The temperature expansion coefficient of an all-ceramic PICMA® stack actuator is approximately -2.5 ppm/K. In contrast, the additional metal contact plates as well as the adhesive layers in a PICA stack actuator lead to a nonlinear characteristic with a positive total coefficient (fig. 3).
When a nanopositioning system is operated in a closed servo loop, this will eliminate temperature drift in addition to nonlinearity, hysteresis, and creep. The control reserve to be kept for this purpose, however, reduces the usable displacement.
For this reason, the temperature drift is often passively compensated for by a suitable selection of the involved materials, the actuator types, and the system design. For example, all-ceramic PICMA® bender actuators show only a minimal temperature drift in the displacement direction due to their symmetrical structure.