  In areas that are inaccessible to humans, such as the lunar surface and
landslide sites, there is a need for multiple autonomous mobile robot systems
that can replace human workers. In particular, at landslide sites such as river
channel blockages, robots are required to remove water and sediment from the
site as soon as possible. Conventionally, several construction machines have
been deployed to the site for civil engineering work. However, because of the
large size and weight of conventional construction equipment, it is difficult
to move multiple units of construction equipment to the site, resulting in
significant transportation costs and time. To solve such problems, this study
proposes a novel growing robot by eating environmental material called GREEMA,
which is lightweight and compact during transportation, but can function by
eating on environmental materials once it arrives at the site. GREEMA actively
takes in environmental materials such as water and sediment, uses them as its
structure, and removes them by moving itself. In this paper, we developed and
experimentally verified two types of GREEMAs. First, we developed a fin-type
swimming robot that passively takes water into its body using a water-absorbing
polymer and forms a body to express its swimming function. Second, we
constructed an arm-type robot that eats soil to increase the rigidity of its
body. We discuss the results of these two experiments from the viewpoint of
Explicit-Implicit control and describe the design theory of GREEMA.
