Low complex sensor-based shared control for power wheelchair navigation

International audienceMotor or visual impairments may prevent a user from steering a wheelchair effectively in indoor environments. In such cases, joystick jerks arising from uncontrolled motions may lead to collisions with obstacles. We here propose a perceptive shared control system that progressively corrects the trajectory as a user manually drives the wheelchair, by means of a sensor-based shared control law capable of smoothly avoiding obstacles. This control law is based on a low complex optimization framework validated through simulations and extensive clinical trials. The provided model uses distance information. Therefore, for low-cost considerations, we use ultrasonic sensors to measure the distances around the wheelchair. The solution therefore provides an efficient assistive tool that does not alter the quality of experience perceived by the user, while ensuring his security in hazardous situations

Comment rejoindre un groupe quand on se déplace en fauteuil ? Etude observationnelle biomécanique des interactions piétons-usagers de fauteuil roulant

International audienceL’étude et la modélisation des interactions entre piétons et usagers de fauteuil roulant électrique (FRE) est un enjeu majeur pour le développement d’assistance à la conduite de tels fauteuils, notamment pour suivre l’intention de déplacement de l’usager tout en évitant une collision avec un piéton à proximité. Pour mieux comprendre les intentions et les distances de proximité piéton-FRE lors de déplacement en groupe, nous avons demandé à un usager de FRE de rejoindre un groupe de deux piétons, marchant côte à côte. Les marcheurs se déplaçaient d’un point de départ à un point d’arrivée situé en face à 20m. Le participant en FRE arrivait perpendiculairement à la trajectoire des marcheurs. Ils devaient alors tous les trois rejoindre ensemble le point d’arrivée. 9 participants marchant (8 hommes, 1 femme, 27ans) et 3 usagers de FRE (3 hommes, 43 ans) ont participé à cette étude. 2 des usagers de FRE étaient ergothérapeutes, 1 avaient une paralysie cérébrale. Trois sessions incluant 1 usager de FRE et 3 marcheurs ont été réalisées. Chaque paire de marcheurs a réalisé 10 essais, pour un total de 20 essais par marcheur et 30 essais pour l’usager en FRE. L’analyse en cours porte sur les adaptations de mouvement de la personne en FRE et des piétons ainsi que leurs positions relatives. Il s’agit alors d’étudier le comportement d’interaction qui permet aux marcheurs et à l’usager de FRE de former un groupe, les distances de proximité ainsi que de potentielles asymétries marcheur-marcheur et marcheur usager de FRE

Low-cost robotic solutions for safe assisted power wheelchair navigation : towards a contribution to neurological rehabilitation

Alors que l’utilisation d’un fauteuil roulant permet aux personnes en situation de handicap de compenser une perte de la mobilité, certaines personnes se voient privées de l’utilisation d’un fauteuil roulant électrique. En effet, la présence de troubles cognitifs ou de la perception visuelle altère la capacité à conduire sans danger. Dans ce contexte, l’accès à la mobilité peut être amélioré par l’apport d’aides techniques adaptées permettant de compenser la perte de mobilité dans tous types d’environnements. Alors que les premiers travaux sur les fauteuils roulants intelligents datent du début des années 80, aucune solution n’est à ce jour sur le marché ou dans les centres de rééducation. Ce travail vise à proposer un ensemble de solutions d’aide à la conduite de fauteuil roulant électrique conçu en collaboration. Le développement de telles aides techniques constitue de multiples défis robotiques mêlant techniques de détection innovantes et méthodes de contrôle partagé avec l’utilisateur. Dans ce travail, un simulateur de conduite visant à appuyer la recherche et le développement de nouvelles solutions robotiques est proposé. Puis des solutions bas coût d’assistance semiautonome à la conduite en intérieur et en extérieur sont détaillées. L’évaluation avec des participants sains nous permet de valider les méthodes mathématiques mises en oeuvre et de fournir des preuves de concept des solutions proposées. Enfin, les premières évaluations cliniques avec des usagers au Pôle MPR Saint Hélier montrent la validation de de la méthode proposée en termes de satisfaction des utilisateurs.While the use of a wheelchair allows people with disabilities to compensate for a loss of mobility, people with severe disabilities are denied the use of a power wheelchair. Indeed, cognitive or visual perception impairments can affect the ability to drive safely. In this context, access to mobility can be improved by providing appropriate assistive technologies to compensate for loss of mobility in all types of environments. While the first research on smart wheelchairs dates back to the early 1980s, no solutions have yet been proposed on the market or in rehabilitation centers and other specialized structures. This work aims to propose a set of solutions for power wheelchair navigation assistance designed in close collaboration with users and therapists. The development of such assistive solutions faces multiple robotic challenges combining innovative detection techniques, shared control with the user. In this work, a driving simulator supporting research and development of new robotic solutions for wheelchair navigation assistance is proposed. Then low-cost semi-autonomous assistance solutions for navigation assistance in indoor and outdoor environments are detailed. The evaluation with able-bodied participants allows to validate the mathematical methods and provide proof of concept of the proposed solutions. Finally, the first clinical evaluations with regular users at Pôle MPR Saint Hélier show the validation of the proposed framework in terms of user satisfaction

