A DC Servo is a motor control system that typically consists of a DC motor, encoder and servo drive. It provides highly accurate and responsive motion control. Common-mode feedback is a control technique used to enhance the performance of a DC servo system.
In a DC servo system, common mode feedback is used to provide a more accurate and stable position feedback signal. It is accomplished by adding an additional sensor between the two output phases of the motor. This sensor can be an optical encoder or a Hall effect sensor.
The basic principle of common-mode feedback is that it detects and corrects motor position errors by comparing the positional difference between the two output phases of the motor. As the motor moves, the output signals of the two phases should remain synchronized. If there is a position error, common-mode feedback will detect the phase difference and pass it as a feedback signal to the servo driver.
The servo drive adjusts the motor's control signal based on the common-mode feedback signal to bring it back to the desired position. By constantly monitoring and correcting for position errors, common-mode feedback helps to improve the accuracy, stability and dynamic response of DC servo systems.