脉冲风洞测力系统建模与载荷辨识方法研究

将载荷辨识技术应用于脉冲燃烧风洞模型测力。用子结构综合法建立了测力试验系统的动力学模型,在时域内将动力学方程进行离散,建立起天平测量信号与模型气动载荷历程之间的线性关系,作为载荷辨识的模型。采用Tikhonov正则化和子空间投影法相结合的混合正则化方法,将高维的、不适定的载荷辨识问题转化为低维的适定问题,以利于快速求解。提出了一种新方法来确定合适的投影子空间维数,然后应用L曲线准则来寻找低维正则化问题的最优正则化参数。最后通过算例验证了系统建模方法的精度和载荷辨识算法的有效性与稳定性。

Dynamic modeling of testing system in impulse facilities and load identification method

Load identification method is applied to force measurements in impulse combustion facilities. The dynamic model of the testing system is derived using substructure synthesis method. Then, the differential equations are discretized to establish the linear relationship between the outputs of balance and the dynamic forces history acting on the aircraft model. A hybrid regularization method which combines the Tikhonov regularization and subspace projection methods is proposed to solve the load identification problem. The hybrid method converts the ill-conditioned large scale problem into a well-posed small scale problem which can be solved easily. A new method is proposed to determine the size of the projection subspace. The L-curve criteria is employed to search the optimal regularization parameter of the dimensional-reduced problem. The accuracy of the structural dynamic modeling method and the effective and stability of the load deification method are validated by a numerical example.