EXOSKELETONS

March 7, 2016


I have a dear friend and neighbor whose oldest son suffers with chronic back problems.  Several years ago he was involved in an automobile accident that left him with significant issues relative to mobility.  He has undergone three surgeries over the past few years, all of which have not improved his condition.   He is in constant pain.  On his best day, he can walk to his wheelchair. Chris is forty-six years old.

When I first read of medical exoskeletons I became very interested in the technology simply thinking that one day my friend may be able to walk comfortably with aid from these devices.  The progress made over the past few years is striking with technology improvements constantly in the news.

There is a huge need for applications designated for our “wounded warriors”.  According to the Paralysis Resource Center, relative to military involvement:

  • 54% of those who reported being paralyzed were males, while 46% were females.
  • 61% of those who reported being paralyzed due to a spinal cord injury were males, while 39% were females.
  • Males were nearly twice as likely (1.77) to incur a spinal cord injury as females.

“According to a study initiated by the Christopher & Dana Reeve Foundation, there are nearly 1 in 50 people living with paralysis — approximately 6 million people. That’s the same number of people as the combined populations of Los Angeles, Philadelphia, and Washington, D.C. And that number is nearly 33% higher than previous estimates showed.”

It means that we all know someone — a brother, sister, friend, neighbor, or colleague — living with paralysis.

A team of researchers in the Control Systems Laboratory, Department of Advanced Science and Technology, Toyota Technological Institute, Nagoya, Japan, have recently unveiled a new exoskeleton designed as a multipurpose assistive device that can be used for both power augmentation and passive and active robotic rehabilitation tasks.

While the overall mechatronic hardware was built several years ago, the control algorithm and software that is being used was built recently finalized.  If you are unfamiliar with the term mechatronic, I would like to offer a definition at this time as follows:

Mechatronics is a multidisciplinary field of engineering that includes a combination of systems engineering, mechanical engineering, electrical engineering, telecommunications engineering, control engineering and computer engineering.

Mechatronic Image

You can see from the logotype above, mechatronics involves several engineering and computer disciplines, all working together to provide operational ability to any electro-mechanical device.  Now, back to our story.

According to Barkan Ugurlu, PhD, who is co-leading the research activities at the Toyota facility, there are three design objectives:  1.) The exoskeleton is multipurpose, 2.) wearable and lightweight, and 3.) inexpensive to manufacture. To address wearability and weight, the researchers used laser molded resin in the upper body with an overall system that can be worn by an individual.  The system has adjustable link lengths to accommodate varying wearer heights. To contain costs, they kept the exoskeleton design simple. The system is actuated via electrical motors, with the control algorithm is built on top of a sensorless architecture. The researchers also used off-the-shelf joint-level compensation and control techniques that are already in the manufacture of robots and robotic devices.  Several designs may be seen as follows:

Exo Hardware

Exo Hardware (2)

While clinical experiments have not been performed, the system performance has been tested with able-bodied individuals, as well as with individuals who are obese and who are underweight. The system performance is not easily influenced by human-wearer parameters, Ugurlu said.

Soldier and Exo

You can see from the JPEG above an application used by an Army Captain to aid mobility.  These applications are happening each day with significant improvements each year.  The need is definitely there as you can see from the following fact:

In considering mobility, companies designing and providing the hardware have also considered lack of mobility for upper-body motion.  The digital below will indicate what is now available.  Please note, lighter, stronger and improvement relative to range of motion is the desired goal.

Exo and Upper Body

The exoskeleton development for the most part is still in the first prototype stage.  Researchers indicate they intend to introduce improved models as their work evolves, such as a model that can help patients with paraplegia walk. “I am specialized in humanoid locomotion and we are going to introduce some of the key techniques from this field to exoskeleton-based paraplegic walking support,” Ugurlu said. “This study is still an ongoing process….”

Upper and lower exoskeleton devices show how engineering and medicine combine efforts to improve the quality of life for individuals otherwise wheelchair-bound.  This is only one example of how technology is addressing human needs.

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