| With the continuous development of fighter performance,post-stall maneuverability has become an important performance index of modern fighters.Some fighters have the ability to fly over stall at high angle of attack,which is of great significance to ensure the maneuverability of fighter jets.It can achieve absolute superiority in fighter air combat.Because the fighter plane produces complex flows such as separation and vortex during stall flight at high angle of attack,the aerodynamic force shows highly nonlinear and unsteady characteristics.In order to accurately obtain the dynamic aerodynamic data of aircraft such as fighter during post-stall maneuver,it is necessary to carry out dynamic derivative test in wind tunnel.At present,the open dynamic derivative experiment technology mostly adopts motor and mechanical transmission mechanism to realize the oscillating motion of the aircraft.The mechanical transmission mechanism will produce inevitable motion error,and it is difficult to achieve higher oscillation frequency by mechanical transmission.In addition,the current dynamic derivative test technology mainly focuses on pitch or roll oscillation,the research on heave oscillation test technology at high angle of attack is less.In this thesis,linear motor is used for the first time to realize high frequency(0～2Hz)heave oscillation of aircraft at high angle of attack(-10 ～90 °).The error of control system is an important source of uncertainty in dynamic derivative test.In order to improve the accuracy of test data,heave oscillation and angle of attack error control are studied.The control system of the tail brace lifting and sinking dynamic derivative test device applied in 3.2m low speed wind tunnel is developed.The main work is as follows:1.The kinematics and dynamics equations of each execution system of the dynamic derivative test device are derived.According to the system parameters,the key components of each execution system are calculated and selected.The angle error model caused by hinge clearance and strut vibration in angle of attack system is established.2.The control system model of linear motor is established,the theoretical formula of parameter tuning of linear motor control system is deduced,and the theoretical optimal parameters of linear motor controller are calculated.A nonlinear control algorithm based on fuzzy control is proposed for error compensation of angle of attack control system with clearance.3.The linear motor control system is simulated by MATLAB/Simulink software,and the system parameters are optimized by the simulation results.The control algorithm of variable angle of attack system with clearance is simulated by Simulink and Adams software,and the errors of different control algorithms are compared.The results show that the fuzzy PID control accuracy is the highest.4.Based on Siemens SMOTION motion controller,the control system of dynamic derivative test device is developed.5.The parameters of linear motor control system are verified and optimized through ground experiments,and the influence of frequency and load on the sinusoidal oscillation accuracy of linear motor is explored.The error of angle of attack is analyzed by experiments.Finally,the dynamic derivative test of the aircraft is carried out in the 3.2m wind tunnel,and the test results show that the technical index of the system meets the expected requirements. |
