Many soldiers are expected to carry heavy loads over extended distances, often resulting in physical and mental fatigue. In this study, the design testing of an autonomous leg exoskeleton is presented. The aim device reduce energetic cost loaded walking. addition, we present Augmentation Factor, a general framework exoskeletal performance that unifies our results with varying abilities previously developed exoskeletons. We battery powered capable providing substantial levels positive...

Advanced upper limb prostheses capable of actuating multiple degrees freedom (DOFs) are now commercially available. Pattern recognition algorithms that use surface electromyography (EMG) signals show great promise as multi-DOF controllers. Unfortunately, current pattern systems limited to activate only one DOF at a time. This study introduces novel classifier based on Bayesian theory provide classification simultaneous movements. approach and two other strategies for movements were evaluated...

Currently, the mobility of above-knee amputees is limited by lack available prostheses that can efficiently replicate biologically accurate movements. In this study, a powered knee prosthesis was designed utilizing novel mechanism, known as clutchable series-elastic actuator (CSEA).The CSEA includes low-power clutch in parallel with an electric motor within traditional actuator. The stiffness series elasticity tuned to match elastically conservative region knee’s torque-angle relationship...

Human joint impedance is the dynamic relationship between differential change in position of a perturbed and corresponding response torque; it fundamental property that governs how humans interact with their environments. It critical to characterize ankle during stance phase walking elucidate regulated locomotion, as well provide foundation for future development natural, biomimetic powered prostheses control systems. In this study, was estimated using model consisting stiffness, damping...

In individuals with lower-limb amputations, robotic prostheses can increase walking speed, and reduce energy use, the incidence of falls development secondary complications. However, safe reliable prosthetic-limb control strategies for robust ambulation in real-world settings remain out reach, partly because have been tested different hardware constrained laboratory settings. Here, we report design clinical implementation an integrated knee-ankle prosthesis that facilitates testing its...

Positive biomechanical outcomes have been reported with lower-limb exoskeletons in laboratory settings, but these devices difficulty delivering appropriate assistance synchrony human gait as the task or rate of phase progression change real-world environments. This paper presents a controller for an ankle exoskeleton that uses data-driven kinematic model to continuously estimate phase, rate, stride length, and ground incline states during locomotion, which enables real-time adaptation torque...

Individuals with poststroke hemiparesis often exhibit mobility deficits, particularly during tasks requiring high lower limb torques. The sit-to-stand transition is consistently marked by asymmetrical weight-bearing between the paretic and unaffected legs. One way to improve characteristics of stroke may be provide assistive knee extension torque a powered exoskeleton. To perform research on biomechanical effects assisting sit-to-stand, unilateral exoskeleton required, which can accurately...

The human ankle joint plays a critical role during walking and understanding the biomechanical factors that govern behavior provides fundamental insight into normal pathologically altered gait. Previous researchers have comprehensively studied kinetics kinematics many tasks, including locomotion; however, only recently been able to quantify how mechanical impedance of varies walking. describes dynamic relationship between position torque perturbation, is often represented in terms stiffness,...

Passive exoskeletons that assist with human locomotion are often lightweight and compact, but unable to provide net mechanical power the exoskeletal wearer. In contrast, powered biologically appropriate levels of power, size mass their actuator/power source designs lead heavy unwieldy devices. this study, we extend design evaluation a powerful autonomous exoskeleton evaluated for loaded walking in (J Neuroeng Rehab 11:80, 2014) case unloaded conditions.The metabolic energy consumption seven...

Most commercially available prosthetic feet do not exhibit a biomimetic torque-angle relationship, and are unable to modulate their mechanics assist with other mobility tasks, such as stairs ramps. In this paper, we present quasi-passive ankle-foot prosthesis customizable curve an ability quickly ankle stiffness between tasks. The is obtained cam-based transmission fiberglass leaf spring. To achieve variable stiffness, the spring's support conditions can be actively modulated by small motor,...

The ankle contributes the majority of mechanical power during walking and is a frequently studied joint in biomechanics. Specifically, researchers have extensively investigated torque-angle relationship for dynamic tasks, such as running. slope this has been termed "quasi-stiffness." However, over time, begun to interchange concepts quasi-stiffness stiffness. This an especially important distinction currently begin investigate appropriate control systems recently developed powered prosthetic...

