A few weeks ago, I ran across an internet ad for commercial exoskeletons. You know, wearable robotic devices like the Amplified Mobility Platforms used by the Resources Development Administration to battle the Na'vi in Avatar or the Armored Personnel Units used for the defense of Zion in the Matrix movie franchise. Powered exoskeletons have been standard fare in science fiction since Robert A. Heinlein's 1959 novel Starship Troopers. My first thought on seeing this ad was, we've finally realized Heinlein's vision. Or have we?
As the name implies, an exoskeleton is worn outside the body. Some can be made of flexible materials, such as gloves. Others are made of rigid parts that supplement the movement of arms, back and legs.
Heinlein envisioned a fully independent powered suit that protected the wearer from environmental hazards like the vacuum of space, or hostile weapons. They also magnified the operator's strength, speed and endurance in battle, and possessed some mean weaponry.
The versions in the ad that I read were created for commercial use. Other companies manufacture models used for physical therapy or neuro-motor augmentation (i.e., personal mobility). Does the US military have some super-secret exoskeleton that will convert a run-of-the-mill grunt into a super soldier?
Commercial Models The websites the ads directed me to touted that powered exoskeletons combined human intelligence and judgement with the power and durability of machinery. The user was controlling the actions of a robot that did the actual work. By augmenting muscular action, the suits reduce exertion and fatigue of the shoulders, back, arms and legs. Commercial exoskeletons are designed for specific applications. In logistics, they are employed in warehouse or military settings loading and unloading heavy boxes and crates, or transferring airport baggage. In industrial environments operators lifted and set massive components, then used their hands for fine manipulation like threading lug nuts, bolts, etc. Their power source was a rechargeable lithium-ion battery, allowing user autonomy.
Given their utility at preventing repetitive stress or injury from overexertion I foresee (maybe in the next five years?), workers in some Amazon warehouse, or in some heavy industry, demanding the company provide exoskeletons as a condition of their labor contract.
Medical Models Long before commercial exoskeletons became available, they were used in medicine. As early as the 1960s the first generation facilitated physical therapy for recovery from injury or temporary paralysis.
Medical exoskeletons are highly diverse and can be categorized in a number of ways: rehabilitation vs mobility aid, upper body vs lower body(or even a smaller body region like a hand or foot), and control strategy.
The most basic direction is a pre-programmed wearable robot that executes predetermined motions. A more complicated device waits for a set of conditions to be met such as detection of a shift in the center of mass by the wearer before executing a motion. Even more complex medical exoskeletons read nerve signals from the spine, arms and legs and produce a proportionate motor activation. The most complicated machines can provide functional electrical stimulation of a wearer's limb(s) as the device controls movement.
Medical exoskeletons can be controlled directly from the brain. I've read some fascinating articles about such advances for controlling prosthetics or providing mobility. But I'll cover the topic of brain implant-machine control in a future Just Over the Horizon edition.
A number of FDA-approved devices provide temporary physical therapy for patients recovering from stoke, brain and spinal cord injury. Their preprogrammed motions retrain limbs to walk or pick up objects. They supply support where needed to avoid compensating and fatigue and overcome muscle weakness. Therapist-controlled assistance can be adjusted from zero to one hundred percent (used for pre-gait muscle training).These devices also record data related to posture and gait, to give
corrective feedback.
Some medical powered exoskeletons provide mobility for those with permanent neuro-muscular weakness due to injury or disease. These apparatuses enable a degree of autonomy and dignity beyond other devices such as motorized wheelchairs.
We live in amazing times. I predict that in the very near future, when combined with brain implants, exoskeletons will allow mobility for para- and quadriplegics.
Military Models In 2013 The Defense Advanced Research Projects Agency (DARPA) initiated a grant program titled Exoskeletons for Human Performance Augmentation. The idea was to develop technology for potential military applications. A number of companies participated. As of 2020, one of these - Sarcos - is providing the US Marines with an exoskeleton based on a commercial version they developed as an outcome of the DARPA program. But rather than deploy in battle, the Guardian Alpha XO is used primarily for logistics support, enabling individual soldiers to lift and move objects weighing up to a thousand pounds.
