Empowering Lives and Enhancing Combat: Emerging Technologies in Robotic Suits and Military Exoskeletons

In recent years, the intersection of technology and healthcare has witnessed remarkable strides, particularly in the realm of assistive devices for individuals with mobility challenges. Simultaneously, military applications have embraced cutting-edge innovations to enhance soldiers’ capabilities on the battlefield. Two noteworthy areas of development are robotic suits for paralyzed individuals and military exoskeletons, each leveraging emerging technologies to redefine possibilities.

Recent advancements in the field leverage artificial intelligence (AI) and online optimization to propel exoskeletons into the realm of ‘real-world’ functionality. This article explores how AI is enhancing exoskeleton controllers, making them adaptable to users and their environments, ultimately redefining the boundaries of human-machine interaction.

Robotic Suits for Paralyzed Individuals:

Addressing Mobility Challenges: The development of robotic exoskeletons or suits has emerged as a beacon of hope for individuals facing paralysis. Through the integration of advanced robotics, artificial intelligence (AI), and biomechanics, these suits aim to restore mobility and independence. Companies like Ekso Bionics and Rewalk have pioneered wearable robotic devices designed to assist people with spinal cord injuries in standing, walking, and even climbing stairs.

Technological Foundations:

A powered exoskeleton (also known as power armor, powered armor, powered suit, exoframe, hardsuit, or exosuit) is a wearable mobile machine that is powered by a system of electric motors, pneumatics, levers, hydraulics, or a combination of technologies that allow for limb movement with increased strength and endurance. The exoskeleton supports the shoulder, waist and thigh, and assists movement for lifting and holding heavy items, while lowering back stress. Its design aims to provide back support, sense the user’s motion, and send a signal to motors which manage the gears.

A powered exoskeleton differs from a passive exoskeleton in the fact that a passive exoskeleton is not powered by a system of electric motors, pneumatics, levers, hydraulics, or a combination of technologies. However, similar to a powered exoskeleton, it does give mechanical benefits to the user. Passive exoskeleton technology is increasingly being used in the automotive industry, with the goal of reducing worker injury (especially in the shoulders and spine) and reducing errors due to fatigue. They are also being examined for use in logistics. These systems can be divided into two categories: exoskeletons for upper-limb for assisting shoulder flexion-extension movements; and exoskeletons for lumbar support for assisting manual lifting tasks.

Performance Goal

Enhancing the usability of mobility aids has long been a critical goal, often hampered by issues leading to abandonment. Key benchmarks for usability include the device’s ability to reduce energy expenditure during motion and ensuring its overall safety. Pioneering visions by Ferris and Herr, predating the accomplishment of breaking the ‘metabolic cost barrier,’ emphasized the need for wearable assistive devices to alter limb-joint dynamics, specifically aiming to decrease the user’s metabolic cost during walking and running. The metabolic cost, being an easily measurable and objective indicator of effort, serves as the gold standard for evaluating lower-limb exoskeleton performance, closely aligning with overall performance within a given gait mode.

Significant strides have been made in recent years to break the metabolic cost barrier, a crucial milestone in exoskeleton development. Achieving this breakthrough involves the deployment of innovative technologies, such as tethered active ankle exoskeletons and autonomous active and passive ankle and hip exoskeletons. For instance, Malcolm and colleagues in 2013 successfully reduced participants’ metabolic cost during walking by 6% using a tethered active ankle exoskeleton. Subsequent breakthroughs in both walking and running domains further solidified the potential of exoskeletons in improving human performance.

For individuals living with paralysis, regaining independence and movement can be a transformative experience. Exoskeletons offer the potential to assist with walking, climbing stairs, and even manipulating objects, restoring lost functionality and significantly improving the quality of life.

Challenges:

While strides have been made, challenges remain, including the need for lightweight, durable materials, and improvements in energy efficiency for prolonged use.

The first technical challenge is related to sensing how can the suit know when and how to move. Without rapid sensing, the lag between the operator desiring to move and the actual movement results in the operator feeling like they are moving through a pool of Jell-O. A second challenge is associated with actuation. Although actuating a knee is straightforward, more complex joints, such as hips and ankles, require very advanced, multi-dimensional actuators. Even the most advanced actuators would still limit the full range of motion for these joints, resulting in a decrease in agility.

