Search Results for author: Brett T. Lopez

Found 10 papers, 3 papers with code

FaSTraP: Fast and Safe Trajectory Planner for Flights in Unknown Environments

3 code implementations8 Mar 2019 Jesus Tordesillas, Brett T. Lopez, Jonathan P. How

The desire of maintaining computational tractability typically leads to optimization problems that do not include the obstacles (collision checks are done on the solutions) or to formulations that use a convex decomposition of the free space and then impose an ad hoc allocation of each interval of the trajectory in a specific polyhedron.

Robotics

FASTER: Fast and Safe Trajectory Planner for Navigation in Unknown Environments

2 code implementations9 Jan 2020 Jesus Tordesillas, Brett T. Lopez, Michael Everett, Jonathan P. How

The standard approaches that ensure safety by enforcing a "stop" condition in the free-known space can severely limit the speed of the vehicle, especially in situations where much of the world is unknown.

Motion Planning Trajectory Planning

Real-Time Planning with Multi-Fidelity Models for Agile Flights in Unknown Environments

2 code implementations2 Oct 2018 Jesus Tordesillas, Brett T. Lopez, John Carter, John Ware, Jonathan P. How

However, in unknown environments, this approach can lead to erratic or unstable behavior due to the interaction between the global planner, whose solution is changing constantly, and the local planner; a consequence of not capturing higher-order dynamics in the global plan.

Robotics

Hierarchical Bayesian Noise Inference for Robust Real-time Probabilistic Object Classification

no code implementations3 May 2016 Shayegan Omidshafiei, Brett T. Lopez, Jonathan P. How, John Vian

This paper presents an approach for filtering sequences of object classification probabilities using online modeling of the noise characteristics of the classifier outputs.

Classification Decision Making +4

Unsupervised Monocular Depth Learning with Integrated Intrinsics and Spatio-Temporal Constraints

no code implementations2 Nov 2020 Kenny Chen, Alexandra Pogue, Brett T. Lopez, Ali-akbar Agha-mohammadi, Ankur Mehta

Monocular depth inference has gained tremendous attention from researchers in recent years and remains as a promising replacement for expensive time-of-flight sensors, but issues with scale acquisition and implementation overhead still plague these systems.

Universal Adaptive Control of Nonlinear Systems

no code implementations31 Dec 2020 Brett T. Lopez, Jean-Jacques E. Slotine

This work develops a new direct adaptive control framework that extends the certainty equivalence principle to general nonlinear systems with unmatched model uncertainties.

Motion Planning Transfer Learning

Adaptive Variants of Optimal Feedback Policies

no code implementations6 Apr 2021 Brett T. Lopez, Jean-Jacques E. Slotine

The stable combination of optimal feedback policies with online learning is studied in a new control-theoretic framework for uncertain nonlinear systems.

Transfer Learning

Unmatched Control Barrier Functions: Certainty Equivalence Adaptive Safety

no code implementations28 Jul 2022 Brett T. Lopez, Jean-Jacques Slotine

This work applies universal adaptive control to control barrier functions to achieve forward invariance of a safe set despite the presence of unmatched parametric uncertainties.

Adaptive Robust Control Contraction Metrics: Transient Bounds in Adaptive Control with Unmatched Uncertainties

no code implementations20 Oct 2023 Samuel G. Gessow, Brett T. Lopez

This work presents a new sufficient condition for synthesizing nonlinear controllers that yield bounded closed-loop tracking error transients despite the presence of unmatched uncertainties that are concurrently being learned online.

Model Predictive Control

Dynamic Adaptation Gains for Nonlinear Systems with Unmatched Uncertainties

no code implementations9 Nov 2023 Brett T. Lopez, Jean-Jacques Slotine

We present a new direct adaptive control approach for nonlinear systems with unmatched and matched uncertainties.

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