The Integration of Sensing and Actuating based on a Simple Design Fiber Actuator towards Intelligent Soft Robots

Integration of multiple functions into a simple unit can simplify the device design and facilitate the miniaturization and portability of soft robots. Actuating and sensing functions are the basis of soft robots to interact with the environment. In this work, a modified melt-spinning method is used to produce liquid crystal elastomer (LCE) fibers with a hollow structure and fill the core with liquid metal (LM) to construct LCE–LM coaxial fibers with integrated sensing and actuation functions. The inner LM generates Joule heat upon an electrical trigger to actuate the outer LCE shell. When LCE–LM coaxial fibers are actuated or loaded with objects, the deformation of LCE shell forces the inner LM to reform, allowing to sense the motion of the fibers or the mass of objects, by measuring the feedback voltage or resistance change of the inner LM. Benefitting from the material selection and structural design, the LCE–LM coaxial fibers with integrated actuating and sensing capability exhibit large reversible contraction (40%) and reliable durability (5000 cycles for actuation and motion sensing). Finally, a soft three-arm Delta robot is fabricated to complete object identification, sorting tasks, and in situ monitoring the motion process.