| High speed aircrafts,such as large passenger aircraft and military aircraft are high-end equipment in the field of aerospace.In order to ensure the service performance,the aerodynamic characteristics of aircrafts in various speed ranges and attitudes must be accurately evaluated.Wind tunnel test is a key means to obtain aerodynamic data of high-speed aircraft.However,under high-attack-angle test conditions,the complex flow field caused by airflow separation can easily induces the violent vibration of the aircraft model support system,which makes in poor quality of aerodynamic data.This kind of vibration has the characteristics of multi-dimensional and cataclysmic.In addition,the model structure is peculiar,the wind tunnel space is limited,and the requirement of aerodynamic shape is strict.It is difficult to suppress the vibration,which has become a bottleneck of aerodynamic evaluation.Therefore,the study on the vibration suppression methods to ensure the high-precision acquisition of multi-dimensional aerodynamic force,is of great significance for the development and batch production of the new generation of high-speed aircraft in our country.In view of the limitations of the existing active vibration suppression methods in vibration monitoring,vibration suppression structure and vibration suppression control methods,this paper aims to explore the active vibration suppression methods for multi-dimensional stochastic vibration,and expand the available test range of active vibration suppression in various types of aircraft models and various test conditions,a vibration suppression method based on piezoelectric control is proposed.The study consists of research on multi-dimensional vibration monitoring and vibration suppression structure design method,real-time control method of vibration suppression for intermittent vibration with large pitch and micro yaw and real-time control method of vibration suppression for multi-dimensional stochastically cataclysmic vibration,which fundamentally ensures the stability and testability of aerodynamic measurement.An active vibration suppression system for wind tunnel model based on real-time monitoring,cooperative action and efficient control is constructed,and the above key technologies are applied and verified.The specific research contents are as follows:(1)With the strict requirements of wind tunnel narrow space and aerodynamic shape of wind tunnel model support structure,for the problem of multi-dimensional vibration monitoring and vibration suppression structure design,the design method research of vibration monitoring and vibration suppression structure is carried out.Firstly,based on the vibration characteristics analysis of cantilever support,the design principle of biaxial symmetry is proposed.By establishing the model of the dimension-reduction monitoring of vibration state,the layout of vibration state monitoring sensors is determined,and the multi-dimensional vibration state full-dimensional monitoring is realized.And then,the load variation law of vibration suppression structure is further clarified,and an embedded vibration suppression structure with multi-actuators integrated and controllable is invented.The layout and structure of the mechanism ensuring the full-dimensional monitoring and adaptive suppression of multi-dimensional vibration,which provides a structure foundation for the development of high-efficiency vibration suppression system with aerodynamic shape keeping in narrow wind tunnel space.(2)Facing the suppression of intermittent vibration with large pitch and micro yaw for the flying-wing aircraft model,for the problem that a single control parameter can't adapt to the suppression of multi-amplitude vibration control and the suppression of stochastic micro vibration in the yaw plane,an intermittent vibration with large pitch and micro yaw control method based on fuzzy parameter adjustment and vibration suppression mechanism cooperative control is proposed.Firstly,the motion equation of the piezoelectric intelligent cantilever support system is constructed to suppress the multi-amplitude pitching vibration accompanied by micro yaw vibration.In order to enhance the damping of the system,combined with the classical proportional differential velocity feedback control as the basic control structure,the vibration suppression control strategy of fuzzy parameter adjustment and vibration suppression mechanism cooperative control is constructed.Then,the range of test conditions are divided,and multiple groups of proportional integral control parameters are adjusted according to the expert prior knowledge.The real-time adjustment method of fuzzy proportional differential control parameters for complex test conditions is proposed,which realizes the multi-condition adaptive adjustment of vibration suppression control parameters.At the same time,to meet the micro vibration suppression demand in yaw plane for the flying-wing wind tunnel model,combined with the spatial dynamic load variation law of vibration suppressor,a control strategy of multi-actuators cooperating with each other is constructed to realize the coordinated and controllable driving of multi-actuators in the vibration suppressor.With this method,the intermittent vibration with large pitch and micro yaw can be effectively suppressed.(3)Facing the suppression of multi-dimensional stochastically cataclysmic vibration for the aircraft model with high-aspect-ratio,for the problem that the complex environment of the wind tunnel results in the characteristics and parameter drift of the vibration suppression system,the complicated construction of test conditions,and the uninterruptable test process,a real-time vibration suppression method for multi-dimensional stochastically cataclysmic vibration is studied.Based on the analysis of the mathematical model structure of the multi-input and multi-output piezoelectric vibration suppression system,the multi-excitation input function of the system is constructed to fully stimulate the system characteristics,and the on-line acquisition method of multivariable modeling data of piezoelectric vibration suppression system is proposed,which transforms vibration vibration suppression mechanism to vibration exciter.On this basis,an parameter estimation method for system mathematical model based on subspace is proposed,and the system mathematical model is obtained.Finally,based on the optimal control theory,a multi-dimensional stochastic vibration suppression control method is proposed with minimum and fastest vibration suppression as the goal.With this method,the multi-dimensional stochastically cataclysmic vibration can be effectively suppressed.Based on the above key technologies,an active vibration suppression system for wind tunnel model is constructed,which is composed of real-time monitoring,cooperative action and efficient control.In the wind tunnel,aerodynamic tests are carried out to verify the suppression method of intermittent vibration with large pitch and micro yaw for the flying-wing aircraft model.At the same time,the vibration suppression experiments for the multi-dimensional stochastically cataclysmic vibration of an aircraft model with high-aspect-ratio were carried out in a space variable attitude wind tunnel test.The experimental results show that,the intermittent vibration with large pitch and micro yaw and the multi-dimensional stochastically cataclysmic vibration were effectively suppressed by the vibration interference suppression method proposed in this paper.The vibration frequency domain attenuation is more than 26dB and 14dB,and the residual vibration is less than 1.53g and 1.74g,respectively.The effectiveness and reliability of the multi-dimensional vibration active control method are verified.The research work provides a strong guarantee for the stable measurement of aerodynamic characteristics in the development of next generation aircrafts. |
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