Exoskeletons and the Swing Phase: Finding the Right Balance

You're walking or climbing stairs while wearing a knee brace. You wouldn't want it to interfere with your movement, right? That's the challenge for exoskeleton designers. They need to make sure their devices don't get in the way during the swing phase of walking or stair climbing. But how much is too much? No one really knows how sensitive people are to small forces at the knee during this phase.Researchers set out to find the answers. They tested different levels of stiffness and damping in a knee brace while people walked and climbed stairs. They measured how the body moved, how muscles worked, and how people felt. They found that people could feel the difference when the knee brace had more than 1. 76 Nm/rad of stiffness while walking, and 2. 95 Nm/rad while climbing stairs. For damping, the limit was about the same for both activities, 0. 29 Nm/rad/s. These numbers are important. They give designers a target range for creating exoskeletons that help, not hinder, our movements.