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Chuchu Fan

63 accepted papers

2026

Bellman Value Decomposition for Task Logic in Safe Optimal Control

RSS 2026poster

Real-world tasks involve nuanced combinations of goal and safety specifications, which often directly compete. In high dimensions, the challenge is exacerbated: formal automata become cumbersome, and the combination of sparse rewards tends to require laborious tuning. In this work, we consider the s…

Cited by 0SourceScholar
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

Optimization of Multi-Agent Flying Sidekick Traveling Salesman Problem over Road Networks

AAAI 2026technical

The mixed truck-drone delivery system has attracted increasing attention for its potential to optimize last-mile logistics. While the Flying Sidekick Traveling Salesman Problem (FSTSP) provides a foundation for modeling the truck-drone collaboration, it falls short of capturing real-world complexiti

Cited by 0SourcePDFScholar
2026

Parameter-Robust MPPI for Safe Online Learning of Unknown Parameters

RA-L 2026

Robots deployed in dynamic environments must remain safe even when key physical parameters are uncertain or change over time. We propose Parameter-Robust Model Predictive Path Integral (PRMPPI) control, a framework that integrates online parameter learning with probabilistic safety constraints. PRMP

Cited by 0SourceScholar
2026

R1-Code-Interpreter: LLMs Reason with Code via Supervised and Multi-stage Reinforcement Learning

ICLR 2026poster

Practical guidance on training Large Language Models (LLMs) to leverage Code Interpreter across diverse tasks remains lacking. We present R1-Code-Interpreter, an extension of a text-only LLM trained via multi-turn supervised fine-tuning (SFT) and reinforcement learning (RL) to autonomously generate…

Cited by 0SourceScholar
2026

ReFORM: Reflected Flows for On-support Offline RL via Noise Manipulation

ICLR 2026poster

Offline reinforcement learning (RL) aims to learn the optimal policy from a fixed dataset generated by behavior policies without additional environment interactions. One common challenge that arises in this setting is the out-of-distribution (OOD) error, which occurs when the policy leaves the train…

Cited by 0SourcecodeScholar
2026

SEED-SET: Scalable Evolving Experimental Design for System-level Ethical Testing

ICLR 2026poster

As autonomous systems such as drones, become increasingly deployed in high-stakes, human-centric domains, it is critical to evaluate the ethical alignment since failure to do so imposes imminent danger to human lives, and long term bias in decision-making. Automated ethical benchmarking of these sys…

Cited by 0SourceScholar
2026

Safety on the Fly: Constructing Robust Safety Filters Via Policy Control Barrier Functions at Runtime

ICRA 2026poster

Control Barrier Functions (CBFs) have proven to be an effective tool for performing safe control synthesis for nonlinear systems. However, guaranteeing safety in the presence of disturbances and input constraints for high relative degree systems is a difficult problem. In this work, we propose the R…

2026

Solving Parameter-Robust Avoid Problems with Unknown Feasibility using Reinforcement Learning

ICLR 2026poster

Recent advances in deep reinforcement learning (RL) have achieved strong results on high-dimensional control tasks, but applying RL to reachability problems raises a fundamental mismatch: reachability seeks to maximize the set of states from which a system remains safe indefinitely, while RL optimiz…

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…

2026

TUMIX: Multi-Agent Test-Time Scaling with Tool-Use Mixture

ICLR 2026poster

While integrating tools like Code Interpreter and Search has significantly enhanced Large Language Model (LLM) reasoning in models like ChatGPT Agent and Gemini-Pro, practical guidance on optimal tool use is lacking. The core challenge is effectively combining textual reasoning, coding, and search f…

Cited by 0SourceScholar
2025

Code-as-Symbolic-Planner: Foundation Model-Based Robot Planning via Symbolic Code Generation

IROS 2025

Recent works have shown great potential of Large Language Models (LLMs) in robot task and motion planning (TAMP). Current LLM approaches generate text- or code-based reasoning chains with sub-goals and action plans. However, they do not fully leverage LLMs’ symbolic computing and code generation cap

