What is the difference between piezoelectric actuators with and without position feedback?
Piezoactuators are not ideal voltage-to-displacement transducers they exhibit nonlinear properties of hysteresis and drift. Although these properties can be overcome by approaching the final destination from one direction (unidirectional approach), a more powerful technique to eliminate them is to use a “feedback control” loop. CVI Melles Griot has developed a range of piezoactuators with a closed loop position feedback sensor. The linearity response of these closed loop devices are better than 0.5%, a d the noise equivalent motion is 5 nm.
