Perception-Feedback Mapping Strategies for Flexible Human-Machine Interfaces

The field of flexible human-machine interfaces (HMIs) has been evolving rapidly with progress in materials science, structural design, device fabrication, and system integration. Developments of advanced flexible sensing and feedback devices have remarkably expanded the perceptual modalities, feedback capabilities, and functional scope of these systems. However, the broader deployment of flexible HMIs depends not only on the device performance of sensing/feedback components, but also on the control strategy that translates sensed signals into command outputs for feedback modules. This review highlights recent progress in such perception-feedback mapping strategies for flexible HMIs. Representative sensing and feedback modules, together with common system-level physical architectures, are briefly introduced as a basis for analyzing the relationship between sensed inputs and feedback outputs. A systematic framework is then proposed based on the principle of signal flow from the perception to the feedback side, allowing perception-feedback mapping strategies to be classified into command-based mapping, continuous mapping, and closed-loop control. Comprehensive discussions on these three categories of mapping strategies are presented, covering their operating principles, system implementation, and practical applications. Finally, we discuss current challenges and future directions toward more robust, generalizable, and integrated flexible HMI systems.