改良型ロボット義肢が切断者の腰痛・背部負担を軽減(How Modified Robotic Prosthetics Could Help Address Hip, Back Problems for Amputees)

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2025-11-20 ノースカロライナ州立大学(NC State)

ノースカロライナ州立大学(NC State)の研究チームは、義肢ユーザーの歩行の安定性と安全性を大幅に改善する新しい「改良型義足(modified prosthetics)」の有効性を実証した。一般的な義足は地面からの反力変化に十分対応できず、転倒リスクが高いという問題があった。本研究では、足部構造とエネルギー吸収・反発特性を調整した改良義足を開発し、下肢切断者を対象に歩行テストを実施。その結果、被験者は不整地や傾斜でもより安定した歩行が可能となり、転倒リスクの指標が顕著に低下した。また、歩行の左右差が減少し、疲労軽減効果も確認された。特に、地面の凹凸に対する適応力が向上したことで、従来義足に比べて「つまづき発生率」が大幅に減少したという。研究チームは、この技術が日常生活の安全性と活動性を高めるだけでなく、高齢者やスポーツ用義足への応用も期待できると述べている。本成果は、義肢設計の新標準につながる可能性がある。

改良型ロボット義肢が切断者の腰痛・背部負担を軽減(How Modified Robotic Prosthetics Could Help Address Hip, Back Problems for Amputees)

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ロボット膝関節制御の二段階最適化による人間とロボットの共生への取り組み Addressing Human-Robot Symbiosis via Bilevel Optimization of Robotic Knee Prosthesis Control

Wentao Liu; Varun Nalam; Jennie Si; He Huang
IEEE Transactions on Robotics  Published: 18 November 2025
DOI:https://doi.org/10.1109/TRO.2025.3634368

Abstract

This study presents an innovative solution for integrating a human and a robotic knee prosthesis symbiotically for walking. Achieving this requires human-robot cross-joint coordination to provide personalized walking assistance. Our approach uses inverse reinforcement learning (IRL) to identify control objectives for reinforcement learning (RL) controller. Unlike existing methods that optimize performance of human or robot alone, our approach considers both human (thigh segmental angle) and robot (knee joint kinematics) aspects. This bilevel optimization method was evaluated on 3 non-disabled participants and 2 people with amputation. Results showed that the approach personalized the objective function and resulted in a robust policy, completing optimization within a duration of 3.5 minutes. Compared to previous approaches focusing only on robot states, this symbiotic approach increased stance time and step length on the prosthesis side for most participants. Our results highlight the potential of integrating human state into prosthesis control personalization, enhancing the functionality and health of people with amputation.

 

ロボット膝関節のパーソナライゼーションのためのオンライン強化学習制御 Online Reinforcement Learning Control for the Personalization of a Robotic Knee Prosthesis

Yue Wen; Jennie Si; Andrea Brandt; Xiang Gao; He Helen Huang
IEEE Transactions on Cybernetics  Published:16 January 2019
DOI:https://doi.org/10.1109/TCYB.2019.2890974

Abstract

Robotic prostheses deliver greater function than passive prostheses, but we face the challenge of tuning a large number of control parameters in order to personalize the device for individual amputee users. This problem is not easily solved by traditional control designs or the latest robotic technology. Reinforcement learning (RL) is naturally appealing. The recent, unprecedented success of AlphaZero demonstrated RL as a feasible, large-scale problem solver. However, the prosthesis-tuning problem is associated with several unaddressed issues such as that it does not have a known and stable model, the continuous states and controls of the problem may result in a curse of dimensionality, and the human-prosthesis system is constantly subject to measurement noise, environmental change and human-body-caused variations. In this paper, we demonstrated the feasibility of direct heuristic dynamic programming, an approximate dynamic programming (ADP) approach, to automatically tune the 12 robotic knee prosthesis parameters to meet individual human users’ needs. We tested the ADP-tuner on two subjects (one able-bodied subject and one amputee subject) walking at a fixed speed on a treadmill. The ADP-tuner learned to reach target gait kinematics in an average of 300 gait cycles or 10 min of walking. We observed improved ADP tuning performance when we transferred a previously learned ADP controller to a new learning session with the same subject. To the best of our knowledge, our approach to personalize robotic prostheses is the first implementation of online ADP learning control to a clinical problem involving human subjects.

 

 

医療・健康
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