The Potential of Exoskeleton Technology

Wyatt Wingenroth

THE POTENTIAL OF EXOSKELETON TECHNOLOGY

Wyatt Wingenroth ()

Wyatt Wingenroth

INTRODUCTION: MECHANICAL EXOSKELETON: IMPROVING THE LIVES OF PATIENTS WITH LIMITED MOBILITY

One of the most important issues in modern medical engineering is the development of a mechanical exoskeleton that will augment the capabilities of humans. Exoskeletons are defined as mechanical devices that are worn by an operator and work in conjunction with the movements of the operator [1]. These exoskeletons can provide a wide range of benefits for people that have access to them. However, according to Dr. HomayoonKazerooni, a professor of mechanical engineering at UC Berkeley and designer of exoskeletons for Ekso Bionics, most commercially available exoskeletons cost from $100,000 to $130,000. For those people suffering from physical disabilities that prevent movement, this is an impossible number to reach because of the lack job opportunities due to their physical disabilities. However, Dr. Kazerooni also believes that it is possible to make these exoskeletons more economical, making the production cost near $10,000 [2]. If this research is continued, not only will this technology be available to better the lives of those with disabilities, it will also improve the medical field through improving rehabilitation techniques, and lead to further innovations in many other fields. This paper will be focusing on all of the different possibilities that can be achieved through continued research in the field of exoskeletons to prove that it is a technology that must continue to be researched.

MEDICAL APPLICATIONS

Increasing Mobility of Physically Disabled Subjects

The foremost application of exoskeleton technology should be the creation of exoskeletal systems that will allow paraplegics to regain the ability to walk. I know a paraplegic man who had the use of his legs taken in an accident when he was younger. I feel terrible when I see him forced to crawl from room to room in his own house, and I know that technology such as this could facilitate his life, as well as the lives of many other disabled people. This is why the work of Dr. Kazerooni and other researchers like him must be continued. Not only will this research make it possible for many people to achieve the power to walk again, but also open the doors for further research and the betterment of existing technology. For example, Dr. Kazerooni has already contributed to the improvement of exoskeletons. He assisted in the development of earlier exoskeletons, including the ExoHiker and ExoClimbermodels in 2005, and the Human Universal Load Carrier (HULC) in 2008 [2]. Models such as these are being improved by many research teams, including that of Michael Goldfarb, professor of engineering at Vanderbilt University and designer of the Vanderbilt exoskeleton model. The Vanderbilt team’s model weighs half as much as most current exoskeletons [2]. This would make the exoskeleton much more portable and much simpler to use. The Vanderbilt model uses three modular pieces that snap together without the use of any tools, which makes it much easier for anyone to transport the exoskeleton wherever they go [2]. It also improves the muscular condition of patients because it does not include a backpack containing the controls like many other models have [2]. Instead, it only covers the hips and legs, makingthe model more portable and putting pressure on the legs, which alleviatesstress on the back and improves the leg muscles of operators through the applied pressure. Exoskeletons such as these could go far in not only improving the lives of many disabled people by giving the ability to walk again, but also in simplifying their lives by making the exoskeletons more practical and simpler.

Rehabilitation of Patients with Physical Disabilities in Extremities

Exoskeletons have also become more extensively used in the field of rehabilitation, specifically for patients that have lost the use of their extremities. For example, strokes often cause long-term physical disabilities in adults [3]. After a stroke, brain cells partially die, resulting in the loss of many motor functions in areas such as the hands and fingers [2]. Exoskeletons are now being researched and used as a method of rehabilitation to help patients regain the ability to use their extremities in the event of a loss of control of certain body parts. In a 2011 Italian experiment, a module used to improve control and strength of the fingers was tested [3]. The HANDEXOS model used in the experiment was tested to see if it was wearable by all subjects to ensure that the model could be commercially successful if the later tests produced positive results. Once it was determined that the HANDEXOS model could be worn by all subjects, the tension and flexion dynamics were then tested to determine the effectiveness of the HANDEXOS model’s capabilities to assist in the use of extremities. Testing showed that the HANDEXOS was more effective than existing hand exoskeletons while also being a more lightweight device [3]. Continued research and production of these models would increase the likelihood of stroke victims being able to recover the motor functions that are lost after a stroke.

