Patent ID: 8717654

Claim:
An optical probe ( 1 , 20 ), the probe comprising an optical guide ( 2 , 25 ) having a distal end ( 3 ); a housing ( 4 , 22 ), the optical guide being mounted inside the housing so that the distal end is displaceable with respect to the housing; and a coil-based actuation system ( 9 , 10 , 21 , 23 ) comprising drive coils ( 9 , 23 ) capable of displacing the distal end by a displacement force induced by driving a drive current through the drive coils; wherein the drive current comprises a set-point current related to a positional set-point and an adjustment term; wherein the adjustment term is determined by a feedback loop comprising: applying the drive current to the drive coils; temporally switching off the drive current and while the drive current is switched off measure a speed of the distal end; and comparing the positional set-point and the measured speed by either deriving from the positional set-point a set-point speed and comparing the set-point speed and the measured speed to derive a difference; or deriving from the measured speed a measured position, and comparing the positional set-point and the measured position to derive a difference, and adjusting the drive current if the difference is above a preset level.