【作者】 张健；

【导师】 袁平；

【作者基本信息】 东北大学 ， 控制理论与控制工程， 2015， 硕士

【摘要】 大飞机的研制对风洞流场精度提出了近乎苛刻的要求,但目前已有的控制方法难以满足流场的高精度要求。预测控制基于预测的未来时刻控制偏差优化控制率,有能力实现高精度控制。因此,本文以暂冲型跨声速风洞为对象,研究使用预测控制实现高精度的风洞流场。本文分析了暂冲型风洞的结构和吹风试验的特点。考虑到气源压力下降会使流场特性随时间发生改变,在控制系统中引入主引回路,通过调节主引压力消除气源压力下降对流场的影响。由于被控量马赫数由非线性公式计算,将被控变量选为总压和静压,以减少系统中的非线性。通过分析阶跃响应数据发现,风洞流场是具有耦合和时滞特性的对象。预测控制考虑了对象的动态特性,所以有能力处理对象的耦合问题,并能够调节存在滞后的对象,说明采用预测控制调节风洞流场是合理的。由于阶跃响应模型可以准确地描述对象的动态特性,而且在风洞流场中可以很容易地测取阶跃响应数据,所以采用阶跃响应模型作为风洞流场预测模型。考虑到风洞控制器的主要任务是消除控制误差,选择使用传统二次型指标作为风洞预测控制器的优化性能指标。考虑到暂冲型风洞吹风试验要求控制系统能够快速调节流场,控制器采用计算量较少的基于预测误差的反馈校正方式。终上所述,选择使用多变量动态矩阵控制作为流场控制器。为提高风洞抵抗攻角扰动的能力,使用攻角补偿静压的预测值,从而构成风洞流场前馈动态矩阵控制器。根据风洞流场近似模型、攻角扰动近似模型及工程经验确定了控制器的参数整定方法。基于LabVIEW软件实现了所设计的风洞预测控制器。通过实际吹风试验验证了风洞预测控制器能够有效调节风洞流场、使吹风试验达到了精度要求,从而验证了控制器的有效性。预测控制器的重复性和鲁棒性也在实际吹风试验中得到了验证。更多还原

【Abstract】 Developing large aircrafts puts forward almost harsh requirements for wind tunnel flow field precision,but existing control methods cannot meet the high-precision requirements in flow field.Predictive Control is able to realize high-precision control because it optimizes control law based on predictive future control deviation.Therefore,this thesis takes an intermittent transonic wind tunnel as the plant,and researches employing Predictive Control to realize high-precision wind tunnel flow field.The structure of this intermittent wind tunnel and the features of its blowing tests are analyzed in this thesis.Considering the diminishing air source pressure will change the flow field characteristics over time,the main ejection pressure loop is introduced in the control system,which contributes to eliminating the impact of the diminishing air source pressure on the flow field.As Mach number is calculated by a nonlinear equation,the controlled variables are selected as stagnation pressure and static pressure to reduce nonlinearity.By analyzing the step response data,it is found that the flow field is a plant with coupling and time-lag.Predictive Control combines plant dynamic characteristics,so it can cope with the coupling and time-lag easily,and thus employing Predictive Control to regulate wind tunnel flow field is reasonable.Because step response model can exactly describe plant dynamic characteristics and it is feasible to measure step response data in the wind tunnel flow field,step response model is used as the predictive model.Considering the main task of wind tunnel controller is to eliminate control deviation,the traditional quadratic index is selected as the optimal cost index.As the intermittent wind tunnel tests require the control system can regulate the flow field rapidly,the controller adopts the less-calculation feedback correction based on predictive control errors.Based on the above-mentioned,the Multivariable Dynamic Matrix Control is selected as the wind tunnel controller.In order to improve the capacity of the wind tunnel to resist the disturbance caused by the angle of attack,this angle is used to compensate the prediction of static pressure.Consequently,the wind tunnel flow field feedforward dynamic matrix controller is constructed.According to the wind tunnel flow field approximation model,the angle of attack approximation model,and engineering experience,the method to tune wind tunnel flow field controller parameters is researched.The designed wind tunnel predictive controller is realized by Lab VIEW software.It is verified that the controller can effectively regulate the wind tunnel flow field and ensure wind tunnel tests reach the required precision,which illustrates the proposed controller is effective.Furthermore,the repeatability and the robustness are verified in the corresponding practical wind tunnel tests respectively.更多还原