Accurate, repetitive, linear motion from biased piezoelectric actuators

A method is described for producing accurate, repetitive, linear motion from biased piezoelectric actuators without the need for feedback from external distance measuring sensors. A precalibration of the actuator determines a voltage profile that produces repeatable linear motion but whose slope is uncertain due to actuator gain variations stemming from bulk polarization changes in the piezoelectric ceramic. Monitoring the current flowing through the actuator at a specified point in the linear part of the motion profile is used to determine and correct for the slope variations.