  Modern particle accelerators and high-energy physics experiments that
deployed up to several hundred of accelerating superconducting RF cavities
require accurate frequency control. This is achieved by using cavity tuners
typically actuated with the piezoelectric ceramic actuators. Piezoelectric
ceramic actuators have become "standard" components of the SRF cavity tuner and
depending on the application could be operated in different environments: in
air, at cryogenic temperature, in vacuum, and submerged in liquid helium.
Different applications place different requirements on the piezo actuators, but
the important parameters common to all applications are the lifetime and
reliability of the actuators. Several programs targeting the development of
reliable piezo actuators are presented in this contribution.
