Soft Electromagnetic Vibrotactile Actuators with Integrated Vibration Amplitude Sensing

Soft vibrotactile devices have the potential to expandthe functionalityof emerging electronic skin technologies. However, those devices oftenlack the necessary overall performance, sensing-actuation feedbackand control, and mechanical compliance for seamless integration onthe skin. Here, we present soft haptic electromagnetic actuators thatconsist of intrinsically stretchable conductors, pressure-sensitiveconductive foams, and soft magnetic composites. To minimize jouleheating, high-performance stretchable composite conductors are developedbased on in situ-grown silver nanoparticles formed within the silverflake framework. The conductors are laser-patterned to form soft anddensely packed coils to further minimize heating. Soft pressure-sensitiveconducting polymer-cellulose foams are developed and integrated totune the resonance frequency and to provide internal resonator amplitudesensing in the resonators. The above components together with a softmagnet are assembled into soft vibrotactile devices providing high-performanceactuation combined with amplitude sensing. We believe that soft hapticdevices will be an essential component in future developments of multifunctionalelectronic skin for future human-computer and human-roboticinterfaces.