Common problems with piezoelectric actuators for haptics and some alternatives

One of the most frequently used actuators for haptics is the piezoelectric actuator. This actuator has many advantages, including high-performance, high fidelity feedback, fast turn-on time, and static deflection. Piezoelectric actuators are also thin, lightweight, and nonmagnetic. However, piezoelectric actuators have their limitations, and they may not be right for every application.


One of the major limitations of piezoelectric actuators is their ability to achieve a long actuation strain. Piezoelectric actuators generally provide 0.1% to 0.15% actuation strain. In contrast, HASEL actuators can provide much greater actuation strain in the range of 10% (contracting) and 100% (expanding). These strain capabilities make HASEL actuators suitable for more applications. This high strain in a small compact actuator is a very unique attribute of HASEL actuators and gives haptic applications more features.


Piezoelectric actuators can achieve higher displacement with specialized geometries designed to operate at a resonant frequency. However, this constrains the operating conditions of a system. A better solution is to offer significant strain over a wide range of frequencies, which is what the HASEL actuator can do. Depending on the form factor, HASEL actuators can provide extremely large bandwidth, from DC all the way to thousands of Hertz actuation frequencies. Haptic devices offer more capabilities when their actuators have high bandwidths.


Finally, another downside to piezoelectric actuators is that they utilize specialized materials such as barium titanate and PZT ceramics. These two materials can contain lead and be brittle and easily broken when deformed, limiting their use for haptic devices. HASEL actuators are flexible and do not require any metal components (including lead). This is a great alternative when the application permits no lead materials, such as what future RoHS directives in the EU are requiring.


Piezoelectric actuators are the long-standing technology for haptics, and they have many advantages, including high-performance, high fidelity feedback, and fast turn-on time. While piezoelectric actuators excel in these areas, they still have their drawbacks. If you are in need of an actuator that is a compelling alternative to the piezoelectric actuator, HASEL actuators from Artimus Robotics may be the solution to your problem.



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 info@artimusrobotics.com.


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