A Novel Design Concept of Digital Hydraulic Drive for Knee Exoskeleton

Hydraulic actuation of exoskeletons has gained interest among researchers due the potentials of high power density and energy recuperation allowing the reduction of mass and space used by the device (when compared to the traditional electrically actuated exoskeletons). However, developing a light and cost-effective design of such exoskeleton remains a key challenge. In this work, a novel design of digitally driven knee exoskeleton is presented. The design uses simple hydraulic cylinders instead of multi-chamber cylinders (which are typically used in digital actuations and are expensive). The design also includes a unique mechanism that is able to satisfy the peak torque requirements during a typical gait cycle with a smaller hydraulic force. This ensures small size of hydraulic components and a moderate power demand from the energy source. To study this exoskeleton design, a numerical model of the exoskeleton and the lower limb is developed in this work. The simulation results show that the design is able to track the motion of the knee in a typical gait cycle as well as satisfy the necessary torque requirements.

Design and Analysis of Lightweight Lower Limb Exoskeleton for Military Usage

Nowadays, due to technological advancement, weapons are becoming smaller in size, which leads to the number of weapons carried by a single person increasing. As the number of weapons is increasing, then the capacity of the load carriage system of military personnel causes a great energy loss to carry weight. Also, carrying a weight of about 25 kg to 50 kg in different terrain causes different foot injuries which create a strain on the human body. An exoskeleton is a device used to replicate the motion of the human body so that humans can be used to control mechanical power for working on different operations which are beyond human strength. The exoskeleton technology makes it possible to reduce the energy loss of military personnel to produce controlled motion of the exoskeleton in different terrain. Hence, this project is aims to design a lower limb exoskeleton for carrying military load carriage systems. The designing and simulating the lower limb exoskeleton is done on fusion 360. Keywords: lower limb exoskeleton, military exoskeleton, exoskeleton design, exoskeleton analysis

Custom-Fit and Lightweight Optimization Design of Exoskeletons Using Parametric Conformal Lattice

This paper presents an integrated design method for the customization and lightweight design of free-shaped wearable devices, illustrated by a lower limb exoskeleton. The customized design space is derived from the 3D scanning models. Based on the finite element analysis, the structural framework is determined through topology optimization with allowable strength. By means of generative design, the lattice library is constructed to fill the frames under different conformal algorithms. Finally, the proposed method is illustrated by the exoskeleton design case.

EXOSEKETONS: A REHAB TECH CONSUMER’S UNEXPECTED MARCH TO ACTION

This paper is both a stakeholder perspectives as well as a ‘case study’ describing a journey from sudden disability to participant and investor in exoskeleton design. It tells of my experiences and opinions, as a successful fashion designer, when my life took a drastic turn on becoming paralysed from the waist down over the course of 24 hours, by a spinal tumour. Getting this diagnosis was ‘the worst day in my life’, and it was quickly followed by the ‘second worst’ when, in my determination to walk again, I received Knee Ankle Foot Orthotics (KAFOs) and was shocked to learn that this appeared to be the best technology solution available on the market ‘suitable’ for use in the community. Initial anger at the system for not being better, at the rehab team for their complacency, and at myself for allowing a feeling of helplessness to take over led to questions such as: what does this say about our society? and what are we all willing to accept, for ourselves and others? This is professional opinion and an essay about how we see ourselves and how others see us. The journey from pre-injury ‘consumer’ to post-injury ‘disabled’ person and learning that being labeled ‘disabled’ leads to the additional handicap of the narrow vision of “cost” taken by the mobility industry where innovative ideas are stripped down to the bare minimum with the excuse that patients are “lucky” to have what they have been “given”. Grappling with these labels and inequities and seeking a better outcome, I became an integral team member of an exoskeleton development team, leading to the design of The Next Generation Exoskeleton! This is MY story, the story of Chloe Angus. It is the story of inclusive, user focused design and is a call to include and respect the end users of all assistive device technology design early in the design process and it is being told from the perspective of a person having experience and success in the world of business. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/37250/28296 How To Cite: Angus C. Exoseketons: a rehab tech consumer’s unexpected march to action. Canadian Prosthetics & Orthotics Journal. 2021; Volume 4, Issue 2, No.2. https://doi.org/10.33137/cpoj.v4i2.37250 Corresponding Author: Chloe AngusChloe Angus Design, Vancouver, BC, Canada.E-Mail: [email protected] ID: https://orcid.org/0000-0002-5468-3121

