Multi-degree-of-Freedom Lumbar-Hip-Assisted Exoskeleton Design and Model-Free Impedance Control Based on Time-Delay Estimation

In this paper, a 4-SPS/CS/2-CRP parallel based lumbar-hip-assisted exoskeleton is proposed to provide various lumbar and hip motion assistance, and a time-delay estimation based model-free impedance control (TDE-MFIC) is proposed to achieve trajectory tracking and assistance effects on the human body. Firstly, the existing exoskeleton in the research group was improved in view of the adjustment of exoskeleton size and parts processing. Secondly, based on the inverse kinematics from body position to push rod motor position, the virtual prototype of exoskeleton and human–machine coupling virtual prototype are established in MATLAB/Simulink. Thirdly, TDE-MFIC is designed to achieve effective trajectory tracking and human–machine interaction. Finally, the effectiveness of the proposed algorithm was verified through co-simulation using SolidWorks and MATLAB/Simulink.