Cited by 10SourceScholar
2025

CodeSteer: Symbolic-Augmented Language Models via Code/Text Guidance

ICML 2025poster

Existing methods fail to effectively steer Large Language Models (LLMs) between textual reasoning and code generation, leaving symbolic computing capabilities underutilized. We introduce CodeSteer, an effective method for guiding LLM code/text generation. We construct a comprehensive benchmark SymBe…

2025

Cost-aware Discovery of Contextual Failures using Bayesian Active Learning

CoRL 2025poster

Ensuring the robustness of robotic systems is crucial for their deployment in safety-critical domains. Failure discovery, or falsification, is a widely used approach for evaluating robustness, with recent advancements focusing on improving sample efficiency and generalization through probabilistic s…

Cited by 0SourceScholar
2025

Discrete GCBF Proximal Policy Optimization for Multi-agent Safe Optimal Control

ICLR 2025poster

Control policies that can achieve high task performance and satisfy safety constraints are desirable for any system, including multi-agent systems (MAS). One promising technique for ensuring the safety of MAS is distributed control barrier functions (CBF). However, it is difficult to design distribu…

2025

HMARL-CBF – Hierarchical Multi-Agent Reinforcement Learning with Control Barrier Functions for Safety-Critical Autonomous Systems

NeurIPS 2025poster

We address the problem of safe policy learning in multi-agent safety-critical autonomous systems. In such systems, it is necessary for each agent to meet the safety requirements at all times while also cooperating with other agents to accomplish the task. Toward this end, we propose a safe Hierarchi…

Cited by 0SourceScholar
2025

Large Language Models Can Solve Real-World Planning Rigorously with Formal Verification Tools

NAACL 2025long

Large Language Models (LLMs) struggle to directly generate correct plans for complex multi-constraint planning problems, even with self-verification and self-critique. For example, a U.S. domestic travel planning benchmark TravelPlanner was proposed in Xie et al. (2024), where the best LLM OpenAI o1…

Cited by 4SourcePDFScholar
2025

Planning Anything with Rigor: General-Purpose Zero-Shot Planning with LLM-based Formalized Programming

ICLR 2025poster

While large language models (LLMs) have recently demonstrated strong potential in solving planning problems, there is a trade-off between flexibility and complexity. LLMs, as zero-shot planners themselves, are still not capable of directly generating valid plans for complex planning problems such as…

Cited by 6SourcePDFScholar
2025

Rare event modeling with self-regularized normalizing flows: what can we learn from a single failure?

ICLR 2025poster

Increased deployment of autonomous systems in fields like transportation and robotics have seen a corresponding increase in safety-critical failures. These failures can be difficult to model and debug due to the relative lack of data: compared to tens of thousands of examples from normal operations,…

Cited by 1SourcePDFScholar
2025

Reliable and Efficient Multi-Agent Coordination via Graph Neural Network Variational Autoencoders

ICRA 2025

Multi-agent coordination is crucial for reliable multi-robot navigation in shared spaces such as automated warehouses. In regions of dense robot traffic, local coordination methods may fail to find a deadlock-free solution. In these scenarios, it is appropriate to let a central unit generate a globa

Cited by 4SourceScholar
2025

Safe Beyond the Horizon: Efficient Sampling-based MPC with Neural Control Barrier Functions

RSS 2025poster

A common problem when using model predictive control (MPC) in practice is the satisfaction of safety beyond the prediction horizon. While theoretical works have shown that safety can be guaranteed by enforcing a suitable terminal set constraint or a sufficiently long prediction horizon, these techni…

Cited by 0PDFScholar
2025

Safety on the Fly: Constructing Robust Safety Filters via Policy Control Barrier Functions at Runtime

RA-L 2025

Control Barrier Functions (CBFs) have proven to be an effective tool for performing safe control synthesis for nonlinear systems. However, guaranteeing safety in the presence of disturbances and input constraints for high relative degree systems is a difficult problem. In this work, we propose the R

