Fig. 1From: System identification: a feasible, reliable and valid way to quantify upper limb motor impairmentsThe Shoulder Elbow Perturbator (SEP), a robotic device to quantify multiple upper limb impairments. a Participant positioned in the SEP with the shoulder abducted in 80°, the forearm strapped (1) to the lever arm of the SEP, and the medial epicondyle of the humerus aligned with the motor rotation axis. b Internals of the SEP showing that the motor (4) transmits a torque through the torque link (3), allowing elbow rotation (2). c Internals of the SEP showing the shoulder abductor manipulation mechanism. The sarrus linkages (5) allow vertical displacement of the arm, and the arm is supported by two springs (6) with an upward force. With the cable routing and pulley configuration, the upward force can be manipulated independently of the linkage position (7). (Modified – with permission from [20])Back to article page