Multi-material Additive Manufacturing of Functional Soft Robot

Abstract

The field of soft robotics has a lot of potential in various in-vivo bio-applications. However, there are several challenges in developing untethered soft robots including ease of fabrication, efficient actuation system and multiple integrated functionalities. This study proposes a fully 3D printed, monolithic soft robot capable of linear and turning locomotion. This multi-modal, multi-material soft robot has a compliant body structure made of magnetic particle-polymer composites and can be 3D printed directly from a digital computer model. The locally programmed magnetic material composition in the posterior and anterior legs allows untethered magnetic actuation. The robot has 3 degrees of freedom and is capable of bi-axial bending in xy plane and z directions. This paper presents design and fabrication process of the soft robot with the novel magnetic field assisted projection stereolithography (M-PSL) technique. The magnetic torque on the robot body during turning locomotion is also measured experimentally and compared with theoretical prediction. Additionally, a controlled dummy drug delivery application in model human stomach and lung is demonstrated to showcase the multi-functionality of the soft robot. A uniquely designed, magnetically controlled drug carrier reservoir is integrated into the anterior leg of the soft robot. This reservoir can hold the liquid drug during locomotion and releases the drug once the robot arrives at the targeted location. With different modes of locomotion and high bending capability, the robot is able to maneuver in confined spaces that represent the inside of human stomach and lungs.