A miniaturized and flexible optoelectronic sensing system for tactile skin

This paper describes the development of a hybrid sensing module consisting of a general purpose electro-optical converter and three MEMS force sensors integrated into flexible substrates for tactile skin applications. The features of the converter, namely its flexible and thin substrate and small dimensions, programmability, optical coding and transmission of the information allow this versatile device to host different sensors, locally preprocess signals, translate this diverse information into a 'common language', and transmit it in a parallel, efficient and robust way to the processing unit. After discussing the major technical requirements, the design of the sensing, electrical and optical subsystems is illustrated, as well as the whole process for the module fabrication. A first characterization of a working prototype, hosting three MEMS force sensors and nine independent optical channels was performed. The global performance in terms of sensitivity, bandwidth and spatial sensing resolution make the presented module suitable to be used as basic element of a complete tactile system, conceived for robotic grasping and manipulation. Several solutions for mass production, improved optical properties and more efficient optical transmission are discussed.