  A key challenge in robotics is to create efficient methods for grasping
objects with diverse shapes, sizes, poses, and properties. Grasping with
hand-like end effectors often requires careful selection of hand orientation
and finger placement. Here, we present a soft, fingerless gripper capable of
efficiently generating multiple grasping modes. It is based on a soft,
cylindrical accordion structure containing coupled, parallel fluidic channels.
It is controlled via pressure supplied from a single fluidic port. Inflation
opens the gripper orifice for enveloping an object, while deflation allows it
to produce grasping forces. The interior is patterned with a gecko-like skin
that increases friction, enabling the gripper to lift objects weighing up to 20
N. Our design ensures that fragile objects, such as eggs, can be safely
handled, by virtue of a wall buckling mechanism. The gripper can integrate a
lip that enables it to form a seal and, upon inflating, to generate suction for
lifting objects with flat surfaces. The gripper may also be inflated to expand
into an opening or orifice for grasping objects with handles or openings. We
describe the design and fabrication of this device and present an analytical
model of its behavior when operated from a single fluidic port. In experiments,
we demonstrate its ability to grasp diverse objects, and show that its
performance is well described by our model. Our findings show how a fingerless
soft gripper can efficiently perform a variety of grasping operations. Such
devices could improve the ability of robotic systems to meet applications in
areas of great economic and societal importance.
