The growing adoption of lattice-based structures in soft robotics creates a need for advanced sensing solutions capable of monitoring their global deformation, particularly compression and extension. In this work, we address this challenge by introducing a novel optical sensor based on two patterned waveguides arranged in an ellipsoidal geometry. This Bidirectional Optical sensor for Actuation Tracking (BOAT) is seamlessly co-printed with a lattice structure actuated by an embedded pneumatic artificial muscle (PAM), and its performance is assessed. During PAM elongation or contraction, the bending of the embedded BOAT waveguides induces output signal variations that enable a clear discrimination between compression and extension states. The designs of both each specific waveguide structure (by surface patterning) and of the sensorized lattice-based unit embedding two BOATs are supported by numerical simulations. Experimental calibration over 100 consecutive pressure cycles ranging from +50 kPa to $-$40 kPa demonstrates a highly repeatable response, allowing a reliable distinction between extension and compression. Finally, sensor feedback is used to implement a digital shadow, enabling continuous synchronization between the whole sensorized unit and its virtual counterpart. These results establish BOAT as a powerful and reliable approach for deformation monitoring in soft lattice-based robotic systems.

翻译：软体机器人中晶格结构的日益普及，促使人们需要能够监测其整体变形（特别是压缩和拉伸）的先进传感解决方案。本研究通过引入一种基于椭圆几何结构中两条图案化波导的新型光学传感器来解决这一挑战。这种用于致动追踪的双向光学传感器与由嵌入式气动人工肌肉驱动的晶格结构无缝共打印，并对其性能进行了评估。在气动人工肌肉伸长或收缩过程中，嵌入式双向光学传感波导的弯曲会引起输出信号变化，从而能够清晰区分压缩和拉伸状态。通过数值模拟支持了每个特定波导结构（通过表面图案化）以及嵌入两条双向光学传感的传感化晶格单元的设计。在+50 kPa至-40 kPa范围内超过100个连续压力循环的实验校准结果表明，该传感器具有高度可重复的响应，能够可靠地区分拉伸和压缩。最后，利用传感器反馈实现了数字孪生，使整个传感单元与其虚拟对应物能够持续同步。这些结果表明，双向光学传感技术是软体晶格机器人系统中变形监测的一种强大且可靠的方法。