Rehabilitation of the Paralyzed Lower Limbs Using Functional Electrical Stimulation: Robust Closed Loop Control

International audienceFunctional electrical stimulation (FES) is used to excite paralyzed muscles that would otherwise be uncontrollable by paraplegic patients. Consequently, the patient could recover partially some of its lower limb functions improving thus the cardiovascular system, increasing oxygen uptake and bettering the whole quality of life. The main challenge that we face when applying FES to the paralyzed lower limbs is to avoid hyperstimulation and to defer the muscular fatigue as much as possible. One of our goals is to compute the needed patterns stimulation (current and/or pulse width) necessary to perform a desired given motion of the knee joint. This later is actuated by two groups of antagonist muscles: quadriceps and hamstrings causing respectively extension and flexion of the knee. The muscle model used in this study is based on a physio-mathematical formulation of the macroscopic Hill and microscopic Huxley concepts. Parameters of the biomechanical model (muscles-knee) were identified based on experimental measures. Afterward, we apply two robust nonlinear control strategies: the High Order Sliding Mode (HOSM) controller and the Model Predictive Controller (MPC) also known as receding horizon controller. These controllers have been evaluated in simulation to hightlight i) their performance in terms of capability of tracking a pre-defined reference trajectory and ii) the robustness against force perturbation and model mismatch. The performances of these controllers have also been compared with a classical pole placement controller

Safe Motion Planning Computation for Databasing Balanced Movement of Humanoid Robots

International audienceMotion databasing is an important topic in robotics research. Humanoid robots have a large number of degrees of freedom and their motions have to satisfy a set of constraints (balance, maximal joint torque velocity and angle values). Thus motion planning cannot efficiently be done on-line. The computation of optimal motions is performed off-line to create databases that transform the problem of large computation time into a problem of large memory space. Motion planning can be seen as a Semi-Infinite Programming problem (SIP) since it involves a finite number of variables over an infinite set of constraints. Most methods solve the SIP problem by transforming it into a finite programming one using a discretization over a prescribed grid. We show that this approach is risky because it can lead to motions which may violate one or several constraints. Then we introduce our new method for planning safe motions. It uses Interval Analysis techniques in order to achieve a safe discretization of the constraints. We show how to implement this method and use it with state-of-the-art constrained optimization packages. Then, we illustrate its capabilities for planning safe motions dedicated to the HOAP-3 humanoid robot

A New Method for Generating Safe Motions for Humanoid Robots

International audienceThis paper introduces a new method for planning safe motions for complex systems such as humanoid robots. Motion planning can be seen as a Semi-Infinite Programming problem (SIP) since it involves a finite number of variables over an infinite set of constraints. Most methods solve the SIP problem by transforming it into a finite programming one by using a discretization over a prescribed grid. We show that this approach is risky because it can lead to motions which violate one or several constraints. Then we introduce our new method for planning safe motions. It uses Interval Analysis techniques in order to achieve a safe discretization of the constraints. We show how to implement this method and use it with state-of-the-art constrained optimization packages. Then, we illustrate its capabilities for planning safe motions for the HOAP-3 humanoid robot

Vers l'utilisation de Bluetooth pour la commande à distance de robots mobiles

International audienceThis paper proposes a solution to control some remote mobile manipulators using Bluetooth technology. Some Bluetooth specifications and performances are presented as well as experimental results. A remote mobile manipulator control case is theoretically studied including the stability analysis with time delay. Some simulations results prove the robustness of this control law versus time delay

Délos : étude de morphologie urbaine - 2017

Données scientifiques produites :Délos par l’EFAWeb SIG de Délos Les travaux programmés pour l’année 2017 se sont déroulés en deux temps. Sur le terrain, les investigations se sont poursuivies, au cours de la dernière semaine d’août, dans le secteur de l’isthme de la presqu’île de Patinioti, au Nord du Stade (Fig. 1). Elles ont été suivies par une première phase d’interprétation des données recueillies en 2014. Fig. 1. La région Nord et la presqu’île de Patinioti, vues du Sud. EFA. Les opéra..

Délos : étude de morphologie urbaine - 2018

Données scientifiques produitesDélos par l’EFAWeb SIG de Délos Cette année encore les activités de terrain liées à l’exploration des secteurs urbains non fouillés, qui a été initiée en 2013, se sont poursuivies ; elles ont été suivies d’une phase de traitement des nouvelles données recueillies dans la région située au Nord du Quartier du Stade. La campagne sur le terrain avait un double objectif. Il s’agissait en premier lieu d’abonder le relevé topographique du secteur situé au Nord du Stade..

Robotic manipulation planning for shaping deformable linear objects with environmental contacts

Humans use contacts in the environment to modify the shape of deformable objects. Yet, few papers have studied the use of contacts in robotic manipulation. In this paper, we investigate the problem of robotic manipulation of cables with environmental contacts. Instead of avoiding contacts, we propose a framework that allows the robot to use them for shaping the cable. We introduce an index to quantify the contact mobility of a cable with a circular contact. Based on this index, we present a planner to plan robot motions. The planner is aided by a vision-based contact detector. The framework is validated with robot experiments on different desired cable configurations

Admittance control for collaborative dual-arm manipulation

Human-robot collaboration is an appealing solution to increase the flexibility of production lines. In this context, we propose a kinematic control strategy for dual-arm robotic platforms physically collaborating with human operators. Based on admittance control, our approach aims at improving the performance of object transportation tasks by acting on two levels: estimating and compensating gravity effects on one side, and considering human intention in the cooperative task space on the other. An experimental study using virtual reality reveals the effectiveness of our method in terms of reduced human energy expenditure