Research On Environmental Simulation Test Of Airborne Fuel Tank And Its Components

Environmental simulation test is used to test the ability of the equipment or load to maintain its original performance in the actual environment by reproducing the working environment conditions in the laboratory.Shock,high and low temperature,height and seal capacity environment simulation tests are carried out for the airborne oil tank and its components.The control algorithm of multi-degree-of-freedom(DOF)shock environment simulation is mainly studied.The multi-DOF electro-hydraulic shaking tables,which are often used in the shock vibration simulation test of large structural specimens,have the advantages of large displacement and strong anti-overturning torque.The amplitude-frequency characteristics of the acceleration frequency response function of the system have a large deviation to OdB with servo control only.It is difficult to achieve high replication precision of the shock waveform.The optimal control strategy of two-DOF shock waveform is proposed to improve the replication accuracy of the reference signals.The main research contents are as follows.Firstly,the servo control loop and the traditional waveform replication algorithm are proposed.The model of a two-DOF electro-hydraulic vibration table and an oil tank and its components is built based on the Matlab/Simulink platform.The servo control method and the traditional waveform replication control method are used to replicate the reference shock waveform.The simulation results show that the accuracy of the traditional waveform replication algorithm does not meet the requirements of the tests for the time varying systems.Secondly,an optimal control method for waveform replication based on quasi-newton algorithm is proposed.The quasi-Newton method is used to identify the frequency characteristics of the system online and modify the drive signal.Compared with the traditional Newton iteration method,the quasi-Newton algorithm,which only uses the first derivative of the objective function for iterative calculation,greatly reduces the calculation amount of the algorithm and is beneficial to the real-time online update of the generalized impedance of the system.The Broyden method,DFP method and BFGS method are used to perform two-DOF shock waveform replication for simulation analysis.The simulation results show that the three quasi-Newton methods can track the changes of the system impedance characteristics and improve the accuracy of the shock waveform replication.Among them,the shock waveform replication accuracy is the highest when the BFGS algorithm is used.Based on the electro-hydraulic shaking table,two-DOF shock waveform replication experiments are conducted.The experimental results verify the correctness of the theory and simulation analysis.Finally,the high and low temperature,height and seal capacity environmental simulation tests of the fuel tank and its components are conducted.The test results show that the fuel tank and its components meet the environmental simulation test requirements.