Fig. 3: Characterization of tendon properties.

a The relationship between tendon input displacement \(\delta m\) and output ideal length \(l\) during motion. b The relationship between joint angle and tendon displacement and velocity; the arrows indicate the trend of joint angle changes. c The relationship between \(\delta M\) and \(\delta m\) under different joint angles and contact conditions. d The results of visual recognition, where the yellow and white fonts represent the identifiers for the markers m and M on each actuation unit, respectively. The yellow line indicates the distance (\(\delta m\)) between marker m and the origin. e Tension variation along the tendon transmission path; f Visual recognition results during the pressing of the force sensor by the fingertip of the ring finger. The data within the red box indicates the length change \(\delta m\) of one tendon controlling the ring finger, and the deformation \(\delta x\) of the series-connected spring. g Fitting results of external torque \({{{\boldsymbol{\tau }}}}_{ext}\) and increment of spring deformation \(\delta {x}_{c}\) under different joint configurations.