Oh Keonyoung, Rymer William Z, Plenzio Ilaria, Mussa-Ivaldi Ferdinando A, Park Seunghan, Choi Junho
IEEE Trans Biomed Eng. 2021 May;68(5):1441-1449. doi: 10.1109/TBME.2020.3038896. Epub 2021 Apr 22.
Several studies have reported that stroke survivors displayed improved voluntary planar movements when forces supporting the upper limb increased, and when impeding forces decreased. Earlier haptic devices interacting with the human upper limb were potentially impacted by undesired residual friction force and device inertia. To explore natural, undisturbed voluntary motor control in stroke survivors, we describe the development of a Decoupled-Operational space Robot for wide Impedance Switching (DORIS) with minimized mechanical impedances. This design is based on a novel decoupling mechanism separating the end effector from a manipulator. While the user manipulates the end effector freely inside the workspace of the decoupling mechanism, to which a manipulator of the robot is attached, the robot detects such change in position using a lightweight linkage system. The manipulator of the robot then follows such movements of the end effector swiftly. Consequently, the user can explore the extended workspace, which can be as large as the manipulator's workspace. Since the end effector is mechanically decoupled from the manipulators and actuators, the user can remain unaffected by the mechanical impedances of the manipulator. Mechanical impedances perceived by the user and bandwidth of the control system were estimated. The developed robot was capable of detecting larger maximum acceleration and larger jerk of the reaching movement in chronic stroke survivors with hemiparesis. We propose that this device can be utilized for evaluating voluntary motor control of the upper limb while minimizing the impact of robot inertia and friction forces on limb behavior.
多项研究报告称，当支撑上肢的力增加且阻碍力减小时，中风幸存者的自愿平面运动有所改善。早期与人类上肢交互的触觉设备可能会受到不期望的残余摩擦力和设备惯性的影响。为了探索中风幸存者自然、不受干扰的自愿运动控制，我们描述了一种具有最小机械阻抗的宽阻抗切换解耦操作空间机器人（DORIS）的开发。这种设计基于一种新颖的解耦机制，将末端执行器与操纵器分离。当用户在解耦机制的工作空间内自由操纵末端执行器时，机器人的操纵器连接到该解耦机制上，机器人使用轻型连杆系统检测位置的这种变化。然后，机器人的操纵器迅速跟随末端执行器的这种运动。因此，用户可以探索扩展的工作空间，其大小可以与操纵器的工作空间一样大。由于末端执行器与操纵器和致动器在机械上解耦，用户不会受到操纵器机械阻抗的影响。估计了用户感知的机械阻抗和控制系统的带宽。所开发的机器人能够检测慢性偏瘫中风幸存者伸手运动中更大的最大加速度和更大的急动度。我们建议该设备可用于评估上肢的自愿运动控制，同时将机器人惯性和摩擦力对肢体行为的影响降至最低。
