Fig. 10
Semi-automatic search in the extensor array with feedback-control for patient 1. The feedback controlled wrist extension/flexion angle α (blue) is displayed over time together with the applied global stimulation intensity u (black; actuating variable). The reference angle αref was set to 15∘ (black dotted line) and the tolerated error bound αbound (gray, dotted line) was ±5∘. An error smaller ±αbound equaled zero at the input of the controller. In the displayed time frame, the location of the VE model was changed by the user. The resulting position of the VE model in the array (red circle) and the corresponding active elements, marked in yellow, are exemplarily shown for four times, together with the measured hand posture. The little finger is depicted in gray, because it was not measured in the experiments. In the interest of a good visualization, the little finger was assigned the same joint angles as the ring finger