Advanced piezoelectric–ferroelectric stack actuator

A conceptual design and an operational algorithm for an advanced piezoelectric–ferroelectric stack actuator are developed. The actuator takes advantage of the large strains due to the domain-switching phenomenon and utilizes the nonlinear range of response of the ferroelectric material. As a result, the proposed conceptual design allows for deformations that are considerably larger than the ones obtained using conventional piezoelectric actuators and contributes to overcoming the travel range and performance limitations of standard actuators. The shape control algorithm is based on a discrete optimization of the domain state of the active layers and it allows the operation and the shape control of the advanced actuator in spite of the nonlinear and hysteretic material response. The conceptual design of the advanced actuator and the capabilities of the shape control algorithm are demonstrated through numerical examples. The results demonstrate the contribution of the approach to extending the operational range of the actuator through a continuous and controllable response. A summary, conclusions, and directions of future research towards realization of the concept close the paper.