High-Precision Control Method For Wind Speed Of Large Transonic Wind Tunnel

Large wind tunnels are important simulation platforms for aerodynamic testing during the development of large aircraft.Wind tunnel experiments on large aircraft put forward higher requirements for the control accuracy of Mach numbers.In this paper,the domestic 2.4m temporary-type transonic wind tunnel is studied,and the high-precision wind tunnel flow field control based on advanced control method is studied.Based on the characteristics of time-delay,inertia and coupling of wind tunnel,combined with the analysis of the structure and test process of 2.4m temporary thrust transonic wind tunnel,the model predictive control method is used to control the key parameters of wind tunnel flow field.Considering that the disturbance caused by the change of the attitude angle of the aircraft is predictable,the feedforward method is used to compensate the disturbance of the attitude angle to the flow field,and the attitude angle disturbance feedforward compensation is introduced in the wind tunnel flow field model prediction controller.design.However,due to the large number of wind tunnel test conditions and strong nonlinearity between working conditions,the models under different working conditions have large differences,and the prediction models and disturbance models of different test conditions use step response experiments.The method is obtained,and the adaptability of the control method is not satisfactory.For the consideration of large wind tunnels with huge energy consumption,it is very uneconomical to obtain prediction models for all working conditions,and for the safety of equipment,it is impossible to obtain the disturbance model under the condition of supercharged high Mach number.To this end,a method based on the fusion of existing working condition models to obtain a new working condition model is proposed.The estimation method of model fusion weight is determined by analyzing various factors affecting the model.For the inaccurate problem of the obtained compensation model,the iterative correction method is used to correct the disturbance model based on the actual control index.Combining the model predictive control algorithm and the particle swarm optimization algorithm,the correction coefficient of the disturbance model is determined to obtain a more accurate disturbance compensation model to ensure the ability of the flow field controller to resist disturbance during the attitude angle change,so that the Mach number control precision of the flow field is The variable angle of attack process reached expectations.The NI with PXI system builds a wind tunnel flow field controller,and uses Labview language to write control algorithms.The blow test in the wind tunnel flow field controller verifies the feasibility of the proposed model fusion scheme and iterative correction scheme.The actual application control effect shows that the Mach number accuracy reaches 0.001,which basically meets the requirements of large aircraft test.