Fig. 4: Signal processing and demonstration in robotic control.

a Flow chart of triboelectric signal processing for manipulation of robotic arms, and the photograph of the exoskeleton sensory system (right arm) with the rotational triboelectric bidirectional back (RTBD-B) sensor, the rotational triboelectric bidirectional shoulder (RTBD-S) sensor, the rotational triboelectric bidirectional elbow (RTBD-E) sensor, the rotational triboelectric bidirectional wrist (RTBD-W) sensor, and the linear triboelectric bidirectional finger (LTBD-F) sensor. b Demonstration of joint works of two robotic arms for picking up the cube and placing it into the box, (i) flow chart of the motions, and the activated arm and the sensors. (ii) the real-time signals during the manipulation, the channels of BF, BB, SF, SB, EF, EB, WF, WB, FF, and FB represent the forward (clockwise) and the backward (counterclockwise) rotations of the RTBD-B sensor, the RTBD-S sensor, the RTBD-E sensor, the RTBD-W sensor, and the LTBD-F sensor. Photo credit: Minglu Zhu, National University of Singapore.