Diffusion-based optical sensors for multimodal strain measurement in soft devices

This paper investigates the use of optically-diffuse, elastomeric substrates to measure complex deformations in soft devices. The proposed sensing method infers the modes and magnitudes of strains induced in an elastomer body by measuring changes in optical attenuation caused by the shifting, dispersion, or concentration of embedded, diffusive particles. Unlike many soft sensing methods, this does not require metallic components at the measurement site and can measure multiple disparate modes of strain in one sensor body. Initial experiments demonstrate that with proper material selection and placement of light emitters and detectors, basic tensile, bending, and pressure-induced strains can be measured reliably. Potential applications include distributed sensing in soft devices, where local strains are measured by light propagation through existing soft devices (actuators, etc.), using only emitter-detector pairs.