Exoskeletons are mechanised frames that can add extra strength into movement while taking the strain off joints. They've hit headlines before - such as when a paraplegic Brazilian man was able to kick off the 2014 World Cup thanks to an exoskeleton that carried signals from his brain to his legs. 

However, they're still in their infancy in terms of development, with few frames commercially available. Despite this, exoskeletons hold a lot of promise for a range of sectors. 

exoskeleton

Here we explain how exoskeletons are being used today, and how they might be used in future. 

Military

To the military, exoskeletons offer the promise of morphing average soldiers into turbo-charged killing machines less prone to human afflictions like fatigue. 

Various countries but the US and Russia in particular are racing to develop exoskeletons that can be deployed in combat. Both have made strides, although the results are yet to be widely released.

The US military has developed an exoskeleton called the Soft Exosuit. The idea was initially developed by Harvard's Wyss Institute for Biologically Inspired Engineering before attracting interest and funding from DARPA - the Defense Advanced Research Projects Agency - an agency of the United States Department of Defense responsible for the development of new technologies for use by the military.  

Recent research found that the suit - made up of material sections that are joined together with cables that power the suit and are controlled by a mobile actuation unit - cuts the amount of energy exertion required by 15 percent. Force can also be applied at joints to give soldiers additional power. 

TALOS (Tactical Assault Light Operator Suit) is another exoskeleton being developed for use by the US army. Lockheed Martin is leading the effort, along with a licence from Canada-based B-TEMIA, which initially developed exoskeletons to help people with mobility issues stemming from degenerative illnesses.

This suit is billed to be bullet-proof, weaponised, and monitor a soldier's vital signs, as well as offering increased strength and durability. Although the initial deadline was missed, a prototype will reportedly be released at some point in 2019.

The sheer weight of all the kit soldiers have to carry make the imperative for this type of tech clear. "The fundamental challenge we're facing with infantry troops is they're carrying too much weight," Paul Scharre at the Center for a New American Security (CNAS) told Reuters.

Russia is also working on a number of different exoskeleton suits. The most well-known of these is Ratnik-3, which is constructed of imposing armour plates and joint motors. Some reports in the summer of 2018 alleged that the prototype had already been used in combat, which commentators assumed referred to use in Syria. However, the suit is billed for official release in 2025.

The biggest barrier to progress in this domain is the limited battery supply afforded by the suits. Batteries have a short life span, meaning the suits cannot stay powered for long - necessitating the need to somehow transport a portable power supply in field deployments, which may not always be practical.

"Exoskeletons with more modest goals, such as lower-body exoskeletons that are designed simply to increase mobility, reduce energy expenditure, and reduce musculoskeletal injuries, may show more promise in the near-term," according to a CNAS report.

Mobility

Whether due to disability, degenerative illness or old age, a major application of exoskeletons is to aid people with mobility problems.

In 2017, a suit was developed that could intelligently predict falls in elderly people and help them remain steady. This is achieved by the suit initiating a counter effect by adjusting movement in response to a fall - at the hip, for example.

Named the Active Pelvis Orthosis (APO), the prototype was developed by researchers at the École Polytechnique Fédérale de Lausanne. Since falls in elderly people can often lead to serious injury or even death, the suit carries obvious appeal.

Soft exosuits have also been tested by researcher Conor Walsh's engineering team at Harvard University. Stroke patients often have difficulty regaining strength and fluidity in their movements and this suit helped them more quickly regain their mobility.

Another group working on creating soft exosuits is Seismic Powered Clothing, which launched a line of activewear clothes with discreet reponsive robotic elements buried within. These, the manufacturers promise, help to power movements as well as aligning posture.

While this type of clothing is obviously more necessary for elderly people, the firm foresees a world where healthy people may don the suits too - for activities such as tennis, or even sitting or standing for extended periods. 

Extreme sports

Perhaps a frivolous application of exoskeleton technology by comparison is in extreme sports like skiing.

Skiing and snowboarding are notorious for being tough on your knees, and some companies are working to reduce the load on your joints through exoskeleton technology.

Roam Robotics is one company that has developed a suit to cushion your joints and ease movement on the slopes. 

The company's suit - currently available to rent for a demo but not to buy - incorporates sensors on the exoskeleton that anticipate the movement you want to make and automatically control torque through actuators (small motors) at your knees. In short, the exoskeleton acts as a shock absorber, relieving pressure from your legs. This means you can ski longer without feeling as much strain.