Help or hindrance?

Exoskeleton not equally suitable for all work

In view of the shortage of skilled workers and demographic change, exoskeletons are becoming increasingly relevant.

(Bild: YouTube)

Hard physical work is not healthy for anyone in the long term - sooner or later, this will lead to back, joint or muscle problems. So-called exoskeletons promise a remedy. Researchers in Graz have now investigated whether and for which activities the technology actually provides support.

In the ExoFitStyria project, the Institute for Innovation and Industrial Management at Graz University of Technology worked with eleven small and medium-sized enterprises in Styria to investigate in which areas exoskeletons provide real relief and in which activities the relief was only slight or the supposed help was even more of an obstacle. 

Advantage for work with a high degree of standardization
Result: "The more consistent my work processes are and the more standardized the activity is, the better the support provided by an exoskeleton is, both objectively and subjectively. This is particularly true if my main activity is only rarely interrupted by secondary activities," says Matthias Wolf from the Institute for Innovation and Industrial Management.

For the study, the research team used passive exoskeletons, which are designed to reduce strain in critical areas with springs and dampers. In contrast to their active counterparts with electric motors, they are much lighter, easier to handle and, with a purchase price of around 2,000 to 4,000 euros, also considerably cheaper, making them more suitable for small and medium-sized companies.

The researchers took a close look at 14 different activities that could be categorized as warehouse work in order logistics, welding, oxy-fuel cutting, coating, assembly of bulky components and industrial painting work.

For the objective measurements, the team used electromyography (EMG) to determine the electrical activity in muscles and thus their strain. The subjective evaluation was carried out using questionnaires on which the test subjects rated the factors of perceived workload, usability and acceptance as well as advantages and limitations.

Most help overhead
The best results in a combination of objective and subjective evaluation were achieved for overhead painting work with shoulder or back support. Here, the scores were positive for usability as well as for reducing the workload and integration into the workflow. Standardized metal and metal cutting work, silo welding and storage work requiring a movement radius of less than five meters also scored well.

The worst results were achieved in storage work with a large movement radius of more than five meters and powder coating work on large surfaces, both of which were carried out with shoulder support. There were too many movements where the user had to work against the support of the exoskeletons. The mechanical assistants are also bulky for longer distances and make it difficult to move around. Constantly putting them on and taking them off would take too much time.

Activities with a movement radius of more than five meters that were carried out with back support landed in the middle of the field: Warehouse work, the assembly of bulky components and loading work. Objective and subjective assessments were not always consistent here, and the improvements were not particularly great. For example, the EMG measurements showed clear muscle relief, but the test subjects did not feel comfortable.

Increasing relevance
"In certain areas of application, exoskeletons can help to relieve the strain on workers and keep them working longer and healthier," explains Wolf. "In view of the shortage of skilled workers and demographic change, this is becoming increasingly relevant. However, it is important to first evaluate whether the job in question really lends itself to this."