Photo-controlled soft robots based on liquid crystal elastomer tubular actuators.

Soft tubular actuators can be widely found in nature and engineering fields. To demonstrate the advantages of soft tubular actuators in potential applications and exploit the unique actuation properties of liquid crystal elastomer (LCE) materials, we fabricated LCE tubular actuators with multiple photo-controlled and programmable actuation modes by using the centrifugal synthesis process. Controlled by the applied light irradiation stimulus, the LCE tubular actuators can exhibit omnidirectional bending motion, large radial contraction/elongation or clockwise/anticlockwise rotation. Using multiple LCE tubular actuators, we built multi-functional non-tethered soft robots, including a two-leg walking robot, cargo-transporting robot, and manipulator-robots. Under moderate photo guides, the two-leg walking robot can realistically simulate human-walking and direction-turning motion, the cargo-transporting robot can efficiently transport cargoes in a forward way, backward way or rotation way, and the manipulator-robots can effectively grasp, lift, install or disassemble objects. Our study provides insights into the development of LCE actuators for constructing compact and multifunctional smart machines.