Optimizing the grasping behavior of a soft robot's gripper

In this study, smart composite materials based on 4D printing technology were used to determine the grasping ability of four-claw gripper of soft robot. First, fused deposition modeling (FDM) is used to prepare polylactic acid (PLA) strips on the surface of a rectangular bamboo substrate to create a single-claw gripper for a smart composite soft robot, while using stimulus (heat) to deform and recover its original shape. Here, the authors first evaluate the deformation and recovery angle of the single-claw gripper of the smart composite soft robot, as well as various processing parameters such as heating temperature and time. This study then used FDM to print PLA ribbons on cross-shaped bamboo sheets to design the four-claw gripper of soft robot and its gripper technology was actuation type. Then, the four-claw gripper of soft robot was used to grab the table tennis ball to test its grasping ability. Finally, four processing parameters (width of claw, pitch of PLA ribbon, heating temperature, and heating time) were applied to determine the grasping ability of the four-claw gripper of soft robot. The optimal processing parameters for the grasping ability of the four-claw gripper of soft robot were width of claw of 20.2 mm, pitch of PLA ribbon of 1 mm, heating temperature of 200°C, and the heating time of 15 s. The authors also applied the operation window of two processing parameters to discuss the success of the grasping ability of the four-claw gripper of soft robot. The innovation of this study is the use of PLA/bamboo composite materials as the four-claw gripper of soft robot and these materials are cheap, easy to obtain, and can be recycled naturally. This study uses a simple thermal stimulus to enable the four-claw gripper of soft robot to easily grasp irregular objects. Highlights: The innovative composite material of polylactic acid and bamboo fabricated by 3D printing. Width of claw and heating temperature are the key factors on grasping ability. Operating window of grasping ability appears on four-claw gripper of soft robot.