With the growing demand for exploring marine resources, underwater manipulators have become essential equipment. However, traditional manipulators mostly use mineral oil as the working medium, which is prone to leakage and causes marine environmental pollution. Although vegetable oil-based hydraulic fluids are more environmentally friendly, they still cannot solve the leakage problem, and seawater intrusion can lead to corrosion and wear of the hydraulic system, reducing the service life of the manipulator. Currently, there is a lack of water hydraulic proportional valves suitable for deep-sea environments, which limits the development of environment-friendly water hydraulic manipulators.

Therefore, Zhenyao WANG, Yinshui LIU, Xi WANG, Yong LIU, Xuemei PAN, Chuanqi GAO, and Defa WU from Huazhong University of Science and Technology, 719 Institute of China Shipbuilding Industry Corporation, and Wuhan Huaxi Special Hydraulic Equipment Co., Ltd. jointly conducted a research entitled “Numerical Analysis and Experimental Verification of a Novel Water Hydraulic Rotary Proportional Valve for an Environment-Friendly Manipulator”.

This study invented a novel water hydraulic rotary proportional valve with a four-way, three-position principle and a plane sealing method. It explored the static and dynamic performance of the valve through mathematical modeling and experimental methods, and built a valve-control swing cylinder system to simulate the working state of the manipulator in a deep-sea simulation device that can replicate 6500-meter ocean depth. The research results show that the numerical and experimental data match well. The proportional valve can achieve zero leakage with a dead zone of approximately 10%. When the input signal amplitude is 5% and 100% of the valve’s full stroke, the bandwidths are 30 Hz and 6 Hz respectively. It can accurately control the swing cylinder on the manipulator’s elbow joint with a rotation angle error of ±0.1°, and has excellent adaptability to deep-sea environments, which is of great significance for promoting the development of water hydraulic manipulators.

The paper “Numerical Analysis and Experimental Verification of a Novel Water Hydraulic Rotary Proportional Valve for an Environment-Friendly Manipulator” is authored by Zhenyao WANG, Yinshui LIU, Xi WANG, Yong LIU, Xuemei PAN, Chuanqi GAO, and Defa WU. Full text of the paper: https://doi.org/10.1007/s11465-025-0820-z.