Search Results for author: Chuchu Fan

Found 32 papers, 7 papers with code

A Meta-framework for Spatiotemporal Quantity Extraction from Text

no code implementations ACL 2022 Qiang Ning, Ben Zhou, Hao Wu, Haoruo Peng, Chuchu Fan, Matt Gardner

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.

Large Language Models to the Rescue: Deadlock Resolution in Multi-Robot Systems

no code implementations9 Apr 2024 Kunal Garg, Jacob Arkin, Songyuan Zhang, Nicholas Roy, Chuchu Fan

Multi-agent robotic systems are prone to deadlocks in an obstacle environment where the system can get stuck away from its desired location under a smooth low-level control policy.

Prompt Engineering

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

no code implementations1 Apr 2024 Mingxin Yu, Chenning Yu, M-Mahdi Naddaf-Sh, Devesh Upadhyay, Sicun Gao, Chuchu Fan

Our method combines the strength of CBF for real-time collision-avoidance control and RRT for long-horizon motion planning, by using CBF-induced neural controller (CBF-INC) to generate control signals that steer the system towards sampled configurations by RRT.

Collision Avoidance Motion Planning

Active Disruption Avoidance and Trajectory Design for Tokamak Ramp-downs with Neural Differential Equations and Reinforcement Learning

no code implementations14 Feb 2024 Allen M. Wang, Oswin So, Charles Dawson, Darren T. Garnier, Cristina Rea, Chuchu Fan

The policy training environment is a hybrid physics and machine learning model trained on simulations of the SPARC primary reference discharge (PRD) ramp-down, an upcoming burning plasma scenario which we use as a testbed.

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

no code implementations21 Nov 2023 Songyuan Zhang, Kunal Garg, Chuchu Fan

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.

Collision Avoidance

Adversarial optimization leads to over-optimistic security-constrained dispatch, but sampling can help

no code implementations10 Oct 2023 Charles Dawson, Chuchu Fan

We show that adversarial optimization is liable to severely overestimate the robustness of the optimized dispatch (when the adversary encounters a local minimum), leading the operator to falsely believe that their dispatch is secure.

Adversarial Attack

Signal Temporal Logic Neural Predictive Control

no code implementations10 Sep 2023 Yue Meng, Chuchu Fan

We conduct experiments on six tasks, where our method with the backup policy outperforms the classical methods (MPC, STL-solver), model-free and model-based RL methods in STL satisfaction rate, especially on tasks with complex STL specifications while being 10X-100X faster than the classical methods.

Model Predictive Control Reinforcement Learning (RL)

Learning to Stabilize High-dimensional Unknown Systems Using Lyapunov-guided Exploration

no code implementations14 Jun 2023 Songyuan Zhang, Chuchu Fan

LYGE employs Lyapunov theory to iteratively guide the search for samples during exploration while simultaneously learning the local system dynamics, control policy, and Lyapunov functions.

Imitation Learning

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

3 code implementations10 Jun 2023 Yongchao Chen, Jacob Arkin, Charles Dawson, Yang Zhang, Nicholas Roy, Chuchu Fan

Rather than using LLMs to directly plan task sub-goals, we instead perform few-shot translation from natural language task descriptions to an intermediate task representation that can then be consumed by a TAMP algorithm to jointly solve the task and motion plan.

Motion Planning Task and Motion Planning +1

NL2TL: Transforming Natural Languages to Temporal Logics using Large Language Models

3 code implementations12 May 2023 Yongchao Chen, Rujul Gandhi, Yang Zhang, Chuchu Fan

Then, we finetune T5 models on the lifted versions (i. e., the specific Atomic Propositions (AP) are hidden) of the NL and TL.

Compositional Neural Certificates for Networked Dynamical Systems

1 code implementation25 Mar 2023 Songyuan Zhang, Yumeng Xiu, Guannan Qu, Chuchu Fan

Specifically, we treat a large networked dynamical system as an interconnection of smaller subsystems and develop methods that can find each subsystem a decentralized controller and an ISS Lyapunov function; the latter can be collectively composed to prove the global stability of the system.

Hybrid Systems Neural Control with Region-of-Attraction Planner

no code implementations18 Mar 2023 Yue Meng, Chuchu Fan

For each system mode, we first learn an NN Lyapunov function and an NN controller to ensure the states within the region of attraction (RoA) can be stabilized.

Model Predictive Control Reinforcement Learning (RL)

ConBaT: Control Barrier Transformer for Safe Policy Learning

no code implementations7 Mar 2023 Yue Meng, Sai Vemprala, Rogerio Bonatti, Chuchu Fan, Ashish Kapoor

In this work, we propose Control Barrier Transformer (ConBaT), an approach that learns safe behaviors from demonstrations in a self-supervised fashion.

Imitation Learning Model Predictive Control

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

no code implementations16 Oct 2022 Ruipeng Zhang, Chenning Yu, Jingkai Chen, Chuchu Fan, Sicun Gao

Learning-based methods have shown promising performance for accelerating motion planning, but mostly in the setting of static environments.

Imitation Learning Motion Planning

Case Studies for Computing Density of Reachable States for Safe Autonomous Motion Planning

no code implementations16 Sep 2022 Yue Meng, Zeng Qiu, Md Tawhid Bin Waez, Chuchu Fan

Recent work provides a data-driven approach to compute the density distribution of autonomous systems' forward reachable states online.

