Design and Motion Analysis of Adjustable Pneumatic Soft Manipulator for Grasping Objects

Soft robots have infinite degrees of freedom (DOFs), extremely strong environmental adaptability, and better human-computer interaction. A soft grasping manipulator can grasp objects in a diversified manner, which is an important application and research direction in terms of soft robots. A pneumatic soft actuator structure was designed on the basis of in-depth analysis of the motion mechanism of a soft robot. A kinematic model for the soft actuator and a model for bending deformation of air cavities were established separately to determine the relationship between the bending angle and air pressure. A novel pneumatic soft manipulator with adjustable grasping diameter was designed by utilizing pneumatic soft actuators to realize adaptive grasping of objects with different diameters (within 200 mm). Finally, a physical manipulator was manufactured and the relationship between the bending angle of the soft grasping robot and pressure intensity was experimentally validated. Moreover, tests were conducted to assess the adaptability of the soft manipulator when grasping objects with different diameters, masses, and shapes in order to verify the effectiveness of the soft manipulator.