“…The swashplate type axial piston pump is the most common power hydraulic component. Owing to simple structure, compact design and high power density, it is widely applied in hydraulic transmission equipments, such as an excavator [2], an aircraft [3], a water hydraulic machine [4,5] and a hydraulic transformer [6], etc. The axial piston pump is mainly composed of three interfaces, such as the slipperswashplate interface, the piston-cylinder interface [7] and the cylinder-valve plate interface [8].…”