Autonomous Driving Density Estimation +2

Cooperative Task and Motion Planning for Multi-Arm Assembly Systems

no code implementations4 Mar 2022 Jingkai Chen, Jiaoyang Li, Yijiang Huang, Caelan Garrett, Dawei Sun, Chuchu Fan, Andreas Hofmann, Caitlin Mueller, Sven Koenig, Brian C. Williams

Multi-robot assembly systems are becoming increasingly appealing in manufacturing due to their ability to automatically, flexibly, and quickly construct desired structural designs.

Motion Planning Multi-Agent Path Finding +1

SABLAS: Learning Safe Control for Black-box Dynamical Systems

1 code implementation6 Jan 2022 Zengyi Qin, Dawei Sun, Chuchu Fan

Control certificates based on barrier functions have been a powerful tool to generate probably safe control policies for dynamical systems.

Reinforcement Learning (RL)

A Theoretical Overview of Neural Contraction Metrics for Learning-based Control with Guaranteed Stability

no code implementations2 Oct 2021 Hiroyasu Tsukamoto, Soon-Jo Chung, Jean-Jacques Slotine, Chuchu Fan

This paper presents a theoretical overview of a Neural Contraction Metric (NCM): a neural network model of an optimal contraction metric and corresponding differential Lyapunov function, the existence of which is a necessary and sufficient condition for incremental exponential stability of non-autonomous nonlinear system trajectories.

Safe Nonlinear Control Using Robust Neural Lyapunov-Barrier Functions

no code implementations14 Sep 2021 Charles Dawson, Zengyi Qin, Sicun Gao, Chuchu Fan

Safety and stability are common requirements for robotic control systems; however, designing safe, stable controllers remains difficult for nonlinear and uncertain models.

Learning Density Distribution of Reachable States for Autonomous Systems

no code implementations14 Sep 2021 Yue Meng, Dawei Sun, Zeng Qiu, Md Tawhid Bin Waez, Chuchu Fan

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.

Reactive and Safe Road User Simulations using Neural Barrier Certificates

1 code implementation14 Sep 2021 Yue Meng, Zengyi Qin, Chuchu Fan

Reactive and safe agent modelings are important for nowadays traffic simulator designs and safe planning applications.

Imitation Learning User Simulation

Density Constrained Reinforcement Learning

no code implementations24 Jun 2021 Zengyi Qin, Yuxiao Chen, Chuchu Fan

We study constrained reinforcement learning (CRL) from a novel perspective by setting constraints directly on state density functions, rather than the value functions considered by previous works.

reinforcement-learning Reinforcement Learning (RL)

Optimal Mixed Discrete-Continuous Planningfor Linear Hybrid Systems

no code implementations16 Feb 2021 Jingkai Chen, Brian Williams, Chuchu Fan

Planning in hybrid systems with both discrete and continuous control variables is important for dealing with real-world applications such as extra-planetary exploration and multi-vehicle transportation systems.

Continuous Control Robotics Systems and Control Systems and Control

Learning Safe Multi-Agent Control with Decentralized Neural Barrier Certificates

1 code implementation ICLR 2021 Zengyi Qin, Kaiqing Zhang, Yuxiao Chen, Jingkai Chen, Chuchu Fan

We propose a novel joint-learning framework that can be implemented in a decentralized fashion, with generalization guarantees for certain function classes.

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

no code implementations16 Dec 2020 Jingkai Chen, Jiaoyang Li, Chuchu Fan, Brian Williams

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, and disturbances.

Motion Planning Robotics Multiagent Systems

Reactive motion planning with probabilistic safety guarantees

no code implementations6 Nov 2020 Yuxiao Chen, Ugo Rosolia, Chuchu Fan, Aaron D. Ames, Richard Murray

Motion planning in environments with multiple agents is critical to many important autonomous applications such as autonomous vehicles and assistive robots.

Autonomous Vehicles Model Predictive Control +1

Statistical Verification of Autonomous Systems using Surrogate Models and Conformal Inference

no code implementations1 Apr 2020 Chuchu Fan, Xin Qin, Yuan Xia, Aditya Zutshi, Jyotirmoy Deshmukh

Our technique uses model simulations to learn {\em surrogate models}, and uses {\em conformal inference} to provide probabilistic guarantees on the satisfaction of a given STL property.

Autonomous Vehicles Prediction Intervals

Partial Or Complete, That's The Question

no code implementations NAACL 2019 Qiang Ning, Hangfeng He, Chuchu Fan, Dan Roth

For many structured learning tasks, the data annotation process is complex and costly.

Exploiting Partially Annotated Data in Temporal Relation Extraction

no code implementations SEMEVAL 2018 Qiang Ning, Zhongzhi Yu, Chuchu Fan, Dan Roth

As a result, only a small number of documents are typically annotated, limiting the coverage of various lexical/semantic phenomena.

Relation Temporal Relation Extraction

Exploiting Partially Annotated Data for Temporal Relation Extraction

no code implementations18 Apr 2018 Qiang Ning, Zhongzhi Yu, Chuchu Fan, Dan Roth

As a result, only a small number of documents are typically annotated, limiting the coverage of various lexical/semantic phenomena.

Relation Temporal Relation Extraction

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