User preference is a promising objective for the control of robotic exoskeletons because it may capture multifactorial nature exoskeleton use. However, to use it, we must first understand its characteristics in context control. Here, systematically measured preferences individuals wearing bilateral ankle during walking. We investigated users’ repeatability identifying their and how changes with walking speed, device exposure, between different technical backgrounds. Twelve naive 12...

Most impedance-based walking controllers for powered knee-ankle prostheses use a finite state machine with dozens of user-specific parameters that require manual tuning by technical experts. These are only appropriate near the task (

Myoelectric control has been used for decades to powered upper limb prostheses. Conventional, amplitude-based employed a single prosthesis degree of freedom (DOF) such as closing and opening the hand. Within last decade, new advanced arm hand prostheses have constructed that are capable actuating numerous DOFs. Pattern recognition proposed greater number DOFs than conventional control, but traditionally limited sequentially controlling one at time. However, able-bodied individuals use...

The cyclic and often linear torque-angle relationship of locomotion presents the opportunity to innovate on design traditional series-elastic actuators (SEAs). In this paper, a novel modification SEA architecture was proposed by adding clutch in parallel with motor within - denoted as CSEA. This addition permits bimodal dynamics where system is characterized an when disengaged passive spring engaged. purpose provide ability store energy tuned series spring, while requiring only reactionary...

Challenges associated with current prosthetic technologies limit the quality of life lower-limb amputees. Passive prostheses lead amputees to walk slower, use more energy, fall often, and modify their gait patterns compensate for prosthesis' lack net-positive mechanical energy. Robotic can provide but may also introduce challenges through controller design. Fortunately, talented researchers are studying how best control robotic leg prostheses, time resources required develop hardware has...

Wearable lower-limb assistive devices have the potential to dramatically improve walking ability of millions individuals with gait impairments. However, most control systems for these do not enable smooth transitions between locomotor activities because they cannot continuously predict user’s intended movements. Intent recognition is an alternative strategy that uses patterns signals detected before movement completion future states. This has already enabled amputees walk and transition...

DATA REPORT article Front. Robot. AI, 19 February 2018Sec. Bionics and Biomimetics Volume 5 - 2018 | https://doi.org/10.3389/frobt.2018.00014

Most controllers for lower-limb robotic prostheses require individually tuned parameter sets every combination of speed and incline that the device is designed for. Because ambulation occurs over a continuum speeds inclines, this design paradigm requires tuning potentially prohibitively large number parameters. This limitation motivates an alternative control framework enables walking range inclines while requiring only limited tunable In work, we present implementation continuously varying...

Mobility disabilities are prominent in society with wide-ranging deficits, motivating modular, partial-assist, lower-limb exoskeletons for this heterogeneous population. This paper introduces the Modular Backdrivable Lower-limb Unloading Exoskeleton (M-BLUE), which implements high torque, low mechanical impedance actuators on commercial orthoses sheet metal modifications to produce a variety of hip- and/or knee-assisting configurations. Benchtop system identification verifies desirable...

The purpose of augmentative exoskeletons is to help people exceed the limitations their human bodies, but this cannot be realized unless choose use these exciting technologies. Although walking efficiency has been highly optimized over generations, have able consistently improve by 10-15%. However, despite measurable improvements, today remain confined laboratory. To achieve widespread adoption, must not only walking, also provide a perceivable benefit wearers.In study, we quantify...

Human joint impedance describes the dynamic relationship between perturbation induced change in position and resulting response torque. Understanding natural regulation of ankle during locomotion is necessary to discern how humans interact with their environments, provide a foundation for design biomimetic assistive devices control systems. This paper estimates terminal stance phase walking using parametric model consisting stiffness, damping, inertia. The accurately described torque,...

We developed an autonomous powered leg exoskeleton capable of providing large amounts positive mechanical power to the wearer during plantarflexion phase walking. The consisted a winch actuator fasted shin which pulled on fiberglass struts attached boot. formed rigid extension foot when proximal end strut was in forward by actuator. This lightweight, geometric transmission allowed electric efficiently produce biological levels at ankle joint. and controlled lithium polymer batteries motor...

Prosthetic feet are spring-like, and their stiffness critically affects the wearer’s stability, comfort, energetic cost of walking. Despite importance in ambulation, prescription process often entails testing a limited number prostheses, which may result patients receiving foot with suboptimal mechanics. To understand resolution prostheses should be individually optimized, we sought to characterize below-knee prosthesis users’ psychophysical sensitivity stiffness. We used novel...