Design and Performance Evaluation of a Hybrid Hand Exoskeleton for Hand Opening/Closing

Finger extensor muscle weakness and flexor hypertonia are the most commonly reported issues among patients suffering from amyotrophic lateral sclerosis (ALS). Moreover, the relative hyperflexion of the wrist and the fingers has limited their ability to open the hand and interact with the external environment voluntarily. In this work, a hybrid hand exoskeleton is developed to prevent the relative hyperflexion of the fingers and wrist and facilitate the users in their functional hand opening by compensating the flexor hypertonia. This exoskeleton, combining a passive device with the soft extra muscle (SEM) glove, assists users in normal hand opening/closing required for some basic activities of daily living. The paper presents kinematic and static models of passive hand exoskeleton design. Moreover, the proposed design is tested and evaluated by comparing the volunteer hand opening with the exoskeleton assistance using the flex sensors attached on the dorsal side of the middle finger, ring finger, and thumb with both healthy subjects and patients.

Effectiveness of Soft Versus Rigid Back-Support Exoskeletons during a Lifting Task

This study investigated the influence of passive back-support exoskeletons (EXOBK) design, trunk sagittal inclination (TSI), and gender on the effectiveness of an exoskeleton to limit erector spinae muscle (ES) activation during a sagittal lifting/lowering task. Twenty-nine volunteers performed an experimental dynamic task with two exoskeletons (two different designs: soft (SUIT) and rigid (SKEL)), and without equipment (FREE). The ES activity was analyzed for eight parts of TSI, each corresponding to 25% of the range of motion (lifting: P1 to P4; lowering: P5 to P8). The impact of EXOBK on ES activity depended on the interaction between exoskeleton design and TSI. With SKEL, ES muscle activity significantly increased for P8 (+36.8%) and tended to decrease for P3 (−7.2%, p = 0.06), compared to FREE. SUIT resulted in lower ES muscle activity for P2 (−9.6%), P3 (−8.7%, p = 0.06), and P7 (−11.1%), in comparison with FREE. Gender did not influence the effect of either back-support exoskeletons on ES muscle activity. These results point to the need for particular attention with regard to (1) exoskeleton design (rigid versus soft) and to (2) the range of trunk motion, when selecting an EXOBK. In practice, the choice of a passive back-support exoskeleton, between rigid and soft design, requires an evaluation of human-exoskeleton interaction in real task conditions. The characterization of trunk kinematics and ranges of motion appears essential to identify the benefits and the negative effects to take into account with each exoskeleton design.

METHODOLOGY FOR A TASK-SPECIFIC AND PERSONALISED DEVELOPMENT OF AN INITIAL EXOSKELETON DESIGN

The use of exoskeletons promises improved ergonomics, empowerment of users and prevention of musculoskeletal disorders. However, the development process is complex and a generic development methodology that will guide and assist designers through it is missing. The goal of this paper is to describe a methodological approach that will assist the conceptual design of exoskeletons. Based on derived methodological requirements, activities 1, 2, and 3 of the VDI 2221 (Methodology for the development of technical products) are specified to adapt the generic guideline to the development process of exoskeletons. These activities include the analysis and determination of the relationship between the use case, product requirements and motions, technical functions, and design solutions. For generating a list of product requirements designers must focus on the workers’ motions and needs for a for a task-specific and personalised development. Use case specific movements are generalised by using rotational and translational basic movements that result in six degrees of freedom and from which a function structure is derived. The method is critically reviewed based on the established methodological requirements.