Dynamic Modeling and Complexity Analysis of Human Lower Limb under Various Speeds

Abstract

Human lower limbs are the most important parts of human body due to their supporting the whole body in the process of human motions. There are many pathological joint diseases and accidental damage, such as traffic accident and falling off from high place, influencing the human daily life seriously. Therefore, dynamic model of human lower limb has received considerable interest from multi-disciplines including flexible mechanisms, smart structures, biomechanics and nonlinear dynamics. This paper establishes the simplified simulation model of human lower limb based on the acquired realistic data from human motions under different speeds. The model can not only describe dynamic characteristics of real lower limb but also can be simulated by realistic human lower limb motion excitation acquired by tri-axial accelerometers and inclinometers in different conditions. Consequently, the detailed dynamic information of human lower limb from the proposed model can be obtained. In order to analyze the variability of human motions, multiscale entropy (MSE) is employed to investigate the complexity of human motion signals for different speeds of motion. Motion transition characteristics under different speeds are exhibited for understanding adaptation mechanism of human motion. The results will be helpful for exoskeleton and lower limb rehabilitation robot.