All posts by Daniel Davies

Lightweight unplugged exoskeletons to aid the mobile and immobile

A lightweight, durable and inexpensive exoskeleton that works by using a pneumatic gel as its motor has been developed by scientists at Hiroshima University.

The device, called the Unplugged Power suit (UPS), consists of three parts: the drive (PGM), the pump – which supplies air pressure for the flexing artificial muscle – and the pipework – which transmits energy between the two.

“The UPS is designed to support human motion where and when needed. It also does not contain any heavy devices. This means that we can customize the UPS to the user’s particular needs such as muscle strength for athletes and rehabilitation,” said associate professor at Hiroshima University Dr Yuichi Kurita.

Image courtesy of Hiroshima University

Image courtesy of Hiroshima University

The UPS’ developers hope that it will be used to improve the quality of life for people who struggle with mobility, and to aid healthy people who enjoy sports activities.

To assist with mobility, the UPS has been stripped of a traditional exoskeleton’s tank, but  is still capable of supplying sufficient power to support human motion.

The sporting community will also benefit from the lack of a tank, which the scientists say will allow athletes to decrease muscle activity during jogging, for instance, which could be quite useful for athletes returning from injury.

The developers imagine the UPS will have different functions added to it so it will be more useful as a monitoring tool. “In the future, we can develop smarter assistive suits including wearable actuators and sensors by using our technique,” said Dr Kurita.

Image courtesy of Hiroshima University

Image courtesy of Hiroshima University

Traditional exoskeletons have had contend with the fact that their bulky frame makes some tasks – like walking upstairs – difficult to do.

Because it is so lightweight the UPS does not suffer from this problem, and as Dr Kurita points out, it is able “to support human hip movement”.

However, the team at Hiroshima University aren’t the only ones testing this kind of technology. Earlier this month it was reported that Swiss sensory motor scientists are working on a new generation of more flexible, less constraining, powered exoskeletons that improve the lives of the severely disabled and paralyzed.

The device being developed by the Swiss Federal institute of Technology, replicates the natural movement of human lower limbs, in an attempt to improve the type of exoskeleton currently being manufactured.

“Hopefully we will build systems that allow you to do more tasks,” said researcher at the Swiss Federal institute of Technology Volker Bartenbach, in an interview with Reuters.

Stanford scientists design solar cells that can capture 97% of light

A material developed by Stanford University scientists may lead to a paradigm shift in the design and fabrication of solar cells.

Currently solar panels are built with a metal wire grid that carries electricity to and from the device. But these wires also prevent sunlight from reaching the solar cell’s semiconductor – which converts sunlight into electricity, and is sandwiched between the metal wires.

The research team have discovered how to hide the reflective metal wires and funnel light directly to the semiconductor below.

“Using nanotechnology, we have developed a novel way to make the upper metal contact nearly invisible to incoming light,” said the lead author of the study Vijay Narasimhan. “Our new technique could significantly improve the efficiency and thereby lower the cost of solar cells.”

The material utilised by the Stanford research team is capable of absorbing 97% of light; that represents a 20 to 22% increase on conventional solar technology.

The system developed to collect sunlight works by placing a 16-nanometer-thick film of gold on a flat sheet of silicon. The gold film is perforated with an array of nanosized square holes, and once the silicon is immersed in a solution of hydrogen peroxide and hydrofluoric acid, the silicon nanopillars emerge through the holes in the gold film.

Narasimhan compares the nanopillar design to a colander in a typical kitchen. “When you turn on the faucet, not all of the water makes it through the holes in the colander, ” he said.

“But if you were to put a tiny funnel on top of each hole, most of the water would flow straight through with no problem. That’s essentially what our structure does: the nanopillars act as funnels that capture light and guide it into the silicon substrate through the holes in the metal grid.”

Image courtesy of Vijay Narasimhan, Stanford University

Image courtesy of Vijay Narasimhan, Stanford University

In order to test the effectiveness of the new solar panels, the nanopillars were put through a series of simulations and experiments.

The researchers discovered that the nanopillar architecture works with contacts made of silver, platinum, nickel and other metals.

“We call them covert contacts, because the metal hides in the shadows of the silicon nanopillars,” said the study’s co-author Ruby Lai. “It doesn’t matter what type of metal you put in there. It will be nearly invisible to incoming light.”

Full findings from the research are available in the journal ACS Nano.