{"title":"Design and Experimental Verification of a Quasi-Passive Variable Stiffness Ankle Exoskeleton for Human Walking Assistance","authors":"Jinlu Wang;Qingcong Wu;Yiqi Zou;Yanghui Zhu;Hongtao Wang;Hongtao Wu","doi":"10.1109/LRA.2025.3526450","DOIUrl":null,"url":null,"abstract":"Exoskeleton robots are an effective method for enhancing human walking ability. This letter introduces a quasi-passive variable stiffness ankle exoskeleton, which absorbs negative work produced during ankle dorsiflexion in the stance phase of the gait cycle and releases energy to assist plantar flexion during push-off. Compared to powered exoskeletons, this design does not require high-power actuators but instead relies on a clutch and elastic component to mimic the interaction between muscles and tendons for assistance. Compared to passive exoskeletons, the designed clutch can adapt to different users. Compared to fixed-stiffness exoskeletons, the novel variable stiffness energy storage mechanism passively adjusts stiffness to mimic the biomechanical properties of the ankle joint. The proposed exoskeleton identifies gait phases based on a control strategy using foot force sensors. This strategy controls the exoskeleton's energy recovery and release by determining the gait cycle phase and changing the clutch state. Finally, a level-ground walking experiment was conducted with six healthy participants. Results showed that wearing the exoskeleton reduced the root mean square (RMS) change rate of soleus EMG activity by 7.25% and decreased the net metabolic rate during walking by 3.6%.","PeriodicalId":13241,"journal":{"name":"IEEE Robotics and Automation Letters","volume":"10 2","pages":"1856-1863"},"PeriodicalIF":4.6000,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Robotics and Automation Letters","FirstCategoryId":"94","ListUrlMain":"https://ieeexplore.ieee.org/document/10829666/","RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ROBOTICS","Score":null,"Total":0}
引用次数: 0
Abstract
Exoskeleton robots are an effective method for enhancing human walking ability. This letter introduces a quasi-passive variable stiffness ankle exoskeleton, which absorbs negative work produced during ankle dorsiflexion in the stance phase of the gait cycle and releases energy to assist plantar flexion during push-off. Compared to powered exoskeletons, this design does not require high-power actuators but instead relies on a clutch and elastic component to mimic the interaction between muscles and tendons for assistance. Compared to passive exoskeletons, the designed clutch can adapt to different users. Compared to fixed-stiffness exoskeletons, the novel variable stiffness energy storage mechanism passively adjusts stiffness to mimic the biomechanical properties of the ankle joint. The proposed exoskeleton identifies gait phases based on a control strategy using foot force sensors. This strategy controls the exoskeleton's energy recovery and release by determining the gait cycle phase and changing the clutch state. Finally, a level-ground walking experiment was conducted with six healthy participants. Results showed that wearing the exoskeleton reduced the root mean square (RMS) change rate of soleus EMG activity by 7.25% and decreased the net metabolic rate during walking by 3.6%.
期刊介绍:
The scope of this journal is to publish peer-reviewed articles that provide a timely and concise account of innovative research ideas and application results, reporting significant theoretical findings and application case studies in areas of robotics and automation.