Casas Rafael, Chen Tianyao, Lum Peter S
IEEE Int Conf Rehabil Robot. 2019 Jun;2019:317-322. doi: 10.1109/ICORR.2019.8779448.
Low impedance and torque control are critical for movement rehabilitation using robotic exoskeletons. A grounded 3 degree of freedom shoulder exoskeleton was designed for movement assistance in shoulder abduction/adduction, flexion/extension, and shoulder internal/external rotation. Two series elastic actuators designs were developed using a linear spring arrangement with a global nonlinear stiffness behavior. RMS errors during application of constant torque were less than.06 Nm in shoulder add/abd and less than.04 Nm in arm rotation as the limb was moved in sinusoidal trajectories up to 3.5 Hz. For abd/adduction, the step response rise time was.05 s, and free mode impedance peaked at.007 Nm/deg during 3.5 Hz oscillations. For arm rotation, the step response rise time was.03 s, and impedance peaked at.023 Nm/deg during 3.5 Hz oscillations. Both SEA designs had performance measurements that were similar to other SEA designs in terms of torque tracking, but with much lower impedance than previously reported.
低阻抗和扭矩控制对于使用机器人外骨骼进行运动康复至关重要。设计了一种接地的三自由度肩部外骨骼，用于辅助肩部外展/内收、屈伸以及肩部内旋/外旋运动。采用线性弹簧布置开发了两种具有全局非线性刚度特性的串联弹性驱动器设计。当肢体以高达3.5Hz的正弦轨迹移动时，在施加恒定扭矩期间，肩部内收/外展的均方根误差小于0.06 Nm，手臂旋转的均方根误差小于0.04 Nm。对于外展/内收，阶跃响应上升时间为0.05 s，在3.5Hz振荡期间自由模式阻抗峰值为每度0.007 Nm。对于手臂旋转，阶跃响应上升时间为0.03 s，在3.5Hz振荡期间阻抗峰值为每度0.023 Nm。两种串联弹性驱动器设计在扭矩跟踪方面的性能测量结果与其他串联弹性驱动器设计相似，但阻抗比之前报道的要低得多。
