62 research outputs found
Etude, conception et réalisation d'un capteur de micro et nano-forces. Application à la mesure d'élasticité des ovocytes.
No full textIn the microrobotic field, the handling of small objects is needed. In order to characterize interactions in the considered working dimensions, force measurements is necessary. Accordingly, we developed a force sensor which uses a passive magnetic levitation principle. Thus, we did not need control loop to ensure the levitation. Total dimensions of the sensor did not exceed a volume of 170 mm x 100 mm x 60 mm. The sensor is formed of a polymeric material leg, being used as effector, on which two permanent magnets are fixed. The leg unit and permanent magnets levitate between two graphite plates using a particular configuration of magnetic bearing. Force measurements with the developed sensor can be done mainly along three directions. The use of this sensor makes it possible to perform force measurements in the range of a few tens of nanonewton (nN) to several milliNewton (mN) with a nanNewton resolution. Both of the magnetic and diamagnetic modeling make it possible to calculate forces according to the position of the suspended magnets. This sensor is currently used for determination of the mechanical characteristics of human cells such as oocyte. This work is undertaken in close cooperation with fertilization team of the CHU of Besançon.Dans le domaine de la microrobotique, la manipulation d'objets de petites tailles (micromécanismes, cellules, etc...) est courante. Afin de caractériser les interactions aux dimensions de travail considérées, la mesure de force en microrobotique est nécessaire. Dans cette optique, nous avons développé un capteur de forces qui repose sur un principe de lévitation magnétique passive et ne nécessitant pas d'asservissement pour assurer la lévitation. Les dimensions globales du capteur n'excèdent pas un volume total de 170 mm x 100 mm x 60 mm. Le capteur est composé d'une tige en matériau polymère, servant d'effecteur, sur laquelle sont fixés deux aimants permanents. L'ensemble tige et aimants permanents lévite entre deux plaques de graphite à l'aide d'une configuration particulière d'aimants porteurs. La mesure de force avec le capteur développé peut se faire principalement suivant trois directions. L'utilisation de ce capteur permet de couvrir une plage de mesure deforce allant de quelques dizaines de nanonewton (nN) à plusieurs milliNewton (mN) avec une résolution de mesure de l'ordre du nanoNewton (nN). Les modèles magnétiques et diamagnétique développés permettent de déterminer les forces qui s'appliquent sur l'effecteur par le biais de la connaissance de la position spatiale de la tige. En terme applicatif, le capteur de forces est actuellement utilisé pour la détermination des caractéristiques mécaniques de cellules humaines de type ovocyte. Ce travail est mené en étroite collaboration avec l'équipe de fécondation in vitro du CHU de Besançon
Design and Study of a Smart Cup for Monitoring the Arm and Hand Activity of Stroke Patients
No full textInternational audienceThis paper presents a new platform to monitor the arm and hand activity of stroke patientsduring rehabilitation exercises in the hospital and at home during their daily living activities. The platformprovides relevant data to the therapist in order to assess the patients physical state and adapt the rehabilitationprogram if necessary. The platform consists of a self-contained smart cup that can be used to perform exercisesthat are similar to everyday tasks such as drinking. The first smart cup prototype, the design of which wasbased on interviews regarding the needs of therapists, contains various sensors that collect information aboutits orientation, the liquid level, its position compared to a reference target and tremors. The prototype alsoincludes audio and visual displays that provide feedback to patients about their movements. Two studies werecarried out in conjunction with healthcare professionals and patients. The first study focused on collectingfeedback from healthcare professionals to assess the functionalities of the cup and to improve the prototype.Based on this paper, we designed an improved prototype and created a visualization tool for therapists. Finally,we carried out a preliminary study involving nine patients who had experienced an ischemic or hemorrhagicstroke in the previous 24 months. This preliminary study focused on assessing the usability and acceptabilityof the cup to the patients. The results showed that the cup was very well accepted by eight of the nine patientsin monitoring their activity within a rehabilitation center or at home. Moreover, these eight patients had almostno concerns about the design of the cup and its usability
A Case Study On Sensors And Techniques For Pedestrian Inertial Navigation
No full textInternational audienceThe interest in location based services is growing in several applications. The literature exhibits a wide spectrum of technology to complement the well-knwon limitations of satellite based positioning systems in constrained environments such as indoors or urban canyons. This paper focuses on inertial sensors and systems to locate pedestrians indoor without infrastructure. The theoretical background of a recently developped beltmounted inertial navigation system (INS) is carefully depicted here. The approach aims to facilitate the equipment and the mobility of the users while maintaining repeatable performance. Therefore, a comparison of the performance in realistic conditions is carried out between foot-mounted and belt-mounted techniques given an inertial measurement unit (IMU) commercialized by XSens. Then, this commercial IMU and an IMU based on ADXL345 and ITG3200 were compared, given the belt-mounted algorithm, in terms of positioning performance. The results, supported by dozens of experiments involving different participants, show that the belt-mounted technique is as efficient as the foot-mounted one since the average error in position is less than 2% of the travelled distance about 200m. Whereas their costs are very different, the commercial and the integrated IMU reach a similar accuracy. The beltmounted device achieve repeatable and efficient pedestrian indoor positioning in real-time with low-cost inertial sensors
