Research On Control Method Of Mach Number For Wind Tunnel

Wind tunnel is an important ground simulation platform for the study of aerodynamic characteristics of air flow rules,aerospace vehicles and other objects.Wind tunnel flow field control system is the core system of wind tunnel,which affects the precision of Mach number,stability of wind tunnel flow field and adjustment time,energy consumption of wind tunnel system and quality of wind tunnel flow field.In order to meet the requirements of the wind tunnel test accuracy in the design process of the large aircraft in China,it needs to improve the precision of Mach number in the flow field of the wind tunnel up to 0.001.For the 2.4m transonic wind tunnel,the PID control currently adopted cannot meet the test requirements.Wind tunnel system is complex,large aircraft needs of wind tunnel test can provide an important basis for the Mach number control precision demanding for the vehicle design,but the existing control methods in long regulation time,overshoot and difficult to achieve high precision flow control shortcomings in finite time are Mach number control.In this thesis,a 2.4m transient transonic wind tunnel is used to design wind tunnel flow field controller.We study the physical quantity which affect Mach number,consider the structure of wind tunnel and characteristics of angle of attack change.So we use predictive control algorithm to control the system of two inputs and two outputs,which main exhaust valve and choke finger are inputs,total pressure and static pressure are outputs.Based on multivariable dynamic matrix control wind tunnel flow field controller is designed,in order to improve the wind attack Angle disturbance resistance,the use of Angle of attack motion compensation prediction of static pressure,thus constitute the attack Angle compensation dynamic matrix wind tunnel flow field controller.In order to ensure the implementation of the controller,the controller parameter setting method based on the firstorder inertia of the wind tunnel flow field and the approximate model of the attack Angle disturbance approximation model is given.Based on Lab VIEW software,the design of wind tunnel prediction controller is realized.The wind tunnel prediction controller can effectively adjust the wind tunnel flow field and make the Mach number meet the precision requirement.The nonlinear of wind tunnel flow field results in different models of different working conditions.If the same model is used in different working conditions,the loss of control accuracy can be caused by mismatch of model.However,for energy consumption and cost considerations,it is not advisable to do step response experiment for each condition.Considering the multiple model control superiority in solving nonlinear problems,the thesis on the basis of the model based on multiple choice,wind tunnel flow field controller was designed using the dynamic matrix control algorithm,the method of multiple model combined with an efficient and dynamic matrix control is verified by actual flow test multi-model dynamic matrix controller can effectively adjust the flow field,the blowing wind tunnel test precision of the flow field parameters of the large aircraft development requirements.