基于不确定性建模新方法的多作动机翼颤振主动抑制

发布时间：2019-06-03 09:50

【摘要】：颤振主动抑制(以下简称为颤振抑制)是近几十年内发展起来的气动弹性新技术,主要得益于经典控制和现代控制的发展和成功应用。随着主动柔性机翼概念的提出,人们从以往着力避免气动弹性的负面效应转向充分利用主动控制技术来获得所需的气动弹性效应,使飞行器具有柔性增大、结构重量下降、飞行包线扩大、机动性能提高等特点,可为下一代飞行器设计提供关键技术。本文以含多操纵面的小展弦比三维机翼风洞模型为研究对象,开展了理论分析、数值模拟和风洞实验一体化的颤振抑制研究。作者设计了颤振抑制控制器,建立了多作动机翼颤振抑制的风洞实验控制系统,并在风洞实验中验证了颤振抑制控制器的有效性。本文的主要工作和学术贡献如下:1.提出了一种气动弹性系统中参数化不确定性建模的新方法。传统方法直接对系统状态矩阵进行不确定性分析,存在重复建模和不确定性耦合问题,使得不确定性模型维数非常高,给控制器综合带来困难。而新方法从气动弹性建模的根源出发,通过对信号进行分析和汇合,避免了不确定性的重复建模,并能够对耦合的不确定项进行解耦,从而大幅减少不确定性模型的维数,进而可以更有效地设计颤振鲁棒控制系统。2.针对含前后缘控制面的二元机翼/外挂系统,使用偶极子网格法,考虑外挂的非定常气动力影响,采用上述建模新方法建立了流速扰动下机翼/外挂气动伺服弹性系统的不确定模型。开环颤振分析验证了新方法的正确性,闭环仿真结果表明基于不确定性建模新方法设计的控制器能够大幅提高颤振临界速度。3.将超声电机作动器应用到三维机翼颤振抑制中,基于超声电机和数字信号处理器(DSP)自行设计和研制了多作动机翼颤振抑制的风洞实验平台,通过DSP的模拟输出实现了前后缘超声电机的精确角度跟随。通过添加额外的输出方程,成功地将二阶微分方程描述的超声电机数学模型合并到多作动机翼的气动伺服弹性系统方程中,设计了多作动机翼颤振抑制的多输入/多输出(MIMO)LQG控制器。风洞实验结果表明,常规的LQG控制器并不能起到颤振抑制的效果,而对控制系统中存在的时滞进行补偿的LQG控制器能够把多作动机翼的颤振临界速度从34.5 m/s提高到37 m/s。4.自行设计并研制了以实时仿真器(AD5435)为核心的具有高实时性的多作动机翼风洞实验控制系统,提出了一种前馈补偿的增量式PID控制方法,能够实现前后缘直流电机的精确角度跟踪。针对流速和空气密度不确定性,采用上述建模新方法建立了多作动机翼的气动弹性系统不确定性模型,分别设计了颤振抑制的单输入/单输出(SISO)和MIMOμ控制器。风洞实验结果表明,SISO控制器能够将机翼颤振临界速度从36.5 m/s提高到39 m/s,而MIMO控制器能够将颤振临界速度从36.5 m/s提高到38 m/s。与LQG控制器相比,μ控制器并没有对时滞进行补偿,但是却能够有效地抑制颤振,验证了μ控制器的鲁棒性。
[Abstract]:Flutter active suppression (hereinafter referred to as flutter suppression) is a new aeroelastic new technology developed in recent decades, which is mainly due to the development and successful application of the classic control and modern control. With the development of the concept of active flexible wing, it is necessary to avoid the negative effect of aeroelasticity from the past to make full use of the active control technology to obtain the required aeroelastic effect, so that the aircraft has the flexibility to increase, the weight of the structure is reduced, the flight envelope is expanded, The mobility can be improved and the key technology can be provided for the design of the next-generation aircraft. In this paper, a three-dimensional wing wind tunnel model with a multi-operating surface is used as the research object, and the theoretical analysis, numerical simulation and the flutter suppression research of wind tunnel experimental integration are carried out. In this paper, the flutter suppression controller is designed, and the wind tunnel experimental control system with multi-action wing flutter suppression is established, and the effectiveness of the flutter suppression controller is verified in the wind tunnel experiment. The main work and academic contribution of this paper are as follows:1. A new method for parametric uncertainty modeling in aeroelastic systems is presented. In the traditional method, the uncertainty analysis of the system state matrix is directly carried out, and the problem of repeated modeling and uncertainty coupling is present, so that the dimension of the uncertainty model is very high, and the difficulty is brought to the synthesis of the controller. The new method, based on the origin of aeroelastic modeling, avoids the repeated modeling of the uncertainty by analyzing and merging the signals, and can decouple the undecided term of the coupling, thus greatly reducing the dimension of the uncertainty model, And the flutter robust control system can be designed more effectively. In view of the two-element wing/ store system with the control surface of the front and rear edge, the unsteady aerodynamic effect of the external store is considered by using the dipole grid method, and the uncertain model of the wing/ external pneumatic servo elastic system under the flow velocity disturbance is established by the new method. The open-loop flutter analysis verifies the correctness of the new method, and the closed-loop simulation results show that the controller designed based on the new method of uncertainty modeling can greatly improve the flutter critical speed. The ultrasonic motor actuator is applied to the flutter suppression of the three-dimensional wing, and a wind tunnel experimental platform is designed and developed based on the ultrasonic motor and the digital signal processor (DSP), and the accurate angle of the front and rear edge ultrasonic motor is realized by the analog output of the DSP. The multi-input/ multiple-output (MIMO) LQG controller for multi-action wing flutter suppression is designed by adding additional output equation, and successfully combining the mathematical model of the ultrasonic motor described by the second order differential equation into the equation of the pneumatic servo elastic system of the multi-action wing. The results of wind tunnel experiment show that the conventional LQG controller can not play the effect of flutter suppression, and the LQG controller that can compensate the time-delay in the control system can increase the flutter critical speed of the multi-acting wing from 34.5 m/ s to 37 m/ s. A multi-action wing wind tunnel experiment control system with high real-time performance based on the real-time simulator (AD5435) is designed and developed. An incremental PID control method for feedforward compensation is proposed, which can realize the accurate angle tracking of the front and rear edge DC motor. In view of the uncertainty of flow velocity and air density, the model of aeroelastic system uncertainty of multi-acting wing is established by using the new method, and the single input/ single output (SISO) and MIMO. mu. controller for flutter suppression are respectively designed. The wind tunnel test results show that the SISO controller can increase the flutter critical speed of the wing from 36.5 m/ s to 39 m/ s, while the MIMO controller can increase the flutter critical speed from 36.5 m/ s to 38 m/ s. In contrast to the LQG controller, the controller does not compensate for the time-delay, but can effectively suppress the flutter and verify the robustness of the.
【学位授予单位】：南京航空航天大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：V215.34;TB535

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