Knee-braced energy harvester: Reclaim energy and assist walking

Xie, Longhan; Li, Xiao Dong; Cai, Siqi; Huang, Guowei; Huang, Ledeng

doi:10.1016/j.ymssp.2019.03.008

Cited by 25 publications

(26 citation statements)

References 21 publications

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“…The knee has been the focus of energy harvesting exoskeletons due to its production of substantial negative power in gait, especially near the end of swing phase of walking (Fig 2). There are several indications that if done correctly it is possible to generate electrical energy while reducing the muscle energetic demands and whole body metabolic cost [19,60,70,71]. With consideration to changing mechanical demands on sloped surfaces, our results suggest potential for harvesting energy using a knee exoskeleton during decline walking due to large increases in knee negative power throughout the gait cycle (Fig 2).…”

Section: Plos Onementioning

confidence: 76%

Mechanics of walking and running up and downhill: A joint-level perspective to guide design of lower-limb exoskeletons

et al. 2020

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Lower-limb wearable robotic devices can improve clinical gait and reduce energetic demand in healthy populations. To help enable real-world use, we sought to examine how assistance should be applied in variable gait conditions and suggest an approach derived from knowledge of human locomotion mechanics to establish a 'roadmap' for wearable robot design. We characterized the changes in joint mechanics during walking and running across a range of incline/decline grades and then provide an analysis that informs the development of lowerlimb exoskeletons capable of operating across a range of mechanical demands. We hypothesized that the distribution of limb-joint positive mechanical power would shift to the hip for incline walking and running and that the distribution of limb-joint negative mechanical power would shift to the knee for decline walking and running. Eight subjects (6M,2F) completed five walking (1.25 m s-1) trials at-8.53˚,-5.71˚, 0˚, 5.71˚, and 8.53˚grade and five running (2.25 m s-1) trials at-5.71˚,-2.86˚, 0˚, 2.86˚, and 5.71˚grade on a treadmill. We calculated time-varying joint moment and power output for the ankle, knee, and hip. For each gait, we examined how individual limb-joints contributed to total limb positive, negative and net power across grades. For both walking and running, changes in grade caused a redistribution of joint mechanical power generation and absorption. From level to incline walking, the ankle's contribution to limb positive power decreased from 44% on the level to 28% at 8.53˚uphill grade (p < 0.0001) while the hip's contribution increased from 27% to 52% (p < 0.0001). In running, regardless of the surface gradient, the ankle was consistently the dominant source of lower-limb positive mechanical power (47-55%). In the context of our results, we outline three distinct use-modes that could be emphasized in future lower-limb exoskeleton designs 1) Energy injection: adding positive work into the gait cycle, 2) Energy extraction: removing negative work from the gait cycle, and 3) Energy transfer: extracting energy in one gait phase and then injecting it in another phase (i.e., regenerative braking).

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Section: Plos Onementioning

confidence: 76%

Mechanics of walking and running up and downhill: A joint-level perspective to guide design of lower-limb exoskeletons

et al. 2020

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“…The main advantage of this method is that it does not require any cognitive load or direct input from the user, making the interaction more intuitive and natural. For this method, generally joint sensors and IMU data (often from the upper body in persons with paraplegia) are processed by a machine learning or fuzzy logic algorithm to recognize the situation [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64], although simpler threshold-based methods have also been proposed [65]. Sometimes, other types of signals such as the ground reaction forces or electromyography (EMG) are also used to infer the movement or the intention of the user [66][67][68][69][70][71].…”

