Soft robotic surface enhances the grasping adaptability and reliability of pneumatic grippers

Soft grippers are an emerging field of robotics in recent years owing to their reduced control complexity, easy fabrication, and excellent compliance. However, the small contact area and force usually limit their grasping reliability. Herein, a soft gripper consisting of two soft robotic surfaces (SRSs) is proposed inspired by Venus flytrap, which can provide enveloping and pinching grasp modes. To guide the design of the gripper, an analytical model of the SRS is developed for both bending inward and outward. The experimental results show an excellent agreement with analytical results, which demonstrates the validity of the analytical model. Additionally, the grasping performance of the soft gripper is investigated experimentally. The results indicate that the grasp and pull-off force depend on the size and shape of objects and applied pressure. As the applied pressure is 60 kPa, the maximum grasp force and pull-off force reach 0.71 N and 8.15 N, respectively. Various grasping experiments are also conducted to study the effect of diverse objects, errors of object position, and SRS installation on the grasping capacity. Our findings demonstrate that our gripper can observably enhance the grasping adaptability and reliability due to the high passive compliance of the SRS allowing a large contact area between the gripper and objects.