Control Technique Research Of Aircraft Double Degree-of Freedom Dynamic Wind Tunnel Test

The flight envelope of modern advanced fighter continues to move forward to large angle-of-attack(AOA)region,which always leads to the movement with severe dynamic characteristics during flight such as the stall maneuver and the high speed uncontrollable movement.Therefore it is quite necessary to develop the research on the flight performance,flight mechanics characteristics and flight control system when aircraft flies through the stall region with large AOA by knowing the nonlinear,unsteady aerodynamic characteristics precisely.In order to solve the problem of dynamic aerodynamic characteristics with large AOA,the dynamic wind tunnel tests have been widely carried out by aviation technology developed countries,in which a variety of flight movements and maneuvering flight processes have been simulated.Before the actual flight of fighters a large number of wind tunnel tests are needed,and the dynamic test is one of the most important.In this thesis the control technique of double degrees of freedom oscillatory tests for aircraft roll,oscillation and pitch/yaw has been investigated.It includes the overall design,hardware design,software design,system debug and application for validation to create a domestic leading technique for aircraft double degrees of freedom dynamic test.This control system uses the pitch/yaw Hydraulic drive together with the rotation axis motor drive,which can solve the problem of large gap in motor drive and heavy load for Hydraulic drive,to achieve the precise uniaxial oscillation,pitch/roll coupling oscillation,yaw/roll coupling oscillation and maneuvering process simulation.Oil source,servo valve,Lenze motor,encoder,B&R controller have been combined in hardware to make an accurate and reliable system.The software can accomplish the functions of setting,moving,stopping,limitation,alarming and feedback by using B&R structured programming language and the hydraulic library.On the basis of PID control mode,the feedback control load is reduced by the feed-forward control of input compensation.The fuzzy control strategy is used to suppress the influence of parameter changes,reduce the impact of the system,enhance the system stability,increase the system robustness,and improve the Hydraulic motion control accuracy.Based on the development of hardware and software,the debug of the static function,dynamic precision and control optimization of single degree of freedom and the coupling motion has been carried out.The standard model is used to verify the control system through the wind tunnel test,and the repeatability precision can reach advanced level.The experimental results show that the system has the advantages of perfect function,reliable operation and high precision and satisfies the predetermined requirements.