| The pressure control system of the rear cabin of the altitude test facility is the key subsystem of the high altitude simulation test of the aero-engine,and the quality of its regulation directly determines the accuracy and reliability of the simulation of the aero-engine air working environment.The pressure control system of the rear cabin in this paper has been upgraded many times,but its controller still adopts the conventional PID control method.When conducting transient tests such as aero-engine high-altitude thrust transients,the pressure control effect of the rear cabin cannot reach the expectation,which affects the safety and performance evaluation of the engine test run.Therefore,it is urgent to study the nonlinear control method of the system controller.At the same time,because the altitude simulation test of the aero-engine is a high-risk test,in order to ensure the safety of the engine and altitude test facility equipment.When improving the controller of the pressure control system of the rear cabin,the nonlinear control method cannot be directly studied through the actual system,it is necessary to establish a simulation model of the pressure control system of the rear cabin.The main research contents include:(1)Functional module division and analysis are carried out for the pressure control system of the rear cabin of the altitude test facility.The hydraulic actuator model,pipe cavity model and butterfly valve flow characteristic model are established by theoretical modeling.(2)In order to improve the accuracy of the simulation model of the pressure control system of the rear cabin,the numerical simulation technology is applied to the system modeling.Aiming at the problem of large error between the model established by the traditional theoretical modeling method of hydraulic actuators and the actual system,the hydraulic actuators are modeled by combining ADAMS,UG,and AMEsim software.First,the hydraulic servo system model was established using AMEsim software,and then the dynamic kinematics simulation analysis of the transmission mechanism was performed using UG and ADAMS software.Finally,a complete hydraulic actuator model was established on AMEsim,and achieve Co-simulation of AMESim/ Simulink.(3)In order to solve the problem that the traditional theoretical method cannot accurately analyze the working characteristics of the exhaust diffuser,this paper uses Fluent software to simulate and analyze the internal flow field of the exhaust diffuser,and proposes a new method for establishing the exhaust diffuser,This method uses the data obtained by simulation to establish the characteristic model of the exhaust diffuser.(4)Aiming at the problem that the traditional PID control method can’t well complete the pressure control of the rear cabin of the altitude test facility,the nonlinear PID control method based on the fal function and the extreme value search algorithm is studied.Then this paper also analyzes the pressure control simulation of the established simulation model.The simulation results show that the state change of the established model coincides with the trend of the real high-altitude simulation test process,which can reflect the dynamic change process of the real system pressure and prove the effectiveness of the system simulation model.Compared with the traditional PID control method,the nonlinear control method studied in this paper makes the system have better adjustment quality,which can effectively improve the simulation accuracy of the rear cabin pressure of the altitude test facility. |
