Bio-Artificial Synergies for Grasp Posture Control of Supernumerary Robotic Fingers

A new type of wrist-mounted robot, the Supernumerary Robotic (SR) Fingers, is proposed to work closely with the human hand and aid the human in performing a variety of prehensile tasks. For people with diminished functionality of their hands, these robotic fingers could provide the opportunity to live with more independence and work more productively. A natural and implicit coordination between the SR Fingers and the human fingers is required so the robot can be transformed to act as part of the human body. This paper presents a novel control algorithm, termed “Bio-Artificial Synergies”, which enables the SR and human fingers to share the task load together and adapt to diverse task conditions. Through grasp experiments and data analysis, postural synergies were found for a seven-fingered hand comprised of two SR Fingers and five human fingers. The synergy-based control law was then extracted from the experimental data using Partial Least Squares (PLS) regression and tested on the SR Finger prototype as a proof of concept

Augmented body: changing interactive body play

This paper investigates the player’s body as a system capable of unfamiliar interactive movement through digital mediation in a playful environment. Body interactions with both digital and non-digital environments are suggested here as a perceptually manipulative exploration area, where by a player altering how they perceive of their body and its operations can create a new playful and original experience. It questions how player interaction can change as perception of the body changes using augmentative technology

Development of Low Cost Supernumerary Robotic Fingers as an Assistive Device

This paper presents the development of new type of wearable robot namely Supernumerary Robotic Finger (SRF) as  an  assistive   robot  for  healthy  people  or  people   with hemiparesis or hemiplegia. SRF comprises of two manipulators attached  in user’s wrist. Three flex sensors are utilized to measure the finger bending of the user’s finger. The posture of SRF is driven by modified glove sensor. The kinematics of both robotic thumb (RT) and robotic finger (RF) is studied using D-H parameter method and RoboAnalyzer software in order to understand the kinematic behavior of this robot. Each of RT and RF has three degrees of freedom (DOF). The posture of RT and RF is controlled using bending angles of thumb and finger from the user that are read by flex sensor. Based on the experimental results for people with healthy hand, the proposed SRF can assist object manipulation task in grasping, holding, and manipulating an object by using single hand when normally it only can be done by using two hands. From the experimental results on a person with healthy hand, the proposed of SRF can be employed as an assistive device for people with hemiparesis or hemiplegia. This device will enable people with diminished hand function work more independently

Supernumerary Robotic Fingers as a Therapeutic Device for Hemiparetic Patients

Patients with hemiparesis often have limited functionality in the left or right hand. The standard therapeutic approach requires the patient to attempt to make use of the weak hand even though it is not functionally capable, which can result in feelings of frustration. Furthermore, hemiparetic patients also face challenges in completing many bimanual tasks, for example walker manipulation, that are critical to patients’ independence and quality of life. A prototype therapeutic device with two supernumerary robotic fingers was used to determine if robotic fingers could functionally assist a human in the performance of bimanual tasks by observing the pose of the healthy hand. Specific focus was placed on the identification of a straightforward control routine which would allow a patient to carry out simple manipulation tasks with some intermittent input from a therapist. Part of this routine involved allowing a patient to switch between active and inactive monitoring of hand position, resulting in additional manipulation capabilities. The prototype successfully enabled a test subject to complete various bimanual tasks using the robotic fingers in place of normal hand motions. From these results, it is clear that the device could allow a hemiparetic patient to complete tasks which would previously have been impossible to perform

Orochi: Investigating Requirements and Expectations for Multipurpose Daily Used Supernumerary Robotic Limbs

