A DC servo motor control system for a CNC lathe is designed and also implemented, where the system consists of power amplifier, velocity control unit and position control unit.
A bipolar pulsewidth modulated amplifier using power transistor is employed for driving the DC servo motor. For an effective control of velocity of the motor, a proportional plus integral action is utilized and the velocity of the motor is assured by converting the frequency of the output of the pulse coder to the corresponding voltages. And a up/down counter and digital to analog converter is used for the control of motor position.
Further, the open loop gain parameters of the two control systems for a lathe with two simultaneously controlled axis are determined to eliminate the steady state contouring error.