Power and Propulsion

Future developments may see the integration of brain-machine interfaces, enabling direct communication between the user’s brain and the robotic suit for more intuitive control.

Actuators

Joint actuators also face the challenge of being lightweight, yet powerful. Technologies used include pneumatic activators, hydraulic cylinders, and electronic servomotors.  Elastic actuators are being investigated to simulate control of stiffness in human limbs and provide touch perception. The air muscle, a.k.a. braided pneumatic actuator or McKibben air muscle, is also used to enhance tactile feedback.

Furthermore, the high-performance motors on recent tethered exoskeleton testbeds have relatively high torque control bandwidth that can be leveraged to render the dynamics of existing or novel design concepts

Joint flexibility

The flexibility of human anatomy is a design issue for traditional “hard” robots. Several human joints such as the hips and shoulders are ball and socket joints, with the center of rotation inside the body. Since no two individuals are exactly alike, fully mimicking the degrees of freedom of a joint is not possible. Instead, the exoskeleton joint is commonly modeled as a series of hinges with one degree of freedom for each of the dominant rotations.

Spinal flexibility is another challenge since the spine is effectively a stack of limited-motion ball joints. There is no simple combination of external single-axis hinges that can easily match the full range of motion of the human spine. Because accurate alignment is challenging, devices often include the ability to compensate for misalignment with additional degrees of freedom

Power control and modulation

A successful exoskeleton should assist its user, for example by reducing the energy required to perform a task.  Individual variations in the nature, range and force of movements make it difficult for a standardized device to provide the appropriate amount of assistance at the right time. Algorithms to tune control parameters to automatically optimize the energy cost of walking are under development. Direct feedback between the human nervous system and motorized prosthetics (“neuro-embodied design”) has also been implemented in a few high-profile cases

Adaptation to user size variations

Humans exhibit a wide range of physical size differences in both skeletal bone lengths and limb and torso girth, so exoskeletons must either be adaptable or fitted to individual users. Any misalignment between the actuators and joints could render the suit useless, and potentially dangerous. The resources associated with making and sustaining a large number of custom suits would be astronomical, while also creating a logistical nightmare.

In military applications, it may be possible to address this by requiring the user to be of an approved physical size in order to be issued an exoskeleton. Physical body size restrictions already occur in the military for jobs such as aircraft pilots, due to the problems of fitting seats and controls to very large and very small people. For soft exoskeletons, this is less of a problem.

Health and safety

While exoskeletons can reduce the stress of manual labor, they may also pose dangers. The US Centers for Disease Control and Prevention (CDC) has called for research to address the potential dangers and benefits of the technology, noting potential new risk factors for workers such as lack of mobility to avoid a falling object, and potential falls due to a shift in center of gravity.

Providing comfort at the human-exoskeleton interface

Regardless of active or passive exoskeleton design, researchers struggle to effectively and comfortably interface exoskeletons to the human body. That is primarily due to the human body having multiple degrees of freedom, deforming tissues, and sensitive points of pressure. Accordingly, many researchers utilize custom orthotic fabrication techniques, and/or malleable textiles (commonly referred to as exo-suits)

Overcoming Challenges through Technology innovations

Advanced Sensors and Actuators: Sophisticated sensors capture the user’s biomechanical data and translate it into precise signals for the exoskeleton’s actuators, enabling natural and coordinated movement.

Artificial Intelligence (AI): AI algorithms interpret user intent and dynamically adjust the exoskeleton’s settings in real-time, ensuring smooth and efficient movement.

Emerging technologies such as AI and machine learning play a pivotal role in enhancing the adaptability and responsiveness of these robotic suits. The devices are equipped with sensors that detect shifts in body weight, movement patterns, and user intent, allowing for intuitive and natural motion. This level of sophistication enables a more seamless integration of the exoskeleton into the user’s daily life.

Adaptive Controllers for Enhanced Human Locomotion: Researchers are actively developing smart controllers that go beyond fixed assistance parameters. By employing machine learning and AI techniques, these controllers continuously update exoskeleton characteristics, optimizing user walking and running economy. Zhang and colleagues, for instance, have introduced a controller that rapidly estimates metabolic profiles. This innovation adjusts ankle exoskeleton torque profiles, enhancing human walking and running efficiency.

