Rozum Robotics has created a closed-loop motion control system with two position encoders integrated into the RDrive servo motors.
The design designates a command that goes to the motor sending a feedback signal with position and speed data coming back. It is the intended purpose of the position encoders to provide the feedback.
The devices convert the mechanical motion into electrical signals and transmit the signals to a controller (or another control device). In this way, the encoders enable tracking the position or speed of a motor.