Mechanical Design of Variable Stiffness Joint Based on Planetary Gear Train and Modular Elastic Element

By referring and combining existing mechanical design ideas of some series configuration VSJs with good stiffness adjustment mechanism schemes, a novel series configuration VSJ based on an equivalent lever mechanism and relying on adjusting the position of the lever pivot to change joint stiffness has been implemented through CAD drawing, 3D printing, and assembly. Due to the wide movable range of the lever pivot, the designed VSJ has a wide adjustable range of stiffness. Moreover, assembly design and modular design have been achieved in terms of elastic output and power transmission, for easy installation and maintenance. The movability and stiffness adjustability of the designed VSJ were preliminarily verified through manual adjustment. The assembly model of the VSJ demonstrates the feasibility of structural design. The stiffness adjustment experiment showed the variable stiffness ability of the designed VSJ.