NIOSH Notes Lack of Study on Industrial Exoskeletons

Despite the growing introduction of industrial exoskeletons across several industry sectors, their benefits and risks have not been well studied, the National Institute for Occupational Safety and Health (NIOSH) recently said in a scientific journal.  Few studies have been made of the health and safety implications of using wearable exoskeletons, NIOSH said in commentary in the December 2019 issue of the American Journal of Industrial Medicine.

Wearable exoskeletons are used to amplify the physical force of workers’ arms and shoulders and reinforce or protect the lower back. Manufacturers claim the robotic devices boost productivity and work quality while reducing the risk of work-related musculoskeletal disorders (MSDs), the institute said in a NIOSH Science Blog post.

Types of exoskeletons include:

• Back-assist exoskeletons to assist during lifting or static holding tasks help workers maintain correct posture and support the lumbar spine.
• Shoulder-assist and tool-holding support exoskeletons can be used to assist in holding heavy tools or to support upper extremities during sustained overhead work.
• Leg-assist devices 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.

Robotic exoskeletons are powered by electric motors, hydraulics, pneumatics, or a combination of the three technologies.

Existing studies have only involved small numbers of participants—many studies had fewer than 15 participants—usually in laboratory settings. The limitations of studies can make it difficult to draw conclusions about the benefits of industrial exoskeletons and their role in injury prevention, according to NIOSH.

NIOSH 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 and 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; and
• Safety hazards potentially associated with exoskeletons while working on elevated surfaces in the construction sector.

Potential Benefits, Risks

Exoskeletons may reduce 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 the potential for exoskeletons to reduce or prevent MSDs, risks associated with exoskeleton use have been reported, 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; and
• The shifting of loads from the shoulders to the legs and lower back.

NIOSH and several other federal agencies participate in the ASTM Committee F48 on Exoskeletons and Exosuits, formed in 2017, 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.

Exoskeletons and exosuits may have a wide range of consumer, industrial, emergency response, medical, and military applications.