A Spring-Based Inductive Sensor for Soft and Flexible Robots

The development of flexible and soft robots generates new needs in terms instrumentation, as large encountered deformations require highly stretchable strain sensors. In this regard, we contribute to the adoption inductive sensors by providing tools model exploit them showing their relevance experimentally. First, estimation based on voltage measurement is proposed. Compared direct inductance evaluation, principle easier implement opens possibility optimize performances tuning circuit components interrogation frequency. performing a single sensor calibration independently via elongation mode during sensing outlined. A detailed characterization then performed, which shows that produces low hysteresis 0.1%, precision order 0.14%, an accuracy 0.9%. Finally, two proofs concept are proposed: 1) integration with pneumatic artificial muscle (PAM) demonstrates added value for model-free precise control system 2) closed-loop bending manipulator using sensor. performance demonstrated, element easy integrate mechanically, strengthening its potential be used structural well.