Smart Objects Ecosystem for Post-Stroke Upper Limbs' Motor Functions Monitoring
No full textInternational audienc
Tactile sensing for dexterous in-hand manipulation in robotics—A review
No full textAs the field of robotics is expanding from the fixed environment of a production line to complex human environments, robots are required to perform increasingly human-like manipulation tasks, moving the state-of-the-art in robotics from grasping to advanced in-hand manipulation tasks such as regrasping, rotation and translation. To achieve advanced in-hand manipulation tasks, robotic hands are required to be equipped with distributed tactile sensing that can continuously provide information about the magnitude and direction of forces at all contact points between them and the objects they are interacting with. This paper reviews the state-of-the-art in force and tactile sensing technologies that can be suitable within the specific context of dexterous in-hand manipulation. In previous reviews of tactile sensing for robotic manipulation, the specific functional and technical requirements of dexterous in-hand manipulation, as compared to grasping, are in general not taken into account. This paper provides a review of models describing human hand activity and movements, and a set of functional and technical specifications for in-hand manipulation is defined. The paper proceeds to review the current state-of-the-art tactile sensor solutions that fulfil or can fulfil these criteria. An analytical comparison of the reviewed solutions is presented, and the advantages and disadvantages of different sensing technologies are compared. (C) 2011 Elsevier B.V. All rights reserved
Micro Systems for the Mechanical Characterization of Isolated Biological Cells: State-of-the-Art
No full textActuation means for the mechanical stimulation of living cells via microelectromechanical systems: A critical review
No full textInternational audienceWithin a living body, cells are constantly exposed to various mechanical constraints. As a matter of fact, these mechanical factors play a vital role in the regulation of the cell state. It is widely recognized that cells can sense, react and adapt themselves to mechanical stimulation. However, investigations aimed at studying cell mechanics directly in vivo remain elusive. An alternative solution is to study cell mechanics via in vitro experiments. Nevertheless, this requires implementing means to mimic the stresses that cells naturally undergo in their physiological environment. In this paper, we survey various microelectromechanical systems (MEMS) dedicated to the mechanical stimulation of living cells. In particular , we focus on their actuation means as well as their inherent capabilities to stimulate a given amount of cells. Thereby, we report actuation means dependent upon the fact they can provide stimulation to a single cell, target a maximum of a hundred cells, or deal with thousands of cells. Intrinsic performances, strengths and limitations are summarized for each type of actuator. We also discuss recent achievements as well as future challenges of cell mechanostimulation
Study of a smart cup for home monitoring of the arm and hand of stroke patients.
No full textConference of 18th International ACM SIGACCESS Conference on Computers and Accessibility, ASSETS 2016 ; Conference Date: 24 October 2016 Through 26 October 2016; Conference Code:124437International audienceIn this work, we present a platform for continuously monitor and guide stroke patient at home during Activities of the Daily Living. The platform consists of a smart cup which embeds sensors that monitor the patient's hand and arm motor activity at different times of the day. The cup detects its orientation, the liquid level, its position on a specific target, as well as tremors. Moreover, displays are provided to guide the patient's movement. Finally, the planned studies with both the therapists and patients are presented
SyMPATHy: Smart glass for Monitoring and guiding stroke PATients in a Home-based context
No full textConference of 8th ACM SIGCHI Symposium on Engineering Interactive Computing Systems, EICS 2016 ; Conference Date: 21 June 2016 Through 24 June 2016; Conference Code:122402International audienceThis paper presents a solution to monitor and guide stroke patients during Activities of the Daily Living. It consists of a self-content smart glass that the patient can use to drink at different times of the day (water, coffee, etc.). The smart glass embeds a series of sensors that track in a transparent way the patients activity in everyday life (glass orientation, liquid level, target reaching and tremors). This solution allows therapists to monitor and analyze easily the Activities of the Daily Living of the patient in order to adapt the weekly rehabilitation sessions with suitable exercises. In addition, the smart glass embeds visual displays aimed at providing gestural guidance information when the patient do not use properly the glass. The paper presents the first prototype of the smart glass by highlighting the methodology adopted to design the software and hardware components of the platform
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