Design and Characterization of the MKA-IV Robot for Ankle Rehabilitation

Abstract

Hemiplegic survivors typically requires ankle rehabilitation to recover ankle motor function with considering the bilateral ankle balance. A new rehabilitation robotic system, named as MingKai Ankle IV (MKA-IV) has been proposed to address these challenges. The proposed rehabilitation robot consists of two symmetrical cascade mechanical platforms with three degree of freedoms (DOFs) each. Each ankle rehabilitation platform is composed of three rotational joints to achieve adduction/abduction, dorsifiexion/plantarflexion and inversion/eversion respectively. The novel symmetrical mechanical configuration allows patient to exercise his/her affected ankle by using the motion data collected from the sound side ankle. The corresponding kinematics has been derived to calculate platform's workspace. The kinematics/dynamics of the ankle rehabilitation robot is analyzed to verify its performance. The simulation had been performed to verify the correctness of the designed mechanical structure to reduce the ankle compensation during training. The experimental results illustrated that the robotic ankle joints can quickly response the input with time delay less than 5ms and maximum overshoot of 11.32%. The ankle training traces demonstrated that the ankle rehabilitation robot is capable of providing a solution for ankle training under different modes.