Auburn student’s ergonomics model helps GM produce ventilators

Published: Aug 7, 2020 9:50 AM

By Cassie Montgomery

When the government invoked the Defense Production Act, the manufacturing of ventilators and other important medical equipment to aid in the fight against the novel coronavirus was taken up by multiple automotive companies, including General Motors. In partnership with the U.S. Department of Health and Human Services, a GM production line that normally produced automotive parts was rapidly transformed to produce ventilators.

To ensure that the physical demands of the new ventilator line did not place workers at an unacceptable risk of injury, GM relied upon a new ergonomics evaluation model developed by Murray Gibson, Auburn University doctoral student in the Department of Industrial and Systems Engineering’s Occupational Safety and Ergonomics Program. Gibson’s model is the Recommended Cumulative Recovery Allowance (RCRA).

“The RCRA calculates the recovery time, in seconds, necessary for a muscle, or muscle group, to recover after applying a force,” Gibson explained. “The higher the force and the longer the duration, the more recovery time is necessary to prevent unacceptable levels of localized muscle fatigue.”

Gibson developed the RCRA model in 2016 while working as an ergonomics consultant at his firm, Saturn Ergonomics Consulting located in Auburn.

“I was frustrated by the limitations of existing evaluation models,” he said. “After months of research and reviewing hundreds of papers, I came across an equation by noted researcher, Dr. Jim Potvin. I built off of Dr. Potvin’s equation and derived a new multi-task evaluation model, the RCRA. Soon after, he and I formalized, published and introduced the RCRA model.”

The excitement of developing the RCRA inspired him to return to Auburn after earning his bachelor of science in 1991 and master’s degree in industrial and systems engineering in 1993. His doctoral advisor, Richard Sesek, the Tim Cook Associate Professor of Industrial and Systems Engineering, described Gibson as the “most creative and practical student” he has ever taught.

Prior to the RCRA, most ergonomic evaluation tools assumed work was single-task – that a worker does the same thing every time. The RCRA is a multi-task evaluation model, capable of modeling a variety of tasks with different forces, different frequencies and varying durations in a single calculation. The model calculates the contribution of each task, clearly identifying which is the highest priority for improvement.

In the rapid rollout of their ventilator line, GM needed to efficiently evaluate the exposures of individual work stations, as well as evaluate the overall cumulative exposure to employees throughout the work shift. The RCRA was the tool they needed. Gibson had recently met one of the GM engineers involved in the ventilator project line through LinkedIn. The engineer asked him to critique their RCRA analysis. Afterward, he was invited to present to GM’s entire ergonomics group.

“GM’s production rate by early May at the Kokomo, Indiana plant was 20 ventilators per hour. The incredible feat was getting the line up and running in just a few weeks,” he said. “This is a neat example of how ergonomics research taking place at Auburn University is helping to fight the COVID-19 crisis.” 

Media Contact: Cassie Montgomery,, 334.844.3668
Murray Gibson, industrial and systems engineering doctoral student

Murray Gibson, industrial and systems engineering doctoral student

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