Search Results for author: Claire J. Tomlin

Found 45 papers, 12 papers with code

Safety Filters for Black-Box Dynamical Systems by Learning Discriminating Hyperplanes

1 code implementation7 Feb 2024 Will Lavanakul, Jason J. Choi, Koushil Sreenath, Claire J. Tomlin

As such, we believe that the new notion of the discriminating hyperplane offers a more generalizable direction towards designing safety filters, encompassing and extending existing certificate-function-based or safe RL methodologies.

Reinforcement Learning (RL)

A Forward Reachability Perspective on Robust Control Invariance and Discount Factors in Reachability Analysis

no code implementations26 Oct 2023 Jason J. Choi, Donggun Lee, Boyang Li, Jonathan P. How, Koushil Sreenath, Sylvia L. Herbert, Claire J. Tomlin

We also formulate a zero-sum differential game between the control and disturbance, where the inevitable FRT is characterized by the zero-superlevel set of the value function.

Out of Distribution Detection via Domain-Informed Gaussian Process State Space Models

no code implementations13 Sep 2023 Alonso Marco, Elias Morley, Claire J. Tomlin

In this paper, we propose (i) a novel approach to embed existing domain knowledge in the kernel and (ii) an OoD online runtime monitor, based on receding-horizon predictions.

Navigate Out-of-Distribution Detection

Stranding Risk for Underactuated Vessels in Complex Ocean Currents: Analysis and Controllers

no code implementations4 Jul 2023 Andreas Doering, Marius Wiggert, Hanna Krasowski, Manan Doshi, Pierre F. J. Lermusiaux, Claire J. Tomlin

We demonstrate the safety of our approach in such realistic situations empirically with large-scale simulations of a vessel navigating in high-risk regions in the Northeast Pacific.

Navigate

Safe Connectivity Maintenance in Underactuated Multi-Agent Networks for Dynamic Oceanic Environments

no code implementations4 Jul 2023 Nicolas Hoischen, Marius Wiggert, Claire J. Tomlin

To address these challenges, we propose a Hierarchical Multi-Agent Control approach that allows arbitrary single agent performance policies that are unaware of other agents to be used in multi-agent systems, while ensuring safe operation.

Optimality Guarantees for Particle Belief Approximation of POMDPs

1 code implementation10 Oct 2022 Michael H. Lim, Tyler J. Becker, Mykel J. Kochenderfer, Claire J. Tomlin, Zachary N. Sunberg

Thus, when combined with sparse sampling MDP algorithms, this approach can yield algorithms for POMDPs that have no direct theoretical dependence on the size of the state and observation spaces.

Recursively Feasible Probabilistic Safe Online Learning with Control Barrier Functions

no code implementations23 Aug 2022 Fernando Castañeda, Jason J. Choi, Wonsuhk Jung, Bike Zhang, Claire J. Tomlin, Koushil Sreenath

This feasibility analysis results in a set of richness conditions that the available information about the system should satisfy to guarantee that a safe control action can be found at all times.

Out-of-Distribution Detection

On the Computational Consequences of Cost Function Design in Nonlinear Optimal Control

no code implementations5 Apr 2022 Tyler Westenbroek, Anand Siththaranjan, Mohsin Sarwari, Claire J. Tomlin, Shankar S. Sastry

However, despite the extensive impacts of methods such as receding horizon control, dynamic programming and reinforcement learning, the design of cost functions for a particular system often remains a heuristic-driven process of trial and error.

reinforcement-learning Reinforcement Learning (RL)

Koopman-Based Neural Lyapunov Functions for General Attractors

1 code implementation23 Mar 2022 Shankar A. Deka, Alonso M. Valle, Claire J. Tomlin

Koopman spectral theory has grown in the past decade as a powerful tool for dynamical systems analysis and control.

