Page 97 - Servo Motors and Industrial Control Theory -

90 4 Electrical DC Servo Motors

In the block diagram Kp is the gain and Kd is the time constant of the lead net-
work and T2 is the time constant of the lag network. Velocity of position feedback
must be used and it is compared with the demand signal and the error is fed to the
Lead-lag network. The output voltage after amplification is fed to the motor. The
presence of a derivative term makes this control strategy similar to PID.