Design and Research of a Multi-Modal Variable Stiffness Soft Gripper

To address the limitations of traditional soft grippers, such as low stiffness and challenges in maintaining posture while gripping heavy objects, this paper introduces an innovative multi-modal variable stiffness soft gripper. The gripper can rapidly adjust its stiffness by modifying the shape of the gripping device, facilitating multi-modal grasping. The paper commences by presenting the variable stiffness strategy and employs finite element analysis to simulate and analyze different modes of the gripping device. Subsequently, the fabrication process of the gripper is detailed, and validation experiments on the Soft Pneumatic Actuator (SPA) motion are conducted. Finally, a series of experiments are performed. The first set verifies a significant range of stiffness variation in the SPA under different modes. The second set confirms that surfaces with protrusions enhance gripping capabilities in various grasping modes. In the third set, special objects are introduced to test the practical grasping capability of the soft gripper. The results highlight the adaptability and potential applications of the proposed multi-modal variable stiffness soft gripper in safe grasping.