重型直升机大型旋翼桨叶复杂工况下运动与变形的三维全场动态检测方法研究

Heavy helicopter rotor blade, which is made of composite materials, is as long as 20 meters in diameter. Due to its super string ratio and elastic design, some extremely complex problems of aerodynamics, dynamics and mutual coupling ineluctably appears. As the blade is the key of flight safety and power, it has urgent requirement for fast and accurate detecting its three-dimensional dynamic deformation in high-speed rotating process under the testing condition of real aircraft, full-scale rotor model and reduce-scale rotor model. Based on 3D digital image correlation method and digital close range industry photogrammetry technology, the images of rotating blade with active projection or spraying speckle pattern can be captured by multiple sets of industrial cameras. So the general rule of blade parameters can be concluded, such as 3D full dynamic deformation, strain distribution and motion parameters. The two previous National Natural Science Foundation have been researched on aircraft deformation test of fixed wing in wind tunnel and air flight. And one finished fund has rated as excellent, while its key technology won the second prize of the State Technological Invention. This project focuses on wide field of rotor deformation and puts forward some anti-interference and compensation methods to reduce the influence of airflow, light, vibration shooting angle, etc. Therefore accurate and reliable data for helicopter rotor's development can be provided.

重型直升机大型复合材料旋翼桨叶直径达20米，采用超大展弦比和弹性设计, 有极其复杂的空气动力学、动力学及相互耦合问题，攸关飞行安全和气动力，急需在空中试飞、全尺寸旋翼试验塔、缩比模型三种试验条件下，快捷精确地检测高速旋转桨叶的三维全场动态变形。本项目采用三维数字图像处理和工业摄影测量方法，通过主动投射或喷涂散斑图案，利用多组工业相机拍摄旋转桨叶视频图像，解算出桨叶三维全场动态变形、应变场及运动参数。课题组承担的前两个自然基金项目研究了固定翼飞机风洞试验和空中试飞的变形检测，一个基金结题评为优秀，关键技术获国家技术发明二等奖。本项目在此基础上将研究对象从固定翼变为旋翼，而且要实现三种旋翼试验条件下的高速旋转变形检测，检测对象和试验环境发生了重大改变，难度更大、环境更复杂。本项目重点研究大视场的旋翼变形检测方法，以及气流、振动、光照、拍摄倾斜角等多种抗干扰和补偿方法，为直升机研制提供可靠数据。

项目组完成了本项目规定的研究任务和各项目标。本项目基于数字图像相关理论、三维视觉理论、摄影测量理论，搭建了直升机旋翼运动与变形高速测量系统，完成了室内等比缩小的旋翼运动与变形测量实验、室外旋翼塔上大型旋翼运动与变形测量实验,完成了重型直升机旋翼在空中试飞试验方案设计。本项目通过在旋翼下表面粘贴标记点和散斑，采用双目相机重建出标记点或散斑点的三维坐标，根据三维坐标计算出旋翼的运动与变形参数。本项目设计了适用于大视场旋翼运动测量的散斑图案，提高了大视场大倾斜角下散斑匹配成功率；提出了基于种子点可靠估计的散斑双时态并行弱相关性匹配方法，解决了直升机桨叶表面点的快速三维重建与变形测量问题；开发了大视场柔性标定技术，解算出测量系统的内外参数，完成大视场点的三维重建；建立了适用于振动环境下直升机桨叶运动与变形测量的抗干扰模型，提高了运动变形参数的测量精度；完成重型直升机旋翼空中试飞、旋翼试验塔、缩小比例模型的详细试验方案。. 本项目的研究成果应用于航空工业直升机设计研究所的旋翼试验，为该单位提供了真实的直升机旋翼高速运动测量数据，解算的运动与变形测量结果满足该所的工程需要，直升机所出具了相应的应用证明。项目执行期间共发表学术论文20篇，其中SCI论文7篇，EI论文7篇。申报国家发明专利6项，授权6项。培养在读博士生8人，毕业博士生2人，在读硕士生10人，毕业硕士生11人。