Friday, 7 October 2016

The Making of a Cyborg #2: Exoskeletons

A prototype HAL suit from Cyberdyne. (Photo by Steve Jurvetson)

In the last instalment of "The Making of a Cyborg", I covered a few of the ways in which robots can replace part of the human body. But in many cases, this kind of approach may not be appropriate. A person might still have their entire body but be unable to move it properly due to issues such as paralysis. Meanwhile, military organisations are constantly researching ways to enable soldiers to run faster and lift heavier objects. Both of these problems may in fact be solvable via robotic exoskeletons: wearable machines capable of enhancing the movement of the human body.

Research into wearable robots can be traced back as far as the 1960s, much of it funded by the likes of the Pentagon and DARPA [1]. The general principle behind these suits' operation is fairly similar to that of robotic limbs: an on-board computer detects the desired movement from the user and the suit's actuators carry this movement out. However, these early efforts were severely limited by the technology available at the time. The actuators in the suits were too bulky to be able to move like real human limbs. The computers weren't powerful enough to respond to the user's commands quickly enough. The suits required power, but any power supply capable of keeping the suit running for any useful length of time was far too bulky to be practical.

The Raytheon Sarcos XOS allows the wearer to lift heavy objects effortlessly. (Photo by John B. Carnett)

It wasn't until after the turn of the century that these suits started to become practical. One of the biggest advancements in military exosuits came with the XOS, created by Steve Jacobsen and his company Sarcos [2]. In this suit, sensors in areas such as the handles detect when the operator begins to make a movement (e.g. bending their arm). The on-board computer then calculates how to move in a way that doesn't put strain on the wearer, and the actuators carry out this movement. These actuators are a collection of hydraulic cylinders that move attached cables, in a manner similar to tendons attached to muscles. Valves in the suit control the flow of hydraulic fluid to the cylinders, meaning fluid is received "on-demand"; therefore power is only consumed while the suit is moving.

Meanwhile, there have also been significant advances in exosuit technology in the medical field. The Hybrid Assistive Limb (HAL) robot, created by the Japanese company Cyberdyne, is designed primarily to assist those with mobility problems, thought the suit can apparently also be used for heavy lifting and rescue work [3]. In this case, rather than sensing the wearer starting to move, the suit detects signals from the wearer's brain indicating an attempt to move, much like robotic limbs. HAL's computer then sends control signals to its power units accordingly. One point of note in this case is that the user's brain adapts to the suit over time -- it detects what sort of movements were produced from the signals it has sent, and is eventually able to emit the correct signals to move easily.

However, these machines still aren't without their share of problems. In the case of HAL, there is a significant "learning period" as the brain adjusts to the suit before the user is able to move easily. Less hi-tech offerings have issues of their own. Powering an exoskeleton is still a major issue, with power supplies usually taking the form of a large bulky backpack. Leicestershire resident Claire Lomas recently completed the Great North Run while both paralysed from the chest down and 16 weeks pregnant using a ReWalk suit [4]. This device is much more difficult to use than those previously mentioned, requiring crutches to even maintain balance. In Mrs Lomas's own words: "It doesn't just walk for me. I have to use the parts that aren't paralysed to make it work."

While current exoskeleton technology is still very much a work in progress, it has come on leaps and bounds in recent years, and the technology's obviously useful applications in both the military and medical fields mean that exoskeletons will likely remain an active research topic in the years to come. In the next instalment of this series, I will finally move on from how robots can assist movement and start to discuss how they can augment other key bodily functions.

- Sam


[1] Bonsor Kiger P. How Exoskeletons Will Work [Internet]. 2001 [cited 6 October 2016]. Available from:

[2] Mone G. Building the Real Iron Man [Internet]. Popular Science. 2008 [cited 6 October 2016]. Available from:

[3] The world's first cyborg-type robot "HAL" [Internet]. Cyberdyne. 2016 [cited 6 October 2016]. Available from:

[4] 'Bionic' woman Claire Lomas completes Great North Run [Internet]. BBC News. 2016 [cited 6 October 2016]. Available from:

No comments:

Post a Comment