Harnessing Magnetorheological Fluids in Implantable Actuators: A Novel Approach to Precision Haptic Feedback in Biological Tissues

Abstract: This research introduces rheACT, an innovative implantable actuator that utilizes magnetorheological (MR) fluids encased in hydrogel to deliver precision haptic feedback. The system leverages the tunable properties of MR fluids, which alter their viscosity in response to external magnetic fields, allowing for real-time, localized tactile feedback when controlled via electromagnetic coils. Designed to be injected sub-dermally, rheACT addresses challenges of biocompatibility and long-term stability through hydrogel encapsulation, which prevents fluid diffusion and can minimize immune responses. Laboratory experiments conducted on animal tissue demonstrated significant mechanical displacement (up to 1.3mm) at lower actuation frequencies (80–100 Hz), indicating the system’s ability to provide distinct and perceivable feedback. A user study further validated the system, showing consistent tactile sensations across varying frequencies and confirming rheACT's potential for precise haptic interaction. Although these findings are within animal tissue testing, results suggest that rheACT could be a reliable, externally controlled solution for applications in human-computer interaction (HCI), prosthetics, and assistive devices, where nuanced and adaptable feedback is crucial. The research highlights the integration of MR fluid technology and smart materials injected into the skin as smart tattoos, paving the way for future clinical and wearable applications that demand responsive, long-term haptic feedback.

Keywords: Haptics, Tactile Interaction, Implantable Actuators, Smart Tattoo, Human System Integrations, Magnetorheological fluids, electromagnetic actuators

DOI: 10.54941/ahfe1005859

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