Figure 3.

Control strategy of the upper-limb exoskeleton. Subjects performed ME or MI according to the cue. The presentation of cue was same as in the decoder-training phase. After the preprocessing and feature extraction for the raw EEG signals, the extracted features were input into the trained decoder and were classified to recognize which movement the subjects were executing or imagining. Depending on the classification result, the intelligent controller sent control signals to the exoskeleton to make it perform the corresponding action. Feedback was given by a vertical bar simulating the active part of the exoskeleton on the computer screen (Scenarios 1 and 2) or by the exoskeleton mounted on the right arm (Scenario 2). The feedback bar moved the same angle as the exoskeleton in real time.