Laurent Praly
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View article: On the existence of KKL observers with nonlinear contracting dynamics (Long Version)
On the existence of KKL observers with nonlinear contracting dynamics (Long Version) Open
KKL (Kazantzis-Kravaris/Luenberger) observers are based on the idea of immersing a given nonlinear system into a target system that is a linear stable filter of the measured output. In the present paper, we extend this theory by allowing t…
View article: Convergence of Nonlinear Observers on R^n with a Riemannian Metric (Part III)
Convergence of Nonlinear Observers on R^n with a Riemannian Metric (Part III) Open
This paper is the third and final component of a three-part effort on observers contracting a Riemannian distance between the state of the system and its estimate. In Part I, we showed that such a contraction property holds if the system d…
View article: Characterizations of Global Transversal Exponential Stability
Characterizations of Global Transversal Exponential Stability Open
We study the relationship between the global exponential stability of an invariant manifold and the existence of a positive semi-definite Riemannian metric which is contracted by the flow. In particular, we investigate how the following pr…
View article: Characterizations of global transversal exponential stability (long version)
Characterizations of global transversal exponential stability (long version) Open
We study the relationship between the global exponential stability of an invariant manifold and the existence of a positive semi-definite Riemannian metric which is contracted by the flow. In particular, we investigate how the following pr…
View article: Estimation of Position and Resistance of a Sensorless PMSM: A Nonlinear Luenberger Approach for a Nonobservable System
Estimation of Position and Resistance of a Sensorless PMSM: A Nonlinear Luenberger Approach for a Nonobservable System Open
We show that the pair (rotor position, resistance) of a nonsalient permanent magnet synchronous motor (PMSM) is not observable in the sensorless setting, namely, when only the electrical signals (voltages and intensities) are measured. How…
View article: Francis-Wonham nonlinear viewpoint in output regulation of minimum phase systems
Francis-Wonham nonlinear viewpoint in output regulation of minimum phase systems Open
International audience
View article: About Robustness of Internal Model-Based Control for Linear and Nonlinear Systems
About Robustness of Internal Model-Based Control for Linear and Nonlinear Systems Open
In this paper we propose a general framework in which the robustness properties and requirements of output regulation schemes can be formally described. We introduce a topological definition of robustness relative to arbitrary steady state…
View article: Expressing an Observer in Preferred Coordinates by Transforming an Injective Immersion into a Surjective Diffeomorphism
Expressing an Observer in Preferred Coordinates by Transforming an Injective Immersion into a Surjective Diffeomorphism Open
When designing observers for nonlinear systems, the dynamics of the given system and of the designed observer are usually not expressed in the same coordinates or even have states evolving in different spaces. In general, the function, den…
View article: Robustness of rotor position observer for permanent magnet synchronous motors with unknown magnet flux
Robustness of rotor position observer for permanent magnet synchronous motors with unknown magnet flux Open
We introduce a new sensorless rotor position observer for permanent magnet synchronous motors which does not require the knowledge of the magnet's flux : only electrical measurements and (approximate) knowledge of the resistance and induct…
View article: Convergence of the gradient algorithm for linear regression models in the continuous and discrete time cases
Convergence of the gradient algorithm for linear regression models in the continuous and discrete time cases Open
We establish convergence to zero of the solutions of \dot \tilde θ(t) = −φ(t)φ(t) \tilde θ(t) or \tilde θ(t) = \tilde θ(t − 1) − φ(t)φ(t) \tilde θ(t − 1) under a possibly vanishing persistent excitation condition.
View article: First Steps Towards Translating HZD Control of Bipedal Robots to Decentralized Control of Exoskeletons
First Steps Towards Translating HZD Control of Bipedal Robots to Decentralized Control of Exoskeletons Open
This paper presents preliminary results toward translating gait and control design for bipedal robots to decentralized control of an exoskeleton aimed at restoring mobility to patients with lower limb paralysis, without the need for crutch…
View article: Transverse Exponential Stability and Applications
Transverse Exponential Stability and Applications Open
We investigate how the following properties are related to each other: i)-A\nmanifold is "transversally" exponentially stable; ii)-The "transverse"\nlinearization along any solution in the manifold is exponentially stable;\niii)-There exis…
View article: Transverse exponential stability and applications
Transverse exponential stability and applications Open
We investigate how the following properties are related to each other: i)-A manifold is "transversally" exponentially stable; ii)-The "transverse" linearization along any solution in the manifold is exponentially stable; iii)-There exists …
View article: Non Lipschitz triangular canonical form for uniformly observable controlled systems
Non Lipschitz triangular canonical form for uniformly observable controlled systems Open
We study the problem of designing observers for controlled systems which are uniformly observable and differentially observable, but with an order larger than the system state dimension : we have only an injection, and not a diffeomorphism…
View article: Sensitivity to High-Frequency Measurement Noise of Nonlinear High-Gain Observers
Sensitivity to High-Frequency Measurement Noise of Nonlinear High-Gain Observers Open
This paper deals with the characterisation of the sensitivity to high-frequency measurement noise of nonlinear high-gain observers. The proposed tool provides bounds for the steady-state estimate in presence of noise when the high-gain par…
View article: Approximate regulation for nonlinear systems in presence of periodic disturbances
Approximate regulation for nonlinear systems in presence of periodic disturbances Open
International audience
View article: NONLINEAR OBSERVER IN THE ORIGINAL COORDINATES WITH DIFFEOMORPHISM EXTENSION AND JACOBIAN COMPLETION
NONLINEAR OBSERVER IN THE ORIGINAL COORDINATES WITH DIFFEOMORPHISM EXTENSION AND JACOBIAN COMPLETION Open
Typical difficulties we face in implementing observers in applications are: – because of physical constraints or observability singularities, the estimated state should remain in some restricted region of the system state manifold ; – obse…
View article: Integral Action in Output Feedback for multi-input multi-output nonlinear systems
Integral Action in Output Feedback for multi-input multi-output nonlinear systems Open
We address a particular problem of output regulation for multi-input multi-output nonlinear systems. Specifically, we are interested in making the stability of an equilibrium point and the regulation to zero of an output, robust to (small)…
View article: On diffeomorphism extension
On diffeomorphism extension Open
We state and prove a result concerning the fact that a diffeomorphism can be " extended " in such a way that its image is R^n