  The properties and applications of auxetics have been widely explored in the
past years. Through proper utilization of auxetic structures, designs with
unprecedented mechanical and structural behaviors can be produced. Taking
advantage of this, we present the development of novel and lowcost 3D
structures inspired by a simple auxetic unit. The core part, which we call the
body in this paper, is a 3D realization of 2D rotating squares. This body
structure was formed by joining four similar structures through softer material
at the vertices. A monolithic structure of this kind is accomplished through a
custom-built multi-material 3D printer. The model works in a way that, when
torque is applied along the face of the rotational squares, they tend to bend
at the vertex of the softer material, and due to the connected-ness of the
design, a proper opening and closing motion is achieved. To demonstrate the
potential of this part as an important component for robots, two applications
are presented: a soft gripper and a crawling robot. Vacuum-driven actuators
move both the applications. The proposed gripper combines the benefits of two
types of grippers whose fingers are placed parallel and equally spaced to each
other, in a single design. This gripper is adaptable to the size of the object
and can grasp objects with large and small cross-sections alike. A novel
bending actuator, which is made of soft material and bends in curvature when
vacuumed, provides the grasping nature of the gripper. Crawling robots, in
addition to their versatile nature, provide a better interaction with humans.
The designed crawling robot employs negative pressure-driven actuators to
highlight linear and turning locomotion.