Solutions robotiques bas coût pour l’aide à la navigation en fauteuil roulant électrique : vers une contribution dans le champ de la rééducation neurologique

While the use of a wheelchair allows people with disabilities to compensate for a loss of mobility, people with severe disabilities are denied the use of a power wheelchair. Indeed, cognitive or visual perception impairments can affect the ability to drive safely. In this context, access to mobility can be improved by providing appropriate assistive technologies to compensate for loss of mobility in all types of environments. While the first research on smart wheelchairs dates back to the early 1980s, no solutions have yet been proposed on the market or in rehabilitation centers and other specialized structures. This work aims to propose a set of solutions for power wheelchair navigation assistance designed in close collaboration with users and therapists. The development of such assistive solutions faces multiple robotic challenges combining innovative detection techniques, shared control with the user. In this work, a driving simulator supporting research and development of new robotic solutions for wheelchair navigation assistance is proposed. Then low-cost semi-autonomous assistance solutions for navigation assistance in indoor and outdoor environments are detailed. The evaluation with able-bodied participants allows to validate the mathematical methods and provide proof of concept of the proposed solutions. Finally, the first clinical evaluations with regular users at Pôle MPR Saint Hélier show the validation of the proposed framework in terms of user satisfaction.Alors que l’utilisation d’un fauteuil roulant permet aux personnes en situation de handicap de compenser une perte de la mobilité, certaines personnes se voient privées de l’utilisation d’un fauteuil roulant électrique. En effet, la présence de troubles cognitifs ou de la perception visuelle altère la capacité à conduire sans danger. Dans ce contexte, l’accès à la mobilité peut être amélioré par l’apport d’aides techniques adaptées permettant de compenser la perte de mobilité dans tous types d’environnements. Alors que les premiers travaux sur les fauteuils roulants intelligents datent du début des années 80, aucune solution n’est à ce jour sur le marché ou dans les centres de rééducation. Ce travail vise à proposer un ensemble de solutions d’aide à la conduite de fauteuil roulant électrique conçu en collaboration. Le développement de telles aides techniques constitue de multiples défis robotiques mêlant techniques de détection innovantes et méthodes de contrôle partagé avec l’utilisateur. Dans ce travail, un simulateur de conduite visant à appuyer la recherche et le développement de nouvelles solutions robotiques est proposé. Puis des solutions bas coût d’assistance semiautonome à la conduite en intérieur et en extérieur sont détaillées. L’évaluation avec des participants sains nous permet de valider les méthodes mathématiques mises en oeuvre et de fournir des preuves de concept des solutions proposées. Enfin, les premières évaluations cliniques avec des usagers au Pôle MPR Saint Hélier montrent la validation de de la méthode proposée en termes de satisfaction des utilisateurs

A shared control solution for safe assisted power wheelchair navigation in an environment consisting of negative obstacles: a proof of concept

International audienc

Model-based upper-limb gravity compensation strategies for active dynamic arm supports

