Methods
To develop 1-DOF underactuated gait rehabilitation robot, we employed the Theo Jansen mechanism for the ankle path generation. Then we formulated the optimization problem, which minimizes the difference between healthy subject's ankle trajectory and the kinematic end point of Theo Jansen mechanism as follows:
where L1-L12 are the link lengths, phuman(tk) is the ankle position of human gait motion capture data at time frame k, pjansen(tk,L) is the kinematic end point of Theo Jansen mechanism at time frame k,
Φ is the rotation angle of the ground and τ is the phase lag.
