舵机非稳态激励识别及瞬态声辐射分析

摘要

When an underwater vehicle changes directions by the steering engine, the opening pro-cess of steering engine generates a high transient radiation noise. So before a steering engine is in-stalled in an underwater vehicle, it is necessary to estimate transient radiation noise of the steering engine. In this paper, based on the vibration test of the steering engine for an underwater vehicle, the transient maximum and mean excitation forces acting on the positions of connections between steering engine and experimental setup are calculated indirectly by least square method of load i-dentification in frequency domain and STFT signal processing method. In addition, the accuracy and feasibility of results are verified. Cylindrical shells with ribs are basic structures which are used in underwater vehicles. By taking excitation forces results as an approximate input, a cylindrical shell whose two tips are simply supported is chosen as calculation model of a cabin of underwater vehi-cle, and the transient maximum and mean radiation noise of shells are calculated separately to esti-mate the steering engine’s characteristics of noise sources. A non-stationary STFT signal processing method to evaluate transient radiation noise of steering engine is provided.%当水下航行器利用舵机改变航向时，舵机的开启会产生很大的瞬态辐射噪声。因此，在舵机安装之前，有必要对舵机的源特性进行评估。文章基于某水下航行器的舵机振动测试试验，应用频域载荷识别中的最小二乘法方法和短时傅里叶变换的信号处理技术，对舵机操舵过程中舵机与试验台架连接的机脚点处的瞬态最大激励力和整体平均激励力分别进行了间接估算，并将估算结果的准确性和可行性进行了验证。考虑到加肋圆柱壳是水下航行器的基本结构形式，文中将估算的激励力结果作为辐射声计算的近似输入，以一个两端简支的加肋圆柱壳体作为水下航行器的一个舱段的计算模型，分别计算了舵机操舵过程中水下瞬态最大和整体平均辐射噪声的大小，提出了一种利用短时傅里叶变换信号处理技术来评估舵机水下瞬态辐射噪声的方法。