Experimental Study of Switching Behaviour in the Transmission of Tension to the Joints of the Finger

Cadaveric experiments and computer simulations have shown that the tendon network of the fingers performs logic computation to preferentially change torque production capabilities. Distribution of input tensions in the tendon network itself regulates how tensions propagate to the finger joints, acting like the switching function of a logic gate. The tendon network as proposed by Winslow (1669–1760) is responsible for this phenomenon; and that a certain switching behavior is exhibited, depending upon the input tension loading. This work explores how this switching behavior varies with different static postures of the finger and under different loading conditions on input tendon terminals. Experimental setup is designed and developed to study this switching behavior, comprising of a bio-mimetic model of middle finger, designed and developed. Winslow’s tendon network as proposed by Winslow is employed over it. Force sensors based on strain gauges are designed and developed in order to measure the tension at the proximal and terminal slips of network. Experiments have been carried out to understand the switching behavior exhibited by rhomboidal tendon network and how it varies under different loading conditions. Its variation with different pre-configured postures under static equilibrium is observed. Results show that indeed the rhomboidal tendon network of Winslow exhibits switching behavior and that they vary under different loads and postures of the finger.