Comparing Piezoelectric and HASEL actuators
Updated: Mar 28, 2022
HASEL actuators are a new type of “smart actuator” technology that is a compelling alternative to long-standing technologies such as piezoelectric actuators. A key benefit of HASEL actuators is the ability to achieve large actuation strain - in some cases as high as 100% - and inherent compliance that results in a more resilient and versatile actuator. The following paragraphs provide a detailed comparison of the two technologies.
HASEL actuators and piezo actuators are both activated by an applied voltage. For HASEL actuators, the applied voltage induces electrostatic forces that cause a liquid-filled structure to change shape. Piezoelectric actuators are made from specialized materials that deform due to applied voltage. The magnitude of voltage required for these actuators types varies. HASEL actuators typically require voltage on the order of 1-10 kV, but the current is very low (< 1 mA). Piezoelectric actuators also require a high voltage for operation, but it's an order of magnitude lower than HASEL actuators, usually in the range of 0.1 to 1 kV.
In terms of performance, these actuation technologies differ significantly when you compare their actuation strain or change in thickness (expanding actuators) or length (contracting actuators). Piezo actuators generally provide 0.1 to 0.15% actuation strain. In contrast, HASEL actuators can provide actuation strain in the range of 10% (contracting) to 100% (expanding). This larger displacement makes HASEL actuators much more suitable for applications requiring 1 - 10 mm stroke or larger.
Piezo actuators can achieve higher displacement with specialized geometries that are designed to operate at a resonant frequency (e.g. cantilever beams), but this constrains the operating conditions of a system. In contrast, HASEL actuators can provide significant strain over a wide range of frequencies (as high as several 100 Hz depending on the application).
Finally, the materials used for HASEL actuators are flexible and do not require any metal components. In contrast, piezoelectric actuators are generally made from specialized materials like barium titanate and PZT ceramics which can contain lead and be brittle and break easily when deformed. As a result, HASEL actuators are a great alternative for applications requiring no lead material, compliance, or deformation. Examples include wearable actuators for haptics and VR or actuators that interact with objects that vary in shape or size.
About Artimus Robotics
Artimus Robotics designs and manufactures soft electric actuators. The technology was inspired by nature (muscles) and spun out of the University of Colorado. HASEL (Hydraulically Amplified Self-healing ELectrostatic) actuator technology operates when electrostatic forces are applied to a flexible polymer pouch and dielectric liquid to drive shape change in a soft structure. These principles can be applied to achieve a contracting motion, expanding motion, or other complex deformations. For more information, please visit Artimus Robotics or contact firstname.lastname@example.org.