Infinite-Horizon Reach-Avoid Zero-Sum Games via Deep Reinforcement Learning

no code implementations18 Mar 2022 Jingqi Li, Donggun Lee, Somayeh Sojoudi, Claire J. Tomlin

We address this problem by designing a new value function with a contracting Bellman backup, where the super-zero level set, i. e., the set of states where the value function is evaluated to be non-negative, recovers the reach-avoid set.

Q-Learning reinforcement-learning +1

Safety and Liveness Guarantees through Reach-Avoid Reinforcement Learning

1 code implementation23 Dec 2021 Kai-Chieh Hsu, Vicenç Rubies-Royo, Claire J. Tomlin, Jaime F. Fisac

Recent successes in reinforcement learning methods to approximately solve optimal control problems with performance objectives make their application to certification problems attractive; however, the Lagrange-type objective used in reinforcement learning is not suitable to encode temporal logic requirements.

Q-Learning reinforcement-learning +1

Compositional Learning-based Planning for Vision POMDPs

1 code implementation17 Dec 2021 Sampada Deglurkar, Michael H. Lim, Johnathan Tucker, Zachary N. Sunberg, Aleksandra Faust, Claire J. Tomlin

The Partially Observable Markov Decision Process (POMDP) is a powerful framework for capturing decision-making problems that involve state and transition uncertainty.

Decision Making

A Computationally Efficient Hamilton-Jacobi-based Formula for State-Constrained Optimal Control Problems

no code implementations25 Jun 2021 Donggun Lee, Claire J. Tomlin

Based on the Lax formula [2], this paper proposes an HJ formula for the state-constrained optimal control problem for nonlinear systems.

Pointwise Feasibility of Gaussian Process-based Safety-Critical Control under Model Uncertainty

no code implementations13 Jun 2021 Fernando Castañeda, Jason J. Choi, Bike Zhang, Claire J. Tomlin, Koushil Sreenath

However, since these constraints rely on a model of the system, when this model is inaccurate the guarantees of safety and stability can be easily lost.

Robust Control Barrier-Value Functions for Safety-Critical Control

no code implementations6 Apr 2021 Jason J. Choi, Donggun Lee, Koushil Sreenath, Claire J. Tomlin, Sylvia L. Herbert

This paper works towards unifying two popular approaches in the safety control community: Hamilton-Jacobi (HJ) reachability and Control Barrier Functions (CBFs).

valid

Analyzing Human Models that Adapt Online

no code implementations9 Mar 2021 Andrea Bajcsy, Anand Siththaranjan, Claire J. Tomlin, Anca D. Dragan

This enables us to leverage tools from reachability analysis and optimal control to compute the set of hypotheses the robot could learn in finite time, as well as the worst and best-case time it takes to learn them.

Autonomous Driving

Risk-sensitive safety analysis using Conditional Value-at-Risk

1 code implementation28 Jan 2021 Margaret P. Chapman, Riccardo Bonalli, Kevin M. Smith, Insoon Yang, Marco Pavone, Claire J. Tomlin

In addition, we propose a second definition for risk-sensitive safe sets and provide a tractable method for their estimation without using a parameter-dependent upper bound.

Scalable Learning of Safety Guarantees for Autonomous Systems using Hamilton-Jacobi Reachability

no code implementations15 Jan 2021 Sylvia Herbert, Jason J. Choi, Suvansh Sanjeev, Marsalis Gibson, Koushil Sreenath, Claire J. Tomlin

However, work to learn and update safety analysis is limited to small systems of about two dimensions due to the computational complexity of the analysis.

Voronoi Progressive Widening: Efficient Online Solvers for Continuous State, Action, and Observation POMDPs

1 code implementation18 Dec 2020 Michael H. Lim, Claire J. Tomlin, Zachary N. Sunberg

This paper introduces Voronoi Progressive Widening (VPW), a generalization of Voronoi optimistic optimization (VOO) and action progressive widening to partially observable Markov decision processes (POMDPs).

