Figure 6: Various applications of naturally camouflaged hydrogel actuators and robots.
From: Hydraulic hydrogel actuators and robots optically and sonically camouflaged in water
(a) Forward fish-like swimming of a hydrogel robotic fish in water. The hydrogel fish can keep the camouflaged state when swimming over rainbow-coloured background owing to its optical transparency. (b) A transparent hydrogel actuator kicks a rubber-ball in water. The high-speed and high-force hydraulic actuation enables effective ball-kicking motion. (c) A transparent hydrogel gripper catches, lifts and releases a live ryukin goldfish. The agile actuation and optical transparency of the hydrogel gripper allow its successful capture of the goldfish. The gripper holds and then releases the captured goldfish without harm owing to the gripper’s softness. Dotted lines are introduced in a–c to indicate the boundaries of transparent hydrogel structures in water. Scale bars, 1 cm (a–c).
