Have you ever wondered why robots are unable to walk and move like we do? Some robots can run, fly, or dance with greater efficiency than humans, but their movements are still mechanical. The reason for this is the bones they don’t have.
Unlike humans and animals, robots do not have real bones or flexible membranes that connect them; they have artificial links and joints made of materials like carbon fiber and steel tubes. According to Robert Katzschmann, a professor of robotics at ETH Zurich, these internal structures allow the robot to make movements, hold objects, and maintain different positions. However, since links and joints are rigid materials, robot bodies are not as flexible, agile, and flexible as human bodies. This is what makes body movements harder.
But they may not need to stay hard for long. A team of researchers from the Swiss Federal Institute of Technology (ETH) Zurich and US-based startup Inkbit have tested a method to 3D print the world’s first robotic hand with an internal structure made up of bones, ligaments, and tendons. of people. What makes the hand even more special is that it is printed using a completely new 3D inkjet printing method called vision controlled jetting (VCJ).
3D printing vs. robotics
Currently, 3D-printed robots are typically made using fast-moving polyacrylates. These polymers are durable and harden quickly during installation. However, to avoid any inaccuracies, “Each printed layer requires mechanical refinement (the process of smoothing the irregular surface by using mechanical energy), which limits the soft surfaces and the types of material chemistries that can be used,” the researchers. notice. This is why standard 3D printed robots are not very flexible and are limited in their designs and applications.
Due to the rapid development of published material, scientists do not have time to make changes at different levels, and they must use separate manufacturing steps and assembly to make different parts of a robot. Once they have finished printing each part, they assemble these different pieces and test them thoroughly, making the process time consuming and tedious.
This is where the proposed VCJ method can make a big difference. This 3D printing process involves the use of soft, slow-curing thiolene polymers. “These have very good elastic properties and return to their original state much faster after pressing than polyacrylates,” tell Katzschmann, one of the authors on the new paper that describes the new method.
3D printing innovation for robots
In a VCJ system, along with a 3D printer, there is a 3D laser scanner that examines each page for visual irregularities as it is stored. “This visual inspection enables the printing process to be completely contactless, allowing for a wide range of possible polymers to be deposited. We, for example, printed with thiol-based polymers because it allows us to create UV light and humidity resistant structures,” Katzschmann told Ars Technica.
After the scan, there is no mechanism of the recorded layer. Instead, the next level is entered in a way that makes up for all the irregularities in the previous level. “The feedback system compensates for these inconsistencies when printing the next stage by calculating any necessary adjustments to the amount of material to be printed in real time and with pinpoint accuracy,” tell Wojciech Matusik, one of the study’s authors and a professor of computer science at MIT.
Furthermore, the researchers say that this control-loop system allows them to execute the robot’s complete strategy at once. “Our robotic arm can be pressed in one way, it doesn’t need an assembly. This greatly speeds up the engineering design process—one can go straight from idea to functional and long-lasting prototype. It avoids expensive middleware and assembly,” Katzschmann added.
Using the VCJ technique, researchers successfully printed a robotic hand that has internal parts similar to a human hand. Equipped with touch pads and pressure sensors, the robotic arm has 19 tendon structures (in humans, tendons are fibrous connective tissue that connect bones and muscles) that allow it to move the hand and the fingers. The hand can sense touch, grasp objects, and stop the fingers when they touch something. (The researchers used MRI data from real human hands to model its construction.)
In addition to the hand, they also printed a robotic heart, a six-legged robot, and a machine that can cause shock around it. Researchers suggest that all these robots work as hybrid soft systems (robots made of soft materials and hard materials) that can succeed hard robots in terms of flexibility and overcome design- and scale-related issues faced by soft robots.
Since soft robots are made of flexible materials like liquids or elastomers, it is tricky for scientists to maintain their geometry and strength at large scales, as materials can do. Struggle to stop they have physical properties and structural integrity. Moreover, it is very easy to control and power a soft robot of a centimeter or a millimeter; that’s why they do less. VCJ, on the other hand, has the potential to give rise to hybrid soft-rigid robots.
“We foresee that VCJ will replace all contact-based inkjet printing methods. With VCJ you can start manufacturing functional parts for robots, medical implants, and many other industries. The high resolution, good material properties, and their long life make prints from the VCJ system very useful for both research and commercial applications,” Katzschmann told Ars Technica.
Nature, 2023. DOI: 10.1038/s41586-023-06684-3 (About DOIs)
Rupendra Brahambhatt is an experienced journalist and filmmaker. It covers science and culture news, and for the past five years, it has been actively working with some of the most innovative news agencies, newspapers, and active media brands. in different parts of the world.