Research Of Soft-sensing System Of Fabric Color In The Batch Dyeing Process

As it is difficult to measure the color of fabric online in the batch dyeing process, there is the only way to measure color offline by the worker when the dyeing process is finished. However, this way causes many problems such as bad quality of products, low pass-rate, high cost, much energy consumption, serious pollution and so on. So on-line color measurement technology is very helpful for stabilizing quality of products and saving energy as well as reducing pollution in the dyeing industry. For solving this technical problem, a soft-sensing method of color measurement is presented, with which the fabric color can be measured by testing the absorbance of the dye solution in the dyeing machine, and an actual soft-sensing device of fabric color is also designed in this paper.The main contributions of this thesis are as follows:1. Study of the K/S value of dyes based on adjustment factorsFor mastering the mechanism of different kinds of dye dyeing different fabric, the relationship between the fabric K/S value and dye concentration is studied and a calculation method of K/S value of dyes based on adjustment factors is presented. By introducing adjustment factors to correct the source data reasonably according to the different concentration of dyes, the relationship between the fabric K/S value and dye concentration will turn linear. With the optimization methods, adjustment factors could be worked out and K/S value of dyes could be obtained according. In this case, both the computer color measuring model and the automatic color correction algorithm are more accurate and reliable, which could be helpful for the online color measurement and the calculation formula of complementary color.2. Study on kinetics model of dyeing and simulationFrom the dyeing thermodynamics and kinetics theories, it is known that there are many factors effecting the uptake rate of dye including dye concentration and dyeing temperature as well as flow rate. Considering these factors, kinetics model of uptake rate is built based on the Fick's law, with which the uptake rate can be predicted at any time, and the color of fabric can be also estimated in the dyeing process. Foremore, a simulation system of dyeing process is designed, which helps to master the dynamic characteristics of the dye and lays the foundation for optimization and control of the process.3. The soft-sensing technology of fabric color in batch dyeing process with low concentration of multi-dyesBased on the determination technology of concentrations of multi-component, a soft-sensing method of dye concentration measurement using Kalman filter is presented. The absorbance of the dye liquor in the dyeing machine is tested by the spectrophotometer in the visible wavelength range. Then the concentrations of dyes are calculated by the Kalman filter algorithm, thus the soft-sensing measurement of the dye concentrations in the batch dyeing machine is achieved, and the color of fabric can be also estimated baesd on the model of color measurement.4. Study on nonlinear filter algorithm applied in soft-sensing systemNonlinear filter algorithm is the main way for reducing measurement noise and improving accuracy in the soft-sensing system. The common nonlinear filtering method such as extended Kalman filter (EKF) and particle filter (PF), on which the theoretical and applied research is very important for improving the level of nonlinear filter. Based on the nonlinear absorbance model, EKF and PF are applied to determine the concentrations of dyes respectively. The feasibility and validity of these methods have been verified by experiments.