Control system structure for simultaneous proportional control. Left: Model and taxonomy for the prosthesis control problem . Right: Control system structure for simultaneous proportional control. The EMG features used are Average amplitude value (AAV), zero crossings (ZC), waveform length (WL) and myopulse (MYOP). In the “gain and threshold adjustments” block, the two axes are spanned by the preliminary activation levels, and the colored sections represent the following: a) Red inner circle: No motion. b) Green sections: Pronation/supination only. c) Blue sections: Open/close only. d) White sections: Pronation/supination and open/close, simultaneously. The “Simultaneous proportional control” section of the paper follows the sequential order of this figure.