US Patent 11502633 Motor position control based on servo-to-edge direction feedback

System, apparatus, and methods for controlling a motor by using servo-to-edge direction feedback are disclosed. An exemplary apparatus comprises: a fiber optic rotary junction (FORJ) having a rotatable portion; a motor to rotate the rotatable portion; a connector to connect the rotatable portion to a rotatable fiber of an imaging probe; a sensor positioned in close proximity to a target and configured to output a signal indicative of which one of at least two distinguishable regions of the target is proximal to the sensor; and a controller configured to control the rotational direction of the motor based on the sensor signal. In one embodiment, the motor is a servo-motor, and the rotation of the motor and/or rotatable portion is controlled by a servo-loop to change the rotation direction of the motor back-and-forth around a predetermined rotational position without the use of an encoder.