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.
The RDrive servo motors use encoders of the absolute type. Such devices are resilient against power outages and signal interruptions because they require no referencing to a start point. You can read the exact motor position from the encoders immediately upon powering on. You will also find that the position information is retained when you power off as well.