内积相关性方法识别凸轮轴阻尼的研究

The Research of Inner Product Correlation Method Recognition Camshaft Damping

传统的半功率带宽法在金属结构的小阻尼系统中识别误差大,提出基于内积相关性识别凸轮轴阻尼比的方法。运用快速傅里叶变换结合连续傅里叶变换的策略诊断出响应的固有频率,根据诊断出的固有频率构造求解信号相关性的函数,与响应信号做内积运算,运算过程中根据Riemann-Lebesgue定理忽略信号负频率项的积分结果,得到信号正负频率项的估计函数。进一步消除负频率项的影响,从原始信号中减去负频率项的估计,将得到的函数作为原始信号,重复步骤,形成迭代,最终依据内积模的极大值识别出阻尼。将内积相关性方法运用于发动机凸轮轴的阻尼识别中,实验结果表明该方法可以准确识别凸轮轴阻尼,具有工程实用性。

Damping ratio is sensitive to crack damage, the traditional half-power bandwidth method has big error in the metal structure of small damping syste~ A method based on the inner product correlation identification Camshaft damping ratio was presented. Using the fast Fourier transform with continuous Fourier transform of the strategy to diagnose the natural frequency, aCcording to the natural frequency of structure to construct the signal correlation function, inner product was conducted between response signal and the constructed exponential functiorL According to Riemann-Lebesgue theorem, signals negative frequency of integral results in the process of operation was ignored and positive frequency term and negative frequency term of the signal was derived. By subtracting negative frequency term from the original signal, using the function as the original signal and repeating steps, the maximum mold inner product and damping ratio was ident^ted~ The method was used in camshaft damping experimental. Experimental results show that this method can accurately ident^y the camshaft damping, the method is practical in engineering.