Can a Robot Hand Firmly Grasp and Move a Jellyfish? [Reading Science]

A robot finger attempting to catch a jellyfish.
[Photo by Harvard University]

[Asia Economy Reporter Kim Jonghwa] Labor provided by robots is essential in industrial sites. In particular, the robot's hand can be considered the most important part of the robot because it is the part that actually exerts labor power.

This robot hand performs tasks such as lifting heavy objects that are difficult for humans or tasks requiring strong force very well. On the other hand, it often fails to perform tasks that any human can easily do.

For example, it cannot move soft creatures like jellyfish, soft objects like pudding, or very small objects that cannot be grasped. A large robot hand cannot hold small objects, and if it grips tightly, the object gets crushed.

Is there a robot hand that can be used in such cases? Although developed, it can be said that it has not yet been commercialized. In August last year, a research team from Harvard School of Engineering and Applied Sciences and Baruch College of the City University of New York developed a soft gripping technology that uses hydraulic pressure to softly close and open fingers and can firmly grasp objects without damaging them.

The gripping technology developed by the joint research team is like robot fingers that can gently grasp very sensitive marine organisms such as jellyfish. Jellyfish are composed of 95% water, so squeezing them hard can destroy their tissues. Therefore, a soft robot hand is needed to observe and experiment on these types of marine organisms in their natural state.

These six robot fingers, made of thin, flat, and flexible silicone pieces, resemble hollow channels. They can be used for very precise tasks, and when filled with water inside, they operate by bending sideways coated with nanofibers.

The grip pressure can apply lower pressure than the existing maximum technology of about 1 kPa (kilopascal), and the fingers can move with less than one-tenth the pressure of a human eyelid. However, these robot fingers wear out and tear after about 100 cycles of gripping and releasing. While useful for jellyfish experiments, this reveals the drawback that they cannot be used for a long time.

There is another study that overcomes these drawbacks. This research involves moving objects with ultrasound without physically grasping them. This is the realization of scenes from the movie "Star Wars," where spaceships are landed or captured with beams. The difference is that while the movie uses beams, the real technology uses ultrasound.

In 2013, a research team at the Swiss Federal Institute of Technology Zurich (ETH) developed technology to freely move toothpicks in the air using ultrasound, and in 2014, a joint research team from the University of Bristol and Sussex University in the UK succeeded in experiments moving objects suspended in the air with ultrasound.

The joint research team used 64 small ultrasonic speakers to move objects in the air, but failed to commercialize it. Highly precise and delicate handling is required to pick up small and fragile objects, and it is currently impossible for robot arms with hard physical contact methods to perform this task.

However, if commercialized, it is judged that the economic feasibility is sufficient when automating production processes such as ultra-precision assembly products like watches assembled from ultra-small parts. Also, since it is not affected by the shape or size of the object, this technology is essential for moving high-purity compounds or hazardous materials that must not be touched or dropped to desired locations.

The ETH research team, known as the birthplace of research on moving objects with ultrasound, predicted, "There are many companies willing to pay any amount of money if they can handle high-purity compounds or hazardous materials that get contaminated with even slight contact without damage, so the economic feasibility is sufficient." We hope to see scenes that were only possible in movies become reality as soon as possible.