Soft Gloves: A Review on Recent Developments in Actuation, Sensing, Control and Applications

Interest in soft gloves, both robotic and haptic, has enormously grown over the past decade, due to their inherent compliance, which makes them particularly suitable for direct interaction with the human hand. Robotic soft gloves have been developed for hand rehabilitation, for ADLs assistance, or sometimes for both. Haptic soft gloves may be applied in virtual reality (VR) applications or to give sensory feedback in combination with prostheses or to control robots. This paper presents an updated review of the state of the art of soft gloves, with a particular focus on actuation, sensing, and control, combined with a detailed analysis of the devices according to their application field. The review is organized on two levels: a prospective review allows the highlighting of the main trends in soft gloves development and applications, and an analytical review performs an in-depth analysis of the technical solutions developed and implemented in the revised scientific research. Additional minor evaluations integrate the analysis, such as a synthetic investigation of the main results in the clinical studies and trials referred in literature which involve soft gloves

Functional Materials and Techniques for Additive Manufacturing in Soft Robotics

This thesis outlines the development of new elastomeric materials and manufacturing processes for soft robotics. Specifically, this work describes the development of custom material formulations for use in additive manufacturing, additive manufacturing processing techniques for silicone elastomers, and multi-component additive manufacturing techniques. Material synthesis and processing is a gap in the field that needs more research to produce more predictable, higher quality, and more scalable soft robot technologies. This thesis includes papers that address the above topics, preceded by an introduction and literature review into additive manufacturing and materials characterization for soft robotics. The first work (Chapter 2) outlines the development of a custom elastomer designed to make biodegradable soft robots via 3D printing. The second work (Chapter 3) shows how liquid silicone thermoset polymers 3d printing can be improved by controlling reaction kinetics and rheology. The last work (Chapter 4) describes the process of using silicone 3D printing to embed multiple discrete sensing and electronic components into a functioning soft wearable device, with a focus on customizability. Each work describes a different part of how materials science plays a role in soft robotics, including the creation of elastomeric material, control of the elastomeric material, and combining the multiple materials in custom device manufacturing. For each work, a soft robot actuator or robot system is developed to emphasize the importance of material behavior and process development in improving soft robot manufacturing

Functional Soft Robotic Actuators Based on Dielectric Elastomers

Dielectric elastomer actuators (DEAs) are a promising soft actuator technology for robotics. Adding robotic functionalities--folding, variable stiffness, and adhesion--into their actuator design is a novel method to create functionalized robots with simplified actuator configurations. We first propose a foldable actuator that has a simple antagonistic DEA configuration allowing bidirectional actuation and passive folding. To prove the concept, a foldable elevon actuator with outline size of 70 mm × 130 mm is developed with a performance specification matched to a 400 mm wingspan micro air vehicle (MAV) of mass 130 g. The developed actuator exhibits actuation angles up to ± 26 ° and a torque of 2720 mN·mm in good agreement with a prediction model. During a flight, two of these integrated elevon actuators well controlled the MAV, as proven by a strong correlation of 0.7 between the control signal and the MAV motion. We next propose a variable stiffness actuator consisting of a pre-stretched DEA bonded on a low-melting-point alloy (LMPA) embedded silicone substrate. The phase of the LMPA changes between liquid and solid enabling variable stiffness of the structure, between soft and rigid states, while the DEA generates a bending actuation. A proof-of-concept actuator with dimension 40 mm length × 10mm width × 1mm thickness and a mass of 1 g is fabricated and characterized. Actuation is observed up to 47.5 ° angle and yielding up to 2.4 mN of force in the soft state. The stiffness in the rigid state is ~90 × larger than an actuator without LMPA. We develop a two-finger gripper in which the actuators act as the fingers. The rigid state allows picking up an object mass of 11 g (108 mN), to be picked up even though the actuated grasping force is only 2.4 mN. We finally propose an electroadhesion actuator that has a DEA design simultaneously maximizing electroadhesion and electrostatic actuation, while allowing self-sensing by employing an interdigitated electrode geometry. The concept is validated through development of a two-finger soft gripper, and experimental samples are characterized to address an optimal design. We observe that the proposed DEA design generates 10 × larger electroadhesion force compared to a conventional DEA design, equating to a gripper with a high holding force (3.5 N shear force for 1 cm^2) yet a low grasping force (1 mN). These features make the developed simple gripper to handle a wide range of challenging objects such as highly-deformable water balloons (35.6 g), flat paper (0.8 g), and a raw chicken egg (60.9 g), with its lightweight (1.5 g) and fast movement (100 ms to close fingers). The results in this thesis address the creation of the functionalized robots and expanding the use of DEAs in robotics

