Real-time tension estimation in the spinning process based on the natural frequencies extraction of the Polyester Filament Yarn

Precise measurement of Polyester Filament Yarn (PFY) tension in the spinning process is critical to ensure good uniformity of product quality. A newly proposed real-time method is used to estimate the tension based on the natural frequencies extraction of the PFY. The theoretical relationship is established among the PFY tension, the spinning speed, and the first natural frequency based on the characteristics of the transverse dynamic vibration of the PFY in the spinning process. Then, an improved wavelet threshold denoising model has been applied to denoising the vibration signals, and the gravity center frequency of the denoised amplitude spectrum is used to extract the natural frequency of the PFY, and then the PFY tension can be estimated efficiently by employing the extracted natural frequencies. To monitor the uniformity of product quality, a new real-time evaluation index, namely the PFY tension fluctuation rate, is proposed to evaluate the overall fluctuation of PFY tension, which can be used for quantitative analysis and comparison of PFY tension. Additionally, the measurement data is of great significance to the evaluation and optimization of the performance of high-speed spinning equipment. The research intends to serve as a basis for the design of the spinning technology as well as its reliable operation.