OptiGap: A Modular Optical Sensor System for Bend Localization

This paper presents the novel use of air gaps in flexible optical light pipes to create coded patterns for use in bend localization. The OptiGap sensor system allows for the creation of extrinsic intensity modulated bend sensors that function as flexible absolute linear encoders. Coded air gap patterns are identified by a Gaussian naive Bayes (GNB) classifier running on an STM32 microcontroller. The fitting of the classifier is aided by a custom software suite that simplifies data collection and processing from the sensor. The sensor model is analyzed and verified through simulation and experiments, highlighting key properties and parameters that aid in the design of OptiGap sensors using different light pipe materials and for various applications. The OptiGap system allows for real-time and accurate bend localization in many robotics and automation applications, in both wet and dry conditions.