Motion pattern discrimination for soft robots with morphologically flexible sensors

Robots composed of soft materials can achieve high deformability and conformity with unstructured and dynamic environments due to their body mechanics. However, it is challenging to gather desirable information about these robots´ behaviors as conventional sensory systems are not designed to detect infinite degrees of freedom on continuum bodies. This paper presents a technical method to sensorize a soft elastic body by using conductive thermoplastic elastomer (CTPE) based strain gauge sensors. Due to its thermoplastic nature, CTPE based sensors can be fabricated in flexible sizes and shapes and integrated into the soft elastic bodies. We analyze soft elastic deformations and extract strain vectors to find finite unique regions on continuum surfaces. Then we use these regions to design the morphologies of our fiber shaped CTPE sensors to discriminate soft robotic behaviors. To demonstrate our approach and show how the programmable sensor morphologies discriminate different motion patterns, we have built a soft elastic prismatic silicone (E = 1.31MPa) block and designed two sensors to discriminate serpentine and twisting patterns.