Tag Archives: exoskeleton

A Second Chance: Robotic Exoskeletons May Be the Future of Mobility for Patients with Spinal Cord Injuries

No one ever imagines themselves getting seriously injured. Accidents do happen though, like car crashes and unexpected sports injuries. These events can drastically change a person’s life, leaving them unable to perform simple daily tasks without assistance, such as walking. One injury that can radically impact a person’s life is a spinal cord injury. There are approximately a quarter of a million people in the United States with spinal cord injuries, and that number grows by 12,500 each year.

The spine is the center of support in the body. It adds structure and facilitates movement. Its other extremely important job is to protect the spinal cord, which is a column of nerves that runs down the length of the neck and back. The spinal cord is part of the nervous system, and it acts as a messenger, taking orders from the brain and relaying these messages to the rest of the body, telling the muscles what to do. If the spinal cord is injured, the messages can’t be delivered properly. This often results in a loss of mobility.

Diagram of the central and peripheral nervous system showing how the spinal cord connects the brain to nerves that run throughout the body
From OpenStax Anatomy and Physiology on Wikimedia Commons

Most people don’t think about the mechanics involved in the simple act of walking. However, in order to walk, various joints such as the hip, knee, and ankle need to work together, rotating and bearing loads to allow for movement. When your foot hits the ground, the ground imparts a force through the foot which is translated up through the lower extremities to the spine. When a spinal cord injury occurs, the brain is unable to communicate with our muscles which inhibits this load bearing and the resulting movement.

Studies have shown that powered exoskeletons have numerous benefits for patients with spinal cord injuries to help with walking and mobility. These powered exoskeletons are built in various ways to bear loads and encourage movement, and a review of different exoskeletons, along with other rehabilitation devices, discusses differences in design and control of the systems. For example, to allow for control of movement, one exoskeleton was built with motors located at the joints while another was designed with a braking system at the joints.

Photo of the Indego powered exoskeleton
Indego Exoskeleton – From Indego.com

One study researched mobility outcomes for patients with injuries that varied in severity and location on the spine. Some patients were paraplegic, which means their lower extremities were paralyzed, and some patients were tetraplegic/quadriplegic, which means the paralysis affected both their lower and upper extremities. Also, some patients had complete spinal cord injuries, which means all feeling was lost below the injury, while others had incomplete spinal cord injuries, which means they had some feeling and some ability to control movement below the injury. This study showed that powered exoskeletons, specifically the Indego exoskeleton, could help a patient move in both indoor and outdoor settings, and there is potential for patients with paraplegia caused by injuries to the lower spine to use this device to allow greater ease of mobility in public spaces. For patients with more severe injuries, such as those with quadriplegia, the powered exoskeleton allowed for slower movement with supervision and occasional assistance from a therapist. These patients also needed assistance with putting on and removing the device. Therefore, the powered exoskeleton won’t help patients with more severe injuries move on their own in public settings, but it was excellent for exercise and rehabilitation.

These exoskeletons are also proven to be safe and feasible. Patients with complete spinal cord injuries did not report discomfort or injury, and they were able to use a powered exoskeleton more easily than previous rehabilitation technology.

Powered exoskeletons may be the future of movement for those who thought they would never walk again. This further reading contains examples of paraplegics who walked using a powered exoskeleton. Another man even walked marathons using one of these devices:

From Freethink on YouTube

There are limitations on these devices, but the robotics field is swiftly evolving, and the technology is giving patients something they never thought they would have: a second chance.

Soft Robotics: Humanizing the Mechanical

Cassie the robot, created by Dr. Mikhail Jones at Oregon State University
Cassie the Robot, developed by Mikhail Jones, Faculty Research Assistant in Mechanical Engineering at Oregon State University.

In media and science-fiction, robots have stereotypically, and perhaps somewhat unfairly, been depicted as mechanical, stiff assemblies of moving joints and complicated circuitry. While this still holds true for many robots designed today, whether for industry or research, the past few years have seen a growing interest in soft robotics in academia, industry, and popular culture. As the name implies, many research groups have begun investing in constructing robots from compliant, softer materials.

Stickybot, a gecko-inspired robot.
Stickybot, a biomimetic robot.

Inspired by the way organisms in nature survive and adapt to their surroundings (formally known as biomimicry), the advantages of soft robotic components lie in their flexibility, sensitivity, and malleability – delicate tasks or interactions involving other people would be better accomplished by robots made of compliant materials rather than one that could potentially cause harm to the object or person. To that end, many of the applications of soft robotic research have already seen results in the medical industry, from invasive surgery to assistive exosuits. By taking inspiration from biological creatures or mechanisms, softer materials like rubbers and plastics can be actuated to accomplish tasks conventional, “hard” robots could struggle with.

