A basic piezoelectric actuator operates on the principle of piezoelectricity, which is the ability of certain materials to generate an electric charge in response to applied mechanical stress or, conversely, to deform when an electric field is applied to them. The most common piezoelectric material used in actuators is a ceramic crystal called lead zirconate titanate (PZT).
The functioning of a basic piezoelectric actuator can be understood through the following steps:
Piezoelectric material: The actuator is constructed using a piezoelectric material, such as PZT, which has a crystal lattice structure that enables the generation of electric charge when subjected to mechanical stress.
Application of voltage: When an electric voltage is applied across the piezoelectric material, it causes the atoms within the crystal lattice to slightly shift from their original positions, resulting in a change in the material's shape.
Mechanical deformation: Due to the applied electric field, the piezoelectric material experiences deformation or changes in dimensions. This deformation can be either elongation or contraction, depending on the polarity of the voltage applied.
Reversible process: The piezoelectric effect is reversible, meaning that if the electric field is removed, the material will return to its original shape. This ability to deform and then return to its initial state is one of the unique characteristics of piezoelectric materials.
Actuator motion: The mechanical deformation of the piezoelectric material can be harnessed to produce motion or displacement in the actuator. For example, if the piezoelectric material is incorporated into a mechanical structure, such as a rod or a stack of discs, the actuator can generate motion along its axis as the material expands or contracts in response to the applied voltage.
Piezoelectric actuators find applications in various fields, including precision positioning systems, adaptive optics, micropositioning devices, ultrasonic transducers, and more. Their ability to respond quickly and accurately to changes in voltage makes them valuable in many electromechanical systems.