Quelques commentaires sur la linéarisation de l'erreur de l'observation multi-sorties

International audienceCe papier donne quelques idées et commentaires sur les conditions géométriques qui permettent de dire si un système non linéaire multi sorties possède, à un changement de coordonnées près, une erreur d'observation linéaire. Plus précisément, nous allons concentrer notre point de vu sur les travaux de Krener et Respondek d'une part et ceux de Xia et Gao d'autre part. Nous allons aussi commenter le "soit disant" contre exemple de Xia et Gao. Puis, nous allons présenter l'algorithme de la linéarisation de l'erreur de l'observation par extension dynamique

Towards Human-like Walking with Biomechanical and Neuromuscular Control Features: Personalized Attachment Point Optimization Method of Cable-Driven Exoskeleton

The cable-driven exoskeleton can avoid joint misalignment, and is substantial alterations in the pattern of muscle synergy coordination, which arouse more attention in recent years to facilitate exercise for older adults and improve their overall quality of life. This study leverages principles from neuroscience and biomechanical analysis to select attachment points for cable-driven soft exoskeletons. By extracting key features of human movement, the objective is to develop a subject-specific design methodology that provides precise and personalized support in the attachment points optimization of cable-driven exoskeleton to achieve natural gait, energy efficiency, and muscle coordination controllable in the domain of human mobility and rehabilitation. To achieve this, the study first analyzes human walking experimental data and extracts biomechanical features. These features are then used to generate trajectories, allowing better natural movement under complete cable-driven exoskeleton control. Next, a genetic algorithm-based method is employed to minimize energy consumption and optimize the attachment points of the cable-driven system. This process identifies connections that are better suited for the human model, leading to improved efficiency and natural movement. By comparing the calculated elderly human model driven by exoskeleton with experimental subject in terms of joint angles, joint torques and muscle forces, the human model can successfully replicate subject movement and the cable output forces can mimic human muscle coordination. The optimized cable attachment points facilitate more natural and efficient collaboration between humans and the exoskeleton, making significant contributions to the field of assisting the elderly in rehabilitation

PLANIFICATEUR DE TRAJECTOIRE AVEC EVITEMENT D’OBSTACLE BASE SUR LA METHODE DES CONTRAINTES POUR ROBOT MOBILE

Dans ce travail nous apportant une contribution à la planification locale de trajectoires pour les robots mobiles non-holonomes avec évitement d’obstacles qui est basé sur la méthode des contraintes et certaines règles heuristiques. La méthode pose des contraintes sur les vitesses permises au robot mobile l’obligeons à s’éloigner des obstacles. Le robot mobile est doté de capteurs ultrason pour mesurer la distance minimale aux obstacles. La modélisation des obstacles et des capteurs par des formes polygonales convexes facilite l’utilisation de procédures de calcul de distance minimales. Les résultats de simulation ont montré la souplesse avec laquelle le robot mobile atteint la cible en traversant des parcours difficile

About the observability of piecewise Linear systems

International audienceIn this paper we give sufficient algebraic condition to characterize the observability of piecewise linear systems. As for the linear systems, this condition is based on the rank of a matrix associated to a piecewise linear system. This matrix takes into account all the observability matrices of the subsystems as well as the matrix of the linear switch. In this paper we give examples and a simulation to highlight our metho

About the observability of piecewise Linear systems

International audienceIn this paper we give sufficient algebraic condition to characterize the observability of piecewise linear systems. As for the linear systems, this condition is based on the rank of a matrix associated to a piecewise linear system. This matrix takes into account all the observability matrices of the subsystems as well as the matrix of the linear switch. In this paper we give examples and a simulation to highlight our metho

About the observability of piecewise dynamical system

International audienceIn this paper, we give some sufficient geometrical conditions to analyse the observability of a class of hybrid systems: piecewise-smooth dynamical systems. For the subclass of piecewise linear systems, the analysis of the observability is refined. Indeed, thanks to the algebraic structure of this subclass, we improve one of these sufficient conditions by using the rank of a matrix associated to a piecewise linear system. This matrix takes into account all the observability matrices of the subsystems as well as the switch linear function. Throughout this paper we give examples to highlight our method

Une condition algébrique pour l'observabilité d'une classe de systèmes hybrides

International audienceDans ce papier nous allons donner une condition géométrique suffisante pour caractériser l'observabilité des systèmes linéaires par morceaux. Comme pour les systèmes linéaires, notre condition est basée sur le rang d'une matrice que nous allons associer aux systèmes linéaires par morceaux. Cette matrice prend en compte toutes les matrices d'observabilité des sous-systèmes ainsi que la fonction linéaire de commutation qui définit le système. Au travers du papier, nous donnerons des exemples pour illustrer notre proposition

About the observability of piecewise dynamical system

International audienceIn this paper, we give some sufficient geometrical conditions to analyse the observability of a class of hybrid systems: piecewise-smooth dynamical systems. For the subclass of piecewise linear systems, the analysis of the observability is refined. Indeed, thanks to the algebraic structure of this subclass, we improve one of these sufficient conditions by using the rank of a matrix associated to a piecewise linear system. This matrix takes into account all the observability matrices of the subsystems as well as the switch linear function. Throughout this paper we give examples to highlight our method

New algorithm for observer error linearization with a diffeomorphism on the outputs

In this paper, we give the necessary and sufficient conditions that guarantee the existence of a diffeomorphism which allows one to transform a multi-output nonlinear dynamical system into a normal observable canonical form. In particular, we propose an algorithm that permits one to derive such diffeomorphism. The main feature of the canonical form is that it is obtained by allowing a diffeomorphism on the outputs and it also allows one to design an observer with linear error dynamics. We first consider multi-output nonlinear dynamical system without inputs. We then extend the results obtained to multi-output nonlinear dynamical system with inputs

Investigation of human-device interaction via predictive simulation

International audienceThe aim of this study is to investigate the interaction characteristics between human upper extremity limb and mobility assistance device, in order to test the effects of different device designs on human arm movement. In this paper, the role of mobility-aid for the human arm was depicted by an ideal generalized spring force appended onto the human elbow joint. The main contribution of this work resides in the use of musculoskeletal modelling and predictive simulation to describe the interaction by exploiting the variables of the equivalent spring force during an elbow flexion movement. Results showed that the different variables of the spring force would result in a variety of levels of human muscle activation, where we can draw a conclusion that interaction characteristics affect the human arm movement. Besides, it is also available for recommending the most suitable force variables in terms of minimization of muscle activation