Search Results for author: Ruigang Wang

Found 16 papers, 6 papers with code

Learning Stable and Passive Neural Differential Equations

1 code implementation19 Apr 2024 Jing Cheng, Ruigang Wang, Ian R. Manchester

We take a recently proposed Polyak Lojasiewicz network (PLNet) as an Lyapunov function and then parameterize the vector field as the descent directions of the Lyapunov function.

Monotone, Bi-Lipschitz, and Polyak-Lojasiewicz Networks

no code implementations2 Feb 2024 Ruigang Wang, Krishnamurthy Dvijotham, Ian R. Manchester

This paper presents a new \emph{bi-Lipschitz} invertible neural network, the BiLipNet, which has the ability to control both its \emph{Lipschitzness} (output sensitivity to input perturbations) and \emph{inverse Lipschitzness} (input distinguishability from different outputs).

Learning Over Contracting and Lipschitz Closed-Loops for Partially-Observed Nonlinear Systems (Extended Version)

1 code implementation12 Apr 2023 Nicholas H. Barbara, Ruigang Wang, Ian R. Manchester

This paper presents a policy parameterization for learning-based control on nonlinear, partially-observed dynamical systems.

Learning Stable and Robust Linear Parameter-Varying State-Space Models

no code implementations4 Apr 2023 Chris Verhoek, Ruigang Wang, Roland Tóth

This paper presents two direct parameterizations of stable and robust linear parameter-varying state-space (LPV-SS) models.

Lipschitz-bounded 1D convolutional neural networks using the Cayley transform and the controllability Gramian

1 code implementation20 Mar 2023 Patricia Pauli, Ruigang Wang, Ian R. Manchester, Frank Allgöwer

We establish a layer-wise parameterization for 1D convolutional neural networks (CNNs) with built-in end-to-end robustness guarantees.

Direct Parameterization of Lipschitz-Bounded Deep Networks

2 code implementations27 Jan 2023 Ruigang Wang, Ian R. Manchester

This paper introduces a new parameterization of deep neural networks (both fully-connected and convolutional) with guaranteed $\ell^2$ Lipschitz bounds, i. e. limited sensitivity to input perturbations.

Image Classification

Learning over All Stabilizing Nonlinear Controllers for a Partially-Observed Linear System

no code implementations8 Dec 2021 Ruigang Wang, Nicholas H. Barbara, Max Revay, Ian R. Manchester

This paper proposes a nonlinear policy architecture for control of partially-observed linear dynamical systems providing built-in closed-loop stability guarantees.

Reinforcement Learning (RL)

Youla-REN: Learning Nonlinear Feedback Policies with Robust Stability Guarantees

no code implementations2 Dec 2021 Ruigang Wang, Ian R. Manchester

This paper presents a parameterization of nonlinear controllers for uncertain systems building on a recently developed neural network architecture, called the recurrent equilibrium network (REN), and a nonlinear version of the Youla parameterization.

Contraction-Based Methods for Stable Identification and Robust Machine Learning: a Tutorial

no code implementations1 Oct 2021 Ian R. Manchester, Max Revay, Ruigang Wang

This tutorial paper provides an introduction to recently developed tools for machine learning, especially learning dynamical systems (system identification), with stability and robustness constraints.

BIG-bench Machine Learning

Recurrent Equilibrium Networks: Flexible Dynamic Models with Guaranteed Stability and Robustness

1 code implementation13 Apr 2021 Max Revay, Ruigang Wang, Ian R. Manchester

RENs are otherwise very flexible: they can represent all stable linear systems, all previously-known sets of contracting recurrent neural networks and echo state networks, all deep feedforward neural networks, and all stable Wiener/Hammerstein models, and can approximate all fading-memory and contracting nonlinear systems.

Nonlinear parameter-varying state-feedback design for a gyroscope using virtual control contraction metrics

no code implementations11 Apr 2021 Ruigang Wang, Patrick J. W. Koelwijn, Ian R. Manchester, Roland Tóth

In this paper, we present a virtual control contraction metric (VCCM) based nonlinear parameter-varying (NPV) approach to design a state-feedback controller for a control moment gyroscope (CMG) to track a user-defined trajectory set.

Lipschitz-Bounded Equilibrium Networks

no code implementations1 Jan 2021 Max Revay, Ruigang Wang, Ian Manchester

In image classification experiments we show that the Lipschitz bounds are very accurate and improve robustness to adversarial attacks.

Generalization Bounds Image Classification

Lipschitz Bounded Equilibrium Networks

no code implementations5 Oct 2020 Max Revay, Ruigang Wang, Ian R. Manchester

In image classification experiments we show that the Lipschitz bounds are very accurate and improve robustness to adversarial attacks.

Generalization Bounds Image Classification

A Convex Parameterization of Robust Recurrent Neural Networks

no code implementations11 Apr 2020 Max Revay, Ruigang Wang, Ian R. Manchester

Recurrent neural networks (RNNs) are a class of nonlinear dynamical systems often used to model sequence-to-sequence maps.

Virtual Control Contraction Metrics: Convex Nonlinear Feedback Design via Behavioral Embedding

no code implementations18 Mar 2020 Ruigang Wang, Roland Tóth, Patrick J. W. Koelwijn, Ian R. Manchester

This paper presents a systematic approach to nonlinear state-feedback control design that has three main advantages: (i) it ensures exponential stability and $ \mathcal{L}_2 $-gain performance with respect to a user-defined set of reference trajectories, and (ii) it provides constructive conditions based on convex optimization and a path-integral-based control realization, and (iii) it is less restrictive than previous similar approaches.

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