Scientists 3D print a Robotic Hand With Human-like bones and tendons

Robots have real bones and the delicate tissues that connect them, in contrast to humans and other animals. Rather, they feature artificial joints and links established of metal tubes and carbon fiber. These internal structures, according to ETH Zurich robotics researcher Robert Katzschmann, enable a robot to move, grasp items, and adopt various positions. Yet, robot bodies lack the softness, flexibility, and agility of human bodies since connections and joints are composed of rigid materials. This provides an explanation for why their motions are so rigid.

3D print

However, it may not be necessary to stay stiff for long. A team of researchers from the Swiss Federal Institute of Technology (ETH) Zurich and the US startup Inkvit have developed a way to 3D print the world’s first robotic hand with a human-like internal structure made of bones, ligaments, and tendons. discovered. What makes this hand even more special is that it was printed using an all-new 3D inkjet deposition process called Vision Control Jetting (VCJ).

3D printing vs. robots

Currently, 3D-printed robots are typically made of fast-curing polyacrylate. These polymers are durable and solidify rapidly during deposition. However, to avoid unevenness, “each printed layer requires mechanical planarization (a process that uses mechanical force to smooth out uneven surfaces), so the level of softness and use “This limits the types of materials chemistry that can be done,” the researchers said. For this reason, traditional 3D printing robots have low elasticity and are limited in shapes and materials.

Because the printed material solidifies quickly, scientists do not have time to make changes to the various layers and use separate manufacturing steps and assemblies to create the various components of a single robot. is needed. Once each part is printed, these various parts are assembled and thoroughly tested, making the process time-consuming and tedious.

Here his proposed VCJ technique can make a big difference. The 3D printing process used ethylene polymer, which is soft and slow to cure. “They have very good elastic properties and even after bending they recover much faster than polyacrylates,” said Katz, one of the authors of a new paper describing this new method. Schumann said.

Rethinking 3D printing for robots

In addition to the 3D printer, the
VCJ system is equipped with a 3D laser scanner that visually checks the surface irregularities of each layer during application. “This visual inspection makes the printing process completely non-contact, allowing for the deposition of a wider range of possible polymers. For example, we have printed with thiol-based polymers that are resistant to UV light and moisture.” “Because you can create structures,” Katzschmann told Ars Technica.

After scanning, the deposited layer is not mechanically planarized. Instead, the next layer is printed to smooth out the irregularities of the previous layer. “The feedback mechanism compensates for these irregularities by accurately calculating in real-time the necessary adjustments to the amount of material printed when printing the next layer,” said one of the study authors and a computer said Professor of Science Wojciech Matusik. At M.I.T.

Additionally, the researchers claim that this closed-loop control system allows them to print the entire robot structure at once. “Our robot hand can be printed in one operation and requires no assembly. This significantly speeds up the technical design process and allows you to create functional, long-lasting prototypes directly from your ideas. “Expensive intermediate tools and assembly are no longer required,” he adds Katzschmann.

Researchers have successfully used VCJ technology to print a robotic hand whose internal structure resembles that of a human hand. Equipped with a touchpad and pressure sensors, this robotic hand has 19 tendon-like structures (in humans, tendons are fibrous connective tissues that connect bones and muscles) that allow it to move its wrists and fingers. ) is provided. Hands can sense touch, grab objects, and stop their fingers when they touch something. (Researchers modeled their design using his MRI data of real human hands.)

Future of VCJ

In addition to hands, robot hearts, six-legged robots, and vibrations We also printed a metamaterial that can absorb. environment. The researchers believe that all of these robots are hybrid soft-rigid systems (made of both soft and hard materials) that outperform hard robots in terms of flexibility and can overcome design and size issues faced by soft robots. I think that it may function like a robot that has been created.

Because soft robots are made of flexible materials such as fluids and elastomers, it can be difficult to maintain the material’s physical properties and structural integrity, making it difficult for scientists to Difficult to maintain shape and strength. Moreover, it is much easier to control and drive soft robots on a centimeter or millimeter scale. Therefore, they are made small. VCJ, on the other hand, has the potential to produce scalable soft-rigid hybrid robots.

“Eventually, we expect VCJ to replace all contact-based inkjet printing methods. VCJ can be used to create functional parts for robotics, medical implants, and a variety of other industries. You can start manufacturing. “The high resolution, suitable material properties, and long lifetime make prints from VCJ systems very useful for both research and commercial applications,” Katzschmann told Ars Technica.

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