Wearable robotic devices have been shown to substantially reduce the energy expenditure of human walking. However, response variance between participants for fixed control strategies can be high, leading hypothesis that individualized controllers could further improve walking economy. Recent studies on human-in-the-loop (HIL) optimization elucidated several practical challenges, such as long experimental protocols and low signal-to-noise ratios. Here, we used Bayesian optimization-an...

The increasing capabilities of exoskeletons and powered prosthetics for walking assistance have paved the way more sophisticated individualized control strategies. In response to this opportunity, recent work on human-in-the-loop optimization has considered problem automatically tuning parameters based realtime physiological measurements. However, common use metabolic cost as a performance metric creates significant experimental challenges due its long measurement times low signal-to-noise...

Individuals with below-knee amputation have more difficulty balancing during walking, yet few studies explored balance enhancement through active prosthesis control. We previously used a dynamical model to show that prosthetic ankle push-off work affects both sagittal and frontal plane dynamics, appropriate step-by-step control of can improve stability. hypothesized this approach could be applied robotic partially fulfill the requirements human thereby reducing balance-related activity...

Abstract Activities and physical effort have been commonly estimated using a metabolic rate through indirect calorimetry to capture breath information. The represents the work hardness used optimize wearable robotic systems. Thus, personalization rapid optimization of are critical. Although respirometry is gold standard for estimating costs, this method requires heavy, bulky, rigid system, limiting system’s field deployability. Here, paper reports soft, flexible bioelectronic system that...

Individuals with lower limb amputation have a high fall risk, which could be partially due to lack of stabilizing control in conventional prostheses. Inspired by walking robots, we hypothesized that modulating prosthetic ankle push-off help improve amputee balance. We developed three-dimensional model, found limit cycles at two speeds, and designed state-feedback controllers made once-per-step adjustments work, fore-aft medial-lateral foot placement, roll resistance. To assess balance,...

Exoskeletons can assist humans during squatting and the assistance has potential to reduce physical demands. Although several squat methods are available, effect of personalized on effort not been examined. We hypothesize that will squatting. developed a human-in-the-loop Bayesian optimization scheme minimize metabolic cost using unilateral ankle exoskeleton. The identified subject-specific parameters for ascending descending took 15.8 min average converge. optimized condition reduced by...

Below-knee amputation is associated with higher energy expenditure during walking, partially due to difficulty maintaining balance. We previously found that once-per-step push-off work control can reduce balance-related effort, both in simulation and experiments human participants. Simulations also suggested changing ankle inversion/eversion torque on each step, response changes body state, could assist In this study, we investigated the effects of modulation effort among amputees (N = 5)...

Abstract Squatting is an intensive activity routinely performed in the workplace to lift and lower loads. The effort perform a squat can decrease using exoskeleton that considers individual worker’s differences assists them with customized solution, namely, personalized assistance. Designing such could be improved by understanding how user’s muscle changes when assistance provided. This study investigated change recruitment activation pattern was provided ankle–foot during squatting we...

Ankle inversion-eversion compliance is an important feature of conventional prosthetic feet, and control inversion, or roll, in active prostheses could improve balance for people with amputation. We designed a tethered ankle-foot prosthesis two independently actuated toes that are coordinated to provide plantarflexion torques. A Bowden cable tether provides series elasticity. The simple lightweight, mass 0.72kg. Strain gauges on the measure torque less than 1% root mean squared (RMS) error....

Ankle inversion-eversion compliance is an important feature of conventional prosthetic feet, and control inversion, or roll, in robotic prostheses could improve balance for people with amputation. We designed a tethered ankle-foot prosthesis two independently-actuated toes that are coordinated to provide plantarflexion torques. This configuration allows simple lightweight structure total mass 0.72 kg. Strain gages on the measure torque less than 2.7% RMS error, while Bowden cable tether...

Abstract Walking is an important activity that supports the health-related quality of life, and for those who need assistance, robotic devices are available to help. Recent progress in wearable robots has identified importance customizing assistance provided by robot individual, resulting adaptation human. However, current implementations minimize role human robot, example, users modifying their movements based on assistance. This study investigated effect visual feedback guide adapting...

The use of wearable robots to provide walking assistance has rapidly grown over the past decade, with notable advances made in robot design and control methods toward reducing physical effort while performing an activity. reduction mainly been achieved by assisting forward progression sagittal plane. Human gait, however, is a complex movement that combines motions three planes, not only but also transverse frontal planes. In plane, hip joint plays key role including balance. However,...

Unilateral, below-knee amputation is associated with an increased risk of falls, which may be partially related to a loss active ankle control. If control can contribute significantly maintaining balance, even in the presence foot placement, this might provide opportunity improve balance using robotic ankle-foot prostheses. We investigated ankle- and hip-based walking stabilization methods three-dimensional model human gait that included plantarflexion, inversion-eversion, hip...

Recent human-in-the-loop (HIL) optimization studies using wearable devices have shown an improved average metabolic reduction by optimizing a small number of control parameters during short-duration walking experiments. However, the slow dynamics, high measurement noise, and experimental time constraints create challenges for increasing to be optimized. Prior work applying gradient descent Bayesian this problem decoupled estimation parameter selection fixed intervals, which imposes hard...

Abstract Individuals with below-knee amputation (BKA) experience increased physical effort when walking, and the use of a robotic ankle-foot prosthesis (AFP) can reduce such effort. The walking could be further reduced if robot is personalized to wearer using human-in-the-loop (HIL) optimization wearable parameters. conventional physiological measurement, however, requires long estimation time, hampering real-time due limited experimental time budget. This study hypothesized that function...

Recent advances in flexible sensors and wireless electronics have driven the development of lightweight ergonomic wearable sensing gloves. Such gloves can be employed mixed reality (MR) environments to give haptic capabilities during interactions with various objects. However, no prior study shows a quantitative measurement physical user object manipulation MR. Here, we report an MR-integrated soft bioelectronic system on glove for quantifying changes user's pinching tasks. We use...

Prosthesis features that enhance balance are desirable to people with transtibial amputation. Ankle inversion/eversion compliance is intended improve on uneven ground, but its effects remain unclear level ground. We posited increasing ankle stiffness during level-ground walking would reduce balance-related effort by assisting in recovery from small disturbances frontal-plane motions. performed a pilot test an ankle-foot prosthesis emulator programmed apply torques proportion the deviation...

Evidence suggests that the metabolic cost associated with locomotive activity of walking is dependent upon ankle stiffness. This stiffness can be a control parameter in an ankle-foot prosthesis. Considering unique physical interaction between each individual below-knee amputation and robotic prosthesis, individually tuned prosthesis may improve assistance benefits. personalization accomplished through human-in-the-loop (HIL) Bayesian optimization (BO). Here, we conducted pilot study to...

Introduction: Recent studies found that wearable exoskeletons can reduce physical effort and fatigue during squatting. In particular, subject-specific assistance helped to significantly effort, shown by reduced metabolic cost, using human-in-the-loop optimization of the exoskeleton parameters. However, measuring cost respiratory data has limitations, such as long estimation times, presence noise, user discomfort. A recent study suggests foot contact forces address those challenges be used an...

Wearable assistive robots can potentially improve the gait of individuals with reduced mobility. To address each individual's unique needs, personalized are necessary. In addition, equipped portable systems required to ensure their practical use in clinical and outdoor settings. We developed evaluated a modular robotic ankle-foot orthosis (AFO) two degrees freedom actuation system, providing ankle plantarflexion in/eversion assistance. The performance was via benchtop testing human subject...