Supernumerary robotic limbs (SRLs) present many opportunities for daily use. However, their obtrusiveness and limitations in interaction genericity hinder their daily use. To address challenges of daily use, we extracted three design considerations from previous literature and embodied them in a wearable we call Orochi. The considerations include the following: 1) multipurpose use, 2) wearability by context, and 3) unobtrusiveness in public. We implemented Orochi as a snake-shaped robot with 25 DoFs and two end effectors, and demonstrated several novel interactions enabled by its limber design. Using Orochi, we conducted hands-on focus groups to explore how multipurpose SRLs are used daily and we conducted a survey to explore how they are perceived when used in public. Participants approved Orochi's design and proposed different use cases and postures in which it could be worn. Orochi's unobtrusive design was generally well received, yet novel interactions raise several challenges for social acceptance. We discuss the significance of our results by highlighting future research opportunities based on the design, implementation, and evaluation of Orochi

A magnetic compatible supernumerary robotic finger for functional magnetic resonance imaging (fMRI) acquisitions: Device description and preliminary results

The Supernumerary robotic limbs are a recently introduced class of wearable robots that, differently from traditional prostheses and exoskeletons, aim at adding extra effectors (i.e., arms, legs, or fingers) to the human user, rather than substituting or enhancing the natural ones. However, it is still undefined whether the use of supernumerary robotic limbs could specifically lead to neural modifications in brain dynamics. The illusion of owning the part of body has been already proven in many experimental observations, such as those relying on multisensory integration (e.g., rubber hand illusion), prosthesis and even on virtual reality. In this paper we present a description of a novel magnetic compatible supernumerary robotic finger together with preliminary observations from two functional magnetic resonance imaging (fMRI) experiments, in which brain activity was measured before and after a period of training with the robotic device, and during the use of the novel MRI-compatible version of the supernumerary robotic finger. Results showed that the usage of the MR-compatible robotic finger is safe and does not produce artifacts on MRI images. Moreover, the training with the supernumerary robotic finger recruits a network of motor-related cortical regions (i.e. primary and supplementary motor areas), hence the same motor network of a fully physiological voluntary motor gestures

Body-Borne Computers as Extensions of Self

The opportunities for wearable technologies go well beyond always-available information displays or health sensing devices. The concept of the cyborg introduced by Clynes and Kline, along with works in various fields of research and the arts, offers a vision of what technology integrated with the body can offer. This paper identifies different categories of research aimed at augmenting humans. The paper specifically focuses on three areas of augmentation of the human body and its sensorimotor capabilities: physical morphology, skin display, and somatosensory extension. We discuss how such digital extensions relate to the malleable nature of our self-image. We argue that body-borne devices are no longer simply functional apparatus, but offer a direct interplay with the mind. Finally, we also showcase some of our own projects in this area and shed light on future challenges

Low-cost Rigid-frame Exoskeleton Glove with Finger-joint Flexion Tracking Mapped onto a Robotic Hand

This thesis provides a representation of a low-cost rigid-frame exoskeleton glove that is used to track finger-joint flexion mapped onto a robotic hand to mimic user movements. The overall setup consists of an exoskeleton glove (exo-glove), sensors, a microcontroller, and a telerobotic hand. The design of the exo-glove is crafted to fit onto a left hand. SolidWorks was used for the prototype designs which were then sent to the Stratasys 400 rapid prototyping machine to be 3D printed in ABS-M30 plastic. The exo-glove houses five rotary position sensors and three flexible sensors to track angle changes of the finger joints from two fingers and a thumb. Five low-pass filters are implemented as signal filtering for the rotary position sensors. An Arduino Mega microcontroller is connected to the sensors of the exo-glove and processes the input values. Using an open-loop controller to control the robotic hand, the values processed by the microcontroller from the exo-glove are sent to the servo motors on the robotic hand to operate the corresponding fingers of the user. Throughout the initial calibration and testing phase, each sensor was tested individually to ensure the sensor functionally performs well. Signal analysis was conducted on the sensors at steady state and while in operation to show fluctuations in sensor readings and response to finger flexion. Experimental results show that averaging sensor data in the processing code yields smoother values and better precision. Due to the use of low-pass filtering with the rotary position sensors, the data sets collected were grouped together tightly compared to the flex sensors without filtering. However, the actual angles measured were not accurately portrayed in sensor readings. The true flexion angles were compared in the data samplings to find a variety of ranges spanning around the angles desired to track. Many of the actual flexion angles were offset from the sensor readings by a variation of degrees, but the data shows the sensor readings were able to follow the general magnitude of the true flexion angles. The precision seen in the data was also apparent in the robotic hand mirroring the posture. Changes in sensor readings caused jerking movements to occur in the robotic fingers but were able to maintain an overall flexion mirroring of the RF exo-glove. There is quarter-second delay between the exo-glove sensor reading and the robotic hand mirroring capability when not implementing averaging. When averaging the sensor values, there was a delay of more than half a second between the exo-glove posture and robotic hand mirroring