Biomechatronics: Harmonizing Mechatronic Systems with Human Beings

This eBook provides a comprehensive treatise on modern biomechatronic systems centred around human applications. A particular emphasis is given to exoskeleton designs for assistance and training with advanced interfaces in human-machine interaction. Some of these designs are validated with experimental results which the reader will find very informative as building-blocks for designing such systems. This eBook will be ideally suited to those researching in biomechatronic area with bio-feedback applications or those who are involved in high-end research on manmachine interfaces. This may also serve as a textbook for biomechatronic design at post-graduate level

The Design and Development of a NIRS Cap for Brain Activity Monitoring

RÉSUMÉ Ce mémoire de maitrise est consacrée à l'étude de casques dédiés aux systèmes d’imagerie clinique basés sur la spectroscopie proche infrarouge (SPIR) et leur rôle en portant cette technologie d'imagerie dans son objectif désigné comme un dispositif d'imagerie portable qui peut être utilisé avec des sujets mobiles. En tant qu’une composante non-électronique, les casques SPIR ont été la plupart du temps à l'écart des études, cependant, avec l'émergence de systèmes portables sur le marché, le rôle de tels casques devient essentiel, voire le chemin critique, pour stabiliser les optodes intégrés dans ces casques. Dans le cadre d'un projet multidisciplinaire de l’équipe Imaginc visant à mettre en oeuvre un dispositif d'imagerie multimodale EEG/SPIR portable, le travail présenté dans ce mémoire a été fait pour répondre aux exigences de plusieurs applications cliniques. Par conséquent, un casque dédié a été identifié permettant de maintenir le contact optodes/cuir chevelu quelle que soit la tâche demandée; En outre, le confort du patient est essentiel particulièrement pour le processus d'installation et pour les séances d'imagerie plus longues. Afin de répondre à ces préoccupations, ce mémoire a porté sur le développement de plusieurs modèles de casques qui sont actuellement utilisés dans les prototypes EEG/SPIR complétés. Cela nous a permis de réaliser la première étude comparative entre les modèles fonctionnels dans différentes conditions distinctes: statique, mouvement de la tête et de la marche. De plus, une méthode de calibration de contact des optodes a été proposée par l'identification de la pression exercée par le contact sur la tête. La pression mesurée permet de maintenir le contact du cuir chevelu/optode requise. Aussi, nous avons proposé un outil pour faire écarter les cheveux du contact optodes avec la tête. Ces dernières conceptions apporteront des solutions appropriées afin de mettre en oeuvre le casque d’enregistrement multimodal tant attendu. Le développement futur, basé sur des concepts de pinces robotiques de casques SPIR, présente un bon potentiel pour introduire des solutions d’installation efficace des optodes.----------ABSTRACT This master thesis is dedicated to the study of near-infrared spectroscopy (NIRS) caps and their role in bringing this imaging technology into its designated goal as a clinical imaging device that can be used with freely moving subjects. As a non-electronic component, NIRS caps have been mostly left out of studies, however, with the emergence of portable NIRS systems into the market, the role of NIRS caps is becoming an integral part as an optode stabilization method. As a part of a multidisciplinary project of the Imaginc group aiming to create a multimodal portable EEG/NIRS imaging device, the work presented herein was made to accommodate the requirements of several clinical applications. Thus, an ideal cap was identified as a design capable of maintaining optode/scalp contact regardless of the required task; moreover, patient comfort is essential specially for longer imaging sessions. In order to address these concerns, the thesis focused on adapting and developing several models that are currently being used in NIRS and EEG systems into our current Imaginc device. This allowed us to perform the first comparative study between the working models in various distinct conditions: static, moving the head and walking. Moreover, a method to calibrate the optode contact was suggested by identifying cap contact pressure on the head and defining the pressure required to maintain good scalp/optode contact in addition to the pressure comfort margin on the head. Also, the design of hair-clearing sockets was presented, which is the first step towards creating a system than can be used by a single person, and reducing the time needed for NIRS system installation. This study concludes by possible future development of NIRS caps based on robotic gripper concepts which may create systems that can provide good optode stability and user comfort

