Based on principle of similitude of electro--hydraulic, the hydraulic systems are regarded as thetopological multipole diagrams composed of certain inde-pendent subsystem multipole models by nodes.

• 依据电液相似系统原理,提出将实际液压系统的物理模型视为由若干个相互独立的子系统多极模型经若干节点拓扑而成的多极图。