Drive of Piezoelectric Actuators Using an Electrical Depoling Process

In conventional drives of piezoelectric actuators, the piezoelectricity of the material itself has not been controlled electrically. A newly-developed electrical depoling process is proposed and applied to piezoelectric actuators in this study. Selectable piezoelectric and non-piezoelectric responses of the piezoelectric element can be obtained using the electrical depoling process. A piezoelectric unimorph and a gripper consisting of two unimorphs are chosen to demonstrate the drive of piezoelectric actuators using electrical depoling. It is shown that displacement is not induced in the electrically depoled samples until the applied field exceeds the critical value. From the electric field dependence of induced displacement, conflicts among ferroelectric domains during polarization switching are suggested to be the origin of the electrically depoled state. It is also demonstrated that electrically depoled piezoelectric ceramics exhibit digital-like displacements. Potential uses for the drive of piezoelectric actuators that use the electrical depoling is also discussed.