Learning models for following natural language directions in unknown environments

ICRA 2015poster

Natural language offers an intuitive and flexible means for humans to communicate with the robots that we will increasingly work alongside in our homes and workplaces. Recent advancements have given rise to robots that are able to interpret natural language manipulation and navigation commands, but…

Cited by 100SourceScholar
2015

Monocular image space tracking on a computationally limited MAV

ICRA 2015poster

We propose a method of monocular camera-inertial based navigation for computationally limited micro air vehicles (MAVs). Our approach is derived from the recent development of parallel tracking and mapping algorithms, but unlike previous results, we show how the tracking and mapping processes operat…

Cited by 8SourceScholar