Abstract:Steering gear is one of the most important marine auxiliary machineries and it is the key equipment for controlling ship course, ensuring navigation security and maneuverability. At present, the hydraulic steering gear is applied in the most of largescale ship. Large hydraulic steering gear is a hydraulic servo system with nonlinear, variable load and variable parameters. In the process of its design, it is necessary to revise the controller repeatedly. To improve the controller design efficient, an identification method based on genetic ant colony algorithm is applied. Firstly, the dynamic equation of hydraulic system is deduced and the mathematical model is setup. Secondly, the measured input and output signal is applied to verify the results. As a results, the identified mathematical model is consistent with the real physical system. This work provides a solid theoretical basis for the future design of steering gear.