  This paper proposes a new variable stiffness soft gripper that enables
high-performance grasping tasks in industrial applications. The design of the
proposed monolithic soft gripper includes a middle bellow and two side bellows
(i.e., fingers). The positions of the fingers are regulated by adjusting the
negative pressure in the middle bellow actuator via an on-off controller. The
stiffness of the soft gripper is modulated by controlling the positive pressure
in the fingers through the use of a proportional air-pressure regulator. It is
experimentally shown that the proposed soft gripper can modulate its stiffness
by 125% within 250ms. It is also shown that the variable stiffness soft gripper
can help improve the safety and performance of grasping tasks in industrial
applications.
