Design Engineering

Robo-Vest looks to save us all from work-related injury

By Tom Renner   

Automation General Automotive Medical airframe Exoskeleton igus

Lightweight exoskeleton benefits health, productivity in manufacturing facilities


In certain professions, nearly 45 per cent of workers experience shoulder pain

Work-related musculoskeletal disorders (WMSD) are a huge problem for many businesses.

ore than 650,000 cases of WMSD cases are reported each year and represent 33 percent of every dollar spent on workers compensation. That translates to approximately $50 billion in lost productivity annually in the U.S., and nearly 70 million physician office visits each year, according to the Centers for Disease Control and Prevention.

In certain professions, nearly 45 percent of workers experience shoulder pain, resulting in missed days, decreased productivity and escalating healthcare costs for business. As a result, more businesses are using ergonomics researchers to closely examine personal lift assist devices.
One such device is the Airframe, a wearable, ergonomic exoskeleton manufactured by Levitate Technologies of San Diego. Originally designed for use by surgeons, the mechanical vest is now used extensively by professionals and skilled trade workers who are exposed to repetitive arm motions and/or stationary arm elevation. During use, the exoskeleton transfers the weight of the arms from the shoulders, neck and back to the core through pads that rest on the outside of the hips, thus relieving muscle and joint strain.

“The benefits of this device have been incredible,” said Terry Butler, former Director of Environmental Health & Safety at the Vermeer Corporation, a manufacturer of industrial and agricultural equipment in Iowa. “The team members who have used this tool are more than happy to use it and have seen more prolonged work activities without feeling fatigued by the end of their shift.”


Surgical Support
When engineer Mark Doyle designed the Airframe in 2013, there were no exoskeletons that allowed a surgeon to move freely while operating. Only stationary delivery systems were in use. Surgeons who used the wearable frame found it had a positive effect.

A study from an Internal Review Board at the hospital where surgeons used the device found fatigue in surgeons who wore the exoskeleton decreased by 50 percent in operations after 12 minutes, and the pain rate decreased by about 25 percent.

But when one major auto manufacturer discovered the benefits of the Airframe for its employees, Levitate switched its marketing focus and ramped up production.

“We became laser focused on manufacturing and our business plan switched,” said Joseph Zawaideh, the Vice President of Marketing and Business Development for Levitate. “We changed our focus.”

exoskeleton working magic for maunfacturing plants

The Airframe doesn’t require a power source, adding to the lightweight nature of the design

The Airframe is now being used in manufacturing plants in aerospace and airplane assembly, heavy machinery, shipbuilding, agriculture, paper and chemical industries. Even the U.S. Navy is using the Airframe for maintenance work. The exoskeleton has also been used extensively at one automobile manufacturing facility in the United States.

“They embraced the Airframe quickly and even mentioned that they do not want to go back to not using it,” Zawaideh said. “Users said that they appreciated that the Airframe is very low profile, lightweight and did not restrict motion.”

By transferring upper extremity load to the body’s core, the device helps sustain high quality performance, protects health and improves overall work conditions. “The difference between the Airframe and other exoskeletons now on the market is that it’s very lightweight, and extremely comfortable,” Doyle said. “It makes motion very natural. We worked hard to make it feel smooth and natural when being worn and activated.”

Reduced weight is key
Keeping the exoskeleton as light as possible was critical in its design. The weight of exoskeletons varies greatly – one currently being used by some military teams weighs staggering 68 kilograms (150 pounds). Lighter models weigh only 6.5 kg (14 pounds).

Providing an adequate power supply for exoskeletons is also one of the significant issues that has stymied many engineers. Doyle’s Airframe doesn’t require a power source, and while Levitate does not disclose the weight of the apparatus, its light weight enables users to wear the product for an average work day without effort.

“Asking human beings to wear a metallic frame and do their jobs is not an easy task,” Zawaideh said. “We needed something that was lightweight, low profile and could adjust to all the different mechanisms and synchronization. It required attention to detail on every screw and every bolt. Our mindset was if you don’t need it, don’t add it.”

As part of that lightweighting process, Doyle chose engineered plastic bushings manufactured by Germany-based igus. The company’s iglide G300 bushing, for example, provided a PV value of 12,000 (psi x fpm) when dry, a density of 1.46 g/cm³ and a high modulus of elasticity, 1,131,000 psi.
The device also includes bushings from igus’ T500, M250 and Z series. In testing, the Airframe exoskeleton generated heat which required that higher-heat rated bushings be used. The iglide bushings also offer the advantage of corrosion resistance and easy installation.

Improving Worker Health
Besides increased productivity and efficiency, the Airframe might also help workers stay healthy. A safety and ergonomic risk assessment at one auto manufacturer found that the Airframe reduced physical work stress by 20 percent.

Levitate also reported the findings of a study it conducted that measured the impact of wearing the Airframe during a series of physical activities that mimic common industrial tasks. During the study, objective measures of shoulder and neck muscle exertion and force were collected via electromyography (EMG) sensors placed on the muscles. Measures of dexterity were collected during tests, and subjective comfort and effectiveness data was collected.

The results indicated a statistically significant reduction in the muscle exertion required to perform the physical tasks, a slight increase in manual dexterity and an overwhelming preference regarding the comfort of the device. The device lessens muscle fatigue of the shoulder and, by supporting the upper arm and offloading weight to the hips, reduces spinal compression forces on the lower back.DE

Tom Renner is an award-winning former journalist who writes extensively on issues in manufacturing, engineering and building trades industries.


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