“…For this reason they are used as assistive robots, attracting the attention of many research groups around the world. Some authors focus their attention on the human-machine interface, proposing alternatives to the control input such as electromyography (EMG) [2,3], bioimpedance [4], BrainComputer Interface (BCI) [5], face detection [6][7][8], or hybrid approaches [9,10]. Others propose different control strategies in order to ensure velocity control, safety and robustness.…”