Rigid-Flexible Coupled Soft Gripper with Treble Modular Fingers

Soft gripper is used in various fields for grasping, handling and manipulating objects. However, soft pneumatic gripper, which is one of the most widely studied grippers in robotics, has limitations in handling different objects and cannot qualify complicated operation tasks with inherent structures and entirely composed of soft materials. Therefore, we present a rigid-flexible coupled soft gripper with treble modular fingers, which has movable frames, air chamber actuator modules and membrane-type sensing module. The rigid frames provide rigidity to allow the gripper generating a large grasping. The actuator modules can be inflated and vacuumed, thereby enabling gripper to execute different grasping operation. The sensing module, inflating a preset pressure, is able to sense grasping force. Furthermore, the work range of gripper is adjustable, changing by contraction and elongation motion of each finger. The gripper transforms from original state to contraction state by vacuuming actuator modules, and from original state to elongation state by inflating actuator modules. Through a multi-channel pneumatic control system with positive and positive-negative pressure output, the gripper achieves flexible and stable grasping for a variety of objects, such as cherry tomato (15 g), apple (204 g), banana (420 g), etc.