A Robotic Assistance Personalization Control Approach of Hip Exoskeletons for Gait Symmetry Improvement
A Robotic Assistance Personalization Control Approach of Hip Exoskeletons for Gait Symmetry Improvement
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DOI：
10.1109/iros55552.2023.10341440
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发表时间：
2023-10
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影响因子：
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通讯作者：
Qiang Zhang;Xikai Tu;Jennie Si;M. Lewek;H. Huang
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作者：
Qiang Zhang;Xikai Tu;Jennie Si;M. Lewek;H. Huang
拥有良好步态对称性的健康人类运动功能依赖于左腿和右腿的有节奏的协调，而这可能会因中风和脊髓损伤等神经疾病而恶化。电动外骨骼是一种很有前途的设备，可以改善受损的人的运动功能，比如步态对称性。然而，考虑到人与机器人交互的不确定性和时变性，从外骨骼提供个性化的机器人辅助以实现最佳步态对称是具有挑战性的，特别是对于患有神经疾病的人。本文提出了一种双侧髋外骨骼的分级控制框架，旨在提供自适应的最优髋关节辅助，控制目标是在行走过程中施加期望的步态对称性。该分层控制框架包括三个控制级别，高层控制基于策略迭代强化学习方法调整三个控制参数，中级控制基于延迟输出反馈控制方法定义期望的辅助力矩曲线，低级控制实现良好的转矩轨迹跟踪性能。为了评估建议的控制框架的可行性，我们招募了5名健康的年轻参与者进行跑步机步行实验，其中模拟了人工步态不对称作为中风后的偏瘫，并且使用所提出的框架仅控制了偏瘫的髋关节。初步实验研究表明，针对髋外骨骼的分级控制框架成功地(不对称指数从8.8%到−0.5%)并且有效地(不到4分钟)通过在偏瘫的髋关节上提供自适应的最佳辅助来实现所需的步态对称性。
Healthy human locomotion functions with good gait symmetry depend on rhythmic coordination of the left and right legs, which can be deteriorated by neurological disorders like stroke and spinal cord injury. Powered exoskeletons are promising devices to improve impaired people's locomotion functions, like gait symmetry. However, given higher uncertainties and the time-varying nature of human-robot interaction, providing personalized robotic assistance from exoskeletons to achieve the best gait symmetry is challenging, especially for people with neurological disorders. In this paper, we propose a hierarchical control framework for a bilateral hip exoskeleton to provide the adaptive optimal hip joint assistance with a control objective of imposing the desired gait symmetry during walking. Three control levels are included in the hierarchical framework, including the high-level control to tune three control parameters based on a policy iteration reinforcement learning approach, the middle-level control to define the desired assistive torque profile based on a delayed output feedback control method, and the low-level control to achieve a good torque trajectory tracking performance. To evaluate the feasibility of the proposed control framework, five healthy young participants are recruited for treadmill walking experiments, where an artificial gait asymmetry is imitated as the hemiparesis post-stroke, and only the ‘paretic’ hip joint is controlled with the proposed framework. The pilot experimental studies demonstrate that the hierarchical control framework for the hip exoskeleton successfully (asymmetry index from 8.8% to − 0.5%) and efficiently (less than 4 minutes) achieved the desired gait symmetry by providing adaptive optimal assistance on the ‘paretic’ hip joint.