Numerical study on dynamics of exoskeleton with rigid-flexible coupling knees based on sagittal gait plan

In this paper, the effects of rigid-flexible coupling knees on the performance of the exoskeleton developed by us for power assist are mainly concerned. The work was conducted through a series of numerical simulation comparisons between rigid-flexible coupling models and pure rigid structure models of the exoskeleton under different loads. Before the dynamic analysis, a flat walking gait plan in sagittal plane was designed for the exoskeleton, and the coupling numerical model of the novel knee was verified through comparing with the experimental result. Compared with the pure rigid knees, the simulation results show that the rigid-flexible coupling knees exert a mixed influence on dynamics of the exoskeleton under different loads. Via the current study, a simple and practical gait plan is acquired for biped exoskeleton to imitate human level walking, and flexible parts utilized in the exoskeleton joints could lead to a vibration of joint driving torque without load, and on the contrary, it contributes to the lower impact ground reaction force and undemanding driving torque requirement with heavy load.