Design and evaluation of a novel flexible bio-robotic foot/ankle based on parallel kinematic mechanism

In this paper, we address the design and evaluation of a novel flexible bio-robotic foot/ankle based on parallel mechanism with three identical UPS prismatic-actuated limbs and a central UR passive limb. After discussing the advantages of using the PKM, the kinematics problem of the PKM are investigated. In particular, to measure the action force at the foot when the bio-robot maintains balance or moves, the cross shaft of the U-joint in the passive limb is modified and intended to be used as an elastic element of the force sensor. Then the development of the integrated force sensor is introduced in detail. The design is helpful for both reliable architecture design and performance improvement of the bio-robot foot/ankle.