A Separation Principle on Lie Groups

For linear time-invariant systems, a separation principle holds: stable observer and stable state feedback can be designed for the time-invariant system, and the combined observer and feedback will be stable. For non-linear systems, a local separation principle holds around steady-states, as the linearized system is time-invariant. This paper addresses the issue of a non-linear separation principle on Lie groups. For invariant systems on Lie groups, we prove there exists a large set of (time-varying) trajectories around which the linearized observer-controler system is time-invariant, as soon as a symmetry-preserving observer is used. Thus a separation principle holds around those trajectories. The theory is illustrated by a mobile robot example, and the developed ideas are then extended to a class of Lagrangian mechanical systems on Lie groups described by Euler-Poincare equations.Comment: Submitted to IFAC 201

Invariant observers for attitude and heading estimation from low-cost inertial and magnetic sensors

International audienceIn this paper we propose invariant nonlinear observers for attitude and heading estimation using directly the measurements from low-cost inertial and magnetic sensors. In particular we propose a simple and easy-to-tune observer where moreover the estimated attitude behaves well even in the presence of magnetic disturbances

Estimation d'état pour les drones aériens

Ce papier fait un (petit) tour d'horizon des problèmes d'estimation d'état dans le cadre des (mini)-drones aériens ; il aborde la question sous l'angle à la fois des algorithmes et de l'information qu'on peut tirer des capteurs les plus courants, en particulier accéléromètres et gyroscopes

A general symmetry-preserving observer for aided attitude heading reference systems

International audienceWe generalize several recent works on nonlinear observers for aided attitude heading reference systems: we propose a symmetry-preserving nonlinear observer which merges the most common measurements available on an aircraft (altitude, Earth-fixed and body-fixed velocity, inertial and magnetic sensors). It can be seen as an alternative to the Extended Kalman Filter, but easier to tune and computationally much more economic. Moreover it has by design a nice geometrical structure appealing from an engineering viewpoint. We illustrate its good performance on simulation and experimental results

The True Role of Accelerometer Feedback in Quadrotor Control

A revisited quadrotor model is proposed, including in particular the so-called rotor drag. It differs from the model usually considered, even at first order, and much better explains the role of accelerometer feedback in control algorithms. The theoretical derivation is supported by experimental data

AUTOMATED MODEL-BASED REORGANIZATION OF SPEECH-TO-TEXT TRANSCRIPTS

Techniques are presented herein that support the automated reorganization of a meeting transcript. According to the presented techniques, when a meeting is recorded it is first transcribed through an automated speech-to-text system. Then, the resulting raw document is decomposed into sections corresponding to different topics, the topics are reorganized into a more coherent and intelligible structure, and missing pieces of information may be identified and then added to the document. Such postprocessing increases the intelligibility and value of meeting transcriptions and ensures that they remain understandable and useful over the long term. Aspects of the presented techniques may leverage large language models (LLMs) and automatic speech recognition (ASR) capabilities