Multi-objective optimization of a wet electromagnet-driven water hydraulic high-speed on/off valve for underwater manipulator in deep sea

Water hydraulic high-speed on/off valves (WHSVs) have the potential to replace the traditional oil hydraulic valves to be used in underwater hydraulic manipulators (UHMs) in the deep-sea environment due to their environmental friendliness, strong anti-pollution ability, and good sealing property. In this paper, we develop and optimize a novel wet electromagnet-driven WHSV to enhance its suitability for UHMs. Firstly, an accurate equivalent magnetic model of the WHSV is derived, considering the leakage flux and nonlinear characteristics. This magnetic model is combined with other physical field models to accurately describe the dynamic behavior of the WHSV and provide a comprehensive simulation framework. Then, the multi-objective optimization and decision-making methods are combined to optimize and determine the structural parameters of the WHSV, achieving a balance between rapid response and light mass. Finally, a WHSV prototype is manufactured and tested based on the optimized structural parameters. Experimental results indicate that the WHSV achieves opening and closing times of 1.63 ms and 1.22 ms, respectively, with the electromagnetic components weighing 75.5 g. These results show a maximum deviation of 7.4 % from the optimization results (1.52 ms, 1.31 ms, 71.6 g). Moreover, the deep-sea simulation test verifies the prototype functionality under a high-pressure condition (110 MPa).