A particle-based exoskeleton robot with extreme transformability

Soft robots that are flexible due to their transformable skeleton can be widely used in various fields where rigid endoskeleton robots are impossible to perform. However, soft robots still have limitations in that they do not work properly when damaged, torn, or separated. Here we show that a particle-based exoskeleton robot, which is encapsulated with far more amounts of hydrophobic particles compared to conventional liquid marbles, can continue to perform various functions under severe damages or deformations. This is thanks to the external particle-laden layer that sufficiently covers the increased surface area of the robot when severely deformed. We quantify the capability of the robot to endure bursting (fracture of external layer) as a function of the particle density. Then we demonstrate that this unconventional robot can perform a variety of functions including merging, penetrating, traversing, stair-descending, engulfing, and discharging, as remotely driven by an ultrasonic field.