A Technological Journey To Help Paraplegics Walk

For more than a millennium, paraplegics and other chronically immobile people have had no choice other than a wheelchair for providing the assisted mobility they need to move about and function in society. While great strides have been made in making cities, buildings and recreational areas more accessible to physically disabled people, all of these advances focus on the wheelchair as the primary means for moving the handicapped from place to place. Despite the fact that wheelchair technology has evolved greatly in recent years—with the development of advanced wheelchairs ranging from remote-controlled, self-propelled models to those specifically designed for use in athletic competitions—a wheelchair can never provide what every mobility-impaired person actually wants: the ability to stand up and walk.

Dr. Amit Goffer, inventor of the ReWalk™ exoskeleton and founder of Argo Medical Technologies, Ltd. (Haifa, Israel) discovered that reality when injuries sustained in a recreational vehicle accident left him paralyzed. Dr. Goffer came to learn firsthand what it is like to live in a wheelchair, which can cause serious health issues, including problems with pressure sores, the urinary, respiratory, cardiovascular and digestive systems, as well as osteoporosis and mental health deterioration. “It amazed me that in the 21st century—where change is measured in nanoseconds—there remained over five million people in the developed world for whom little had changed since the early 1900s,” Dr. Goffer said. “The sedentary wheelchair—with all its known detrimental impacts on physical and mental health, productivity and inclusion in society—was the only standard for assisted-mobility.”

With his personal experience and years of work founding and building a medical imaging technology company, Dr. Goffer set out to change that state of affairs by embarking on a technological journey to create an upright alternative to wheelchairs that would enable paraplegics and other mobility-impaired people to stand up and walk. As a man of vision and determination, he recognized that helping people who had lost the use of their legs but retained the use of their arms represented a first step in eventually helping those with his condition. Dr. Goffer founded Argo (www.argomedtec.com) in 2001 for the purpose of developing the ReWalk exoskeleton, a wearable, motorized, quasi-robotic suit that allows paraplegics and other mobility-impaired people to stand, walk and even climb stairs. Throughout Argo’s first five years of operation, Dr. Goffer labored on the concept on his own with limited resources and low levels of investment. During this time, Dr. Goffer developed the first proof-of-concept prototype. That effort was rewarded by acceptance into TechnionSeed (www.technionseed.co.il), a technological incubator located in Haifa’s MATAM High-Tech Industrial Park that is associated with the Technion, Israel’s renowned Institute of Technology and the birthplace of some of the world’s most innovative technologies. Residence in the incubator facilitated an initial round of investment in 2006 by the Chief Scientist Office of Israel’s Ministry of Industry, which was supplemented by two Israeli venture capital firms: VitaLife SCP VC and ProSeed VC.

Refining the Concept

To complete the industrial design for the product, as part of the process of developing a commercially viable, functional design that was ready for clinical trials, Argo contracted with Taga Innovations, Ltd. (www.tagapro.com), one of the largest and most successful design, engineering and product development consultancies in Israel. Because the process of obtaining certifications from government regulators in Israel, Europe and the U.S. often takes years to complete, the company needed to compress the development cycle in order to retain its advantage of being first-to-market with this type of exoskeleton.

“The ReWalk is the first product of its kind,” explains Uri Attir, Argo’s CEO. “Although much work has gone into the use of exoskeletons by military researchers who are trying to create super soldiers, the ReWalk’s use of an exoskeleton for assisted mobility of physically impaired persons represents a true innovation. One of the reasons we engaged Taga was to accelerate the development process so we could maintain and extend our lead over potential competitors.”

Taga assumed responsibility for creating a viable industrial design in less than two years. According to Taga Chief Industrial Designer, Nimrod Sapir, the consultancy began the program with a period of intensive research followed by industrial design, virtual simulation and physical testing. “Our first order of business was to research the state-of-the-art in robotics, limb-exercising machines for the disabled, and exoskeletons. While we took some of our inspiration and ideas from what we learned—such as how to create working joints and use straps to connect human limbs with mechanical motion—the industrial design we came up with together with Argo’s input was unique.”

Sapir began the highly iterative process of creating a range of functional designs using SolidWorks® (Concord, MA) 3D CAD software. He attributes much of the speed of the design effort to working in SolidWorks as the common CAD development platform for all vendors, partners and contributors. “SolidWorks provided us with the parametric design, visualization and design communication tools we needed to collaborate with Argo and other partners in an efficient manner,” Sapir said.

