Position Control of a 3D Printed Soft Finger with Integrated Soft Pneumatic Sensing Chambers

Abstract

Soft robots require robust soft and flexible sensors that can undergo large deformations repeatedly. This work reports on soft robotic fingers with embedded soft pneumatic sensing chambers that are directly 3D printed without requiring postprocessing. A low-cost and open-source fused deposition modeling (FDM) 3D printer that employs an off-the-shelf soft thermoplastic poly(urethane) (TPU) was used to fabricate the monolithic fingers and sensing chambers. These pneumatic sensing chambers have multiple advantages including very fast response to any change in their internal volume, linearity, negligible hysteresis, repeatability, reliability, stability over time, long lifetime and very low power consumption. The performance of these chambers is accurately predicted, and their topologies are optimized using finite element modeling (FEM). Also, the flexion of the soft robotic finger is predicted using a geometric model for use in real-time position control. The position control of the soft robotic finger is achieved using feedback signals from the soft pneumatic sensing chambers embedded in the finger.