Animation of pneumatic muscle.
Animation of pneumatic air muscle used as robotic actuators.

The most common method of moving these robotic parts is with changes in internal pressure. By creating a “hard”, skeletal frame, and surrounding it with soft, sealed membranes, changes in pressure allow the designer to control its components precisely. By decreasing the pressure and creating a vacuum, the robotic section would shrink or crumple, and increasing it would do the opposite. Researchers at Harvard developed “artificial muscles” by taking this concept a step further; using origami, they were able to design soft robotic mechanisms that could orient themselves into tunable positions as the pressure was changed inside the membrane (as a side note, origami is used in a surprising number of research fields, one of the most famous being satellite deployment). Compared to the challenge of precisely controlling prismatic (sliding) joints and servos in conventional robotics, the compliance of the materials used allow for finer control and smaller ranges of applied forces that are better suited for precise tasks.

Animation of a person demonstrating the Miura fold on a piece of paper
The Miura fold pictured here is often used to deploy large surfaces while minimizing volume, such as for satellites.

Another significant advantage of soft robots over their stiff counterparts is their adaptability to environmental conditions. Generally speaking, robots do not do well in water (or lava, for that matter), but it would have little effect on robots covered in a sealed, pressurized “skin”. This is what inspired NASA in 2015 to fund research into soft robots that could explore the oceans of one of Jupiter’s moons, Europa.  Similarly, a light-activated underwater robotic manta ray was designed at a centimeter scale to study the effect of environmental cues on controllable robots.

Schematic and pictures of soft robot design.
A soft-legged robot with walking capabilities.

While research in soft robotics is still relatively new, it has the potential to significantly affect the role of robots in our daily lives. As a softer, safer, and more environmentally robust alternative to “hard” robots, wearable robotic devices, exploratory robotic fish, and personal medical attendants could soon become commonplace for the general public.

Continue reading Soft Robotics: Humanizing the Mechanical

Superhero Technology for Super Kids

Researchers have begun using exoskeletons (similar to Iron Man’s suit) to aid children with cerebral palsy in danger of losing their ability to walk.

The problem…

The effect of crouch gait on human posture.
The National Center for Simulation in Rehabilitation Research, 2010

Cerebral palsy is a developmental disorder that affects the ability to move and maintain balance in the body. This neurological condition caused by damage to the brain before birth affects the body and muscles in ways that make it hard for those affected to walk as they get older. There are several different biological symptoms that lead to the difficulty of walking. According to the Mayo Clinic, these issues can include stiff muscles (spasticity), loose muscles, exaggerated reflexes, lack of muscle coordination (ataxia), and the presence of involuntary muscle movements.

These issues compound as children grow older and the normal movements needed for walking can be lost. Specifically, spasticity leads to continuous contractions causing a permanent deformation of the muscles in the legs. For those with cerebral palsy it is seen in the form of crouch gait (pictured above), where patients’ knees bow inward, It is common for those with cerebral palsy to lose their ability to walk when they reach adulthood due to crouch gait.

The solution…

Researchers from the NIH Clinical Center Rehabilitation Medicine Department looked to attack these problems by using exoskeletons to provide a rigid, mechanical, and guided support for the body. The goal of the exoskeleton was to simply assist the participants by alleviating the muscles’ desire to cause a bending of the knees. However, this needed to be done while the participants still had full control of their own walking.

Functional & Applied Biomechanics Section, Rehabilitation Medicine Department, NIH Clinical Center, 2017 

The exoskeleton was tested on seven patients with cerebral palsy, aged 5 through 19, who had been diagnosed with crouch gait, but still had the ability to walk at least 30 feet without crutches or other forms of assistance. The results showed that patients did not lose their ability to use their own muscles and increased their knee angle positively by an average of 13 degrees and a maximum of 37 degrees. This creates a sturdier posture that is conducive to a longer life of walking.

The future…

The use of an exoskeleton as treatment for crouch gait is both promising and needed. Current treatments include physical therapy, surgery, or the use of muscle relaxers. Physical therapy has not proved to be effective in the long term, while surgery and the injections of muscle relaxers are invasive and painful for patients.

The exoskeleton technology is still young. Researchers want to extend the tested time with their current patients, create exoskeletons that can be used outside of a clinical environment, and attempt to use the technology on those who have already started losing movement.

There is hope that this technology can significantly help these children. Exoskeletons have been used to help restore movement in paralyzed adults during rehab for strokes or spinal cord injuries.

At the 2014 World Cup, a paraplegic man kicked a soccer ball while wearing a robotic exoskeleton. Additionally, researchers at Carnegie Mellon have developed walk aiding ankle bracelets that can be worn outside of a lab and adjust their movements to each user’s needs.