Soft exoskeletons

Forget Iron Man: skintight suits are the future of robotic exoskeletons Dr Steve Davis, senior lecturer in robotics, University of Salford.

Translation: Ilya Khel, Hi-News

The exoskeletons of the future will be tight-fitting suits

Not so long ago, children with a rare neurological disease were able to walk for the first time, thanks to a new robotic exoskeleton. These devices – which are essentially robotic suits that give artificial movement to the user's limbs – are becoming an increasingly common way of helping people who are unable to use their legs to walk. But while modern exoskeletons are mostly clunky, heavy devices, new technologies can make them much easier to use and more natural. You've probably already guessed what it's all about: artificial leather.

Exoskeletons have been developed since the 1960s. The first exoskeleton was a bulky set of legs and clawed gloves, only vaguely resembling an Iron Man suit. He had to use the power of hydraulics to help industrial workers lift hundreds of kilograms of weight. That project was unsuccessful and didn't work, but the subsequent options got better and better. Today, people can finally use exoskeletons to partially enhance their own capabilities, re-learn to walk with their help, or even interact with computers using touch or "tactile" feedback.

Usually these devices consist of a chain of links and power joints that work in tandem with a person's own bones and joints. Artificial limbs are securely attached to the limbs of a person and continue his movements. The exoskeleton can be controlled using a computer – for example, if it performs a physiotherapy routine – or by monitoring the electrical activity in the user's muscles and supporting the force they create.

Heavy and painful

Despite half a century of research, exoskeletons are still not used everywhere. This is largely because they were uncomfortable to wear for long periods of time, because people's bodies are different from suits that are made as one procrustean bed. Some exoskeletons are better suited to the human body, but if the robotic joints and the user's real joints do not rotate synchronously, discomfort or pain may occur. All this is compounded by the rigidity of each part of the suit.

Another problem, especially with exoskeletons for the upper body, is their weight, since they are made of durable materials that can hold heavy weights and support the body. Modern suits also don't handle temperature changes or rain very well, which complicates their use in the real world. And people still can't get used to their appearance.

To make exoskeletons more practical and pleasant to look at, we will need innovations: we will have to make them a "second skin", and not a giant robotic suit. Usually exoskeletons use heavy electric motors, but lightweight drives can also be used as pneumatic muscles. They can apply similar efforts as electric motors, only they will weigh several times less. Such muscles consist of a rubber chamber surrounded by a woven sleeve. Under pressure, they increase in diameter and contract in length, pushing the joint. And even though they are made of lightweight materials, they can apply force that is enough to lift many hundreds of kilograms.

Soft robotics

And yet, even these lightweight actuators must be attached to a rigid mechanical structure on the user's body. Scientists from the Center for Autonomous Systems and Robotics at the University of Salford are developing another alternative: soft robotics. This technology uses physically soft advanced materials for the same tasks that traditional rigid robotic devices perform. They are especially well suited for interacting with people, since soft often means light and when colliding with a person there will be less chance of injury.

They have recently developed a new "soft continuum drive" that bends like an elephant's trunk. Unlike a traditional rigid robotic joint, meeting resistance in one part of the body, it will bend in all directions along its entire length.

By wearing a suit made of a material that fits snugly to the body with such drives, we could get a soft exoskeleton that bends exactly at the locations of the wearer's joints. Therefore, the suit is quite suitable for different users without the need to mechanically adjust or calibrate it. Plus, the system is lightweight, and it can be worn as clothing instead of a bulky mechanical frame.

Exoskeletons are starting to be sold commercially, and we are likely to see a lot of new things in the coming years. In 2012, a paralyzed woman, Claire Lomas, even completed the London Marathon in an exoskeleton.

But there are still many engineering problems that will have to be solved before we see the widespread use of such systems. At a minimum, we need a way to fuel these suits without having to connect to the network every half hour.

Portal "Eternal youth" http://vechnayamolodost.ru  06.07.2016