Publications

Risk-Averse Model Predictive Control for Racing in Adverse Conditions - T. Lew, M. Greiff, F. Djeumou, M. Suminaka, M. Thompson, J. Subosits, - Under Review - 2024
Project Page / Paper - A risk-averse controller that can reason over uncertainty.

First, Learn What You Don’t Know: Active Information Gathering for Driving at the Limits of Handling - A. Davydov, F. Djeumou, M. Greiff, M. Suminaka, M. Thompson, J. Subosits, T. Lew - Under Review - 2024
Project Page / Paper - Unstable systems are difficult to simultaneously learn and control.

Convex Hulls of Reachable Sets - T. Lew, R. Bonalli, M. Pavone - Under Review - 2024
Project Page / Paper / Code - We study the structure of convex hulls of reachable sets of nonlinear systems (dx/dt=f(x)+g(x)w).

One Model to Drift Them All: Physics-Informed Conditional Diffusion Model for Driving at the Limits - F. Djeumou, T. Lew, N. Ding, M. Thompson, M. Suminaka, M. Greiff, J. Subosits - CoRL - Outstanding Paper Award - 2024
Project Page / Paper - A multimodal diffusion-based vehicle model for MPC.

Estimating the Convex Hull of the Image of a Set with Smooth Boundary: Error Bounds and Applications - T. Lew, R. Bonalli, L. Janson, M. Pavone - DCG - 2024
Project Page / Paper / Code - We study the problem of estimating the convex hull of the image of a compact set with smooth boundary.

Sample Average Approximation for Stochastic Programming with Equality Constraints - T. Lew, R. Bonalli, M. Pavone - SIOPT - 2024
Project Page / Paper / Code - We revisit the sample average approximation (SAA) approach for general non-convex stochastic programming and apply the method to stochastic optimal control problems.

Exact Characterization of the Convex Hulls of Reachable Sets - T. Lew, R. Bonalli, M. Pavone - CDC - Outstanding Student Paper Award - 2023
Project Page / Paper / Presentation / Code - We give a finite-dimensional characterization of the convex hulls of reachable sets of nonlinear systems (dx/dt=f(x)+w).

Risk-Averse Trajectory Optimization via Sample Average Approximation - T. Lew, R. Bonalli, M. Pavone - RA-L - 2023
Project Page / Paper / Code - A sample-based approach to risk-averse trajectory optimization.

Robotic Table Wiping via Reinforcement Learning and Whole-body Trajectory Optimization - T. Lew, S. Singh, M. Prats, J. Bingham, J. Weisz, B. Holson, X. Zhang, V. Sindhwani, Y. Lu, F. Xia, P. Xu, T. Zhang, J. Tan, M. Gonzalez - ICRA - 2023
Project Page / Paper / Blog Post / Video - We propose an effective strategy for table wiping combining the strengths of reinforcement learning and whole-body trajectory optimization.

Sequential convex programming for non-linear stochastic optimal control - R. Bonalli, T. Lew, M. Pavone - ESAIM: COCV - 2022
Project Page / Paper / Code - We propose a sequential convex programming framework for non-linear finite-dimensional stochastic optimal control.

Convex Optimization for Trajectory Generation: A Tutorial on Generating Dynamically Feasible Trajectories Reliably and Efficiently - D. Malyuta, T. Reynolds, M. Szmuk, T. Lew, R. Bonalli, M. Pavone, B. Açıkmeşe - CSM - Outstanding Paper Award - 2022
Project Page / Paper / Code - A comprehensive tutorial on convex trajectory optimization.

Robust-RRT: Probabilistically-Complete Motion Planning for Uncertain Nonlinear Systems - A. Wu, T. Lew, K. Solovey, E. Schmerling, M. Pavone - ISRR - 2022
Project Page / Paper / Code - A robust sampling-based motion planning algorithm.

A Simple and Efficient Sampling-based Algorithm for General Reachability Analysis - T. Lew, L. Janson, R. Bonalli, M. Pavone - L4DC - 2022
Project Page / Paper / Code / Video - We analyze a sampling-based reachability analysis algorithm.

Data-Driven Chance Constrained Control using Kernel Distribution Embeddings - A. J. Thorpe*, T. Lew*, M. M. K. Oishi, M. Pavone - L4DC - 2022
Project Page / Paper / Code - We present a data-driven algorithm for efficiently computing stochastic control policies for general joint chance constrained optimal control problems.

Analysis of theoretical and numerical properties of sequential convex programming for continuous-time optimal control - R. Bonalli, T. Lew, M. Pavone - TAC - 2022
Project Page / Paper / Code - We analyze general SCP procedures for continuous-time optimal control.

Safe Active Dynamics Learning and Control: A Sequential Exploration-Exploitation Framework - T. Lew, A. Sharma, J. Harrison, A. Bylard, M. Pavone - T-RO - 2022
Project Page / Paper / Video / More Hardware Results - How can robots safely learn their dynamics?

Nebula: Quest for robotic autonomy in challenging environments; team costar at the darpa subterranean challenge - A. Agha-mohammadi et al - JFR - 2022
Project Page / Paper / CoSTAR-NeBula website - We present the algorithms, hardware, and software architecture deployed by the team CoSTAR in the DARPA SubT Challenge.

Control Barrier Functions for Cyber-Physical Systems and Applications to NMPC - J. Schilliger, T. Lew, S. Richards, S. Hänggi, M. Pavone, C. Onder - RA-L - 2021
Project Page / Paper - We propose a CBF formulation that accounts for delays.

Sampling-based Reachability Analysis: A Random Set Theory Approach with Adversarial Sampling - T. Lew, M. Pavone - CoRL - 2020
Project Page / Paper / Video / Code - New efficient sampling-based reachability analysis algorithms.

Chance-Constrained Sequential Convex Programming for Robust Trajectory Optimization - T. Lew, R. Bonalli, M. Pavone - ECC - 2020
Project Page / Paper / Code - We propose an algorithm for chance-constrained trajectory optimization.

Learning-based warm-starting for fast sequential convex programming and trajectory optimization - S. Banerjee, T. Lew, R. Bonalli, A. Alfaadhel, I. Alomar, H. Shageer, M. Pavone - AeroConf - 2020
Project Page / Paper / Code - A learning-based strategy to warm-start trajectory optimization tools.

Contact Inertial Odometry: Collisions are your Friends - T. Lew*, T. Emmei*, D. Fan, T. Bartlett, A. Santamaria-Navarro, R. Thakker, A. Agha-mohammadi - ISRR - 2019
Project Page / Paper / Video - How can a drone fly blindly, when all its exteroceptive sensors have failed?

Chance-Constrained Optimal Altitude Control of a Rocket - T. Lew, F. Lyck, G. Müller - EUCASS - 2nd Best Student Paper Award in Flight Dynamics, GNC and Avionics - 2019
Project Page / Paper / Launch Video / ARIS website - We propose a control algorithm for a rocket to accurately reach a target apogee.

Investigation of specific wheel-terrain interaction aspects using an advanced single wheel test facility - P. Oettershagen, T. Lew, A. Tardy, S. Michaud - ASTRA - 2019
Project Page / Paper - We identify limitations of wheel-soil interaction models and present a new method.

Trajectory optimization on manifolds: A theoretically-guaranteed embedded sequential convex programming approach - R. Bonalli, A. Bylard, A. Cauligi, T. Lew, M. Pavone - RSS - 2019
Project Page / Paper / Code - A new SCP trajectory optimization algorithm on manifolds.