A motor-free exosuit cuts the energy cost of walking by 13.9%

A team led by Wei Yu at Hebei University of Technology in Tianjin has built a hip-assistive exosuit driven entirely by artificial muscle, with no electric motors and no pneumatics anywhere in the device. The work was published in Science Advances on 10 July 2026 (DOI 10.1126/sciadv.aec6917).

The actuator is a dielectric elastomer — a rubber that contracts under an electric field. The group reformulated it with highly polar compounds, which both strengthened the material and made it more responsive to the field, then drew it into cylindrical fibres as thin as 850 micrometres and as long as 250 millimetres. A single fibre lifts more than 400 grams, over 1,300 times its own mass. Two ten-fibre bundles weighing 6 grams drive the hip joint.

On a treadmill at 4 km/h, the suit reduced the energy a wearer spends walking by an average of 13.9 percent, measured by oxygen consumption; Tech Xplore reports six healthy volunteers were tested. Yu notes the device has only been run under laboratory conditions, and that long-term stability and reliability still need to be verified.