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How quiet are HASEL actuators?

Updated: Sep 23

Silent actuation is a key benefit of HASEL actuation technology for applications that are sensitive to noise. Typical electromagnetic and pneumatic actuators generate a significant amount of noise. The lack of pneumatic noise, moving components, and motor whine makes HASEL actuators noiseless compared to pneumatic and electromagnetic linear actuators. Sometimes the noise of electromagnetic and pneumatic technologies can be reduced with additional noise-dampening system designs or components, but inherent differences in the technologies and actuation mechanics make HASEL actuators an ideal option for truly silent operation.


The video below shows a comparison between pneumatic actuators, electromagnetic actuators, and the HASEL electrostatic actuator.



Traditional linear actuators are complex and consist of many moving parts that generate noise. Below is a summary of the noise source by technology.


Pneumatics

For pneumatic actuators, a lot of noise comes from a variety of pneumatic system components. The compressor that provides compressed air to the pneumatic actuator is usually the loudest component because it generates so much mechanical noise. Compressors have motors, bearings, seals, pistons, diaphragms, rods, crankshafts, cylinders, and valves, which all independently emit noise. In large-scale industrial environments, one or two massive compressors supply all the compressed air for the entire building. The supply of a big building requires a lot of output from these large compressors, and they generate a lot of noise during operation. Other industries, such as medical devices or automotive, often have a smaller local compressor that supplies compressed air to an independent system. However, these compressors and pumps still generate noise, and the closer proximity to the user requires more noise-mitigation considerations from the designers. Other pneumatic system components, such as regulators, valves, dryers, and filters also emit loud sounds as they operate with compressed air. If the pneumatic system design requires venting, the vent itself can be extremely noisy as there is an abrupt blowing noise of the compressed air quickly expanding as the vent releases. There can also be noise from the actuator slamming into the end of its travel, depending on the type of pneumatic actuator. Overall, the noise generated by pneumatic systems can vary from major safety concerns (if people are near loud industrial compressors) to user experience issues (if the noise from the product is disturbing the users). Even if the product designers can mitigate the noise locally, such as with acoustic dampening foam, this will often create additional issues, such as heat transfer problems due to the pneumatic system overheating when densely packed in foam.


Electromagnetics

Traditional electromagnetic linear actuators, which use electric motors, operate using electromagnetic principles. The components required to facilitate the electromagnetic principles, such as the winding, rotor, bearings, air gap, and dynamic seals, all contribute to the noise of this type of actuator. The drivetrain makes noise too, such as the gearboxes to change the motor speed, and the lead screw or rack and pinion to translate to linear motion. Traditional electric linear actuators are complex and consist of many moving parts which generate mechanical noise. Since electromagnetic actuators can usually be identified by the distinct “whine” noise during operation, this can have detrimental effects on the application or users. If this noise is loud enough to be dangerous, then safety precautions, such as wearing earplugs, can reduce the ability of the operator to communicate or be aware of their surroundings. In other applications, this noise can reduce the effectiveness of the product, such as when stealth is needed for military applications. Finally, the noise can disturb the peace of users in consumer products or medical device applications.


Electrostatics

Specialty electric actuators made by Artimus Robotics are completely noiseless because the unique HASEL technology operates on electrostatic principles. There are only three components of a HASEL actuator and these do not have any mechanical or electrical noise. HASEL actuation is a soft material that changes shape so there are no moving mechanical parts to slide, rub, or roll. There is no “whine” noise and no mechanical noise from moving parts. Additionally, HASEL actuation is a closed system so there is no need for an external supply of compressed air and no pumping or venting of compressed air. The only noise emitted during operation is the thin polymer film changing shape during actuation. This can be heard if listening very closely in the video above.



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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