Section: Movements Recognition (Mov)mentioning

confidence: 99%

Review of control strategies for lower-limb exoskeletons to assist gait

Baud

Manzoori

Ijspeert

et al. 2021

J NeuroEngineering Rehabil

161

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Background Many lower-limb exoskeletons have been developed to assist gait, exhibiting a large range of control methods. The goal of this paper is to review and classify these control strategies, that determine how these devices interact with the user. Methods In addition to covering the recent publications on the control of lower-limb exoskeletons for gait assistance, an effort has been made to review the controllers independently of the hardware and implementation aspects. The common 3-level structure (high, middle, and low levels) is first used to separate the continuous behavior (mid-level) from the implementation of position/torque control (low-level) and the detection of the terrain or user’s intention (high-level). Within these levels, different approaches (functional units) have been identified and combined to describe each considered controller. Results 291 references have been considered and sorted by the proposed classification. The methods identified in the high-level are manual user input, brain interfaces, or automatic mode detection based on the terrain or user’s movements. In the mid-level, the synchronization is most often based on manual triggers by the user, discrete events (followed by state machines or time-based progression), or continuous estimations using state variables. The desired action is determined based on position/torque profiles, model-based calculations, or other custom functions of the sensory signals. In the low-level, position or torque controllers are used to carry out the desired actions. In addition to a more detailed description of these methods, the variants of implementation within each one are also compared and discussed in the paper. Conclusions By listing and comparing the features of the reviewed controllers, this work can help in understanding the numerous techniques found in the literature. The main identified trends are the use of pre-defined trajectories for full-mobilization and event-triggered (or adaptive-frequency-oscillator-synchronized) torque profiles for partial assistance. More recently, advanced methods to adapt the position/torque profiles online and automatically detect terrains or locomotion modes have become more common, but these are largely still limited to laboratory settings. An analysis of the possible underlying reasons of the identified trends is also carried out and opportunities for further studies are discussed.

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“…The lower limbs pull the cable in the swing stage of the walking cycle, one end of each cable is connected to the human lower tibia, and the other end F I G U R E 7 Different energy harvesters with center mass motion during human walking. A, An energy harvester that convert intermittent, bidirectional, low-speed and high torque mechanical power into electrical energy developed by Li et al 75 B, A energy harvester with a spring damping mechanism with spiral spring and generator developed by Xie et al 76 C, A knee-mounted biomechanical energy harvester developed by Chen et al 77 D, An innovative biomechanical energy harvester based on the regenerative braking developed by Cervera et al 78 E, A light cable pulley harvester installed on the knee joint developed by Fan et al 79 F, An energy harvester with a one-way clutch driving gear system developed by Rubinshtein et al 80 G, An energy harvester capture the linear displacement between the buttocks and ankles developed by Michael et al 81 H, An energy harvester based on lightweight large fiber composite (MFC) developed by Gao et al 82 [Colour figure can be viewed at wileyonlinelibrary.com] is connected to the pulley. The movement of two limbs is to be incorporated into a single generating unit.…”

Section: Electromagnetic Inductionmentioning

confidence: 99%

Different kinds of energy harvesters from human activities

Zhou

Han

et al. 2021

Intl J of Energy Research

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Human has abundant energy and can achieve energy from different human daily activities with energy harvesters. It can provide power for the wearable electronic devices, and the micro implanted electronic devices. Achieve the purpose of assisting movement, reducing metabolism, detecting life signals, and measuring metabolism level. Energy sources are mainly divided into mechanical energy and biochemical energy. According to the biomechanical energy achieved from different parts of the body, the energy harvesters are classified. The working principle, design idea, wearing style, and materials of the energy harvesters are compared and analyzed. It is indicated that the biochemical energy harvesting technology based on cell and molecular level is an innovative method which can be used for low-power devices with great potential. While mechanical energy technology based on the principle can achieve more energy, but larger and heavy structure will lead to poor wearing experience. Meanwhile, they should complement each other and excavate human energy. This paper is not only a summary of the current research, but also points to weaknesses and outlines possible improvements that are suitable for practical applications through comparison and analysis of different energy harvesters. Novelty Statement Human has abundant energy and can achieve energy from different daily activities. Energy sources are divided into mechanical energy and biochemical energy. The biochemical energy harvesters based on cell and molecular level is an innovative method which can be used for low-power devices. While mechanical energy harvesters can achieve more energy. This paper provides useful information for researchers to develop energy harvesters suitable for practical application in daily life.

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Knee-braced energy harvester: Reclaim energy and assist walking

Cited by 25 publications

References 21 publications

Mechanics of walking and running up and downhill: A joint-level perspective to guide design of lower-limb exoskeletons

Mechanics of walking and running up and downhill: A joint-level perspective to guide design of lower-limb exoskeletons

Review of control strategies for lower-limb exoskeletons to assist gait

Different kinds of energy harvesters from human activities

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