Tele-Rehabilitation system for human lower limb using electrical stimulation based on bilateral teleoperation

This paper considers tele-rehabilitation system by using the electrical stimulation based on the bilateral teleoperation for a human lower limb. The tele-rehabilitation means that a physical therapist rehabilitates a patient who is away from the physical therapist. When the therapist cannot check the condition of the patient directly, the haptic interface is used to feel the condition by the haptic sense. And the therapist moves the patient's lower limb by using the electrical stimulation indirectly through the haptic interface. In this way, the system that both the therapist side and the patient side are controlled each other is called as the bilateral teleoperation. However, the time delays of the communication cause the instability for the bilateral teleoperation. First, the mathematical model of a human lower limb is considered by using the linearization, the phase-lead filter is designed. Next, the paddle system as a haptic interface is modeled, the feedback controller is proposed. The scattering transformations and wave filters are constructed. Finally, the proposed tele-rehabilitation system is verified with respect to the stabilization and the control performance in the simulation and the experiment. As a result, the stability is compensated, the position error between the paddle and human lower limb is small.