Fusion of User and Exoskeleton: Smart controllers, empowered by AI, enable exoskeletons to move past traditional fixed assistance. These controllers create a closed-loop with users, adapting to physiological cues and maintaining optimal assistance across varying conditions. Machine learning and AI techniques fuse information from sensors on both the user and the device. This integration enables exoskeletons to discern user locomotion states (running, walking, descending ramps, ascending stairs) and adjust parameters accordingly, showcasing the potential for highly adaptive and intuitive interactions.

AI-Powered Bionic Hands: Exoskeleton controllers leveraging artificial intelligence (AI) and online optimization are advancing toward real-world functionality.  Zhang and colleagues, for instance, have developed a controller that rapidly estimates metabolic profiles and adjusts ankle exoskeleton torque profiles to optimize human walking and running economy. This shift towards smart controllers involves constant updates of exoskeleton characteristics to enhance user mobility. By integrating machine learning and AI techniques, researchers aim to merge information from both user and device sensors, enabling exoskeletons to discern various locomotion states and adjust parameters accordingly.

Researchers have achieved a significant breakthrough in prosthetic technology, enabling a direct connection between prosthetic limbs and the nervous system through electrodes.

This innovation, described as “life-changing,” aims to enhance the comfort and reliability of prostheses for individuals facing amputation. The method involves osseointegration, a surgical procedure anchoring a permanent implant to the skeleton, combined with reconstructive surgery to link the bionic hand directly to the patient’s nervous system and skeleton.

The groundbreaking procedure was successfully performed on Karin, a Swedish woman who lost her right arm in a farming accident nearly two decades ago. The integration of titanium implants in her bones, coupled with the use of electrodes, allowed for the creation of electromuscular constructs, providing reliable neural control fixated into the skeleton. Published in the journal Science Robotics, the research emphasized that conventional artificial limbs often face limitations in control and comfort, challenges overcome by this neuro-musculoskeletal interface.

Professor Max Ortiz Catalan, leading neural prosthetics research at the Bionics Institute, hailed the achievement as promising for individuals facing limb loss, citing Karin’s ability to use the prosthesis comfortably in daily activities. The surgery, led by Professor Rickard Branemark, showcased the potential of combining osseointegration with reconstructive surgery, implanted electrodes, and artificial intelligence to restore human function in an unprecedented way. The Mia Hand, the robotic hand used in the procedure, offers both technical performance and aesthetic customization, promoting user acceptance and pride in their prosthetic limbs.

Wearable Robotics for Fall Prevention: Addressing the critical issue of falls, researchers are exploring AI-based robotics systems for predicting and preventing falls, particularly in older adults. Falls have substantial individual and collective well-being costs, estimated at $50 billion per year in direct medical expenses. The risk of future falls doubles after an initial fall, making prevention crucial.

Wearable devices, functioning as exoskeletons around the hip area, utilize AI to detect fall-related conditions. The system, trained through simulations mimicking human motion and balance recovery, activates torque to specific leg areas to prevent falls. This predictive approach, coupled with vision perception for hazard detection, offers a comprehensive solution for fall prevention.

Brain-Computer Interfaces (BCIs): These interfaces bypass traditional control methods, allowing users to directly control the exoskeleton with their thoughts, offering a more natural and intuitive experience.

Military Exoskeletons:

On the military front, exoskeletons have evolved from science fiction to tangible assets on the battlefield. These powered suits, worn by soldiers, amplify strength, endurance, and overall combat capabilities. Military exoskeletons are designed to carry heavy loads, provide stability, and reduce the physical strain on soldiers during extended missions.

Today’s exoskeletons allow soldiers to carry 17 times more weight than normal and march with significantly less strain on the body. With an XOS 2 suit, for example, a solider can carry 400 pounds but feel the weight of only 23.5. Practically, exoskeletons are designed to assist soldiers in a wide array of support tasks, including loading supplies and ammunition, getting heavy missiles onto airplanes, and repairing ships.

