Fig. 6: Experimental results of speed control for the photon-driven DC motor system.

a Photograph of the experimental setup. b,c The system’s performance during both halt and initiation phases with rejection of ripple. Initially, the brushed DC motor maintains a constant speed of 347 rpm under a load torque of 40 mNm. At about 6 s, the speed command is adjusted to 0 rpm, and then back to 347 rpm at about 14 s; global picture (b) and local picture (c).