风洞动态试验对象姿态的视频测量及其运动规律建模

Dynamic wind tunnel test object is connected with motion mechanism through a bar-cantilever beam. Because of the insufficient in rigidity, the wide spectrum of vibration phenomenon is induced under unsteady aerodynamic loads.Therefore,the attitude parameters of test object are obviously different with that set by control system of test facility. The accuracy and reliability of existing inertial attitude sensors are not high in Dynamic wind tunnel test. Therefore, a new method is proposed to measure attitude parameters and model the movement of test object in complex flow: ① the mechanism of the complex flow coupling with the measured object's movement influencing videogrammetric error is revealed in this project, the model used to control error and analyze sensitivity for videogrammetric measurement of attitude parameters is established, a new method to minimize the measuring error of videogrammetry in complex flow is studied; ② a method is studied to construct basis functions of modified scaling based on the integration of multi-domain(time/frequency/space),the differential of discrete measurement data is converted to differential on each domain basis function and the results are unified to time-domain space by excellent multi-domain basis function set, which describe the features of oscillation ,transient and random very well. As s result, the movement regularity model of the time series measured data is obtained to solve the problems of error amplification caused by the direct differentiation with the time series measured data including wide spectrum of vibration information, measuring errors and loss of local peak. The experiments are carried out to evaluate and improve the method and the model established in this project.

风洞动态试验对象通过杆式悬臂梁承载结构与运动机构相连，在非定常气动力作用下因支撑刚度不足易出现宽频谱振动现象，导致其姿态参数与运动机构的姿态参数差异明显，而现有惯性测姿传感器在此环境中测量精度与可靠性不高。为此，提出复杂流动中机械姿态的视频测量(Videogrammetry）及其运动规律建模新方法:①通过研究复杂流动耦合被测对象运动对视频测量误差的影响机理，创建姿态视频测量误差控制及其敏度分析模型，构建复杂流动中视频测量误差最小化控制方法；②从时/频/空等多域联合的角度，研究多域融合变尺度基函数构造方法，利用构建的表征振荡型、瞬变型及随机型三类时变特征优秀的多域基函数集，将离散测量数据的微分转换为对各域基函数的微分并统一到时域空间，获得姿态角时序测量数据的运动规律模型，解决对含宽频谱振动信息、测量误差、局部峰值有丢失的时序测量数据直接微分所导致的误差放大问题。通过实验评价完善所建立的方法。

风洞动态试验对象通过杆式悬臂梁承载结构与运动机构相连，在非定常气动力作用下因支撑刚度不足易出现宽频谱振动现象，导致其姿态参数与运动机构的姿态参数差异明显，而现有惯性测姿传感器在此环境中测量精度与可靠性不高。为此，1）本项目提出了基于前方交会的五点相对定向方法，本文方法仅利用5个同名像点既可获得两张像片的相对位置（相对定向）立体模型，Nikon D800的7组5点相对定向实验结果表明：在测量长度为920.604mm的标尺长度时，其标准不确定度为920.6429±0.0696mm，误差为0.0389mm。2）建立了风洞动态试验对象姿态角的视频测量误差控制方法，推导了基于长度的风洞动态试验对象姿态角测量误差分析模型，测量误差0.0389mm，代入推导的误差分析模型，可知本文方法姿态角的静态测量误差 ；3）建立了基于单应性矩阵的迎角单目视频测量方法，以加权共线误差为目标函数，根据像面重投影误差确定权重系数取值，优化相机位姿估计结果，具有精度高、鲁棒性好的优点，且满足全局收敛条件，在参考点坐标数据包含不同程度测量误差的情况下，所得相机位姿估计结果明显优于正交迭代算法；风洞试验表明：基于单应性矩阵的迎角单目视频测量，在±4°范围内，7个迎角阶梯中最大的标准差仅为0.0118°，已达到0.01°的国际先进水平，具有较强的工程实用价值。4）建立了高速风洞飞行器模型姿态运动规律建模方法，解算模型的姿态运动参数和旋转中心运动轨迹。亚洲最大的2米×2米超声速风洞实验表明：本方法能有效捕捉实验模型的姿态运动规律，模型旋转中心的运动轨迹与天平在俯仰与偏航方向上测得的气动力吻合，提高了风洞实验数据的精准度，促进了我国飞行器研制的精细化设计进程，具有实用价值。