Logistics

History indicates that there are two critical factors that all new technologies must account for – logistics and enemy reactions. Unfortunately, exoskeletons have shortcomings in both areas. For the suit to be effective, it must be worn by a large number of soldiers, so the defense community would need to procure a large number of these suits. However, while most uniform items come in standard sizes, each exoskeleton must be custom fit to its user. Additionally, the exoskeleton must adapt as the user’s body changes.

Vulnerability

Second, enemies will adapt to any new technology injected into the battlefield. The complexity of a combat suit lends itself to many vulnerabilities, with the largest weakness being the person inside the suit. In the comic books, Ironman can be thrown around and survive; however, basic physics would dictate that the sudden acceleration and deceleration should crush his internal organs, killing him. Though the suit can be built to survive significant blasts and being thrown tremendous distances, the user inside of it would likely still be killed. The logical approach to counter these issues is to take the human out of the suit, which in turn takes away the need for an exoskeleton

Advanced Materials and Design: The development of military exoskeletons involves the use of advanced materials such as carbon fiber and titanium to ensure durability without compromising agility. The design focuses on providing support to key areas like the legs and back, reducing the risk of injuries and fatigue. Additionally, modular designs allow for customization based on mission requirements.

Integrated Technologies: Military exoskeletons are not merely mechanical structures; they incorporate sophisticated technologies. Augmented reality (AR) displays in helmets, health monitoring systems, and enhanced connectivity are integral components. These features not only optimize combat effectiveness but also contribute to situational awareness and overall soldier well-being.

Striking a Balance: Striking a balance between increased soldier capabilities and the ethical implications of augmented warfare remains a challenge. Regulations and guidelines are essential to ensure the responsible and ethical use of exoskeleton technology in military contexts.

Challenges and Future Directions in Military Exoskeletons: The military sector is actively exploring exoskeletons to enhance soldiers’ physical capabilities. Current exoskeletons allow soldiers to carry significantly heavier loads with reduced strain. However, challenges such as logistics, custom fitting, and potential vulnerabilities need addressing.

Military exoskeleton projects like TALOS outline ambitious goals, emphasizing survivability, operator interface, C4I capabilities, power and energy solutions, and human factors.

The Tactical Assault Light Operator Suit (TALOS) project aimed to create an exoskeleton to enhance the armor capacity of Special Forces operators, addressing survivability, operator interface, visual augmentation, situational awareness, targeting, mission planning, execution, command and control, communications, computing, intelligence, power, energy, and human factors. In terms of survivability, TALOS focused on developing materials and structures for next-gen ballistic and blast protection, minimizing weight, and providing advanced protection against rifle rounds. Desired features included transparent ballistic materials for helmet visors, fully-enclosed armored helmet systems, and technologies to reduce electromagnetic and acoustic signatures. The project explored both lightweight and powered exoskeletons to enhance operator strength and agility, supporting distributed payloads.

The operator interface, visual augmentation, situational awareness, targeting, mission planning, and execution aspects of TALOS aimed to provide enhanced awareness through multi-sensory displays. The project also targeted robust, modular, high-bandwidth communications and computing platforms for integrated information processing. The Command, Control, Communications, Computing & Intelligence (C4I) aspects included forward-looking features like man-worn networked intelligence, non-radio frequency communications, and computer vision. The Power and Energy focus involved developing technologies for power generation, management, and storage, with an emphasis on energy-harvesting exoskeletons to reduce the need for spare batteries and logistical challenges. Lastly, the Human Factors aspect concentrated on man-machine pairing, incorporating bio-mechanical modeling, simulation, and technologies for optimizing human performance in terms of thermal management, efficiency, and physical and cognitive states.

Future Directions

As the military-industrial complex continues its pursuit of exoskeleton development, advancements in associated fields, particularly in biomechanical sensing within the prosthetics community and the creation of smarter motors in the consumer product sector, contribute to overcoming technical challenges. With a significant focus on energy in global research and development, the quest for lighter and safer power options is ongoing.

Gregory S. Sawicki and colleagues emphasize the need for collaborative efforts among engineers, physiologists, clinicians, psychologists, and designers to refine exoskeleton technology, evaluate human performance, integrate exoskeletons into rehabilitation interventions, understand user interaction, and plan for spatial considerations. Establishing guidelines that continuously evolve will pave the way for symbiotic relationships between humans and machines, blurring the lines between the two. The convergence of exoskeleton hardware, software, and the user’s biological systems holds the promise of steering neuromechanical structure and function, ushering in a new class of devices capable of influencing human movement over various timescales.

