High-Force Soft Printable Pneumatics for Soft Robotic Applications

Hong Kai Yap, Hui Yong Ng, and Chen-Hua Yeow. Soft Robotics. September 2016, 3(3): 144-158. doi:10.1089/soro.2016.0030.

This work presents a novel technique for direct 3D printing of soft pneumatic actuators using 3D printers based on fused deposition modeling (FDM) technology. Existing fabrication techniques for soft pneumatic actuators with complex inner geometry are normally time-consuming and involve multistep processes. A low-cost open-source consumer 3D printer and a commercially available printing material were identified for printing soft pneumatic actuators with complex inner geometry and high degree of freedom. We investigated the material properties of the printing material, simulated the mechanical behavior of the printed actuators, characterized the performances of the actuators in terms of their bending capability, output forces, as well as durability, and demonstrated the potential soft robotic applications of the 3D printed actuators. Using the 3D printed actuators, we developed a soft gripper that was able to grasp and lift heavy objects with high payload-to-weight ratio, which demonstrated that the actuators were able to apply high forces. To demonstrate the ability of the actuators to achieve complex movements, such as bidirectional bending movements, we also developed wearable hand and wrist exoskeletons that were able to assist finger flexion and wrist flexion–extension. The proposed technique is the first-in-class approach to directly 3D print airtight soft pneumatic actuators for soft robotic applications using FDM technology.