Design and Automatic Fabrication of Novel Bio-Inspired Soft Smart Robotic Hands

Soft material robots are developing rapidly benefited from their inherent flexibility, adaptability and safety compared to rigid-bodied robots. However, most soft robots are unable to offer high force/strength due to the low rigidity of soft materials that they are composed of. Absence of position feedback is another problem for soft robots. In this research, we aim to address these two challenges in a novel designed soft smart robotic hand. The design of this soft hand is also delicately considered to make it 3D printable, which shortens the design cycle and reduces the fabrication time. This hand consists of five fingers and a palm, all of which can be actuated independently. The finger is designed with two chambers: one air-tight active chamber which can be actuated by compressed air, one passive chamber filled with loosely arranged particles. During bending actuation, particles inside the passive chamber are squeezed by pressurized air, which causes passive jamming. As a result, the stiffness of the finger is strengthened during bending, which endows the hand with larger force output and load-holding capability. Furthermore, position feedback modules made of conductive elastomers are integrated and co-printed with the finger during fabrication. In this research, a hand prototype is manufactured and several experiments regarding to its characteristics and performance are conducted for evaluation. From experimental results, the soft hand achieves maximum holding weight of 1.452kg with particles and 0.8425kg without particles at same actuation pressure of 450kPa.