As recently as 2019 the US Army ran the TALOS exoskeleton project. Consider that the Army's advised weight of a soldier's backpack is fifty pounds. But in practice, packs can weigh up to a hundred forty pounds when adding body armor, night vision goggles and radio systems. The Army has a keen interest in improving soldiers' ability to haul that amount of gear and still participate in battle. But the program was put on hold.
In March of this year, the Army issued a Request for Information to commercial exoskeleton providers for any devices that would be suitable for enhancing soldier performance and reducing fatigue. Perhaps the Army is scaling back their vision of a fully mechanized foot soldier. So far, the vision of a Starship Troopers-esque exoskeleton has eluded the US military. And probably will for the next thirty years.
A number of technological problems have yet to be overcome. The first is power supply. Lithium-ion batteries need frequent charging due to the tremendous power consumption of exoskeletons. Other options are even less desirable. Hydrogen fuel cells emit too much heat to be safe for the operator. Tethered units limit the range of use to a nearby power source, such as a truck-mounted generator.
Another challenge is limited flexibility. Human hip and shoulder joints are marvels of engineering. They allow an astounding range of motion that so far, no mechanical system has been able to duplicate. The best medical exoskeletons require three rigid hinges to approximate the three dimensional movement of hip joints. While the mobility they provide is miraculous, their movements are awkward to even the most casual observer. In the heat of battle, fluid motion is a supreme requirement to target weapons or avoiding dangerous exposure to enemy fire.
Another significant issue is response lag. This is the time differential between the wearer's input, and the device's movement. Exoskeletons are not agile. This is not an asset during a firefight, or when needing to dodge a falling tree or object. To put this in perspective, I have yet to see a video of two people using these suits playing "catch".
Exoskeletons have their critics. In 2020 Forbes wrote an article critical of the military's pursuit of the technology. Per Forbes, the devices must be custom fitted to each individual soldier. The feature deemed this a dealbreaker. However, in my opinion, the use of interchangeable components largely gets around this obstacle. For example, rather than issuing a complete exoskeleton, the Army would issue a helmet size W, a shoulder/arm component size X, a thorax size Y, and leg units size Z.
I thought the Forbes article's more cogent argument was that while the suit may survive the forces generated in battle, the human inside likely would not. Imagine the scenario of an exoskeleton-wearing soldier being thrown by an IED explosion. In The Avengers: Endgame movie Iron Man is repeatedly flung hundreds of feet against solid objects as he battles Thanos. Tony Stark's brain and internal organs would be catastrophically damaged by the resulting forces (his later exposure to the Infinity Stones notwithstanding).
Most likely uses of exoskeletons over the next thirty years will be medical/therapy, logistics (transferring heavy boxes, crates), industrial assembly (automotive, shipbuilding, farm and heavy machinery manufacturing), commercial construction, and mining.
Speaking of mining, if combined with a pressure suit and environmental controls, an exoskeleton would be perfect for mining on Mars. Look for their use in my upcoming book, Blood Moon.
Do you or someone you know have personal experience with a powered exoskeleton? If you're willing to share your impressions with me, reply directly to this email. I'd love to hear from you.
For Further Readinghttps://www.sarcos.com/products/guardian-xo-powered-exoskeleton/https://www.suitx.com/https://exoskeletonreport.com/2016/06/medical-exoskeletons/https://eksobionics.com/eksohealth/https://rewalk.com/https://en.wikipedia.org/wiki/Powered_exoskeletonhttps://www.zdnet.com/article/u-s-marines-to-get-alpha-exoskeleton-for-super-strength/https://www.forbes.com/sites/vikrammittal/2020/08/17/military-exoskeletons-science-fiction-or-science-reality/?sh=25f346aca69ehttp://www.technovelgy.com/ct/content.asp?Bnum=506https://www.thedefensepost.com/2022/03/30/us-army-exoskeleton/ 
