Many health and safety professionals think of wearable technology in terms of “sensor” instrumentation – such as monitoring devices for body temperature or for sampling air contaminants. However, exoskeletons have elevated this technology to the level of human/robotics interaction. For many years, comic books and more recently Hollywood, have capitalized on these futuristic concepts (for example, The Avengers Iron Man^® series). But with the latest available technology, some of these uses are starting to become a reality.

Exoskeletons have been around in various forms since the 1800’s. One of the first-generation uses was by the military, and now both the U.S. Army and Navy are experimenting with this technology to enhance the capabilities of service personnel.

In the medical field, exoskeletons have assisted both medical providers (such as surgeons’ use to reduce fatigue during surgery) and patients with mobility issues. These advances are critical to improving quality of life issues. Exoskeletons have been designed for use on patients with spinal cord injuries, Parkinson’s disease and multiple sclerosis.¹ Unfortunately, since many of these devices are still in the development phase, their costs reflect this and can be in the $50,000-$100,000 range.

Industrial uses of exoskeletons are now catching up; with more versions still under development. The most common applications are in industries such as vehicle manufacturing assembly lines where workers must engage materials traveling above shoulder level. Fortunately, the industrial version cost range is in the more manageable neighborhood of $4,000-$7,000.²

What Are Exoskeletons and How Do They Work

According to the National Institute for Occupational Safety and Health (NIOSH), exoskeletons can be used to amplify the physical force of a worker’s arms and shoulders and reinforce or protect the lower back. Some manufacturers claim the devices can also boost productivity and work quality while reducing the risk of work-related musculoskeletal disorders (MSDs).³

Types of industrial exoskeletons include:

• Back-assist exoskeletons that assist during lifting or static holding tasks to help workers maintain correct posture and support the lumbar spine
• Shoulder-assist and tool-holding support exoskeletons used to assist in holding heavy tools or to support upper extremities during sustained overhead work
• Leg-assist devices that support the ankle, hip, or knee joint while moving or carrying a load; or serve as an alternative to a chair to provide relief from standing for long periods of time ³

Some exoskeletons are powered by electric motors/batteries, hydraulics, pneumatics, or a combination of these power sources. In addition, some use simple mechanical advantage – such as cams and pulley-type systems – that utilize power generated by the wearers themselves. The latter is important when the technology is used in areas where appropriate electrical ratings are required.⁴

Although limited in scope, some manufacturers of exoskeletons have conducted their own research to demonstrate the benefits to workers. EMG (electromyography) measurements were used to show how the exoskeletons reduced fatigue and helped the worker maintain certain postures which can ultimately reduce the likelihood of injury.⁴ However, there are potential issues with purchasing “off-the-shelf versions” − including size limitations for smaller workers; and protecting the devices from potentially harmful powders and other chemicals, for example, in the pharmaceutical industry. Additionally, workers must be trained in exoskeleton uses, limitations and potential hazards.

Due to some of these issues, NIOSH believes more studies are needed and has planned research projects to study the following:

• Application of exoskeletons in the mining industry
• Effects of back-assist exoskeletons in manual materials handling in the wholesale/retail trade sector
• Evaluation of exoskeleton systems in reducing hand-transmitted vibration
• Feasibility of using exoskeletons for safe patient handling in the healthcare sector
• Longitudinal health effects of passive shoulder exoskeletons in the manufacturing sector
• Safety hazards potentially associated with exoskeletons while working on elevated surfaces in the construction sector ^{3, 5}

Potential Benefits vs. Risks

According to NIOSH, exoskeletons may also reduce both spinal muscle loading and muscle fatigue during dynamic lifting tasks. Upper extremity exoskeletons, along with an appropriate ergonomics program, may help prevent shoulder injuries or MSDs. Despite their potential to reduce or prevent MSDs, some other risks associated with exoskeleton uses were identified during the 2018 NIOSH National Symposium, including:

• Chemical burns or skin irritation caused by corrosive fluid leaks from batteries
• Compressed nerves and pressure wounds from prolonged use
• Cumbersome or unwieldy exoskeletons that limit a wearer’s ability to avoid collision with a moving object
• An exoskeleton that may increase the length of time a worker can hold a tool but increase exposures to hand-transmitted vibration, noise and respirable toxins
• An increased load to the spine while using heavy tools
• Over-reliance on exoskeletons to address risks that could be eliminated through engineering controls
• Powered exoskeletons that move the wearer’s joints beyond normal range of motion
• The shifting of loads from the shoulders to the legs and lower back ^{3, 5}

In 2017, NIOSH and several other federal agencies formed the ASTM Committee F48 on Exoskeletons and Exosuits to develop voluntary consensus standards for exoskeletons and exosuits. The group’s subcommittees are developing guidance and voluntary standards to address ergonomics, performance, quality, and safety issues.³

Finally, before considering exoskeletons, the identified task should be thoroughly assessed prior to going directly to a PPE solution. Use of a traditional “hierarchy of controls” (elimination, substitution, engineering, and administrative) is always the preferred option for making any task safer.

Additional Resources

HETI’s Certified Industrial Hygienists and safety professionals are available to assist employers with a variety of services – including ergonomic assessment of the workplace. If recommended, HETI can also assist in identifying and sourcing exoskeletons that make sense for the organization.

References:

¹ Daniel P. Ferris, Aaron J. Young, in Encyclopedia of Biomedical Engineering

² https://ohsonline.com/Articles/2018/10/01/Industrial Exoskeletons-What You’re Not Hearing

³ https://blogs.cdc.gov/niosh-science-blog/2020/01/07/industrial-exoskeletons/

⁴ Professional Safety, March 2019, “Exoskeletons Used as PPE for Injury Prevention”, Terry Butler and Jason C. Gillette

⁵ NIOSH 2019 Proceedings of 2018 ErgoX Symposium: Exoskeletons in the Workplace-Assessing Safety Usability & Productivity, NIOSH Publication No. 2020-102