Effect of Hip Assistance Modes on Metabolic Cost of Walking With a Soft Exoskeleton

Cao, Wujing; Chen, Chunjie; Hu, Hongyue; Fang, Kai; Wang, Xinyu

doi:10.1109/tase.2020.3027748

Cited by 67 publications

(39 citation statements)

References 32 publications

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“…1). We first optimized hip-only, knee-only, and ankle-only assistance to compare the best possible assistance of each single joint (N = 3, 1F 2M, 61 -90 kg, age [19][20][21][22][23][24][25][26]. We next optimized two-joint assistance in different combinations to evaluate the benefit of adding a second joint (N = 1, M, 90 kg, 26).…”

Section: Resultsmentioning

confidence: 99%

“…Exoskeletons have improved walking by reducing metabolic cost, but larger improvements may be necessary for widespread adoption of exoskeleton products. Reductions in metabolic cost have been demonstrated from assisting one or two joints (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19), with the largest metabolic cost reduction being around 18% relative to walking in no exoskeleton (14,17) and 24% relative to walking in an exoskeleton with no torques applied (12). Despite demonstrated improvements, exoskeletons are in a nascent stage of commercial development, and widespread adoption has not yet occurred (6).…”

Section: Introductionmentioning

confidence: 99%

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Comparing optimized exoskeleton assistance of the hip, knee, and ankle in single and multi-joint configurations

Franks

Bryan

Martin

et al. 2021

Preprint

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Exoskeletons that assist the hip, knee, and ankle joints have begun to improve human mobility, particularly by reducing the metabolic cost of walking. However, direct comparisons of optimal assistance of these joints, or their combinations, have not yet been possible. Assisting multiple joints may be more beneficial than the sum of individual effects, because muscles often span multiple joints, or less effective, because single-joint assistance can indirectly aid other joints. In this study, we used a hip-knee-ankle exoskeleton emulator paired with human-in-the-loop optimization to find single-joint, two-joint, and whole-leg assistance that maximally reduced the metabolic cost of walking for three participants. Hip-only and ankle-only assistance reduced the metabolic cost of walking by 26% and 30% relative to walking in the device unassisted, confirming that both joints are good targets for assistance. Knee-only assistance reduced the metabolic cost of walking by 13%, demonstrating that effective knee assistance is possible. Two-joint assistance reduced the metabolic cost of walking by between 34% and 42%, with the largest improvements coming from hip-ankle assistance. Assisting all three joints reduced the metabolic cost of walking by 50%, showing that at least half of the metabolic energy expended during walking can be saved through exoskeleton assistance. Changes in kinematics and muscle activity indicate that single-joint assistance indirectly assisted muscles at other joints, such that the improvement from whole-leg assistance was smaller than the sum of its single-joint parts. Exoskeletons can assist the entire limb for maximum effect, but a single well-chosen joint can be more efficient when considering additional factors such as weight and cost.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparing optimized exoskeleton assistance of the hip, knee, and ankle in single and multi-joint configurations

Franks

Bryan

Martin

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Some studies have assisted able-bodied participants walking as slowly as 1.1 m/s [5] and others have assisted able-bodied participants walking as quickly as 1.5 m/s [6][7][8]. Many successful exoskeletons apply torque at the hip, ankle or both [5][6][7][8][9][10][11][12][13][14][15] and have reduced the metabolic cost of walking by up to 24% [12]. Whole-leg assistance can reduce metabolic cost even further.…”

Section: Introductionmentioning

confidence: 99%

Optimized hip-knee-ankle exoskeleton assistance at a range of walking speeds

Bryan

Franks

Song

et al. 2021

Preprint

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Background: Effective autonomous exoskeletons will need to be useful at a variety of walking speeds, but we do not know how optimal exoskeleton assistance should change with speed. Optimal exoskeleton assistance may increase with speed similar to biological torque changes or a well-tuned assistance profile may be effective at a variety of speeds. Methods: We optimized hip-knee-ankle exoskeleton assistance to reduce metabolic cost for three participants walking at 1.0 m/s, 1.25 m/s and 1.5 m/s. We measured metabolic cost, muscle activity, exoskeleton assistance and kinematics. We performed two tailed paired t-tests to determine significance. Results: Exoskeleton assistance reduced the metabolic cost of walking compared to wearing the exoskeleton with no torque applied by 26%, 47% and 50% at 1.0, 1.25 and 1.5 m/s, respectively. For all three participants, optimized exoskeleton ankle torque was the smallest for slow walking, while hip and knee torque changed slightly with speed in ways that varied across participants. Total applied positive power increased with speed for all three participants, largely due to increased joint velocities, which consistently increased with speed. Conclusions: Exoskeleton assistance is effective at a range of speeds and is most effective at medium and fast walking speeds. Exoskeleton assistance was less effective for slow walking, which may explain the limited success in reducing metabolic cost for patient populations through exoskeleton assistance. Exoskeleton designers may have more success when targeting activities and groups with faster walking speeds. Speed-related changes in optimized exoskeleton assistance varied by participant, indicating either the benefit of participant-specific tuning or that a wide variety of torque profiles are similarly effective.

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“…Additionally, ReChair reduces the patient's tension on gait rehabilitation machine. Compared with LLE for rewalk [3,[7][8][9][10][11][12][13], ReChair focuses on restand and remobility. e multiposture transformation avoids the complications caused by lying down for a long time.…”

Section: Discussionmentioning

confidence: 99%

“…To provide daily assistive systems and substitute the residual neurological deficits that prevent the return to upright bipedal ambulation, LLEs are applied in the course of daily rehabilitation [7][8][9]. LLEs are usually able to carry the person wearing them, providing walking assistive force and keeping the body balance.…”

Section: Introductionmentioning

confidence: 99%

Development and Evaluation of a Rehabilitation Wheelchair with Multiposture Transformation and Smart Control

Cao

Wang

et al. 2021

Complexity

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Stroke and other neurological disorders have an effect on mobility which has a significant impact on independence and quality of life. The core rehabilitation requirements for patients with lower limb motor dysfunction are gait training, restand, and mobility. In this work, we introduce a newly developed multifunctional wheelchair that we call “ReChair” and evaluated its performance preliminarily. ReChair seamlessly integrates the mobility, gait training, and multiposture transformation. ReChair driving and multiposture transformation are done using the voice, button, and mobile terminal control. This work describes the functional requirements, mechanical structure, and control system and the overall evaluation of ReChair including the kinematic simulation of the multiposture transformation and passive lower limb rehabilitation training to quantitatively verify the motion capability of ReChair, the voice control system evaluation that shows how the voice recognition system is suitable for home environment, the sensorless speed detection test results that indicate how the wheel speeds measured by sensorless method are appropriate for travelling control, and the passive and balance training test results that show how the lower limb rehabilitation training in daily life by ReChair is convenient. Finally, the experimental results show that ReChair meets the patients’ requirements and has practical significance. It is cost-effective, easy to use, and supports multiple control modes to adapt to different rehabilitation phases.

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Effect of Hip Assistance Modes on Metabolic Cost of Walking With a Soft Exoskeleton

Cited by 67 publications

References 32 publications

Comparing optimized exoskeleton assistance of the hip, knee, and ankle in single and multi-joint configurations

Comparing optimized exoskeleton assistance of the hip, knee, and ankle in single and multi-joint configurations

Optimized hip-knee-ankle exoskeleton assistance at a range of walking speeds

Development and Evaluation of a Rehabilitation Wheelchair with Multiposture Transformation and Smart Control

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