Gaussian Process-based Min-norm Stabilizing Controller for Control-Affine Systems with Uncertain Input Effects and Dynamics

no code implementations14 Nov 2020 Fernando Castañeda, Jason J. Choi, Bike Zhang, Claire J. Tomlin, Koushil Sreenath

This paper presents a method to design a min-norm Control Lyapunov Function (CLF)-based stabilizing controller for a control-affine system with uncertain dynamics using Gaussian Process (GP) regression.

regression

Approximate Solutions to a Class of Reachability Games

no code implementations1 Nov 2020 David Fridovich-Keil, Claire J. Tomlin

In this paper, we present a method for finding approximate Nash equilibria in a broad class of reachability games.

Collision Avoidance

Dynamically Computing Adversarial Perturbations for Recurrent Neural Networks

no code implementations7 Sep 2020 Shankar A. Deka, Dušan M. Stipanović, Claire J. Tomlin

Convolutional and recurrent neural networks have been widely employed to achieve state-of-the-art performance on classification tasks.

Technical Report: Adaptive Control for Linearizable Systems Using On-Policy Reinforcement Learning

no code implementations6 Apr 2020 Tyler Westenbroek, Eric Mazumdar, David Fridovich-Keil, Valmik Prabhu, Claire J. Tomlin, S. Shankar Sastry

This paper proposes a framework for adaptively learning a feedback linearization-based tracking controller for an unknown system using discrete-time model-free policy-gradient parameter update rules.

reinforcement-learning Reinforcement Learning (RL)

Feedback Linearization for Unknown Systems via Reinforcement Learning

no code implementations29 Oct 2019 Tyler Westenbroek, David Fridovich-Keil, Eric Mazumdar, Shreyas Arora, Valmik Prabhu, S. Shankar Sastry, Claire J. Tomlin

We present a novel approach to control design for nonlinear systems which leverages model-free policy optimization techniques to learn a linearizing controller for a physical plant with unknown dynamics.

reinforcement-learning Reinforcement Learning (RL)

A Hamilton-Jacobi Reachability-Based Framework for Predicting and Analyzing Human Motion for Safe Planning

no code implementations29 Oct 2019 Somil Bansal, Andrea Bajcsy, Ellis Ratner, Anca D. Dragan, Claire J. Tomlin

We construct a new continuous-time dynamical system, where the inputs are the observations of human behavior, and the dynamics include how the belief over the model parameters change.

Bayesian Inference Human motion prediction +1

Sparse tree search optimality guarantees in POMDPs with continuous observation spaces

1 code implementation10 Oct 2019 Michael H. Lim, Claire J. Tomlin, Zachary N. Sunberg

Partially observable Markov decision processes (POMDPs) with continuous state and observation spaces have powerful flexibility for representing real-world decision and control problems but are notoriously difficult to solve.

An Iterative Quadratic Method for General-Sum Differential Games with Feedback Linearizable Dynamics

1 code implementation1 Oct 2019 David Fridovich-Keil, Vicenc Rubies-Royo, Claire J. Tomlin

Iterative linear-quadratic (ILQ) methods are widely used in the nonlinear optimal control community.

Systems and Control Computer Science and Game Theory Multiagent Systems Robotics Systems and Control

PowerSGD: Powered Stochastic Gradient Descent Methods for Accelerated Non-Convex Optimization

no code implementations25 Sep 2019 Jun Liu, Beitong Zhou, Weigao Sun, Ruijuan Chen, Claire J. Tomlin, Ye Yuan

In this paper, we propose a novel technique for improving the stochastic gradient descent (SGD) method to train deep networks, which we term \emph{PowerSGD}.

Closed-loop Model Selection for Kernel-based Models using Bayesian Optimization

no code implementations12 Sep 2019 Thomas Beckers, Somil Bansal, Claire J. Tomlin, Sandra Hirche

In this work, we present a framework to optimize the kernel and hyperparameters of a kernel-based model directly with respect to the closed-loop performance of the model.