Tactile displays, design and evaluation

Fritschi M. Tactile displays, design and evaluation. Bielefeld: Universität Bielefeld; 2016.This thesis presents the design and development of several tactile displays, as well as their eventual integration into a framework of tactile and kinesthetic stimulation. As a basis for the design of novel devices, an extensive survey of existing actuator principles and existing realizations of tactile displays is complemented by neurobiological and psychophysical findings. The work is structured along three main goals: First, novel actuator concepts are explored whose performance can match the challenging capabilities of human tactile perception. Second, novel kinematic concepts for experimental platforms are investigated that target an almost unknown sub-modality of tactile perception: The perception of shear force. Third, a setup for integrated tactile-kinesthetic displays is realized, and a first study on the psychophysical correlation between the tactile and the kinesthetic portion of haptic information is conducted. The developed devices proved to exceed human tactile capabilities and have already been used to learn more about the human tactile sense

Soft Robotics: Design for Simplicity, Performance, and Robustness of Robots for Interaction with Humans.

This thesis deals with the design possibilities concerning the next generation of advanced Robots. Aim of the work is to study, analyse and realise artificial systems that are essentially simple, performing and robust and can live and coexist with humans. The main design guideline followed in doing so is the Soft Robotics Approach, that implies the design of systems with intrinsic mechanical compliance in their architecture. The first part of the thesis addresses design of new soft robotics actuators, or robotic muscles. At the beginning are provided information about what a robotic muscle is and what is needed to realise it. A possible classification of these systems is analysed and some criteria useful for their comparison are explained. After, a set of functional specifications and parameters is identified and defined, to characterise a specific subset of this kind of actuators, called Variable Stiffness Actuators. The selected parameters converge in a data-sheet that easily defines performance and abilities of the robotic system. A complete strategy for the design and realisation of this kind of system is provided, which takes into account their me- chanical morphology and architecture. As consequence of this, some new actuators are developed, validated and employed in the execution of complex experimental tasks. In particular the actuator VSA-Cube and its add-on, a Variable Damper, are developed as the main com- ponents of a robotics low-cost platform, called VSA-CubeBot, that v can be used as an exploratory platform for multi degrees of freedom experiments. Experimental validations and mathematical models of the system employed in multi degrees of freedom tasks (bimanual as- sembly and drawing on an uneven surface), are reported. The second part of the thesis is about the design of multi fingered hands for robots. In this part of the work the Pisa-IIT SoftHand is introduced. It is a novel robot hand prototype designed with the purpose of being as easily usable, robust and simple as an industrial gripper, while exhibiting a level of grasping versatility and an aspect comparable to that of the human hand. In the thesis the main theo- retical tool used to enable such simplification, i.e. the neuroscience– based notion of soft synergies, are briefly reviewed. The approach proposed rests on ideas coming from underactuated hand design. A synthesis method to realize a desired set of soft synergies through the principled design of adaptive underactuated mechanisms, which is called the method of adaptive synergies, is discussed. This ap- proach leads to the design of hands accommodating in principle an arbitrary number of soft synergies, as demonstrated in grasping and manipulation simulations and experiments with a prototype. As a particular instance of application of the method of adaptive syner- gies, the Pisa–IIT SoftHand is then described in detail. The design and implementation of the prototype hand are shown and its effec- tiveness demonstrated through grasping experiments. Finally, control of the Pisa/IIT Hand is considered. Few different control strategies are adopted, including an experimental setup with the use of surface Electromyographic signals