| With the rapid development of ship manufacturing,the tonnage ship displacement is bigger and bigger,and it need to better quality ship steering gear to meet increasing requirements of ship maneuvering.Direct drive volume control rotary vane steering gear has advantages of compact structure,small occupation area,convenient installation,easy maintenance,energy-saving and environment-friendly,etc.And it has attracted a wide attention for its advantages.But direct drive hydraulic contol electro-hydraulic servo system has not so good dynamic characteristic,hydraulic system itself contains complex nonlinear characteristics,which limiting the application of rotary vane steering gear.In addition,with the development of science and technology,as well as the weapons,explosives in military campaigns are used more frequent,the probability of ship and its equipment attacked by non-contact explosion is higher.In the marine battle it can make the whole system failure when the steering gear is attacked by the non-contact underwater explosion Therefore,it is necessary to study the dynamic characteristics of direct drive rotary vane steering gear servo system,to get the response characteristics of ship equipments by the non-contact underwater explosion impact disturbances,to enhance the system robustness.Firstly,shock load characteristic of underwater explosion are particularly learned.It mainly focuses on fluid-solid coupling phenomena of ship equipment structure response impacted by non-contact underwater explosion shock load.According to structural mechanics,fluid mechanics and finite element theory,rudder structure fluid-solid coupling equation of non-contact underwater explosion shock response is derived.Combined with the characteristics of the fluid-solid coupling equation,it proposes the computation calculation method as the numerical solution of structure response.Finite element model of the rudder structure with actual size is established by using finite element software ANSYS,dominant dynamics analysis software LS-DYNA is used to simulate the whole process of rudder structure subjected to non-contact under water explosion shock load,and Arbitrary Lagrangian-Eulerian(ALE)method is particularly studied to solve the fluid-solid coupling problem of underwater explosion process.Dynamic response of the structure is given.The prediction of shock environment is very difficult to get in ship equipment anti-shock design.Auto-regressive moving average(ARMA)model is proposed to make prediction of shock environment of ship equipment.With multiple groups of simulation data,ARMA model of shock environment is established,and genetic algorithm is introduced to determine the order of ARMA model.It is proved effectiveness of ARMA model through the analysis of residual sequence characteristics.Based on the relationship between acceleration response Fourier spectrum and pseudo velocity spectrum,the prediction results are used as the input of rotary vane steering gear anti-shock design.Spectrum analysis etc is used to study anti-shock character of rotary vane steering gear.Fatigue analysis of rotary vane steering gear bolt is also got by of equivalent stress nephogram and distribution map fatigue life plot.Results show that the designed shock environment prediction of rotary vane steering gear can not work a long time.It proves the feasibility of the proposed shock environment prediction method.The basic structure of direct drive volume control rotary vane steering gear servo system is proposed in the paper.In view of the existing problems of variable voltage,variable frequency speed regulation system and controlled slip frequency variable frequency speed regulation system of asynchronous motor,vector control is used for asynchronous motor.Also the basic principle of vector control variable frequency speed regulation system is described in detail.Mathematical model of asynchronous motor is set up.On the basis,the model of direct drive rotary vane steering gear servo system is established,including the loop of synchronous motor,pump control hydraulic power mechanism,feedback sensor link,etc.And simulation analysis is done to the designed vector control variable frequency speed regulation system,validating the rationality of the designed control system,to get the parameters of the speed regulation system.Then direct drive rotary vane steering gear servo system response characteristics with the regular disturbance are analyzed,and system robustness is discussed.For the problems of direct drive rotary vane steering gear control system with nonlinear character and uncertain external disturbance,sliding mode variable structure control strategy is proposed.And fuzzy control is used to eliminate vibration.Fuzzy sliding mode variable structure controller is designed for direct drive rotary vane steering gear servo system.System control law,switching function and fuzzy control rules are proposed,and stability of the designed control system is theoretically verified.Combining with nonlinear friction characteristics of the hydraulic system itself and underwater explosion shock environment of rotary vane steering gear,dynamic performances of the servo system with different external disturbance are simulated.It is to verify that the designed fuzzy sliding mode variable structure control strategy can eliminate vibration,effectively improve the dynamic performance of system,and enhance the system robustness. |
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