Bayesian Optimization Model Selection

Efficient Iterative Linear-Quadratic Approximations for Nonlinear Multi-Player General-Sum Differential Games

1 code implementation10 Sep 2019 David Fridovich-Keil, Ellis Ratner, Anca D. Dragan, Claire J. Tomlin

We benchmark our method in a three-player general-sum simulated example, in which it takes < 0. 75 s to identify a solution and < 50 ms to solve warm-started subproblems in a receding horizon.

Systems and Control Robotics Systems and Control

Safely Probabilistically Complete Real-Time Planning and Exploration in Unknown Environments

no code implementations19 Nov 2018 David Fridovich-Keil, Jaime F. Fisac, Claire J. Tomlin

We present a new framework for motion planning that wraps around existing kinodynamic planners and guarantees recursive feasibility when operating in a priori unknown, static environments.

Robotics Systems and Control

Context-Specific Validation of Data-Driven Models

no code implementations14 Feb 2018 Somil Bansal, Shromona Ghosh, Alberto Sangiovanni-Vincentelli, Sanjit A. Seshia, Claire J. Tomlin

We propose a context-specific validation framework to quantify the quality of a learned model based on a distance measure between the closed-loop actual system and the learned model.

Budget-Constrained Multi-Armed Bandits with Multiple Plays

no code implementations16 Nov 2017 Datong P. Zhou, Claire J. Tomlin

Secondly, for the adversarial case in which the entire sequence of rewards and costs is fixed in advance, we derive an upper bound on the regret of order $O(\sqrt{NB\log(N/K)})$ utilizing an extension of the well-known $\texttt{Exp3}$ algorithm.

Multi-Armed Bandits

Planning, Fast and Slow: A Framework for Adaptive Real-Time Safe Trajectory Planning

2 code implementations12 Oct 2017 David Fridovich-Keil, Sylvia L. Herbert, Jaime F. Fisac, Sampada Deglurkar, Claire J. Tomlin

Motion planning is an extremely well-studied problem in the robotics community, yet existing work largely falls into one of two categories: computationally efficient but with few if any safety guarantees, or able to give stronger guarantees but at high computational cost.

Systems and Control Computer Science and Game Theory

Hamilton-Jacobi Reachability: A Brief Overview and Recent Advances

1 code implementation21 Sep 2017 Somil Bansal, Mo Chen, Sylvia Herbert, Claire J. Tomlin

Hamilton-Jacobi (HJ) reachability analysis is an important formal verification method for guaranteeing performance and safety properties of dynamical systems; it has been applied to many small-scale systems in the past decade.

Systems and Control Dynamical Systems Optimization and Control

Goal-Driven Dynamics Learning via Bayesian Optimization

no code implementations27 Mar 2017 Somil Bansal, Roberto Calandra, Ted Xiao, Sergey Levine, Claire J. Tomlin

Real-world robots are becoming increasingly complex and commonly act in poorly understood environments where it is extremely challenging to model or learn their true dynamics.

Active Learning Bayesian Optimization

FaSTrack: a Modular Framework for Fast and Guaranteed Safe Motion Planning

no code implementations21 Mar 2017 Sylvia L. Herbert, Mo Chen, SooJean Han, Somil Bansal, Jaime F. Fisac, Claire J. Tomlin

We propose a new algorithm FaSTrack: Fast and Safe Tracking for High Dimensional systems.

Robotics

Using Neural Networks to Compute Approximate and Guaranteed Feasible Hamilton-Jacobi-Bellman PDE Solutions

no code implementations10 Nov 2016 Frank Jiang, Glen Chou, Mo Chen, Claire J. Tomlin

To sidestep the curse of dimensionality when computing solutions to Hamilton-Jacobi-Bellman partial differential equations (HJB PDE), we propose an algorithm that leverages a neural network to approximate the value function.

On the Powerball Method for Optimization

no code implementations24 Mar 2016 Ye Yuan, Mu Li, Jun Liu, Claire J. Tomlin

We propose a new method to accelerate the convergence of optimization algorithms.

Cannot find the paper you are looking for? You can Submit a new open access paper.