Robotic Exoskeleton Hand with Pneumatic Actuators

With modern developments of smart portable devices and miniaturization of technologies, society has been provided with computerized assistance for almost every daily activity but the physical aspects have been frequently ne-glected. It is currently possible to make robots that process information thru neural networks, that identify and mimic facial expressions and that replace manual labour in assembly plants, getting ever closer to skills associated to human beings. In spite of these technological advances being kept close to they remain separate of humans, replacing or providing assistance with other pe-ripheral tasks, not generally adopting a direct physical symbiotic user assis-tance path. In this dissertation a robotic exoskeleton hand will be described that al-lows for human-machine bidirectional interaction making it possible to provide physical activities with the electromechanical assistance similarly. This system is designed to mimic the human hands functionalities and biomechanical struc-ture, as well sensing and controlling systems. A partial prototype was also built, using components easily acquired in the market, as a proof of concept

ReHand - a portable assistive rehabilitation hand exoskeleton

This dissertation presents a synthesis of a novel underactuated exoskeleton (namely ReHand2) thought and designed for a task-oriented rehabilitation and/or for empower the human hand. The first part of this dissertation shows the current context about the robotic rehabilitation with a focus on hand pathologies, which influence the hand capability. The chapter is concluded with the presentation of ReHand2. The second chapter describes the human hand biomechanics. Starting from the definition of human hand anatomy, passing through anthropometric data, to taxonomy on hand grasps and finger constraints, both from static and dynamic point of view. In addition, some information about the hand capability are given. The third chapter analyze the current state of the art in hand exoskeleton for rehabilitation and empower tasks. In particular, the chapter presents exoskeleton technologies, from mechanisms to sensors, passing though transmission and actuators. Finally, the current state of the art in terms of prototype and commercial products is presented. The fourth chapter introduces the concepts of underactuation with the basic explanation and the classical notation used typically in the prosthetic field. In addition, the chapter describe also the most used differential elements in the prosthetic, follow by a statical analysis. Moreover typical transmission tree at inter-finger level as well as the intra- finger underactuation are explained . The fifth chapter presents the prototype called ReHand summarizing the device description and explanation of the working principle. It describes also the kinetostatic analysis for both, inter- and the intra-finger modules. in the last section preliminary results obtained with the exoskeleton are shown and discussed, attention is pointed out on prototype’s problems that have carry out at the second version of the device. The sixth chapter describes the evolution of ReHand, describing the kinematics and dynamics behaviors. In particular, for the mathematical description is introduced the notation used in order to analyze and optimize the geometry of the entire device. The introduced model is also implemented in Matlab Simulink environment. Finally, the chapter presents the new features. The seventh chapter describes the test bench and the methodologies used to evaluate the device statical, and dynamical performances. The chapter presents and discuss the experimental results and compare them with simulated one. Finally in the last chapter the conclusion about the ReHand project are proposed as well as the future development. In particular, the idea to test de device in relevant environments. In addition some preliminary considerations about the thumb and the wrist are introduced, exploiting the possibility to modify the entire layout of the device, for instance changing the actuator location

Novel Adaptive Gripping Device for Tasks Requiring Fine Motor Control

Fine motor control is essential for a student’s success in school, and beneficial for their independence and quality of life. A C6 spinal cord injury left our client with a severe lack of fine motor control and complete paralysis below his shoulders. The goal of this project was to design and produce a novel device to aid the user in performing tasks requiring fine motor control in order to increase his independence. There are no current devices available that fit our client’s specific need. A device was designed to be lightweight, portable, easy to use, and purely mechanical. It was shown to be successful through a series of tests, allowing the client to complete tasks requiring fine motor control more quickly and efficiently than before, increasing his independence and quality of life

Impact of Ear Occlusion on In-Ear Sounds Generated by Intra-oral Behaviors

We conducted a case study with one volunteer and a recording setup to detect sounds induced by the actions: jaw clenching, tooth grinding, reading, eating, and drinking. The setup consisted of two in-ear microphones, where the left ear was semi-occluded with a commercially available earpiece and the right ear was occluded with a mouldable silicon ear piece. Investigations in the time and frequency domains demonstrated that for behaviors such as eating, tooth grinding, and reading, sounds could be recorded with both sensors. For jaw clenching, however, occluding the ear with a mouldable piece was necessary to enable its detection. This can be attributed to the fact that the mouldable ear piece sealed the ear canal and isolated it from the environment, resulting in a detectable change in pressure. In conclusion, our work suggests that detecting behaviors such as eating, grinding, reading with a semi-occluded ear is possible, whereas, behaviors such as clenching require the complete occlusion of the ear if the activity should be easily detectable. Nevertheless, the latter approach may limit real-world applicability because it hinders the hearing capabilities.</p

