In their solution, moulds and sacrificial water-soluble hollow cores are printed using fused filament fabrication. The team’s findings are detailed in Cyborg and Bionic Systems.
Bio-inspired soft robots have shown the ability to handle uncertainty and adapt to unstructured environments. However, their availability is partially restricted by time-consuming, costly, and highly supervised design-fabrication processes, often based on resource-intensive iterative workflows.
“We propose fabricating soft actuators using widely available and affordable processes, combining single step cast moulding with the FFF printing of sacrificial water-soluble cores. The actuator’s mechanical operability is defined through FEA using a nonlinear hyperplastic material model,” study author Professor Pedro Neto said in a statement.
Although the use of sacrificial mould cores is common in the fabrication of soft actuators, this process is highly dependent on the chamber geometry and requires specific conditions such as the solvent temperature and flow, among other factors.
“We propose a heated water circuit to speed up the dissolution of the hollow core’s material, ensuring complete removal from the actuator’s walls, even for intricate chamber geometries,” said the study authors.
The process was validated and demonstrated through the integrated design fabrication of three pneu-net inspired actuators featuring bending and linear motion capabilities when pressurised.
Three actuators capable of bending and linear motion were designed, fabricated, integrated, and demonstrated as three different bio-inspired soft robots: an earthworm-inspired robot, a four-legged robot, and a robotic gripper.
“We demonstrate the availability, versatility, and effectiveness of the proposed methods, contributing to accelerating the design and fabrication of soft robots. This study represents a step toward increasing the accessibility of soft robots to people at a lower cost.” said Afonso Silva from the Department of Mechanical Engineering, University of Coimbra.
According to the team, the FEA effectively assisted in ensuring the mechanical operability and functionality of the actuators, allowing them to anticipate the effects of different input pressures on their elongation and bending.
Moreover, FEA-assisted design eliminated the lengthy and costly trial-and-error design-fabrication processes, which often lead to the fabrication of multiple prototypes.
Looking forward, the team said hyperplastic material models will likely and automatically adapt, not only to the material’s properties but also to the geometry of the actuators.
In addition, the printing of sacrificial cores could be achieved using alternative water-soluble materials that are less dependent on storage and printing conditions.
The Engineer - Report calls for Industrial Strategy and Minister for Manufacturing
A good point but I think Diogenes (after finding an honest man) should look for a suitable person in the government And I have often thought that...