  Fruit harvesting has recently experienced a shift towards soft grippers that
possess compliance, adaptability, and delicacy. In this context, pneumatic
grippers are popular, due to provision of high deformability and compliance,
however they typically possess limited grip strength. Jamming possesses strong
grip capability, however has limited deformability and often requires the
object to be pushed onto a surface to attain a grip. This paper describes a
hybrid gripper combining pneumatics (for deformation) and jamming (for grip
strength). Our gripper utilises a torus (donut) structure with two chambers
controlled by pneumatic and vacuum pressure respectively, to conform around a
target object. The gripper displays good adaptability, exploiting pneumatics to
mould to the shape of the target object where jamming can be successfully
harnessed to grip. The main contribution of the paper is design, fabrication,
and characterisation of the first hybrid gripper that can use granular jamming
in free space, achieving significantly larger retention forces compared to pure
pneumatics. We test our gripper on a range of different sizes and shapes, as
well as picking a broad range of real fruit.
