Engineers identify usability barriers in workplace exoskeleton systems

Wearable exoskeletons can help reduce physical strain in the workplace and protect employees from injury, but the technology has yet to achieve widespread adoption. A new study published in PLOS One by engineers at The University of Texas at El Paso may explain why: The technology is still too complex and cumbersome for everyday use. 

"Our research suggests that a critical factor influencing exoskeleton success may be largely overlooked: how easy they are to assemble, put on, and take off," said UTEP's Arunkumar Pennathur, Ph.D., who led the study. "The exoskeletons that win in the workplace may not be the most sophisticated ones, but the ones a worker can actually get on quickly and correctly."

Pennathur is an associate professor in the Department of Industrial, Manufacturing and System Engineering who leads a UTEP lab focused on human performance and behavior. One of its goals is to help workers in high-strain industries like health care, manufacturing and construction. 

The study evaluated four occupational exoskeleton systems currently in the marketplace - the Ironhand, Chairless Chair, Skelex and Laevo - and examined the amount of time it took participants to assemble, don, remove and disassemble each device. The UTEP team also analyzed the number of procedural steps, the number of parts involved and usability issues that users encountered during setup.

They found that the simplest device took 39 steps to set up, while the most complex took 110 steps. Each additional step increased completion time - with assembly time ranging from six-and-a-half minutes to 25 minutes - while usability problems further slowed performance with failure rates of up to 49% for one device.

A device that's helpful to wear from a biomechanics standpoint is useless if it takes half an hour to assemble or needs a second person to put on."

Arunkumar Pennathur, University of Texas at El Paso

The study was done in a lab setting with engineering students serving as participants and plenty of time to spare. 

"The natural next step is to test these devices under real-world conditions - actual workers, time pressure, busy environments, and repeated use across a full shift, where setup time really starts to cost money," said Jessica Sanchez-Balandran, the lead co-author in the study said. 

The team hopes their findings help guide the next generation of exoskeleton design for manufacturers seeking to bring exoskeleton technology from the research lab to the workplace. Even if an exoskeleton effectively reduces physical strain, workers may be reluctant to use it if setup is time-consuming, confusing or prone to errors, they said. As a result, usability represents a critical barrier to workplace adoption.

Pennathur said, "Our message to designers is this: Reduce the number of steps, eliminate the need for special tools and body measurements, build in self-aligning connections and provide clear 'you got it right' feedback, and make sure one person can do the whole thing alone."

Contributors to the research are UTEP students Alejandra Martinez Fernandez and Laura Tovar, and Associate Professor Priyadarshini Pennathur, Ph.D.