Trajectory planning of a novel lower limb rehabilitation robot for stroke patient passive training

Abstract

A new applicable sitting/lying lower limb rehabilitation robot is proposed to help stroke patients. It can realize the sitting/lying training postures to fit people in all the rehabilitation stages. Based on the modularization design, the movable seat can be separated from and grouped into the lower limb rehabilitation robot, which is convenient for patients to sit down. As the most important part of lower limb rehabilitation robot, the mechanical leg design theory is introduced in detail. According to the physician clinical suggestions, a new trajectory planning method is proposed based on the dual quartic polynomial interpolation method. It could realize the adjustment of each joint maximum velocity during the training on account of patient recovery. The accelerations of the joints at target position equal zero, which will reduce impact loads on the patients damaged leg. Also, the dwell time the joints staying at the target angular positions can be increased. Those advantages make the lower limb rehabilitation robot more suitable for stroke patient passive training. Combined with the virtual reality technique, a specific motion-playback scene is designed to improve the patient enthusiasm in the training. Finally, a preliminary experimental trial has been conducted to demonstrate the design of the prototype, the motion-playback scene, and the trajectory planning method feasible.