Design and kinematic analysis of a deployable mechanism for soft sheets grasping

In the automation process of the garment industry, a notable challenge arises from the presence of flexible materials characterized by irregular shapes, posing difficulties for robotic grasping. This article addresses this challenge by proposing a gripper manipulator centered around the 4 P-RRP quadrilateral cone folding mechanism as the core driving mode, with the angled four-bar linkage mechanism serving as the extension arm. Utilizing screw theory, the developability of the 4 P-RRP four-pyramid mechanism with one degree of freedom is verified, forming the basis for its adoption as the central driving mechanism. Furthermore, an in-depth analysis of the geometric properties of the robot's extension arm leads to the derivation of an optimal folding ratio structure, which is seamlessly integrated into the robot design. Kinematic equations for the mechanism are formulated and solved using the D-H parameter method to obtain the kinematic solution. The investigation demonstrates that the manipulator utilizing the quadrilateral cone folding mechanism significantly enhances adaptability to irregular shapes. By incorporating this proposed mechanism, robots can efficiently manipulate flexible materials across various garment manufacturing applications.