Power exoskeleton builds “Hercules”

Whether it is the individual Gatling power armor in the movie “The Wandering Earth” or the biochemical nanosuit in the game “Crysis”, humans have never given up on the exploration of the concept of “super soldier” driven by powered exoskeleton. , And put on a coat of science fiction.

Power armor in the movie “Edge of Tomorrow”

As the name suggests, the power exoskeleton is a set of human body augmentation system driven by external power, attached to the outside of the human body. By implanting a sensor in the brain or close to the skin, it can perceive the changes in the bioelectricity of the human before performing an action, thereby judging the wearer’s action intention in advance, and driving a very fast response servo motor to “copy” these actions On the driving joint, the wearer becomes an omnipotent super soldier.

The evolutionary history of dynamic exoskeleton
“Exoskeleton” is not the first to be owned by humans. It is ubiquitous in organisms such as shrimps, crabs, insects, etc. It generally refers to a hard external structure that can configure and protect the soft internal organs of organisms. From an evolutionary point of view, in ancient fish, the ancestors of modern spinal organisms, the internal and external skeletons are distinct, and even the skulls and scapulas of modern humans evolved from the exoskeletons of ancient vertebrates.

In the long course of evolution, vertebrates slowly faded away from the outer skeleton that was not conducive to movement, and evolved into what they are today. However, with the development of science and technology, people have rekindled their enthusiasm for this ancient physiological structure.

Tracing back to the source, the concept of power exoskeleton can be traced back to the 19th century British illustrator Robert Seymour, an illustration “Walking By Steam”. The painting shows cars, airplanes, and a huge walking machine powered by steam, which can probably be regarded as the prototype of the concept of powered exoskeleton.

The time came to 1965. In the shadow of the Cold War, many equipment that only existed in science fiction were brought into reality, and the power exoskeleton was no exception. The Hardiman device, which is driven by a motor-hydraulic hybrid, jointly developed by the U.S. military and General Motors, has become the first truly powered exoskeleton manufactured by humans.

19th Century Illustration “Walking BySteam”

However, from the current technical perspective, it is more like a small construction machine, because it does not have high-precision motion sensors to replicate human movements. Although the force feedback sensor on the arm part can realize simple grasping, the leg part can only carry people forward at a fixed rhythm like a robot.

The many problems encountered during Hardiman’s research and development process temporarily reduced human enthusiasm for research and development of power exoskeleton. Entering the 21st century, the famous XOS-2 powered exoskeleton system, also funded by the US Department of Defense Advanced Research Projects Agency (DARPA), led by Raytheon, is obviously closer to the exoskeleton armor in science fiction works. The XOS-2 powered exoskeleton system released in 2010 allows soldiers to easily lift 90 kilograms of heavy objects, and can perform more flexible movements such as climbing and kicking.

/ Power source is always the most troublesome issue on the road of power exoskeleton equipment development. /

XOS-2 won the 2010 “Time” magazine “Most Shocking” Invention Award. The military field power exoskeleton similar to XOS-2 also includes the HULC system with a kinetic energy recovery system led by Lockheed Martin.

HULC is derived from the BLEEX lower extremity exoskeleton system developed by the University of California, Berkeley in 2000. The design focuses on the support structure of the waist and legs. HULC uses a lighter and stronger titanium material on the basis of BLEEX, incorporates a modular design concept, and adds a kinetic energy recovery system, which uses the kinetic energy generated by people changing feet when walking to recover part of the energy for the device.

However, even so, HULC can only guarantee that the wearer will continue to travel for an hour at a speed of 4.8 kilometers per hour, carrying a weight of 90 kilograms. This situation is improved in the ONYX system, also developed by Lockheed Martin, the successor of HULC. It can automatically adjust the power according to the terrain condition of the wearer and the load carried. After being equipped with a 5.4 kg battery pack, it can reach a maximum operating time of 16 hours.

my country’s military-grade power exoskeleton has also frequently appeared in news reports in recent years. The handling exoskeleton developed by the 206 Institute of the Second Academy of China Aerospace Science and Industry Corporation participated in the recovery of the “Chang’e-5” returner, so that the handling operations that originally required two people could only be completed by one person. Its standard battery can provide about 4 hours of battery life under comprehensive working conditions.

Passive exoskeletons are more suitable for modern battlefields
Based on the above cases, it is not difficult to find that the source of power is always the most troublesome problem on the development of power exoskeleton equipment. A series of exoskeleton systems that do not require external power supply, represented by the K-2 passive exoskeleton developed in Russia, not only effectively avoid the problem of insufficient battery life, but also because of the cancellation of heavy batteries and power components. Very light. After it was put into use in the Syrian battlefield, it was deeply loved by Russian soldiers.

