This article presents a locomotion controller for lower limb exoskeletons so as to enable the combined robot and user system to exhibit compliant walking characteristics when interacting with the environment. This is of critical importance to reduce the excessive ground reaction forces during the walking task execution with the aim of improved environmental interaction capabilities. In robot-aided walking support for paraplegics, the user has to actively use his/her upper limbs via crutches to ensure overall balance. By virtue of this requisite, several issues may particularly arise during touchdown instants, e.g., upper body orientation fluctuates, shoulder joints are subject to excessive loading, and arms may need to exert extra forces to counterbalance these effects. In order to reduce the upper body effort via compliant locomotion, the controller is designed to manage the force/position tradeoff by using an admittance controller in each joint. For proof of concept, a series of exoskeleton-aided walking experiments were conducted with the participation of nine healthy volunteers, four of whom additionally walked on an irregular surface for further performance evaluation. The results suggest that the proposed locomotion controller is advantageous over conventional high-gain position tracking in decreasing undesired oscillatory torso motion and total arm force, adequately reducing the required upper body effort.

中文翻译：

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主动顺从控制可减少外骨骼支撑步行中的上半身努力

本文提出了一种用于下肢外骨骼的运动控制器，使组合机器人和用户系统在与环境交互时表现出顺从的步行特性。这对于减少步行任务执行期间过度的地面反作用力以提高环境交互能力至关重要。在截瘫患者的机器人辅助步行支持中，用户必须通过拐杖主动使用他/她的上肢以确保整体平衡。由于这个必要条件，在触地瞬间可能会特别出现几个问题，例如，上身方向波动，肩关节承受过大的负荷，并且手臂可能需要施加额外的力来抵消这些影响。为了通过顺应性运动减少上半身的努力，控制器旨在通过在每个关节中使用导纳控制器来管理力/位置权衡。为了验证概念，在九名健康志愿者的参与下进行了一系列外骨骼辅助步行实验，其中四人另外在不规则表面上行走以进行进一步的性能评估。结果表明，所提出的运动控制器在减少不希望的躯干摆动和总臂力方面优于传统的高增益位置跟踪，充分减少了所需的上身努力。其中四人另外在不规则的表面上行走以进行进一步的性能评估。结果表明，所提出的运动控制器在减少不希望的躯干摆动和总臂力方面优于传统的高增益位置跟踪，充分减少了所需的上身努力。其中四人另外在不规则的表面上行走以进行进一步的性能评估。结果表明，所提出的运动控制器在减少不希望的躯干摆动和总臂力方面优于传统的高增益位置跟踪，充分减少了所需的上身努力。