Looking ahead, industry experts such as Rogier Barents and Gaurav Genani envision a future where exoskeleton solutions become commonplace in households within the next decade, with substantial augmentation of human strength through powered exoskeletons. They further anticipate exponential evolution in wearable technologies over the next 25 years, envisioning a fusion of advanced materials, sensors, and actuators with the human body.

Industry Advancements

In the last years, the number of companies with the aim to create exoskeletons that can help the paralyzed has multiplied. Countless examples can be mentioned here. In 2018, Japanese robotics company Cyberdyne has received approval from the FDA to make its lower-body exoskeleton, known as Hybrid Assisted Limb or HAL, available to U.S. patients. Other companies are working on exoskeleton-style devices, too, including Ekso Bionics of Berkeley, Calif., Argo Medical Technologies Ltd. in Israel, and Rex Bionics in New Zealand. The Ekso device and Argo’s exoskeleton called ReWalk are only available in rehabilitation centers and hospitals in the U.S. for now.

Italian engineers at the Perceptual Robotics Laboratory developed what they called a Body Extender, a robot that can help move heavy objects as an exoskeleton by lifting about 50 kilograms in each of its hands. However, teams at Swiss companies Hocoma and Reha Technology are also working on robotic structures helping those in need, and a lot more startups are joining them all around Europe. For example, a French startup, Wandercraft, developed an exoskeleton to allow users to walk hands-free, or Spanish Marsi Bionics has been working on a wearable gait structure specifically designed for children with neuromuscular diseases.

Transitioning from exoskeletons to bionic hands, BrainRobotics has developed an innovative prosthetic hand powered by artificial intelligence. This next-generation hand offers precise control over individual fingers, enabling users to perform diverse gestures and grips. The AI-driven hand connects to a smartphone app, maintaining a charge throughout the day and providing users with a customizable and intuitive experience. With lower expected costs compared to existing options, BrainRobotics aims to make advanced prosthetics accessible to a broader audience.

There are a new breed of construction worker in Canada, using wearable machinery to do work faster and with less fatigue.  An exoskeleton’s frame eases the strain of heavy lifting or repetitive tasks. It protects a person’s joints and muscles from injury. Many in the industry say the days of workers damaging their bodies to make a buck could soon be over as exoskeletons become more common on construction sites. Some of the suits work like a lever, using counterweights to lift objects. The latest version is a fully powered motorized suit that can enhance a user’s strength and stamina. The hope is this technology will attract younger workers and allow older employees to stay on the job longer, which would benefit an industry facing a labour shortage.

Examples of Leading Exoskeleton Technologies:

• ReWalk: This exoskeleton allows individuals with paraplegia to walk upright and navigate various terrains, empowering them with newfound freedom and mobility.
• EksoNR: This exoskeleton assists patients with spinal cord injuries and other neurological conditions with standing and walking, promoting rehabilitation and improving their quality of life.
• Sarcos Guardian XO: This exoskeleton is designed for both industrial and military applications, providing soldiers with superhuman strength and endurance for carrying heavy equipment and tackling challenging tasks.

Conclusion:

The emergence of robotic suits for paralyzed individuals and military exoskeletons represents a convergence of technological prowess, humanitarian goals, and military strategy. These innovations underscore the transformative impact of technology on human capabilities, offering newfound hope to those with mobility challenges and providing soldiers with tools that could redefine the future of warfare.

The integration of artificial intelligence into exoskeleton controllers marks a transformative era in assistive technologies. From empowering individuals with advanced prosthetic hands to enhancing soldiers’ capabilities on the battlefield, AI-driven innovations promise a future where man and machine seamlessly collaborate. As these technologies continue to advance, the prospects for enhancing human potential, both in civilian and military contexts, are bound to expand, fostering a future where technology is a catalyst for empowerment and resilience.

As research progresses, the potential applications of AI in exoskeletons extend beyond mobility assistance, opening doors to a new frontier of human augmentation and empowerment.