An Enveloping Soft Gripper with High-Load Carrying Capacity: Design, Characterization and Application

Soft grippers exhibit impressive grasping performance with great simplicity, compliance, adaptability, and robustness. However, it is a great challenge for them to achieve high-load carrying capacity. Here, we present a soft fabric gripper to achieve high-load carrying capacity. The gripper features a simple structure, easy fabrication, low cost, and high load capacity. As the operating part of the gripper, the cylindrical, unstretchable, and airproof fabric is folded from its axial middle to form two concentric cylindrical layers. The closed cavity between the inner layer and outer layer can be inflated so that to press the inner layer contracting inward to envelop the object achieving grasping. A growth-morphology gripper can be easily achieved by just folding the fabric with more layers, which can perform more friendly interaction with the inner object and the outer environments. The grasping mechanism is studied, and the load capacity is analyzed theoretically and validated experimentally through mechanical load tests. The experiment results validate the theoretical analysis and demonstrate the high-load carrying capacity of the enveloping soft gripper. Profiting from the advantages of the growth morphology of the gripper, a larger-scale prototype is assembled for the application of bore well rescue. The test results demonstrate that the larger-scale prototype can hold 55 kg at 0.09 bar.