Surpassing "predecessors", only 7.8 mm! The new wireless amphibious origami robot can flip and roll

When we think of robots, the images that come to our mind are probably mostly huge machines that perform repetitive tasks over and over again without much intelligence.

However, this is not the case.

In the world of robots, there is also a class of extremely small (perhaps only nanometer-scale) but very flexible micro-robots that can not only move freely in liquid environments and complete tasks such as picking up and transporting objects, but can also be driven by magnetic fields and light with very high speed, precision and agility.

Due to their small size and diverse functions, microrobots have become one of the current research hotspots in the field of robotics. They are expected to perform a variety of tasks and have multiple potential biomedical applications.

However, existing origami robots require complex systems to achieve versatility and have limited motion modes, making them unable to move on land and in water simultaneously.

Now, a research team from Stanford University has solved this problem by developing a new type of wireless amphibious millimeter-scale origami robot.

It is reported that this amphibious robot can use magnets and origami folding to perform multi-directional rotation-based movements, move in a variety of environments and perform a variety of tasks, such as controlled liquid drug delivery and directional solid cargo transportation.

The related research paper was published in the scientific journal Nature Communications under the title "Spinning-enabled wireless amphibious origami millirobot".

(Source: Nature Communications)

The research team said that the new millimeter-scale origami robot may be used as a minimally invasive device for biomedical diagnosis and treatment in the future.

The smaller and simpler, the better

If you've ever swallowed a round pill hoping it would cure whatever ails you, from stomach cramps to headaches, you know that most medicines aren't designed to treat pain and disease in a precise location.

In recent decades, although over-the-counter drugs have cured many diseases, scientists have also been exploring methods to deliver targeted drugs that can accurately treat complex diseases such as cardiovascular disease and cancer, and microrobots are one of the important directions.

Unlike swallowing a pill or injecting a liquid, drug-delivering microrobots retain the drug until it reaches its target, then release it in high concentrations.

In this research work, the new millimeter-scale origami robot has a cross-sectional diameter of only 7.8 mm and is composed of a Kresling origami (a hollow cylinder composed of triangles) pattern and an attached magnet disk.

At the same time, utilizing the folding/unfolding capabilities of Kresling origami, the new millimeter-scale origami robot can not only achieve actions such as rolling, flipping and rotating, but can also deliver liquid drugs by pumping.

The research team also highlighted that the rotational motion provides an adsorption mechanism that could be used to deliver cargo.

As shown in the figure below, the new millimeter-scale origami robot has the ability to move along a specific trajectory or deliver drugs.

Figure ｜ Adaptive movement in water

Figure｜Climbing

Figure | Directional transportation of liquid medicine in water

Moreover, the new millimeter-scale origami robot can function normally whether on, on the surface, underwater, or inside the mucus-filled pig stomach.

Figure｜Amphibious freight transport

Figure: Movement in a pig stomach containing viscous fluid

The research team said that the groundbreaking nature of this research work lies in that it goes beyond most origami-based robot designs, which previously only used the foldability of origami to control the robot's deformation and movement.

In addition to studying how the folds enable the robot to perform certain actions, the research team also considered how the dimensions of each fold's exact shape affect the robot's rigid motion when unfolded.

Another unique design of the new millimeter-scale origami robot is the combination of certain geometric features. The longitudinal hole in the center and the lateral slits tilted upward on the sides can reduce liquid resistance, thereby ensuring better movement of the robot.

It is reported that the robot can not only provide a convenient way to effectively dispense medicines, but can also be used to carry instruments or cameras into the body, thus changing the way doctors examine patients.

The team is also working on using ultrasound imaging to track the robot's movements without having to cut open organs.

Looking forward to the next 10 years

Robotics is a forward-looking discipline that aims to help humanity overcome a range of major challenges, especially in the medical field.

Last November, Harvard Medical School analyzed eight key research themes in the field of medical robotics from 2010 to 2020 in a review article, and reviewed the many exciting advances made by scientists in the field of medical robotics in the past 10 years.

The eight key research topics are: robotic laparoscopy, non-laparoscopic robots for minimally invasive surgery, assistive wearable robots, therapeutic rehabilitation robots, capsule robots, magnetically driven robots, soft robots and continuum robots.

Figure | Examples of clinical applications of 8 key research topics (Source: Science Robotics)

Among them, magnetically driven robotics technology is becoming increasingly mature, and engineering and medical papers are growing exponentially, but its development trend depends to a certain extent on whether the clinical application of microrobots can be rapidly developed.

Of the more than 19,000 engineering papers on medical robotics since 1990, only a handful can be considered applicable to existing commercial medical robots, and even those with high technical impact have only a few patent citations.

To some extent, this phenomenon may be due to the serious lag between technology development and corresponding commercial applications, or the mismatch between technology research and the reality of medical device commercialization.

Therefore, applying robotics technology to clinical practice requires more than just writing widely cited research articles. Instead, real clinical needs must be identified and relevant technologies must be developed to meet these needs.

Current trends in magnetic actuation suggest that research into magnetically tipped catheters and endoscopes is also returning to its roots, allowing scientists to produce more economically operable medical devices on a smaller scale than complex wire-pulling or motor-assisted devices that can harmlessly penetrate the entire human body.

In the next 10 years, we may see magnetically driven robotic technology catalyze more effective medical treatments, thereby accelerating commercialization and clinical applications.

References:

https://www.nature.com/articles/s41467-022-30802-w

https://news.stanford.edu/press/view/44011

https://mp.weixin.qq.com/s/woC7712grcw1IzHKLF6Pig