Modeling and Design of Dynamic Series-parallel Hybrid Lower-limb Mechanism

Humanoid robots are required to exhibit exceptional dynamic motion capabilities, particularly in the lower extremities, while undertaking repetitive, high-intensity, or high-risk tasks in human environments. However, the intricate lower limb structure and high limb mass ratio give rise to substantial errors when relying on reduced-order models. This research presents a novel evaluation methodology that effectively analyzes the mechanical properties of lower limb structures during the design phase. This methodology facilitates early detection and optimization of structural issues, thereby enhancing the motion performance and stability of humanoid robots. Furthermore, a novel design approach for the lower limb structure is proposed, employing a series-parallel coupling multistage transmission structure. This design enables the attainment of a compact overall structure and robust power output by integrating the drive structure of the knee and ankle into the thigh and pelvis. Finally, the practical implementation of this method is realized, demonstrating its efficacy in reducing joint load through running simulations.