Constructing the haptic interaction loop for immersive VR/AR systems

The pursuit of hyper-realistic immersive virtual and augmented reality is fundamentally bottlenecked by the ‘Ghost Hand’ phenomenon, a severe sensory mismatch between advanced audio-visual rendering and impoverished physical interaction. To eliminate this asymmetry, this review conceptualizes a closed-loop ‘Human-Machine-Environment’ haptic interaction framework comprising sensing, processing, and feedback. Distinct from existing reviews that merely regard flexibility as a basic material advantage, this work centers on the system-level engineering realization of complete haptic interactive loops. We systematically evaluate the continuous evolution of hardware architectures toward imperceptible, flexible electronic skins. At the input terminal, we explore how bio-inspired microstructures and novel transduction mechanisms enable multimodal signal decoupling and high-fidelity sensory digitization. For the output terminal, we analyze advancements in kinesthetic, cutaneous, and thermal haptic actuation that physically reconstruct digital stimuli for the human nervous system. Furthermore, we highlight the integration of these components into intelligent wearable systems, where deep learning architectures and in-sensor edge computing overcome the inherent nonlinearity and latency of soft materials. Finally, we validate this closed-loop framework across diverse applications, including robotic teleoperation, medical rehabilitation, and immersive entertainment, while delineating the remaining engineering challenges surrounding the power-portability paradox and multimodal crosstalk. Ultimately, this review establishes that closing the physical haptic loop is the requisite cornerstone for transitioning from passive observation to fully embodied, active interaction in the metaverse.