Experimental analysis of the bending response of soft gripper fingers

In this paper a common design for soft actuators with internal pneumatic networks is analysed for the application of passively compliant soft gripper fingers, which can effectively grasp complex and delicate objects. The behaviour of a soft finger upon actuation is primarily determined through its predefined morphology. Hence, understanding the effects of key design parameters on the desired bending response is essential to design improved soft fingers. An experiment was designed to analyse the effects of two dimensionless design parameters defining the geometry of the internal pneumatic channels, on measurable parameters that describe the bending response of soft fingers as well as the generated contact forces. Soft finger samples were designed and produced based on combinations of different levels of the studied parameters, with the same outer dimensions and material. The experiment setup utilises a pneumatic control board for controlling the actuation and a vision system for measuring the bending response, which can be modified to analyse other designs of soft actuators. The results of the experiment identified the best performing soft finger design, explaining the effect of the studied factors in enhancing its desired response. The outcome of this work serves as a step towards a more structured design guideline that can be followed to create soft fingers with an enhanced and more predictable grasping behaviour.