Evaluation of Motor Primitive-Based Adaptive Control for Lower Limb Exoskeletons
In order to assist after-stroke individuals to rehabilitate their movements, research centers have developed lower limbs exoskeletons and control strategies for them. Robot-assisted therapy can help not only by providing support, accuracy, and precision while performing exercises, but also by being...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2020-12-01
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| Series: | Frontiers in Robotics and AI |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/frobt.2020.575217/full |
| _version_ | 1819058950591479808 |
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| author | Polyana F. Nunes Icaro Ostan Adriano A. G. Siqueira |
| author_facet | Polyana F. Nunes Icaro Ostan Adriano A. G. Siqueira |
| author_sort | Polyana F. Nunes |
| collection | DOAJ |
| description | In order to assist after-stroke individuals to rehabilitate their movements, research centers have developed lower limbs exoskeletons and control strategies for them. Robot-assisted therapy can help not only by providing support, accuracy, and precision while performing exercises, but also by being able to adapt to different patient needs, according to their impairments. As a consequence, different control strategies have been employed and evaluated, although with limited effectiveness. This work presents a bio-inspired controller, based on the concept of motor primitives. The proposed approach was evaluated on a lower limbs exoskeleton, in which the knee joint was driven by a series elastic actuator. First, to extract the motor primitives, the user torques were estimated by means of a generalized momentum-based disturbance observer combined with an extended Kalman filter. These data were provided to the control algorithm, which, at every swing phase, assisted the subject to perform the desired movement, based on the analysis of his previous step. Tests are performed in order to evaluate the controller performance for a subject walking actively, passively, and at a combination of these two conditions. Results suggest that the robot assistance is capable of compensating the motor primitive weight deficiency when the subject exerts less torque than expected. Furthermore, though only the knee joint was actuated, the motor primitive weights with respect to the hip joint were influenced by the robot torque applied at the knee. The robot also generated torque to compensate for eventual asynchronous movements of the subject, and adapted to a change in the gait characteristics within three to four steps. |
| first_indexed | 2024-12-21T14:03:21Z |
| format | Article |
| id | doaj.art-9cac1fff54484908a7280bbbb43c1f8a |
| institution | Directory Open Access Journal |
| issn | 2296-9144 |
| language | English |
| last_indexed | 2024-12-21T14:03:21Z |
| publishDate | 2020-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Robotics and AI |
| spelling | doaj.art-9cac1fff54484908a7280bbbb43c1f8a2022-12-21T19:01:19ZengFrontiers Media S.A.Frontiers in Robotics and AI2296-91442020-12-01710.3389/frobt.2020.575217575217Evaluation of Motor Primitive-Based Adaptive Control for Lower Limb ExoskeletonsPolyana F. NunesIcaro OstanAdriano A. G. SiqueiraIn order to assist after-stroke individuals to rehabilitate their movements, research centers have developed lower limbs exoskeletons and control strategies for them. Robot-assisted therapy can help not only by providing support, accuracy, and precision while performing exercises, but also by being able to adapt to different patient needs, according to their impairments. As a consequence, different control strategies have been employed and evaluated, although with limited effectiveness. This work presents a bio-inspired controller, based on the concept of motor primitives. The proposed approach was evaluated on a lower limbs exoskeleton, in which the knee joint was driven by a series elastic actuator. First, to extract the motor primitives, the user torques were estimated by means of a generalized momentum-based disturbance observer combined with an extended Kalman filter. These data were provided to the control algorithm, which, at every swing phase, assisted the subject to perform the desired movement, based on the analysis of his previous step. Tests are performed in order to evaluate the controller performance for a subject walking actively, passively, and at a combination of these two conditions. Results suggest that the robot assistance is capable of compensating the motor primitive weight deficiency when the subject exerts less torque than expected. Furthermore, though only the knee joint was actuated, the motor primitive weights with respect to the hip joint were influenced by the robot torque applied at the knee. The robot also generated torque to compensate for eventual asynchronous movements of the subject, and adapted to a change in the gait characteristics within three to four steps.https://www.frontiersin.org/articles/10.3389/frobt.2020.575217/fullrehabilitation roboticsmotor primitivesexoskeletonlower limbsbiomechatronics |
| spellingShingle | Polyana F. Nunes Icaro Ostan Adriano A. G. Siqueira Evaluation of Motor Primitive-Based Adaptive Control for Lower Limb Exoskeletons Frontiers in Robotics and AI rehabilitation robotics motor primitives exoskeleton lower limbs biomechatronics |
| title | Evaluation of Motor Primitive-Based Adaptive Control for Lower Limb Exoskeletons |
| title_full | Evaluation of Motor Primitive-Based Adaptive Control for Lower Limb Exoskeletons |
| title_fullStr | Evaluation of Motor Primitive-Based Adaptive Control for Lower Limb Exoskeletons |
| title_full_unstemmed | Evaluation of Motor Primitive-Based Adaptive Control for Lower Limb Exoskeletons |
| title_short | Evaluation of Motor Primitive-Based Adaptive Control for Lower Limb Exoskeletons |
| title_sort | evaluation of motor primitive based adaptive control for lower limb exoskeletons |
| topic | rehabilitation robotics motor primitives exoskeleton lower limbs biomechatronics |
| url | https://www.frontiersin.org/articles/10.3389/frobt.2020.575217/full |
| work_keys_str_mv | AT polyanafnunes evaluationofmotorprimitivebasedadaptivecontrolforlowerlimbexoskeletons AT icaroostan evaluationofmotorprimitivebasedadaptivecontrolforlowerlimbexoskeletons AT adrianoagsiqueira evaluationofmotorprimitivebasedadaptivecontrolforlowerlimbexoskeletons |