Controls of servomotors for carry hospital robots

Two methods for controlling servomotors with pulse encoders are presented for improving the movement of a carry hospital robot (CHR) along a desired line. Some simulation studies have been executed for the design of a PI controller or optimal regulator for the control of the DC servomotor. By applying the simulation results, we actually design a PI controller in an analogue circuit and experimentally compare the results of the PI control with those of a PLL (Phase Locked Loop) control. It is then clarified that the latter approach is effective in improving the accuracy of the CHR.