Experimental investigation on adaptive grasping of a novel 3D-MSSPA gripper in complex space

Abstract

Many achievements for soft grippers are made in the structure design and grasping of target objects. However, there are limited studies on grasping objects with different attributes by soft grippers with omnidirectional bending capabilities within environments containing obstacles. In this paper, drawing inspiration from the multi-segment structure of the biological finger, a 3D-multi-segment soft pneumatic actuator (3D-MSSPA) with a strong envelope and omnidirectional independent bending is designed and manufactured. Additionally, we developed a novel prototype for a soft gripper prototype. A quasi-static model is proposed to effectively describe the bending deformation of 3D-MSSPA. The experimental results show that, for an applied pressure of 40kPa, the single segment SPA achieves a maximum bending angle of 175.2°, aligning closely with the theoretical prediction. Furthermore, the omnidirectional bending ability of multi-segments is analyzed through the finite element method, and a position compensation method for gravity deviation is presented. Through experiments, the pressure fore and lifting force of the soft gripper are investigated, yielding maximum values of 11N and 4.08N, respectively. These results serve as a benchmark for the mass grasping range of the target objects. Finally, the experiments are conducted to demonstrate the soft gripper’s adaptive and flexible grasping capabilities for objects with varying attributes, in both free space and complex space with obstacles. These experiments showcase their ability to avoid obstacles, adaptively grasp objects, and their good envelope ability. The proposed 3D-MSSPA can provide good inspiration and reference for flexible applications, particularly in fields such as post-disaster rescue and rehabilitation medicine.