Closed loop position control of a linear PZT poly-actuator

Abstract

Piezoelectric stack actuators have many advantageous characteristics including power density, backdrivability, and their ability to efficiently hold a force for long periods of time. The stack actuator was integrated into a high-gain amplification mechanism which in turn was integrated into a poly-actuator, an actuator made up of several units. A proportional controller was used to close the loop around position, but it was unable to combat several significant disturbances. A PI controller was implemented to overcome steady-state error and two dynamic regimes were found due to the non-linear friction at the output. This friction was characterized and possible uses of the two regimes were explored, particularly at resonance.