Development and Testing of a soft-rigid Gripper with Dual-mode Continuously Reconfigurable Workspace

The inherent safety and shape adaptability of soft grippers offer significant advantages in robot–environment interaction. However, several limitations still remain, such as the nonlinear relationship between the input force and the resulting deformation of the soft components, particularly under large deformations, which increases control complexity. Moreover, the range of motion is constrained by the deformation capacity of the soft materials, and the actuation force strongly depends on their stiffness. This work presents a gripper consisting of three soft fingers, which are actuated in proximity to the object to be grasped, and a rigid dual-mode base mechanism capable of continuously prepositioning and preorienting the fingers before grasping. The proposed soft-rigid design of the gripper preserves the advantages of safety and adaptability of soft materials, while avoiding large deformations and ensuring a linear force-deformation relationship thanks to the reconfigurable workspace. The design and testing processes are presented. Qualitative and quantitative experiments demonstrate the device adaptability to objects with different shapes and dimensions.