{"title":"Stride-Wise Adaptive Assistance Strategy for Ankle Exoskeleton Under Varying Walking Conditions","authors":"Weihao Yin;Zhibo Jing;Jianquan Ding;Jiaqi Han;Jianda Han;Juanjuan Zhang","doi":"10.1109/TNSRE.2025.3602098","DOIUrl":null,"url":null,"abstract":"Efficient and effective personalized assistance strategies are crucial for enhancing exoskeleton performance under varying walking conditions. We proposed a novel real-time adaptive assistance strategy to generate personalized and stride-wise customized ankle exoskeleton assistance profiles that adjusted to diverse and varying human locomotion demands. This approach tuned the assistance magnitude and timing online, starting from a profile pre-optimized during medium constant-speed walking, based on real-time ankle momentum estimation. It eliminated re-optimization processes when gait changes and solved assistance customization during transitional gaits. We recruited ten participants and validated the performance of our approach in two testing scenarios: a single-gait walking condition other than the pre-optimized one, and a varying-gait walking condition, which included multiple distinct steady-state gaits and their transition states. For the single-gait (high-speed walking) case, the stride-wise adaptive assistance of a unilateral ankle exoskeleton reduced muscle activity by <inline-formula> <tex-math>$35.9~\\pm ~16.8$ </tex-math></inline-formula>% compared to no assistance, demonstrating a level of assistance comparable to the state-of-the-art approach (human-in-the-loop optimization), but with improved time efficiency. For the varying-gait case, the stride-wise adaptive assistance reduced muscle activity by <inline-formula> <tex-math>$28.4~\\pm ~15.4$ </tex-math></inline-formula>% compared to no assistance, and by <inline-formula> <tex-math>$28.1~\\pm ~15.9$ </tex-math></inline-formula>% during their transition states. These results demonstrated the efficiency and effectiveness of the proposed stride-wise adaptive assistance strategy in assistance personalization and customization under multiple, unknown, un-optimized, changing conditions, as well as during transitional gaits. This approach has the potential to significantly enhance the performance of real-life exoskeletons.","PeriodicalId":13419,"journal":{"name":"IEEE Transactions on Neural Systems and Rehabilitation Engineering","volume":"33 ","pages":"3488-3497"},"PeriodicalIF":5.2000,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11137377","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Transactions on Neural Systems and Rehabilitation Engineering","FirstCategoryId":"5","ListUrlMain":"https://ieeexplore.ieee.org/document/11137377/","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, BIOMEDICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Efficient and effective personalized assistance strategies are crucial for enhancing exoskeleton performance under varying walking conditions. We proposed a novel real-time adaptive assistance strategy to generate personalized and stride-wise customized ankle exoskeleton assistance profiles that adjusted to diverse and varying human locomotion demands. This approach tuned the assistance magnitude and timing online, starting from a profile pre-optimized during medium constant-speed walking, based on real-time ankle momentum estimation. It eliminated re-optimization processes when gait changes and solved assistance customization during transitional gaits. We recruited ten participants and validated the performance of our approach in two testing scenarios: a single-gait walking condition other than the pre-optimized one, and a varying-gait walking condition, which included multiple distinct steady-state gaits and their transition states. For the single-gait (high-speed walking) case, the stride-wise adaptive assistance of a unilateral ankle exoskeleton reduced muscle activity by $35.9~\pm ~16.8$ % compared to no assistance, demonstrating a level of assistance comparable to the state-of-the-art approach (human-in-the-loop optimization), but with improved time efficiency. For the varying-gait case, the stride-wise adaptive assistance reduced muscle activity by $28.4~\pm ~15.4$ % compared to no assistance, and by $28.1~\pm ~15.9$ % during their transition states. These results demonstrated the efficiency and effectiveness of the proposed stride-wise adaptive assistance strategy in assistance personalization and customization under multiple, unknown, un-optimized, changing conditions, as well as during transitional gaits. This approach has the potential to significantly enhance the performance of real-life exoskeletons.
期刊介绍:
Rehabilitative and neural aspects of biomedical engineering, including functional electrical stimulation, acoustic dynamics, human performance measurement and analysis, nerve stimulation, electromyography, motor control and stimulation; and hardware and software applications for rehabilitation engineering and assistive devices.