Fig. 4: Untethered robots powered by soft electronic pumps.

a Design and operational principle of soft robotic fish. A circular soft electronic pump is implanted into the robotic fish to achieve the swing of the tail fin. b Tail fin actuation in air. c Time-lapse of the untethered swimming motion underwater of the fish. d Computer-generated rendering of the robotic vehicle. A square soft electronic pump is implanted into the robotic vehicle to achieve its forward motion. e Schematic of the robotic vehicle powered by the wireless power transfer system. The emitting coils are closely arranged in two layers, and the on/off of the emitting coils is determined according to the position at which the robotic vehicle is at this moment and the next moment. f Time-lapse of the robotic vehicle moving on the top of the emitting coils. Schematics of the robotic vehicle are inserted in the upper left and right corner of each picture.