Gait asymmetry is a significant clinical characteristic of hemiplegic gait that most stroke survivors suffer, leading to limited mobility and long-term negative impacts on their quality of life. Although a variety of exoskeleton controls have been developed for robot-assisted gait rehabilitation, little attention has been paid to correcting the gait asymmetry of stroke patients following the assist-as-need (AAN) principle, and it is still challenging to properly share control between the exoskeleton and stroke patients with partial motor control. In view of this, this article proposes an AAN hip exoskeleton control with human-in-the-loop optimization to correct gait asymmetry in stroke patients. To realize the AAN concept, an objective function was designed for real-time evaluation of the subject's gait performance and active participation, which considers the variability of natural human movement and guides the online tuning of control parameters on a subject-specific basis. In this way, patients were stimulated to contribute as much as possible to movement, thus maximizing the efficiency and outcomes of post-stroke gait rehabilitation. Finally, an experimental study was conducted to verify the feasibility and effectiveness of the proposed AAN control on healthy subjects with artificial gait impairment. For the first time, the common hypothesis that AAN controls can improve human active participation was validated from the biomechanics viewpoint.

翻译：步态不对称是偏瘫步态的重要临床特征，多数脑卒中幸存者受此困扰，导致活动能力受限并对其生活质量产生长期负面影响。尽管目前已开发出多种用于机器人辅助步态康复的外骨骼控制方法，但遵循按需辅助原则矫正脑卒中患者步态不对称的研究仍显不足，且在具有部分运动控制能力的脑卒中患者与外骨骼之间实现恰当的控制权分配仍具挑战性。鉴于此，本文提出一种融合人在环优化的按需辅助式髋关节外骨骼控制方法，用于矫正脑卒中患者的步态不对称。为实现按需辅助理念，本研究设计了用于实时评估受试者步态表现与主动参与度的目标函数，该函数综合考虑了人体自然运动的变异性，并指导基于个体差异的控制参数在线调节。通过这种方式，激励患者尽可能多地参与运动，从而最大化脑卒中后步态康复的效率和效果。最后，通过实验研究验证了所提按需辅助控制在模拟步态障碍的健康受试者上的可行性与有效性。本研究首次从生物力学角度验证了"按需辅助控制能提升人类主动参与度"这一普遍假设。