Multi-objective co-design and COMSOL evaluation of flexible piezoresistive sensor arrays with finger-interdigitated architecture

Achieving a balance between high spatial resolution, minimal crosstalk, and long-term stability remains a critical challenge in the design of flexible tactile sensor arrays for robotic applications. While increasing array density enhances perception, it often compromises signal integrity due to mechanical coupling. To address these conflicting objectives, this paper proposes a multi-objective co-design strategy for a finger-interdigitated piezoresistive sensor based on carbon nanotubes and polyimide. Using the COMSOL Multiphysics simulation platform, the performance of three array density configurations—2 × 2, 3 × 3, and 4 × 4—under static pressure and creep conditions was systematically analyzed. A key theoretical finding is that the normalized piezoresistive sensitivity remains independent of array density, demonstrating the excellent scalability of the proposed architecture. Performance trade-offs, however, are significant: the low-density (2 × 2) array offers superior mechanical isolation but suffers from greater long-term drift, while the high-density (4 × 4) array provides the best creep resistance and wide-range stability at the cost of higher crosstalk. A comprehensive evaluation reveals that the 3 × 3 array achieves an optimal balance, with moderate crosstalk and excellent stability, making it the most suitable configuration for practical applications such as robotic fingers that require both sensing accuracy and reliability. This study provides a theoretical foundation and design guidelines for optimizing the trade-offs in high-density flexible skins.