Walking Strategies and Performance Evaluation for Human-Exoskeleton Systems under Admittance Control
Lower-limb exoskeletons as walking assistive devices have been intensively investigated in recent decades. In these studies, intention detection and performance evaluation are important topics. In our previous studies, we proposed a disturbance observer (DOB)-based torque estimation algorithm and an...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-08-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/20/15/4346 |
| _version_ | 1797560358971375616 |
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| author | Chiawei Liang Tesheng Hsiao |
| author_facet | Chiawei Liang Tesheng Hsiao |
| author_sort | Chiawei Liang |
| collection | DOAJ |
| description | Lower-limb exoskeletons as walking assistive devices have been intensively investigated in recent decades. In these studies, intention detection and performance evaluation are important topics. In our previous studies, we proposed a disturbance observer (DOB)-based torque estimation algorithm and an admittance control law to shape the admittance of the human-exoskeleton system (HES) and comply with the user’s walking intention. These algorithms have been experimentally verified under the condition of no ground reaction force (GRF) in our previous studies. In this paper, we devised and integrated with the exoskeleton control system a sensing and communication module on each foot to measure and compensate for GRF. Rigorous theoretical analysis was performed and the sufficient conditions for the robust stability of the closed-loop system were derived. Then, we conducted level ground assistive walking repeatedly with different test subjects and exhaustive combinations of admittance parameters. In addition, we proposed two tractable and physically insightful performance indices called <i>normalized energy consumption index</i> (NECI) and <i>walking distance</i> in a <i>fixed period of time</i> to quantitatively evaluate the performance for different admittance parameters. We also compared the energy consumption for users walking with and without the exoskeleton. The results show that the proposed admittance control law reduces the energy consumption of the user during level ground walking. |
| first_indexed | 2024-03-10T17:59:00Z |
| format | Article |
| id | doaj.art-e509ce05468a4199aefabfc63b04ed1f |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T17:59:00Z |
| publishDate | 2020-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-e509ce05468a4199aefabfc63b04ed1f2023-11-20T09:03:52ZengMDPI AGSensors1424-82202020-08-012015434610.3390/s20154346Walking Strategies and Performance Evaluation for Human-Exoskeleton Systems under Admittance ControlChiawei Liang0Tesheng Hsiao1Department of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu 300093, TaiwanDepartment of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu 300093, TaiwanLower-limb exoskeletons as walking assistive devices have been intensively investigated in recent decades. In these studies, intention detection and performance evaluation are important topics. In our previous studies, we proposed a disturbance observer (DOB)-based torque estimation algorithm and an admittance control law to shape the admittance of the human-exoskeleton system (HES) and comply with the user’s walking intention. These algorithms have been experimentally verified under the condition of no ground reaction force (GRF) in our previous studies. In this paper, we devised and integrated with the exoskeleton control system a sensing and communication module on each foot to measure and compensate for GRF. Rigorous theoretical analysis was performed and the sufficient conditions for the robust stability of the closed-loop system were derived. Then, we conducted level ground assistive walking repeatedly with different test subjects and exhaustive combinations of admittance parameters. In addition, we proposed two tractable and physically insightful performance indices called <i>normalized energy consumption index</i> (NECI) and <i>walking distance</i> in a <i>fixed period of time</i> to quantitatively evaluate the performance for different admittance parameters. We also compared the energy consumption for users walking with and without the exoskeleton. The results show that the proposed admittance control law reduces the energy consumption of the user during level ground walking.https://www.mdpi.com/1424-8220/20/15/4346exoskeletonadmittance controlground reaction forcewalking strategyhuman-exoskeleton systemnormalized energy consumption index |
| spellingShingle | Chiawei Liang Tesheng Hsiao Walking Strategies and Performance Evaluation for Human-Exoskeleton Systems under Admittance Control Sensors exoskeleton admittance control ground reaction force walking strategy human-exoskeleton system normalized energy consumption index |
| title | Walking Strategies and Performance Evaluation for Human-Exoskeleton Systems under Admittance Control |
| title_full | Walking Strategies and Performance Evaluation for Human-Exoskeleton Systems under Admittance Control |
| title_fullStr | Walking Strategies and Performance Evaluation for Human-Exoskeleton Systems under Admittance Control |
| title_full_unstemmed | Walking Strategies and Performance Evaluation for Human-Exoskeleton Systems under Admittance Control |
| title_short | Walking Strategies and Performance Evaluation for Human-Exoskeleton Systems under Admittance Control |
| title_sort | walking strategies and performance evaluation for human exoskeleton systems under admittance control |
| topic | exoskeleton admittance control ground reaction force walking strategy human-exoskeleton system normalized energy consumption index |
| url | https://www.mdpi.com/1424-8220/20/15/4346 |
| work_keys_str_mv | AT chiaweiliang walkingstrategiesandperformanceevaluationforhumanexoskeletonsystemsunderadmittancecontrol AT teshenghsiao walkingstrategiesandperformanceevaluationforhumanexoskeletonsystemsunderadmittancecontrol |