Fig. 7.

Four tasks realized by newly prescribed modes extended from the five basic modes. a Object selective transportation. The robot can use Mode D1 to transport large beads (diameter: 0.99 mm ± 0.025 mm, density: 1.05 g⋅cc^-1) while expelling small beads (diameter: 500–600 µm, density: 1.05 g⋅cc^-1). It can also use Mode D2 to transport small beads and leave behind large beads. b Burrowing for camouflage and searching in fine beads (diameter: 200–300 µm density: 1.05 g⋅cc^-1) with Mode E. c Locally mixing two food dyes with different colors using Mode F. d Generating a desired concentrated chemical path. The robot can swim upwards to create a straight chemical path with Mode C. It can also be steered in 2D to create a desired S-shaped chemical path with Mode G