International audienceNeuromuscular disorders (NMDs) may induce difficulties to perform daily life activities in autonomy. For people with NMDs affecting the upper-limb mobility, dynamic arm supports (DASs) turn out to be relevant assistive devices. In particular, active DASs benefit from an external power source to support severely impaired people. However, commercially available active devices are controlled with push buttons, which adds cognitive load and discomfort. To alleviate this issue, we propose a new force-based assistive control framework. In this preliminary work, we focus on the computation of a feedforward force to compensate upper-limb gravity. Four strategies based on a biomechanical model of the upper limb, tuned using anthropometric measurements, are proposed and evaluated. The first one is based on the potential energy of the upper-limb, the second one makes a compromise between the shoulder and elbow torques, the third one minimizes the sum of the squared user joint torques and the last one uses a probabilistic approach to minimize the expected torque norm in the presence of model uncertainties. These strategies have been evaluated quantitatively through an experiment including nine participants with an active DAS prototype. The activity of six muscles was measured and used to compute the mean effort index (MEI) which represents the global effort required to maintain the pose. A statistical analysis shows that the four strategies significantly lower the MEI (p-value < 0.001)

Model-based upper-limb gravity compensation strategies for active dynamic arm supports

International audienceNeuromuscular disorders (NMDs) may induce difficulties to perform daily life activities in autonomy. For people with NMDs affecting the upper-limb mobility, dynamic arm supports (DASs) turn out to be relevant assistive devices. In particular, active DASs benefit from an external power source to support severely impaired people. However, commercially available active devices are controlled with push buttons, which adds cognitive load and discomfort. To alleviate this issue, we propose a new force-based assistive control framework. In this preliminary work, we focus on the computation of a feedforward force to compensate upper-limb gravity. Four strategies based on a biomechanical model of the upper limb, tuned using anthropometric measurements, are proposed and evaluated. The first one is based on the potential energy of the upper-limb, the second one makes a compromise between the shoulder and elbow torques, the third one minimizes the sum of the squared user joint torques and the last one uses a probabilistic approach to minimize the expected torque norm in the presence of model uncertainties. These strategies have been evaluated quantitatively through an experiment including nine participants with an active DAS prototype. The activity of six muscles was measured and used to compute the mean effort index (MEI) which represents the global effort required to maintain the pose. A statistical analysis shows that the four strategies significantly lower the MEI (p-value < 0.001)

Model-based upper-limb gravity compensation strategies for active dynamic arm supports

International audienceNeuromuscular disorders (NMDs) may induce difficulties to perform daily life activities in autonomy. For people with NMDs affecting the upper-limb mobility, dynamic arm supports (DASs) turn out to be relevant assistive devices. In particular, active DASs benefit from an external power source to support severely impaired people. However, commercially available active devices are controlled with push buttons, which adds cognitive load and discomfort. To alleviate this issue, we propose a new force-based assistive control framework. In this preliminary work, we focus on the computation of a feedforward force to compensate upper-limb gravity. Four strategies based on a biomechanical model of the upper limb, tuned using anthropometric measurements, are proposed and evaluated. The first one is based on the potential energy of the upper-limb, the second one makes a compromise between the shoulder and elbow torques, the third one minimizes the sum of the squared user joint torques and the last one uses a probabilistic approach to minimize the expected torque norm in the presence of model uncertainties. These strategies have been evaluated quantitatively through an experiment including nine participants with an active DAS prototype. The activity of six muscles was measured and used to compute the mean effort index (MEI) which represents the global effort required to maintain the pose. A statistical analysis shows that the four strategies significantly lower the MEI (p-value < 0.001)

Design of an immersive simulator for assisted power wheelchair driving

International audienceDriving a power wheelchair is a difficult and complex visual-cognitive task. As a result, some people with visual and/or cognitive disabilities cannot access the benefits of a power wheelchair because their impairments prevent them from driving safely. In order to improve their access to mobility, we have previously designed a semi-autonomous assistive wheelchair system which progressively corrects the trajectory as the user manually drives the wheelchair and smoothly avoids obstacles. Developing and testing such systems for wheelchair driving assistance requires a significant amount of material resources and clinician time. With Virtual Reality technology, prototypes can be developed and tested in a risk-free and highly flexible Virtual Environment before equipping and testing a physical prototype. Additionally, users can " virtually " test and train more easily during the development process. In this paper, we introduce a power wheelchair driving simulator allowing the user to navigate with a standard wheelchair in an immersive 3D Virtual Environment. The simulation framework is designed to be flexible so that we can use different control inputs. In order to validate the framework, we first performed tests on the simulator with able-bodied participants during which the user's Quality of Experience (QoE) was assessed through a set of questionnaires. Results show that the simulator is a promising tool for future works as it generates a good sense of presence and requires rather low cognitive effort from users