Piezoelectric actuators

Over the last few decades, interest in piezoelectric actuators has led to sustained research, resulting in numerous solutions that are now commercially available. They are mainly used in high-tech applications (micro-systems, photonics, medical, space), as well as in consumer products such as camera autofocus systems and fuel injectors.

The appeal of this technology is driven by the energy density, wide actuation bandwidth and rigidity offered by piezoelectric materials. Indeed, the actuators on offer often offer form factors that enable excellent integration. What's more, some actuators offer sub-micrometric or even nanometric accuracies. A large number of solutions are available, based on a variety of functionalities.

In addition to these properties, the limiting factor in the use of such actuators is their low deformation. The solutions generally proposed to increase useful strokes tend to reduce stiffness and available forces, or to use friction, which promotes wear and degrades efficiency. The integration of piezoelectric actuators therefore requires in-depth study, taking these different aspects into account.

With this in mind, this article first looks at the conversion principles involved in piezoelectric materials (§ 1 ) and some intrinsic limitations associated with the most widely used piezoelectric ceramics (§ 2 ). Next, the main actuation solutions based on static or dynamic amplification are presented (§ 3 ), before examining some power supply solutions compatible...