An apparatus for positioning a device relative to tissue may include an emitter and a detector coupled to the device. The emitter may emit energy onto the tissue. The detector may detect energy reflected from the tissue. The detector may also generate a detector output signal indicative of a characteristic of the reflected energy. The apparatus may also include a processor that receives the detector output signal from the detector. The processor may determine whether there has been relative movement between the device and the tissue based on the detector output signal. The processor may also generate a processor output signal based on the relative movement. The apparatus may also include an actuator assembly engaging the device. The actuator assembly may receive the processor output signal from the processor. The actuator assembly may also move the device based on the processor output signal.
