Introducing a hydraulic system, its principle, characteristics, structural composition, and working parameters of various equipment.

Hydraulic systems rank among the most significant power transmission methods in modern engineering applications. Due to their high power density, controllability, and flexibility, hydraulic systems are widely used in construction machinery, machine tools, aircraft machinery, metallurgical machinery, and automated lines. Based on the theoretical principles of pneumatic and hydraulic transmission, this paper presents a research-oriented review of hydraulic systems, encompassing the basic principles, system properties, system composition, and operating parameters of typical hydraulic machines. Based on pneumatic and hydraulic transmission principles, the working principles of hydraulic pumps, control valves, hydraulic actuators, and auxiliary devices will be explained, and mathematical expressions describing pressure, flow, force, speed, and power relationship equations will be discussed. Various hydraulic circuits, speed-load characteristic curves, and system performance discussed in this paper form a basis that aims at clarifying a structure-function relationship and contributes as a theoretical and practical basis to hydraulic system designing, analyzing, and engineering.