基于 HHT 的转动惯量测量技术研究

为提高扭摆法测量大型回转体转动惯量的测量精度，克服线性转动惯量测量模型及周期法转动惯量计算的弊端，开展了基于希尔伯特-黄变换(HHT)的转动惯量测量技术研究。建立了考虑摩擦阻力矩的非线性转动惯量测量模型，在此基础上，通过经验模态分解提取了角位移主分量，利用希尔伯特变换识别了扭摆系统的瞬时阻尼系数和瞬时无阻尼固有频率，最后利用最小二乘法拟合得到非线性模型参数，精确求解了转动惯量。研制了一套大型回转体转动惯量测量系统，对不同组合的标准件进行转动惯量测量试验，验证了基于HHT的转动惯量计算方法的可行性。大量试验测量结果表明，本系统转动惯量测量相对误差小于0.2%,测量精度显著优于传统的周期法测量结果。

Research on measuring technology of moment of inertia based on HHT

The measuring technology of moment of inertia based on Hilbert-Huang Transform ( HHT) is conducted to improve themeasurement precision of the moment of inertia of large rotary body by the torsional pendulum method and to overcome the disadvantagesof the traditional linear measurement model and the periodic method for calculating the moment of inertia. A nonlinear measuring modelof moment of inertia considering friction resistance moment is formulated. On this basis of the model, the principal component of angulardisplacement is extracted by the empirical mode decomposition and the instantaneous damping coefficient and instantaneous undampednatural frequency are identified by Hilbert transform. The nonlinear model parameters are fitted by the least square method, and themoment of inertia is calculated accurately. A system for measuring the moment of inertia of a large rotary body is developed, and therotational inertia measurement tests verify the feasibility of calculating the moment of inertia based on HHT are implemented on differentcombinations of standard parts. The measurement results of a large number of standard parts show that the relative error of the system isless than 0. 2% , the measurement precision of the interia using HHT is observably better than that of the traditional period method.