Research On The Design And Control Srategy Of The Ship Steering Engine Loading System

For the practical engineering project of rudder loading testbed with 100 tons of loading force, a load simulation system for marine steering gear has been designed, optimized, and its control strategies has been theoretically studied. As a hardware-in-the-loop test equipment for simulating the force condition when the rudder is in the working state, a load simulation system has the advantages of saving the experiment cost, shortening development cycle, improving the success rate, high reliability, etc.. Its product development has important s trategic significance and economic value in the area of aviation, military weapons, vehicles and ships, etc..With a research history more than 40 years, the load simulation system has been mainly applied to the field aircraft. According to a marine steeri ng gear with large inertia mass and hydrodynamic force in a wide frequency range, the load simulation system for it has been proposed to make high frequency and large output force loading.In this paper, the research contents mainly include these points as followed.First of all, the major components of the load simulation system have been preliminary designed with calculation and model selection, according to the technology index requirements of the actual project and the analysis of basic principle. Then the mathematical model of the load simulation system has been established in the form of block diagram. By using the software of Simulink, simulated analysis of inertial loading equipment and loading system has been made respectively to find the existing problems in its performance. As a result of time-domain simulation and frequency-domain simulation, the inertial loading equipment has been found defects of low frequency width and small damping ratio; although the loading system has had good loading precision in active loading, the superfluous force will increase rapidly when rising the loading frequency in passive loading, which would make loading precision worse or even distortion.Moreover, the existing problems in the performance of inertial loading equipment has been found related to nonlinear transfer from flow to rotate speed of hydraulic motor. To solve this problem, the method of changing structure parameter has been found by simulation analysis. After that, the method of determining structure parameters in quantitative calculation has been proposed by creating ideal hydraulic motor frequency characteristic curve. This method has been proved that it can effectively improve the performance of the inertial loading equipment through simulation analysis.Lastly, by analyzing the principle and characteristics of the superfluous force, it has been proved the differential features existing in the superfluous force, which can be eliminated by using speed feedforward compensation strategy. Furthermore, internal model control strategy has been used to restrain the superfluous force in high frequency loading. By simulation with Simulink, the composite control algorithm of speed feedforward compensation strategy and internal model control strategy has been proved to effectively restrain the superfluous force and improve the loading precision of the loading system.