Distributed soft sensing for tactile-driven interaction in natural and artificial systems

Soft sensing can empower robots with new capabilities and broaden the understanding of our world. The objective of this thesis is to investigate new methods for developing distributed deformable tactile sensing systems that can be embedded into continuum soft robots and integrated into the environment. The goal is to enhance robotic systems’ interaction with the environment through touch, a crucial aspect often overlooked compared to vision-based interaction. The remarkable capabilities of the elephant trunk in sensing and manipulation tasks serve as an inspiration to study manipulators driven by touch. However, due to the uniqueness of the large mammal, there is a need to develop a methodology from scratch to shed light on its prehensile and tactile capabilities. In pursuit of this objective, a two-fold approach was undertaken. Firstly, innovative soft-sensing technologies were investigated, focusing on transduction mechanisms, material structures, new algorithms, and data analysis techniques. The aim was to better interpret the complex signals generated by soft sensors and to investigate useful solutions for achieving distributed sensing in continuum robots. Additionally, the elephant trunk and its skin were taken as a model to explore soft yet strong sensing methods for developing tactile-driven tasks in bioinspired continuum grippers. The research outcomes include point and distributed sensing solutions that provide an elaborated tactile image. A soft optical waveguide skin and an array of inductive soft sensors offer real-time interfaces to retrieve pressure maps and strain sensing. The material properties and sensor morphology were studied extensively, enabling the optimization of soft sensors’ behavior through innovative conditioning and characterization methods. The combination of physical properties and intelligent data processing maximizes the capabilities and applicability of the sensors. Furthermore, the study of the elephant’s tactile-based behavior provided insights into new approaches in robotics to interact with objects of various sizes, states of matter, and different environments without the need for specialized tools. The development of sensorized objects facilitated the safe quantification of tactile interaction and grasping experiments. Additionally, the findings contributed to creating a multimodal and modular soft optical skin capable of sensing pressure and strain. The morphology of the elephant trunk’s dorsal skin played a significant role in shaping the preliminary requirements of the modules. Overall, this research lays the foundation for empowering tactile-driven continuum manipulators and paves the way for future advancements.