HULC system

The K-2 exoskeleton weighs only 2 kilograms. It transmits 50% to 80% of the soldier’s weight to the ground through a simple mechanical structure. The “third hand” worn around the waist can be mounted with light machine guns and minesweeping devices. The various weapon configurations inside, also played a role in increasing the weight of the soldiers.

K-2 passive exoskeleton developed in Russia

The individual passive exoskeleton of the Chinese People’s Liberation Army equipped with health soldiers also adopted this design idea. After being worn, it can reduce 70% of the body’s weight when standing, allowing small female hygienists to carry a large amount of medical supplies, and can carry 70 kg of wounded persons to the front line in time.

In general, the existing military-grade power exoskeleton is limited by the low energy density of the battery pack and technical thresholds such as sensor signal acquisition. The main purpose is still to increase the soldier’s weight-bearing capacity.

XOS-2 Power Exoskeleton System

The passive exoskeleton without the power supply is obviously more in line with the military’s requirements at this stage. To achieve the flexible posture of super soldiers in science fiction works, it is necessary for humans to make a major breakthrough in brain-computer interfaces, obtain more intuitive driving signals, and supplement them with a powerful source of power. Such as the miniature cold nuclear fusion “Ark Reactor” used by the protagonist in the movie “Iron Man”, or more practical low-noise fuel-fired generators, fuel cells, etc.

If the above-mentioned breakthroughs are really made in the future, then the form of war will be profoundly changed. Individual heavy armor that can resist 12.7mm bullets will be equipped in large quantities, and the small-caliber medium-power bullets commonly used in countries around the world will also be eliminated. On the contrary, the “looks beautiful” military-grade power exoskeleton will probably never become the protagonist on the battlefield.

Let the paraplegic stand up again

Exoskeleton support equipment Ekso GT

Compared with the military field, the application of power exoskeleton in the civilian field is also worthy of attention. In 2012, Ekso Bionics of the United States launched the first exoskeleton scaffold device Ekso GT, and cooperated with the local neurorehabilitation center to allow paraplegic patients to regain the ability to stand and perform walking training.

Since 2017, the famous car manufacturer Ford has also begun to cooperate with Ekso Bionics to develop the industrial exoskeleton equipment Ekso Vest, and after one year, it will be equipped in Ford’s 15 regions of the world. The work intensity of the workers in the automobile assembly line reduces the incidence of lumbar muscle strain and improves their work efficiency.

/ Civil-grade exoskeleton usually only provides a few hours of battery life, which greatly limits the range of movement of the wearer. /

Nowadays, the power exoskeleton products of dozens of companies, including Ekso Bionics, have been widely used in the factories of many famous companies around the world. The HAL (Hybrid Assistive Limb, meaning Hybrid Assistive Limb) exoskeleton developed by Cyberdyne of Japan since 2004 and officially released in 2008 has also been deeply cultivated in the medical field for many years. It has now been launched to the fifth generation. It has been used in the debris cleaning operations of the island nuclear power plant accident.

However, the high cost and the tens of thousands of dollars in selling prices limit individual users’ desire to purchase civilian-grade exoskeleton. Moreover, the price of this device greatly exceeds its value in the eyes of insurance companies, and it is often excluded in insurance clauses.

This makes most of the sales targets of exoskeletons concentrated in large rehabilitation centers, hospitals or factories. And similar to the bottleneck encountered by military-grade exoskeletons, civilian-grade exoskeletons usually only provide a few hours of battery life, which greatly limits the wearer’s range of motion.

Enhanced prosthesis: the integration of man and machine
Compared with the exoskeleton armor attached to the outside of the body, it directly replaces part of the body’s prosthetic limbs. It is also a frequent visitor of science fiction games and movies. In “Cyberpunk 2077”, the protagonist can be implanted with electronic eyes with environmental analysis functions, a mantis knife hidden in his arm, and a series of enhanced prostheses such as reinforced tendons that can achieve double jumps.

Similar to “Cyberpunk 2077”, games that use prosthetic modification as a selling point include “Destroyer”, “Metal Gear Rise: Revenge”, “Sekiro: Shadows Die Twice”, and “Devil May Cry 5”. Although in real life, prosthetics is only a means to improve the quality of life of the disabled, it is clear that people have higher expectations for it.

Perhaps in the not-so-distant future, human beings with sound limbs will also take the initiative to accept prosthetic modification for extraordinary abilities, like the protagonist of “Cyberpunk 2077”. The boundaries between humans and machines are gradually blurring. Games and film and television works have portrayed the future of prosthetic limbs and powered exoskeletons. Will the definition of human beings change accordingly? let us wait and see.