Cited by 9SourceScholar
2025

Scalable Surrogate Verification of Image-Based Neural Network Control Systems Using Composition and Unrolling

AAAI 2025technical

Verifying safety of neural network control systems that use images as input is a difficult problem because, from a given system state, there is no known way to mathematically model what images are possible in the real-world. We build upon recent work that considers a surrogate verification approach,…

Cited by 4SourcePDFScholar
2025

Solving Multi-Agent Safe Optimal Control with Distributed Epigraph Form MARL

RSS 2025poster

Tasks for multi-robot systems often require the robots to collaborate and complete a team goal while maintaining safety. This problem is usually formalized as a Constrained Markov decision process (CMDP), which targets minimizing a global cost and bringing the mean of constraint violation below a us…

Cited by 0PDFScholar
2025

Steering Large Language Models between Code Execution and Textual Reasoning

ICLR 2025poster

While a lot of recent research focuses on enhancing the textual reasoning capabilities of Large Language Models (LLMs) by optimizing the multi-agent framework or reasoning chains, several benchmark tasks can be solved with 100\% success through direct coding, which is more scalable and avoids the co…

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

ConBaT: Control Barrier Transformer for Safe Robot Learning from Demonstrations

ICRA 2024poster

Large-scale self-supervised models have recently revolutionized our ability to perform a variety of tasks within the vision and language domains. However, using such models for autonomous systems is challenging because of safety requirements: besides executing correct actions, an autonomous agent mu…

Cited by 1SourceScholar
2024

Efficient Motion Planning for Manipulators with Control Barrier Function-Induced Neural Controller

ICRA 2024poster

Sampling-based motion planning methods for manipulators in crowded environments often suffer from expensive collision checking and high sampling complexity, which make them difficult to use in real time. To address this issue, we propose a new generalizable control barrier function (CBF)based steeri…

Cited by 7SourcecodeScholar
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

Learning-Based Bayesian Inference for Testing of Autonomous Systems

RA-L 2024

For the safe operation of robotic systems, it is important to accurately understand its failure modes using prior testing. Hardware testing of robotic infrastructure is known to be slow and costly. Instead, failure prediction in simulation can help to analyze the system before deployment. Convention

Cited by 2SourceScholar
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 Bayesian approach to breaking things: efficiently predicting and repairing failure modes via sampling

CoRL 2023poster

Before autonomous systems can be deployed in safety-critical applications, we must be able to understand and verify the safety of these systems. For cases where the risk or cost of real-world testing is prohibitive, we propose a simulation-based framework for a) predicting ways in which an autonomou…

Cited by 11SourceScholar
2023

Density Planner: Minimizing Collision Risk in Motion Planning with Dynamic Obstacles using Density-based Reachability

ICRA 2023poster

Uncertainty is prevalent in robotics. Due to measurement noise and complex dynamics, we cannot estimate the exact system and environment state. Since conservative motion planners are not guaranteed to find a safe control strategy in a crowded, uncertain environment, we propose a density-based method…

Cited by 6SourcecodeScholar
2023

Enforcing safety for vision-based controllers via Control Barrier Functions and Neural Radiance Fields

ICRA 2023poster

To navigate complex environments, robots must increasingly use high-dimensional visual feedback (e.g. images) for control. However, relying on high-dimensional image data to make control decisions raises important questions; particularly, how might we prove the safety of a visual-feedback controller…

Cited by 35SourceScholar
2023

Neural Graph Control Barrier Functions Guided Distributed Collision-avoidance Multi-agent Control

CoRL 2023poster

We consider the problem of designing distributed collision-avoidance multi-agent control in large-scale environments with potentially moving obstacles, where a large number of agents are required to maintain safety using only local information and reach their goals. This paper addresses the problem…

Cited by 33SourcecodeScholar
2023

Shield Model Predictive Path Integral: A Computationally Efficient Robust MPC Method Using Control Barrier Functions

