279 research outputs found

    Energy efficiency analysis and design optimization of an actuation system in a soft modular lower limb exoskeleton

    Get PDF
    One of the critical aspects in the design of an assistive wearable robot is the energy efficiency of the actuation system, since it affects significantly the weight and consequently the comfort of the system. Several strategies have been used in previous research, mostly based on energy harvesting, compliant elements for mechanical energy accumulation (springs or elastic cords), ratchets and clutches. However, the design of the optimal actuator arrangement is highly dependent on the task, which increases significantly the complexity of the design process. In this work we present an energy efficiency analysis and design optimization of an actuation system applied to a soft module lower limb exoskeleton. Instead of performing a comparison between predefined mechanism arrangements, we solve a full optimization problem which includes not only the mechanism parameters, but also the mechanism architecture itself. The optimization is performed for a walking task using gait data from a stroke subject, and the result is a set of actuator Arrangements with optimal parameters for the analyzed task and selected user. The optimized mechanism is able to reduce the energy requirements by 20-65%, depending of the joint. The proposed mechanism is currently under development within the XoSoft EU project, a modular soft lower-limb exoskeleton to assist People with mobility impairments

    A review on design of upper limb exoskeletons

    Get PDF

    A Bamboo-inspired Exoskeleton (BiEXO) Based on Carbon Fiber for Shoulder and Elbow Joints

    Get PDF

    ReHand - a portable assistive rehabilitation hand exoskeleton

    Get PDF
    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

    Comparative study of actuation systems for portable upper limb exoskeletons.

    Get PDF
    During the last two decades, a large variety of upper limb exoskeletons have been developed. Out of these, majority are platform based systems which might be the reason for not being widely adopted for post-stroke rehabilitation. Despite the potential benefits of platform-based exoskeletons as being rugged and reliable, stroke patients prefer to have a portable and user-friendly device that they can take home. However, the types of actuator as well as the actuation mechanism used in the exoskeleton are the inhibiting factors why portable exoskeletons are mostly non-existent for patient use. This paper presents a quantitative analysis of the actuation systems available for developing portable upper arm exoskeletons with their specifications. Finally, it has been concluded from this research that there are not many stand-alone arm exoskeletons which can provide all forms of rehabilitation, therefore, a generic solution has been proposed as the rehabilitation strategy to get best out of the portable arm exoskeletons
    • …
    corecore