This paper introduces a compact and lightweight stiffness modulator that provides stiffness adjustment without performing deliberate mechanical work. Designed for human augmentation, the device complements natural muscle co-contraction to reduce muscle activity and metabolic cost. Experiments demonstrate its ability to augment the human knee joint during a sit-to-stand task, showing reduced muscle effort while consuming minimal battery power.
Why it matters: Portable stiffness modulation has long been a challenge for human augmentation. This work demonstrates a practical implementation that can support everyday movements efficiently, opening the door to wearable devices that enhance mobility while conserving energy.
