Reflective markers are attached to a blue 3D printed apparatus above and below the user’s knee, as well as two metal plates on the exoskeleton leg. (Credit: N. Hanacek/NIST)

Researchers at the National Institute of Standards and Technology (NIST) have developed a new measurement method to test whether an exoskeleton and the person wearing it are moving smoothly and in harmony.

In a new report, the researchers describe an optical tracking system (OTS) not unlike the motion capture techniques used by filmmakers to bring computer-generated characters to life.

The OTS uses special cameras that emit light and capture what is reflected back by spherical markers arranged on objects of interest. A computer calculates the position of the labeled objects in 3D space. This approach was used to track the movement of an exoskeleton and test pieces, called “artifacts,” fastened to its user.

After fixing markers to the legs and plates, the team used the OTS and a digital protractor to measure knee angles throughout their full range of motion. By comparing the two sets of measurements, they were able to determine that their system was capable of accurately tracking leg position.

The tests also established that their system could calculate the separate motions of the legs and exoskeletal plates, allowing the researchers to show how closely aligned the two are while moving.

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Medical Design Briefs Magazine

This article first appeared in the October, 2020 issue of Medical Design Briefs Magazine.

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