SoPCAS Finger: A Three-Dimensional Printed Soft Finger with Pneumatic Chambers for Simultaneous Actuation, Sensing, and Controlled Grasping

Controlled grasping using soft robotic grippers is a significant challenge that hinders their deployment in unstructured environments. This work presents a directly three-dimensional (3D) printed soft pneumatic finger that involves separate chambers for soft pneumatic-based control, actuation, and sensing (SoPCAS) simultaneously. The actuation chamber of the finger is designed as a pneumatic network that expands upon pressurization, and its sensing chamber is designed as a thin wall soft pneumatic chamber embedded with a solid air pressure sensor that measures the volume change ( i.e ., pressure change) when the finger is in contact with its environment. The soft finger is 3D printed using a commercially available thermoplastic polyurethane (TPU) and a fused deposition modeling (FDM) 3D printer. The SoPCAS finger is characterized in terms of repeatability, hysteresis, force–pressure relationship, and stability ( i.e ., airtightness). Two SoPCAS fingers are used to develop a gripper that highlights the usage of the actuation and sensing components in real-time closed-loop feedback grasping applications using a simple and manually tuned proportional-integral (PI) controller. The gripper demonstrates successful grasping of various objects with different weights, shapes, textures, and stiffnesses, making SoPCAS finger a promising candidate for applications requiring real-time force/pressure control in highly dynamic and unstructured environments.