RA-L 2023

Model Predictive Path Integral (MPPI) control is a type of sampling-based model predictive control that simulates thousands of trajectories and uses these trajectories to synthesize optimal controls on-the-fly. In practice, however, MPPI encounters problems limiting its application. For instance, it

Cited by 43SourceScholar
2023

Solving Stabilize-Avoid via Epigraph Form Optimal Control using Deep Reinforcement Learning

RSS 2023poster

Tasks for autonomous robotic systems commonly require stabilization to a desired region while maintaining safety specifications. However, solving this multi-objective problem is challenging when the dynamics are nonlinear and high-dimensional, as traditional methods do not scale well and are often l…

2022

A Meta-framework for Spatiotemporal Quantity Extraction from Text

ACL 2022long

News events are often associated with quantities (e.g., the number of COVID-19 patients or the number of arrests in a protest), and it is often important to extract their type, time, and location from unstructured text in order to analyze these quantity events. This paper thus formulates the NLP pro…

Cited by 13SourcePDFScholar
2022

Learning Safe, Generalizable Perception-Based Hybrid Control With Certificates

RA-L 2022

Many robotic tasks require high-dimensional sensors such as cameras and Lidar to navigate complex environments, but developing certifiably safe feedback controllers around these sensors remains a challenging open problem, particularly when learning is involved. Previous works have proved the safety

Cited by 69SourceScholar
2022

Learning-based Motion Planning in Dynamic Environments Using GNNs and Temporal Encoding

NeurIPS 2022accept

Learning-based methods have shown promising performance for accelerating motion planning, but mostly in the setting of static environments. For the more challenging problem of planning in dynamic environments, such as multi-arm assembly tasks and human-robot interaction, motion planners need to cons…

Cited by 20SourcePDFScholar
2022

Robust Counterexample-guided Optimization for Planning from Differentiable Temporal Logic

IROS 2022poster

Signal temporal logic (STL) provides a powerful, flexible framework for specifying complex autonomy tasks; however, existing methods for planning based on STL specifications have difficulty scaling to long-horizon tasks and are not robust to external disturbances. In this paper, we present an algori…

Cited by 12SourcecodeScholar
2021

Learning Density Distribution of Reachable States for Autonomous Systems

CoRL 2021poster

State density distribution, in contrast to worst-case reachability, can be leveraged for safety-related problems to better quantify the likelihood of the risk for potentially hazardous situations. In this work, we propose a data-driven method to compute the density distribution of reachable states f…

Cited by 21SourceScholar
2021

Learning Safe Multi-agent Control with Decentralized Neural Barrier Certificates

ICLR 2021poster

We study the multi-agent safe control problem where agents should avoid collisions to static obstacles and collisions with each other while reaching their goals. Our core idea is to learn the multi-agent control policy jointly with learning the control barrier functions as safety certificates. We p…

Cited by 175SourcePDFScholar
2021

Safe Nonlinear Control Using Robust Neural Lyapunov-Barrier Functions

CoRL 2021poster

Safety and stability are common requirements for robotic control systems; however, designing safe, stable controllers remains difficult for nonlinear and uncertain models. We develop a model-based learning approach to synthesize robust feedback controllers with safety and stability guarantees. We ta…

Cited by 210SourcecodeScholar
2021

Scalable and Safe Multi-Agent Motion Planning with Nonlinear Dynamics and Bounded Disturbances

AAAI 2021technical

We present a scalable and effective multi-agent safe motion planner that enables a group of agents to move to their desired locations while avoiding collisions with obstacles and other agents, with the presence of rich obstacles, high-dimensional, nonlinear, nonholonomic dynamics, actuation limits,…

Cited by 44SourcePDFScholar
2020

Reactive motion planning with probabilisticsafety guarantees

CoRL 2020

Motion planning in environments with multiple agents is critical to many important autonomous applications such as autonomous vehicles and assistive robots. This paper considers the problem of motion planning, where the controlled agent shares the environment with multiple uncontrolled agents. First

Cited by 0SourcePDFScholar