The Effects of Incline Level on Optimized Lower-Limb Exoskeleton Assistance: A Case Series
For exoskeletons to be successful in real-world settings, they will need to be effective across a variety of terrains, including on inclines. While some single-joint exoskeletons have assisted incline walking, recent successes in level-ground assistance suggest that greater improvements may be possi...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IEEE
2022-01-01
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| Series: | IEEE Transactions on Neural Systems and Rehabilitation Engineering |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/9851636/ |
| _version_ | 1827927079622017024 |
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| author | Patrick W. Franks Gwendolyn M. Bryan Ricardo Reyes Meghan P. O'Donovan Karen N. Gregorczyk Steven H. Collins |
| author_facet | Patrick W. Franks Gwendolyn M. Bryan Ricardo Reyes Meghan P. O'Donovan Karen N. Gregorczyk Steven H. Collins |
| author_sort | Patrick W. Franks |
| collection | DOAJ |
| description | For exoskeletons to be successful in real-world settings, they will need to be effective across a variety of terrains, including on inclines. While some single-joint exoskeletons have assisted incline walking, recent successes in level-ground assistance suggest that greater improvements may be possible by optimizing assistance of the whole leg. To understand how exoskeleton assistance should change with incline, we used human-in-the-loop optimization to find whole-leg exoskeleton assistance torques that minimized metabolic cost on a range of grades. We optimized assistance for three non-disabled, expert participants on 5 degree, 10 degree, and 15 degree inclines using a hip-knee-ankle exoskeleton emulator. For all assisted conditions, the cost of transport was reduced by at least 50% relative to walking in the device with no assistance, which is a large improvement to walking comparable to the benefits of whole-leg assistance on level-ground (N = 3). Optimized extension torque magnitudes and exoskeleton power increased with incline. Hip extension, knee extension and ankle plantarflexion often grew as large as allowed by comfort-based limits. Applied powers on steep inclines were double the powers applied during level-ground walking, indicating that greater exoskeleton power may be optimal in scenarios where biological powers and costs are higher. Future exoskeleton devices could deliver large improvements in walking performance across a range of inclines if they have sufficient torque and power capabilities. |
| first_indexed | 2024-03-13T05:47:03Z |
| format | Article |
| id | doaj.art-90c6ad5080244d209fd9e1b77f55362f |
| institution | Directory Open Access Journal |
| issn | 1558-0210 |
| language | English |
| last_indexed | 2024-03-13T05:47:03Z |
| publishDate | 2022-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Transactions on Neural Systems and Rehabilitation Engineering |
| spelling | doaj.art-90c6ad5080244d209fd9e1b77f55362f2023-06-13T20:08:55ZengIEEEIEEE Transactions on Neural Systems and Rehabilitation Engineering1558-02102022-01-01302494250510.1109/TNSRE.2022.31966659851636The Effects of Incline Level on Optimized Lower-Limb Exoskeleton Assistance: A Case SeriesPatrick W. Franks0https://orcid.org/0000-0001-7736-9023Gwendolyn M. Bryan1Ricardo Reyes2https://orcid.org/0000-0002-8089-6681Meghan P. O'Donovan3Karen N. Gregorczyk4Steven H. Collins5https://orcid.org/0000-0002-3997-3374Department of Mechanical Engineering, Stanford University, Stanford, CA, USADepartment of Mechanical Engineering, Stanford University, Stanford, CA, USADepartment of Mechanical Engineering, Stanford University, Stanford, CA, USADEVCOM Soldier Center, Natick, MA, USADEVCOM Soldier Center, Natick, MA, USADepartment of Mechanical Engineering, Stanford University, Stanford, CA, USAFor exoskeletons to be successful in real-world settings, they will need to be effective across a variety of terrains, including on inclines. While some single-joint exoskeletons have assisted incline walking, recent successes in level-ground assistance suggest that greater improvements may be possible by optimizing assistance of the whole leg. To understand how exoskeleton assistance should change with incline, we used human-in-the-loop optimization to find whole-leg exoskeleton assistance torques that minimized metabolic cost on a range of grades. We optimized assistance for three non-disabled, expert participants on 5 degree, 10 degree, and 15 degree inclines using a hip-knee-ankle exoskeleton emulator. For all assisted conditions, the cost of transport was reduced by at least 50% relative to walking in the device with no assistance, which is a large improvement to walking comparable to the benefits of whole-leg assistance on level-ground (N = 3). Optimized extension torque magnitudes and exoskeleton power increased with incline. Hip extension, knee extension and ankle plantarflexion often grew as large as allowed by comfort-based limits. Applied powers on steep inclines were double the powers applied during level-ground walking, indicating that greater exoskeleton power may be optimal in scenarios where biological powers and costs are higher. Future exoskeleton devices could deliver large improvements in walking performance across a range of inclines if they have sufficient torque and power capabilities.https://ieeexplore.ieee.org/document/9851636/Exoskeletonwalking assistancehuman-in-the-loop optimizationmetabolic costincline |
| spellingShingle | Patrick W. Franks Gwendolyn M. Bryan Ricardo Reyes Meghan P. O'Donovan Karen N. Gregorczyk Steven H. Collins The Effects of Incline Level on Optimized Lower-Limb Exoskeleton Assistance: A Case Series IEEE Transactions on Neural Systems and Rehabilitation Engineering Exoskeleton walking assistance human-in-the-loop optimization metabolic cost incline |
| title | The Effects of Incline Level on Optimized Lower-Limb Exoskeleton Assistance: A Case Series |
| title_full | The Effects of Incline Level on Optimized Lower-Limb Exoskeleton Assistance: A Case Series |
| title_fullStr | The Effects of Incline Level on Optimized Lower-Limb Exoskeleton Assistance: A Case Series |
| title_full_unstemmed | The Effects of Incline Level on Optimized Lower-Limb Exoskeleton Assistance: A Case Series |
| title_short | The Effects of Incline Level on Optimized Lower-Limb Exoskeleton Assistance: A Case Series |
| title_sort | effects of incline level on optimized lower limb exoskeleton assistance a case series |
| topic | Exoskeleton walking assistance human-in-the-loop optimization metabolic cost incline |
| url | https://ieeexplore.ieee.org/document/9851636/ |
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