Assistance in the use of Arm Muscles

Exoskeletons have also been used as a tool in assisting with the rehabilitation and strengthening of arm muscles. In a 2010 study published by ASME (American Society of Mechanical Engineers), a group of researchers tested how drastically arm movements could be assisted through the use of an exoskeleton. The main focus of the experiment was the testing of a common arm motion: an arm curl with a dumbbell [1].The motion was tested in the form of a standard arm curl; an arm curl with constant assistance, created by a force applied at the elbow; an arm curl with variable assistance, which comes from a force that varies with the flexion of the arm; and an arm curl assisted by an exoskeleton. The use of the exoskeleton allowed for much less force from the muscles to be used, proving that the exoskeleton was the most effective method of reducing the force placed on an arm during simple actions [1]. This will allow for improvements to rehabilitation in those who have experienced severe damage to an arm or muscle. The use of exoskeletons in this way will allow for dead brain cells to recover through motion of the arms. When brain cells are dead as the result of a stroke, they can be recovered through repetition of motion, which is typically prevented because of the lack of control of the body after a stroke [4]. When an exoskeleton is used in this process, it allows motion to occur and the motion in the arms due to the exoskeleton allows the brain cells to be recovered so the body does not lose all functionality in any of the affected areas.

ADDITIONAL APPLICATIONS

Military Exoskeleton Usage

The military has also investigated the use of exoskeletons, particularly for the purpose of augmenting the abilities of humans. Powered exoskeletons have the potential to enhance the strength and endurance of normal humans [5]. These exoskeletons can be used in conjunction with muscles to apply additional torque when performing actions to, in essence, make the operator of the exoskeleton stronger [5]. The military has also investigated the use of Dr. Kazerooni’s HULC system, which allows for users to carry loads of up to two hundred pounds for an extended period [2]. This would be incredibly helpful for soldiers that are deployed in dangerous parts of the world, because it would remove the strain of carrying all of their gear, and allow them to be more alert and effective because of the reduction in fatigue.

Applications in Industry

It is even possible for exoskeletons to be used in many industries. For example, in futuristic science fiction, a mechanical being or person controlling a mechanical suit are often sources of manual labor. However, with the potential to augment the strength of humans, a future similar to this is not far away. If an exoskeleton is developed to cover the entire body, it could eventually grow into a similar form of suit to allow for incredible amounts of physical labor to be performed by one person. Research on exoskeletons could also lead to advances in safety for rescue workers. If exoskeletons are improved, they could eventually evolve into full-body suits that provide protection for firefighters that must rescue people in danger in burning buildings.

CONCLUSION

Exoskeletons are an incredible technology that we must continue to research. It can provide amazing health benefits, from allowing paraplegics to walk, to helping stroke victims regain motor functions. Exoskeletons can also be used to improve the military and could lead to even further improvements in industry and safety. However, many of these things are out of reach economically, which is why the work of groups such as Dr. Kazerooni’s and Dr. Goldfarb’s must be continued so all people can have access to exoskeletons.

REFERENCES

[1] P. Agarwal, V. Krovi, L. Lee, F. Mendel, M. Narayanan. (2010). “Simulation-Based Design of Exoskeletons Using Musculoskeletal Analysis.” Proceedings of the ASME 2010 International Design Engineering Technical Conference. (Online Report).

[2] L. Mertz. (2012). “The Next Generation of Exoskeletons.” IEEE Pulse. (Online Article).

[3] M. Carrozza, A. Chiri, F. Giovacchini, S. Roccella, F. Vecchi, N. Vitiello. (2012). “Mechatronic Design and Characterization of the Index Finger Module of a Hand Exoskeleton for Post-Stroke Rehabilitation.” IEEE/ASME Transactions on Mechatronics. (Online Article).

[4] A. Brown. (2013). “Modular Exoskeleton Set for Commercialization.” Mechanical Engineering Magazine. (Online Article).

[5] M. Carrozza, S. De Rossi, T. Lenzi, N. Vitiello. (2012). “Intention-Based EMG Control for Powered Exoskeletons.” IEEE Transactions on Biomedical Engineering. (Online Article).

ACKNOWLEDGMENTS

I would like to thank Connor Martin, Andy James, Chris Greathouse, Andrew Gackenbach, and Evan Skapik for inspiration and providing a good work environment as we shared a work space.

I would also like to thank the librarians for showing me more effective ways to research a topic.

I would also like to thank my roommate for his constant encouragement while I worked on this paper.