4 results about "Nonlinear excitation" patented technology

The invention discloses a spatial gear transmission system reliability evaluation method fusing failure physics and degradation data, and belongs to the technical field of mechanical reliability engineering and fault prediction. The method aims to solve the problem of reliability evaluation of the spatial gear transmission system under the conditions of extreme environment, small sample, multi-failure mode coupling and significant individual difference. The method comprises the following steps: firstly, establishing a gear dynamics model considering nonlinear excitation to obtain dynamic meshing force; then, respectively constructing wear and fatigue degradation models based on failure physics; then, introducing an inverse Gaussian random process considering individual differences to carry out single failure mode reliability modeling; and finally, a Copula function is utilized to construct a binary correlation competition failure model, and system-level reliability comprehensive evaluation is realized. Through the technical route of physical mechanism driving, uncertainty quantification and data statistics fusion, a complete evaluation system is formed, and key technical support is provided for on-orbit health management and life prediction of the space gear transmission system.

The invention discloses a rotor bearing transmission system fault dynamics analysis method, solves the problem of low vibration response prediction precision of an existing turbine rotor bearing system fault dynamics analysis method, and belongs to the technical field of ship power systems, rotor dynamics and fault diagnosis. The method comprises the following steps: constructing a low-pressure rotor-bearing-cartridge receiver system coupling kinetic model, and based on the model, coupling a rotor, a disc, a bearing and a cartridge receiver to obtain an overall kinetic equation of the system; constructing a system simulation model under multi-fault excitation based on the overall kinetic equation of the system and the multi-fault nonlinear excitation force; and solving the system simulation model to obtain an axis trajectory, vibration displacement, acceleration time domain, frequency domain and envelope spectrum response of the system under different working conditions, and carrying out inherent characteristic analysis and fault response analysis. According to the method, multi-component flexibility and nonlinear coupling are considered, and the vibration response prediction precision is improved.

This invention discloses a method for identifying mutual inductance and mutual capacitance parameters in a hybrid-coupled wireless power transfer system, applicable to wireless power transfer systems where inductive and capacitive coupling coexist. Under the condition of a fixed system operating frequency, this method acquires time-domain signals such as primary-side voltage, primary-side current, and primary-side coil terminal voltage. A steady-state interval is selected, and the fundamental phasor is extracted using the synchronous integration method. Combined with known parameters such as compensation capacitor, coil self-inductance, and parasitic resistance of the compensation capacitor and coil, a system of complex equations including mutual inductance and mutual capacitance is established and solved to obtain the target parameters. Compared with existing methods that require changing the frequency or adding additional measurement circuits, this invention only requires a small number of voltage and current measurements to complete the identification of mutual inductance and mutual capacitance. The steps are simple, the implementation cost is low, and effective identification can still be achieved through the fundamental phasor even in the presence of inverter / rectifier nonlinear excitation.

The invention relates to the technical field of voice recognition, in particular to a smart home voice control user recognition method and system based on voiceprint analysis. The method comprises the following steps: acquiring a frequency domain reference spectrum corresponding to an original reference signal and a frequency domain residual spectrum corresponding to a microphone acquisition signal; determining a non-linear excitation intensity based on the frequency domain reference spectrum; determining a linear coherence degree based on the frequency domain reference spectrum and the frequency domain residual spectrum; obtaining an envelope correlation coefficient according to the low-frequency driving energy and the high-frequency residual energy; obtaining an initial interference index by combining the nonlinear excitation intensity, the linear coherence degree and the envelope correlation coefficient, determining a nonlinear interference index according to a residual-reference energy ratio, and performing weighted suppression on the frequency domain residual spectrum to generate a weighted amplitude spectrum; mel spectrum features are extracted based on the weighted amplitude spectrum, and then user identity authentication is achieved. According to the method, the extraction precision and the recognition accuracy of the user voiceprint features in complex acoustic environments such as background sound playing are improved.