Conception et évaluation d'actionneurs à embrayages magnétorhéologiques pour la robotique collaborative

La robotique collaborative se démarque de la robotique industrielle par sa sécurité dans le but de travailler en collaboration avec les humains. Toutefois, la majorité des robots collaboratifs sériels reposent sur un actionnement à haut ratio de réduction, ce qui augmente considérablement la masse reflétée à l’effecteur du robot, et donc, nuit à la sécurité. Pour pallier cette masse reflétée et maintenir un seuil minimal de sécurité, les vitesses d’opération sont abaissées, nuisant ainsi directement à la productivité des entreprises. Afin de minimiser la masse reflétée à l’effecteur, les masses des actionneurs ainsi que leur inertie reflétée doivent être minimisés. Les embrayages à fluide magnétorhéologique (MR) maintenus en glissement continus découplent l’inertie provenant de la source de puissance, souvent un moteur et un réducteur, offrant ainsi un actionneur possédant un haut rapport couple-inertie. Toutefois, les embrayages MR, utilisés de façon antagoniste, ajoutent des composantes à l’actionneur ce qui réduit la densité de couple, et donc, augmente la masse reflétée à l’effecteur du robot. Certains actionneurs MR [1–3] ont été développés, mais leur basse densité de couple contrebalance leur faible inertie lorsqu’utilisés comme actionneurs aux articulations de robots collaboratifs sériels. Cette constatation a mené à ma question de recherche : Comment profiter de la faible inertie des actionneurs MR pour maximiser les performances dynamiques des robots collaboratifs sériels? L’objectif de ce projet de recherche vise donc à étudier le potentiel des embrayages MR en robotique collaborative. Pour ce faire, deux architectures MR sont développées et testées expérimentalement. La première architecture consiste en une articulation robotisée modulaire comportant des embrayages MR en glissement continu et possédant un rapport couple/masse et une taille équivalente à l’actionneur d’Universal Robots (UR) de couple égal, mais possédant un rapport couple/inertie 150 fois supérieur. À l’intérieur de l’articulation, deux chaines de puissance (2 moteurs et 2 embrayages MR) indépendantes se rejoignent à la sortie du joint offrant ainsi une redondance et augmentant la densité de couple comparativement à une architecture standard (1 moteur pour 2 embrayages MR). La deuxième architecture étudiée consiste en un actionnement délocalisé du robot où les embrayages MR sont situés à la base du robot et une transmission hydrostatique à membranes déroulantes achemine la puissance aux articulations. Cette architecture a été testée expérimentalement dans un contexte de bras robotisé surnuméraire. Contrairement à l’articulation MR, cette architecture n’offre pas une modularité habituellement recherchée en robotique sérielle, mais offre la possibilité de réduire l’inertie de la structure avec la délocalisation de l’actionnement. Finalement, les deux architectures développées ont été comparées à une architecture standard (haut ratio avec réducteur harmonique) afin de situer le potentiel du MR en robotique collaborative. Cette analyse théorique a démontré que pour un robot collaboratif sériel à 6 degrés de liberté, les architectures MR ont le potentiel d’accélérer 6 et 3 fois plus (respectivement) que le robot standard d’UR, composé d’actionneurs à hauts ratios