Soft Electromagnetic Vibrotactile Actuators with Integrated Vibration Amplitude Sensing

Abstract

Soft vibrotactile devices have the potential to expand the functionality of emerging electronic skin technologies. However, those devices often lack the necessary overall performance, sensing-actuation feedback and control, and mechanical compliance for seamless integration on the skin. Here, we present soft haptic electromagnetic actuators that consist of intrinsically stretchable conductors, pressure-sensitive conductive foams, and soft magnetic composites. To minimize joule heating, high-performance stretchable composite conductors are developed based on in situ-grown silver nanoparticles formed within the silver flake framework. The conductors are laser-patterned to form soft and densely packed coils to further minimize heating. Soft pressure-sensitive conducting polymer-cellulose foams are developed and integrated to tune the resonance frequency and to provide internal resonator amplitude sensing in the resonators. The above components together with a soft magnet are assembled into soft vibrotactile devices providing high-performance actuation combined with amplitude sensing. We believe that soft haptic devices will be an essential component in future developments of multifunctional electronic skin for future human−computer and human−robotic interfaces.

Towards high performance and durable soft tactile actuators

“…9d). 218 The soft magnetic composites were fabricated by blending NdFeB microparticles with silicone, followed by a magnetization process. During curing, these particles were oriented in a specific direction using a strong permanent magnet.…”

“…If heat dissipation remains inadequate, it can elevate the device temperature due to Joule heating, potentially causing thermal damage to soft components or discomfort to the skin. 217,218 Thus, soft materials with elevated thermal conductivity may be introduced to enable the safe and efficient operation of soft electromagnetic tactile devices.…”