Structural design and intelligent control of lower limb knee rehabilitation exoskeleton based on motion intention estimation method

Abstract

In modern society, physical disabilities induced by knee related diseases are gaining attentions, where demand for rehabilitation exoskeletons for single knee joint assisted treatment is increasing. Meanwhile, most rehabilitation exoskeletons of medical industry are designed based on entire lower extremity of human body, and there are relatively few exoskeleton robots for single joint rehabilitation. In this paper, the structure of exoskeleton based on actual motion characteristics of human knee joint is designed by Solidworks, and a virtual prototype through joint simulation with Simscape Multibody is generated to provide a platform for building control system later. The generated virtual prototype is validated by an intelligent controller which is based on an ultra-local model, a linear extended state observer (LESO) and a sliding mode sub-controller (SMC). Finally, considering factors like actual control system and human-machine interaction, a joint angle estimation model based on surface electromyography (sEMG) signal is used to obtain predicted angle as desired input in control system to further validate the rationality of human-machine interaction (HCI).