Closed-Loop Haptic Feedback System Enabled by Synergistic Integration of Tattoo-Style Flexible Strain Sensors

A fully integrated closed-loop haptic feedback system is developed to address the critical limitations of current gesture recognition platforms, specifically the lack of bidirectional tactile interaction and signal stability. This system features a synergistic integration of multimodal sensing units and feedback actuators to achieve high-fidelity human-machine interaction. In terms of gesture recognition, a Tattoo-Style Flexible Strain Sensor (TFSS) based on PDMS/MWCNT/AgNPs composite was fabricated. It exhibits high conformability and robust electrical performance, achieving a sensitivity of 1.39 and rapid response (65 ms), while maintaining excellent stability over 3000 cycles. In terms of the feedback loop, a Foam-based Flexible Pressure Sensor (FFPS) was developed with a sensitivity of 8.37×10⁻³ kPa⁻¹ and a low detection limit of 0.6 g. Crucially, by integrating these sensors with eccentric rotating mass (ERM) vibrators via a custom hardware-software architecture, a real-time closed-loop tactile feedback mechanism was constructed. This architecture enables the system to convert the mechanical perception of robotic grasping into differentiated haptic signals for the user. Experimental results demonstrate outstanding system-level performance in both high-precision gesture decoding and responsive tactile feedback, providing a comprehensive solution for next-generation immersive wearable electronics.