Research On Superfluous Force Suppression Of Load Simulator For Missile Launcher

Load simulator is a kind of hardware-in-loop simulation device.Using load simulator to study practical problems has a series of advantages such as low cost,short cycle and convenient research.The load simulator of the missile launcher belongs to the passive electro-hydraulic servo loading system.The nonlinear characteristics and the existence of the superfluous force seriously affect the loading performance of the loading system.With the progress of science and technology and the need of the development of military equipment,the requirements of the performance of the load simulator are becoming higher and higher.Therefore,the research of high performance load simulator has important theoretical and practical significance.At first,the structure and working principle of load simulator for missile launch vehicle are introduced.In order to analyze the accuracy and simplicity,the equivalent model of the load simulator is set up,and the relevant assumptions are made.The control block diagram of loading system and erection system is established,and the overall mathematical model of load simulator is deduced accurately.Then the scrambling and scrambling loading characteristics of the loading system are analyzed respectively,and the frequency characteristic curves of the loading system are obtained by MATLAB simulation.The lag correction of the loading system increases the low frequency gain of the system,and improves the stability of the system.Starting from the generating mechanism of excess force,the dynamic characteristics of superfluous force are analyzed.The compound control method is used to restrain the superfluous force.First,the basic principle of the compound control is expounded.The feedforward compensation link is set up by the principle of structure invariance,and the loading system is controlled with the PID closed loop control.The feasibility of compound control is verified by co-simulation using AMESim and Simulink.Compared with single control systems,compound control can not only ensure the stability of the system,but also improve the control accuracy of the system.The dual valve compensation scheme is determined through analyzing the characteristics of the pressure servo valve and the flow servo valve in controlling the loading force and compensating the forced flow.The AMESim simulation shows that the double valve compensation can effectively suppress the superfluous force.In view of the difficulties of high quality speed signal acquisition,the control signal of servo valve is improved.The simulation results show that the double valve compensation scheme based on pressure signal can achieve the effect of reducing the superfluous force.The improved scheme not only includes the advantage of original double valve compensation,but also overcomes the limitation of the compensation scheme in practical engineering application.Compared with compound control,double valve compensation is simpler,more stable and more reliable.