Patent ID: 8437587

Claim:
A method comprising: inhibiting modification of an electric signal generated by a piezoelectric tube by controlling a switch to switchably electrically decouple actuator drive signals from a first line coupled with the piezoelectric tube; detecting the electrical signal generated by the piezoelectric tube as a result of mechanical deformation of the piezoelectric tube while the actuator drive signals are switchably electrically decoupled from the piezoelectric tube due to said inhibiting on a second high impedance line having an impedance of at least one mega ohm which is coupled between a voltage detector and the first line, the piezoelectric tube operable to actuate a cantilevered optical fiber inserted though the piezoelectric tube, wherein detecting the electrical signal comprises detecting the electrical signal during a period of active braking; determining an active braking actuator drive signal based at least in part on the electrical signal generated by the piezoelectric tube that is detected during the period of the active braking, the active braking actuator drive signal operable to cause the piezoelectric tube to reduce movement of the cantilevered optical and fiber; applying the active braking actuator drive signal to the piezoelectric tube; detecting a second electrical signal generated by the piezoelectric tube; and determining to stop active braking based at least in part on the detected second electrical signal indicating an increase in movement of the piezoelectric tube.