Novel soft bending actuator based power augmentation hand exoskeleton controlled by human intention

This article presents the development of a soft material power augmentation wearable robot using novel bending soft artificial muscles. This soft exoskeleton was developed as a human hand power augmentation system for healthy or partially hand disabled individuals. The proposed prototype serves healthy manual workers by decreasing the muscular effort needed for grasping objects. Furthermore, it is a power augmentation wearable robot for partially hand disabled or post-stroke patients, supporting and augmenting the fingers’ grasping force with minimum muscular effort in most everyday activities. This wearable robot can fit any adult hand size without the need for any mechanical system changes or calibration. Novel bending soft actuators are developed to actuate this power augmentation device. The performance of these actuators has been experimentally assessed. A geometrical kinematic analysis and mathematical output force model have been developed for the novel actuators. The performance of this mathematical model has been proven experimentally with promising results. The control system of this exoskeleton is created by hybridization between cascaded position and force closed loop intelligent controllers. The cascaded position controller is designed for the bending actuators to follow the fingers in their bending movements. The force controller is developed to control the grasping force augmentation. The operation of the control system with the exoskeleton has been experimentally validated. EMG signals were monitored during the experiments to determine that the proposed exoskeleton system decreased the muscular efforts of the wearer

State-of-the-Art of Hand Exoskeleton Systems

This paper deals with the analysis of the state-of-the-art of robotic hand exoskeletons (updated at May 2011), which is intended as the first step of a designing activity. A large number of hand exoskeletons (both products and prototypes) that feature some common characteristics and many special peculiarities are reported in the literature. Indeed, in spite of very similar functionalities, different hand exoskeletons can be extremely different for the characteristics of their mechanism architectures, control systems and working principles. The aim of this paper is to provide the reader with a complete and schematic picture of the state-of-the-art of hand exoskeletons. The focus is placed on the description of the main aspects that are involved in the exoskeleton design such as the system kinematics, the actuator systems, the transmission parts and the control schemes. Additionally, the critical issues provided by the literature analysis are discussed in order to enlighten the differences and the common features of different practical solutions. This paper may help to understand both the reasons why certain solutions are proposed for the different applications and the advantages and drawbacks of the different designs proposed in the literature. The motivation of this study is the need to design a new hand exoskeleton for rehabilitation purposes

Mathematical Modeling and Empirical Validation of a Conceptual Exoskeleton for Astronaut Glove Augmentation

Space presents numerous difficulties for astronauts conducting their work, not the least of which is the spacesuit that is worn to protect them from space. It has long been known that a spacesuit is difficult to work in, especially the rigid and pressurized gloves that put strain on the astronaut\u27s hands, frequently leading to injuries. Astronaut gloves inhibit more than 50% of their strength in some cases [1]. NASA and other space agencies have been working to alleviate these problems by attempting to mechanically augment the gloves to reduce the exertions of the astronaut. To date, no augmentation systems have been implemented into spacesuits and prototypes are actively undergoing design and development [2] [3]. Currently existing prototypes are impractical, unconformable, or not effectively augmenting the astronaut as evidenced by the non-implementation of such systems to date. This work presents a novel conceptual exoskeleton design for astronaut glove augmentation and a mathematical model that is used to predict its performance. In addition, experiments were conducted to validate the math model. The conceptual exoskeleton is designed to overcome the shortcomings of previous attempts to augment astronaut gloves by using rigid linkages actuated by a single tendon routed through them. This system operates exclusively on the dorsal surface of the hand, limiting the restrictions to the palmar surface of the hand. The mathematical model presents a method to equate the tendon tension to the contact force between the linkages and the object that is being grasped. Two representative models of the conceptual exoskeleton were built and tested. The experimental fixture, custom designed and fabricated, used a Pliance Pressure Pad to measure the total forces produced by the system. The measured force values were then compared to predictions made by the system to assess the accuracy of the mathematical model. The experimental configurations of the systems were measured using a machine vision system. The mathematical model was shown to accurately predict the contact forces produced by the representative test rigs. Relationships between the contact forces developed in a grasp and the readings from a Jamar Grip Dynamometer were then used to estimate the magnitude of grip strength that the full exoskeleton could develop [4]. These estimations indicate that the conceptual system would be able to recover up to 124% of the strength that astronauts lose to their gloves