Virtual Prototyping via Simulation

Taga was able to complete the industrial design on the ReWalk exoskeleton so quickly because it used SolidWorks design software to combine virtual prototyping and simulation functions with advanced surfacing and industrial design modeling capabilities. The team downloaded a model of a human being from 3DContentCentral.com, a free online directory from SolidWorks Corporation that offers downloadable 2D and 3D CAD parts and models from leading component manufacturers and SolidWorks users. Working with the human model, Taga was able to design, simulate and prototype the exoskeleton entirely in software, which saved time and reduced costs.

“There are a lot of challenges to design something that imitates human walking, including universal fit for a broad range of user height and weight measurements, as well as a low profile that is both contemporary and user friendly,” stressed Taga Design Engineer Assaf Barel, who completed the bulk of the engineering for the ReWalk exoskeleton. “SolidWorks enabled us to be creative in addressing all of these challenges. The finished product is strong, compact, lightweight and works like a human body.”

“We had to use motorized assemblies that created substantial forces to move sizable loads, but at the same time we had to make sure the mechanism did not hurt or injure the person who was wearing it,” noted Jeffrey Meyer, vice president of engineering at Taga. “In SolidWorks, we were able to test different joints on a human model to study how the exoskeleton interacts with a person and avoid problems like bending the knee in the wrong direction.”

Working in this manner, the Taga team gleaned important information about the design, such as the fact that the greatest loads are generated while climbing stairs due to the need to stand and push off of one leg. “Because we were able to visualize what would happen when a person climbs a set of stairs wearing the exoskeleton in SolidWorks, we came to understand things like how much force we needed, how strong certain parts needed to be, and what material we should use to ensure strength while minimizing weight. We also discovered that we needed to provide support under the thigh and duplicate the action of extra muscles in the ankle joint,” Meyer said. Because Taga personnel performed simulations in the same modeling environment in which designs were created, the team saved time associated with numerous design iterations. “My part was to use design and surfacing tools to produce shapes that were both aesthetically pleasing to the eye and ergonomically comfortable for the user,” Sapir pointed out. “The other engineers on the team were able to simulate, analyze and improve design performance more quickly and easily because we were all working in SolidWorks.  This type of collaborative approach resulted in the perfect marriage of a modern, fashionable form with an ergonomic fit and validated function.”

Working in the SolidWorks CAD environment also facilitated design reviews and Argo approvals, which Taga CEO Amit Barak facilitated as the project leader and primary liaison. Because Argo also uses SolidWorks software, the company was able to combine and coordinate Taga’s industrial design with the ReWalk’s mechanical and electronic systems and controls, all within the same design environment.

Delivering a Major Innovation in Assisted Mobility

After a compressed two-year development cycle, the B-1 prototype of the ReWalk exoskeleton entered clinical trials at the Neurological Rehabilitation Department of the Chaim Sheba Medical Center, the largest hospital in Israel, in February 2008.  By using an integrated design and simulation environment to evaluate the design before manufacturing a single part, Taga created a functional industrial design in the B-0 prototype that was more than sufficient following a few modifications to the mechanics for beginning patient trials with the B-1 prototype. “We are very proud of the fact that we conducted most of the simulations of forces and motion in SolidWorks and that the design worked the first time,” Meyer stressed. “It’s a credit to the accuracy of the SolidWorks simulations that we could carry out several design revisions and iterations in software—avoiding the delays and costs we would have incurred in building and testing physical prototypes—and produced a design that performed so well that we began tests with patients in just one month’s time.

Meyer added that the ability to show and visualize how the design functions and why design changes needed to be made in the SolidWorks 3D virtual environment contributed to the accelerated development cycle and eliminated the need for expensive prototypes. “With SolidWorks, we could visualize how parts would interact with the human body and test for interferences by performing mechanical simulations. Saving on prototypes was certainly important, but even more critical was the need to shorten the development cycle and accelerate the start of clinical trials, so Argo could achieve its goal of being first-to-market,” Meyer said.

Following the first round of clinical trials in Israel, the ReWalk is scheduled for major clinical trials in Europe and the United States in 2009, with commercial availability slated for sometime in 2010. The industrial design has already captured to major awards: the 2007 Annual Design Award in the Concept Category from the Israeli Ministry of Industry and Trade, and the 2007 Best Project Award for Design & Engineering from SolidWorks Israel.

“The successful introduction of the product will represent a major innovation in assisted mobility, give paraplegics and other mobility-impaired individuals a life outside of a wheelchair that allows them to interact eye-to-eye with their fellow men, and fulfill the first step in Dr. Goffer’s technological journey to leverage technology to help the handicapped and the disabled to walk.”

Freelance writer Tim Trainer is principal of Trainer Writing Services and has written about the CAD/CAM/CAE industry for more than a decade. For more information on SolidWorks, contact Nancy Buchino at (978) 318-5262.